[GMCnet] So, about removing the Onan heads and looking for carbon...

[Robin Hood]

What am I looking for, exactly, and what do I do with it when I find it?

I need to remove the Onan cover from over the heads and clean the cooling fins.
I need to take off the cylinder heads and "look for carbon" but I've
never done this before so I don't really know what I'm looking for.
Surely somebody has documented the process on the GMC photo site?
If there's any carbon, I have to clean it away. Whether this requires
chemicals or just a damp rag I don't know. Neither do i know what it's
even necessary in the first place... but I do know I don't want to get
back into my Onan once I've got it in the coach.
Need a carb kit from JimK just to be on the safe side. My chemdip
prolly ate the gaskets in the needle/seat (I didn't know that stuff
was removable),


--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome
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[Steven Ferguson]

Just pull them, glass bead blast them, or have it done. It should be
relatively inexpensive as it takes less than 15 minutes. You can reuse the
old head gaskets if you haven't torn them during removal. Just spray about
5 coats of silver paint on both sides of them and they'll seal just fine.
Clean the head bolts and reassemble. I can't remember the torque specs but
I'm sure someone here will chime in.

--
Fathom the hypocrisy of a nation where every citizen must prove they have
health insurance......but not everyone has to prove they're a citizen.
Steve Ferguson
Sierra Vista, AZ

[Robin Hood]

It's around 19 ft-lbs, MUST use a torque wrench. I've got the manuals
and specs and all, as well as off-list advice on the importance of
proper torquing. :)

[Ken Henderson]

Steve,

Pore Robin Hood don't even know he's gotta scrape the hard black stuff off
the tops of the pistons -- & you didn't tell him! :-)

Ken H.

On Mon, Dec 10, 2012 at 8:52 AM, Steven Ferguson wrote:

> Just pull them, glass bead blast them, or have it done. It should be
> relatively inexpensive as it takes less than 15 minutes. You can reuse
> the
> old head gaskets if you haven't torn them during removal. Just spray
> about 5 coats of silver paint on both sides of them and they'll seal just
> fine.
> Clean the head bolts and reassemble. I can't remember the torque specs
> but I'm sure someone here will chime in.

> ...

[Robin Hood]

Pretty much this! :) So i'm looking for something on the pistons that
looks like a pan when my wife burns dinner? :) I've managed to go my
whole life without seeing the insides of an engine, except for some
individual pieces of an old Pontiac 400 that made a bid for freedom at
oh-dark-thirty in the middle of nowhere Arkansas, but that's another
story.

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Johnny Bridges]

Clean  the carbon with a wire brush, or a scraper.  Alls you need to do is look out for the sealing surface where the head gasket goes and don't dig into the metal there.  If there's carbon on the heads and piston tops it will be obvious.  wire brush it off.  If you have a steady hand, use a wire brush in a drill, it's easier.  Use a hand brush to clear the crud outa the fins.  There are solvents, but they're nasty stuff to mess with and the brush works well.  A carb rebuild kit is a Good Idea after all these years, it will have gaskets and seals which haven't hardened and thus still seal.
 
--johnny
'76 23' transmode norris
'76 palm beach

[mr.er...@gmail.com]

Or
Convert to propane and just let it burn off

FREE WIFI @ Mickey D

[Rob Mueller]

Robin,

You can clean the carbon (black / brown stuff) off the heads and the top of the piston with Easy Off Oven Cleaner.

The heads are easy:

1) Put several layers of news paper down on your garage floor
2) Lay the heads on the newspaper with the carbon facing up
3) Spray the heads with Easy Off
4) Let it soak in and loosen the carbon
5) Scrap / wire brush the carbon stuff off
6) Spray them again if it all didn't come off

The pistons are a bit tricky

1) Turn over the Onan until one of the pistons is all the way up in the cylinder
2) Spray it with Easy Off
3) Let it soak in and loosen the carbon
4) Scrap / wire brush the carbon off
5) Spray them again if it all didn't come off
6) When all the carbon is off the piston take a can of WD-40 and spray it in the space between the piston and cylinder start at
12:00 and go counter clockwise down to 6:00. Repeat going from 12:00 to 6:00 clockwise. Do this several time to get all the Easy Off
out between the piston and cylinder.
7) Rotate the Onan enough to lower the piston about 1/2 inch in the cylinder and wipe the bore out
8) Return the piston to its original position and repeat the WD-40 spray.

I used this procedure on Harleys a lot and never had any problems.

Regards,
Rob M.

From: Robin Hood

What am I looking for, exactly, and what do I do with it when I find it?

I need to remove the Onan cover from over the heads and clean the cooling fins.
I need to take off the cylinder heads and "look for carbon" but I've
never done this before so I don't really know what I'm looking for.
Surely somebody has documented the process on the GMC photo site?
If there's any carbon, I have to clean it away. Whether this requires
chemicals or just a damp rag I don't know. Neither do i know what it's
even necessary in the first place... but I do know I don't want to get
back into my Onan once I've got it in the coach.
Need a carb kit from JimK just to be on the safe side. My chemdip
prolly ate the gaskets in the needle/seat (I didn't know that stuff
was removable),

--
Robin

[Robin Hood]

Is there a trick to getting the cylinder head off once the 10 bolts
and washers and nuts is accomplished? I can't seem to get it to budge.
Also, the left side cylinder head cooling fins are COVERED in oil.

http://youtu.be/CeExXjNEPUQ

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Rob Mueller]

Robin,

I'm going to suggest the following, HOWEVER, before you do it see what the general consensus is about the idea.

1) Screw four bolts back into the head at each "corner" leaving them about 1/8" away from the head.
2) Put the spark plug back into the head on that side,
3) Disconnect the leads from both spark plugs.
4) Hit the start button.
5) The compression should separate the head from the block.

Regards,
Rob M.

[crsa...@frontiernet.net]

Worked for me when I did it that way.

Marcus

[Robin Hood]

Well, that didn't work. Any other ideas? I left the spark plug in, and
cranked, and it didn't come loose. All 8 nuts and two bolts, with all
washers, have been removed. WHat's holding this thing on?

On Mon, Dec 10, 2012 at 8:30 PM, crsa...@frontiernet.net
<crsa...@frontiernet.net> wrote:
> Worked for me when I did it that way.
>
> Marcus
>
> ----- Original Message -----
> From: "Rob Mueller" <robmu...@iinet.net.au>
> To: gmc...@temp.gmcnet.org
> Date: Mon, 10 Dec 2012 21:27 -0500
> Subject: Re: [GMCnet] So, about removing the Onan heads and looking for carbon...
>
>> Robin,
>>
>> I'm going to suggest the following, HOWEVER, before you do it see what the general consensus is about the idea.
>>
>> 1) Screw four bolts back into the head at each "corner" leaving them about 1/8" away from the head.
>> 2) Put the spark plug back into the head on that side,
>> 3) Disconnect the leads from both spark plugs.
>> 4) Hit the start button.
>> 5) The compression should separate the head from the block.
>>
>> Regards,
>> Rob M.
>>
>>

[Craig Lechowicz]

Robin,
On mine, the two bolts were actually studs with nuts on them, and the studs stayed in the block. The bottom one was seriously corroded to the cylinder head. I was able to put two nuts on it, tighten them very tight against them and work it back and forth using two wrenches to keep the nuts tight to each other while wiggling the stud back and forth. Liberal Kroil application seemed to help Once I got it to turn semi-freely I was able to work the head off the stud.
--
Craig Lechowicz
'77 Kingsley, Waterford, MI

[Rob Mueller]

Robin,

Well that's an AW S#!T!

How about a picture of the head; the Onan NOT yours! ;-)

Regards,
Rob M.

-----Original Message-----
From: Robin Hood

Well, that didn't work. Any other ideas? I left the spark plug in, and
cranked, and it didn't come loose. All 8 nuts and two bolts, with all
washers, have been removed. WHat's holding this thing on?

Robin

[Steven Ferguson]

A gentle tap with a soft hammer also works. Just make sure all the bolts
are removed. Once the bolts are out, it's usually varnish that's making
the seal. As for the oil, once you remove the oil filter, you will see an
adapter between it and the engine. The gasket between the engine and
adaptor is usually the culprit. I tried a replacement, it leaked. I made
my own and as far as I know, it has never leaked.

Is there a trick to getting the cylinder head off once the 10 bolts
> and washers and nuts is accomplished? I can't seem to get it to budge.
> Also, the left side cylinder head cooling fins are COVERED in oil.
>
>

--

[Robin Hood]

I'm at work and cant post to GMCPhotos from here. I was able to upload
a photo to my Facebook page... If anyone just can't wait to see a
picture of a left hand Onan NH6kw cylinder head, feel free to send me
a friend request. Otherwise, I'll upload it when I get home, and maybe
shoot a short video.

Actually, i shot one last night. I was convinced that cranking the
engine to pop loose the cylinder head would make for a very
interesting video. I even enlisted the assistance of my lovely wife to
be my Igor ("Igor! Pull The Switch!")

Alas, nothing happened. The Onan just clicked, or maybe clacked, and
then did nothing. I about had a hissy fit I was so pissed. I was
convinced that somehow, I had done something and nuked the control
board or something else horrible (that is, electrical/electronic and
hard to diagnose) had happened.

Turned out to just be a low battery. An hour or twoon the charger at
10 amps and it turned over just fine. I just didn't pop loose the
cylinder head is all. :(

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Robin Hood]

About those "studs"... At the moment, to the best of my understanding
and belief, there were two actual bolts (located in the bottommost two
holes) and eight "studs" with washers and nuts on them in the
remaining holes that collectively hold the cylinder head on. To the
best of my understanding and belief, those studs are part of the
engine block, and are not mechanically connected to the cylinder head
(that is, they're not threaded through the cylinder head) other than
the washers and nuts (currently removed). It would seem to me that the
the cylinder head should seperate from the block and come straight
off.

Something is sticking the cylinder head to the block. They only meet
at the gasket and those studs, so I guess that's where the sticking
point is? Perhaps some sort of penetrating lubricant/oil/degreaser
something... PB Blaster perhaps should be sprayed liberally all over
the place?

The hammer idea is a good one, too. :)

[John R. Lebetski]

Proves it's slways better to ask before getting out the hammer and pry bar.
--
John Lebetski
Chicago, IL
77 Eleganza II
Source America First

[Matt Colie]

Robin,

Some person that previously worked on the engine may have use an adhesive on the gaskets. It doesn't take much, or you could have the rusty stud as Craig suggested, but, want a simple clean and fun thing to try?

Get an length of small line. Take off the flywheel cover. Roll the engine back a quarter turn from the timing mark. Take out both spark plugs and feed in a couple of feet of small line into one side only. Leave the tail out. (Just don't bother cutting the line - it will be clean and can still be used.) Roll the engine up to compression. It should not be able to do over the top. - Good

Put a couple of the nuts back on so the head doesn't fall on the floor and get hurt.

Now, Roll the engine backwards until it hits the rope from the other side.

Ready?
Grab the flywheel and give it a good hard spin. When the piston hits the ball of line, it will should break the head loose without any prying or hammering on castings.

Fun? Now you can do the other side.

Oh, and by left side, do you mean the oil filter side? If yes, it is either the filter adapter or the LOP switch that is leaking. Do and will not be a big issue while the machine is out of the coach.

Matt
--
Matt & Mary Colie
'73 Glacier 23 Chaumière (say show-me-air) Just about as stock as you will find
SE Michigan - Twixt A2 and Detroit

[Robin Hood]

It's the left side when you''re facing it as if it were installed in
the coach. The side OPPOSITE from the oil filter.

So put 1/4 inch nylon line into the cylinder and spin the flywheel by
hand then? That does sound kind of fun, actually. :)

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Ken Burton]

Do not put too much rope in it. You want the piston to hit the top and the rope just Before Top Dead Center. Stuff a little in and try it. Add a little more only if necessary. If it hit too soon you can bend a still open valve. Also if you can identify the compression stroke then do it on the compression stroke since both valves are closed during that time.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Robin Hood]

I'm guessing the compression stroke will be the one where the spark
plug hole leaks the most air (since the intake and exhaust valves will
both be closed).

I was bad yesterday and blew my diet by drinking two 20oz cokes and
eating the workplace cafeteria's alleged beef strogonoff. In penance,
i climbed 110 stories (one World Trade Center's worth) on one of those
stair climber dealies at the gym, and was in no shape to mess with the
Onan last night.

I did manage to hose down the various bolts and studs and whatnot with
PB Blaster. I did the intake and exhaust manifolds, as well as the
flywheel cover, just for good measure. I reckon most of that stuff is
coming off eventually anyway. I'd kind of like to get the intake and
exhaust manifolds powdercoated. Probably the cylinder heads, too. I
can do that, right?

I'll hose everything down with PB Blaster again tonight, and let it
soak in even further, and see if I can pull off the cylinder heads
this weekend before I try that rope trick.

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Rob Mueller]

Robin,

Here's an animation of a Otto Cycle engine aka four stroke. Yes Otto was a Kraut! Naturlich! ;-)

http://www.animatedengines.com/otto.html

Scroll down and each of the four strokes is explained.

To put it in the vernacular prettying up the Onan is like putting perfume on a pig. In fact a pig that hides in an enclosed pen at
that!

Call your local Onan dealer:

CUMMINS MID-SOUTH, LLC (2462)
325 New Highway 49 S
Richland, MISSISSIPPI 39208
Phone: (601) 932-7016

Buy a can or two of the "Official" Onan green (?) paint.

Don't bother to paint the exhaust manifold as the paint will burn off in a heartbeat.

Regards,
Rob M.

-----Original Message-----
From: Robin Hood

I'm guessing the compression stroke will be the one where the spark
plug hole leaks the most air (since the intake and exhaust valves will
both be closed).

I was bad yesterday and blew my diet by drinking two 20oz cokes and
eating the workplace cafeteria's alleged beef strogonoff. In penance,
i climbed 110 stories (one World Trade Center's worth) on one of those
stair climber dealies at the gym, and was in no shape to mess with the
Onan last night.

I did manage to hose down the various bolts and studs and whatnot with
PB Blaster. I did the intake and exhaust manifolds, as well as the
flywheel cover, just for good measure. I reckon most of that stuff is
coming off eventually anyway. I'd kind of like to get the intake and
exhaust manifolds powdercoated. Probably the cylinder heads, too. I
can do that, right?

I'll hose everything down with PB Blaster again tonight, and let it
soak in even further, and see if I can pull off the cylinder heads
this weekend before I try that rope trick.

Robin

[Robin Hood]

Don't they have some sort of high tech coatings these days for high
temperature parts? I reeeeeealy dislike rust. When i changed my
Catalina's front drum brakes to discs, I had the spindles and steering
arms and control arms and related parts powdercoated a glossy black.
It wasn't terribly expensive and it looked sharp, although the parts
will likely never be seen.

And I want any future oil leaks (my clinder heads are COVERED in the
stuff) to be glaringly obvious. :)

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Rob Mueller]

Robin,

Sure they do; Google Hi-temp exhaust coatings, let us know how much they want to coat the exhaust manifold.

The reason I suggested calling Onan is I would be surprised if powder coaters would be able to match the color of the Onan and I
reckon a multi green toned Onan will look weird.

Regards,
Rob M.

-----Original Message-----
From: Robin Hood

Don't they have some sort of high tech coatings these days for high
temperature parts? I reeeeeealy dislike rust. When i changed my
Catalina's front drum brakes to discs, I had the spindles and steering
arms and control arms and related parts powdercoated a glossy black.
It wasn't terribly expensive and it looked sharp, although the parts
will likely never be seen.

And I want any future oil leaks (my clinder heads are COVERED in the
stuff) to be glaringly obvious. :)

[D C _Mac_ Macdonald]

Who actually sees the bloody thing unless
it is hauled out for servicing? BFD!

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
*[ ]~~~[][ ][|\
*--OO--[]---O-*

> From: robmu...@iinet.net.au
> To: gmc...@temp.gmcnet.org
> Date: Fri, 14 Dec 2012 01:01:31 +1100
> Subject: Re: [GMCnet] So, about removing the Onan heads and looking for carbon...
>

[Robin Hood]

True, and I recognize that 100 dollars would be better spent in other
areas than merely on fancy paint. But I swear, stuff just seems to RUN
better when it's cleaned up and prettified. :) Sometimes I wonder if
the the Native Americans were onto something with their beliefs about
spirits of inanimate objects. :)

On Thu, Dec 13, 2012 at 8:12 AM, D C _Mac_ Macdonald <k2...@hotmail.com> wrote:
>
> Who actually sees the bloody thing unless
> it is hauled out for servicing? BFD!
>
>

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Carl Stouffer]

Robert Mueller wrote on Thu, 13 December 2012 06:35
> Robin,

>
>
>
> To put it in the vernacular prettying up the Onan is like putting perfume on a pig. In fact a pig that hides in an enclosed pen at
> that!
>
> Call your local Onan dealer:
>
> CUMMINS MID-SOUTH, LLC (2462)
> 325 New Highway 49 S
> Richland, MISSISSIPPI 39208
> Phone: (601) 932-7016
>
> Buy a can or two of the "Official" Onan green (?) paint.
>
> Don't bother to paint the exhaust manifold as the paint will burn off in a heartbeat.
>
> Regards,
> Rob M.

I agree with Rob on this. However, that didn't stop me from trying to 'pretty up' my Onan a little. I went over the intake manifold with a wire wheel and took the paint off the aluminum. No need to paint it. It looks good that way. I also brushed down the exhaust manifold and painted it with VHT header paint. I did the same with the exhaust manifolds on the 455, and both still look good. I'm not sure it would be a good idea to coat the heads with anything. I recognize they were painted green from the factory, but I think the bare aluminum would dissipate heat better
--
Carl S.
'75 ex Palm Beach
Tucson, AZ.

[James Hupy]

Robin, if you are thinking of painting the heads, I use a high heat flat
black "shake n shoot" paint like derusto or krylon. Gordon Jennings from
Cycle magazine did a comparison test of coatings on heat dissapation.
Turned out that flat black transferred more heat than cast aluminum or any
gloss coating including powder coat. Granted the testing was before the
invention of Vht coatings, which make some wild ass claims about
themselves. Some of the ceramic header coatings actually serve to contain
the exhaust heat within the tubes. Jwik.
Jim Hupy
Salem, Or
78 Gmc Royale 403

[Robin Hood]

Hmm. Maybe having a place bead blast the cylinder heads may be the
best thing after all. I'd hate to choose a paint that acted as an
insulator. I still want to find something to pain the exhaust manifold
with, though. I've seen photos of black exhaust manifolds, and I like
the look. And stainless mufflers too. :)

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Carl Stouffer]

Robin, Here's what it looks like with the VHT on the Manifold. You could get the intake bead blasted too. VHT is available at most 'speed shops'.

http://www.gmcmhphotos.com/photos/onan-mount-replacement/p43925-onan-mounts.html

[Carl Stouffer]

James Hupy wrote on Thu, 13 December 2012 08:41

Interesting about the flat black. I would have thought that no coating would be preferable, but I can see where a black coating might absorb heat from one side of the head and help to transfer it to the cooling fin surfaces. I can't imagine a light coating of VHT would contain much heat in the exhaust, but if it did, it would be a good thing. especially in a confined space like the generator compartment.

[Matt Colie]

Ken Burton wrote on Thu, 13 December 2012 00:09

> Do not put too much rope in it. You want the piston to hit the top and the rope just Before Top Dead Center. Stuff a little in and try it. Add a little more only if necessary. If it hit too soon you can bend a still open valve. Also if you can identify the compression stroke then do it on the compression stroke since both valves are closed during that time.

Ken,

It's an L-head (Flat Head). Valves are in the picture. Even if a piece of line gets trapped under a valve (no easy to do), it has only the valve spring for force.

Matt

--
Matt & Mary Colie
'73 Glacier 23 Chaumière (say show-me-air) Just about as stock as you will find
SE Michigan - Twixt A2 and Detroit

[Rob Mueller]

Jim,

When I was a tech rep for Hamilton Standard I seem to remember being told by one of the engineers that black anodized aluminum
transferred heat best, followed by flat black painted aluminum, followed by unpainted aluminum.

Also remember reading that chrome plated anything was the worst thing for heat transfer, just as it reflected light on the outside
it reflected heat on the inside.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: James Hupy

Robin, if you are thinking of painting the heads, I use a high heat flat
black "shake n shoot" paint like derusto or krylon. Gordon Jennings from
Cycle magazine did a comparison test of coatings on heat dissapation.
Turned out that flat black transferred more heat than cast aluminum or any
gloss coating including powder coat. Granted the testing was before the
invention of Vht coatings, which make some wild ass claims about
themselves. Some of the ceramic header coatings actually serve to contain
the exhaust heat within the tubes. Jwik.
Jim

[Mike Miller]

While a rusty exhaust manifold doesn't real effect anything, I agree that the big rusty thing across the top of the generator doesn't help as a first impression on reliability.

Kelvin did something on his 455 that he got from the Datsun world: <http://www.gmcmhphotos.com/photos/455-r-amp-r-engine-work/p11282.html>

"Had the manifolds blasted and then slathered them with anti-seize. Once \"baked\" on, it aluminimzed the cast iron. This coating last better than any spray on paint that I\'ve found and touchup is easy. A messy solution, however. Wrapped them in plastic to handle."

I always thought that this would be a good thing to do to the Onan exhaust manifold. ... just never tried it. I do not see the need unless I am doing a complete rebuild and "pretty up" of the whole coach. (IE: Just make it run.)

Robin Hood wrote on Thu, 13 December 2012 05:39
> Don't they have some sort of high tech coatings these days for high temperature parts? I reeeeeealy dislike rust. ...

>
> On Thu, Dec 13, 2012 at 7:36 AM, Rob Mueller <robmu...@iinet.net.au> wrote:
>

> > ...

> > Don't bother to paint the exhaust manifold as the paint will burn off in a heartbeat.

> > ...


--
Mike Miller -- Hillsboro, OR -- on the Black list
(#1)'73 26' exPainted D. -- (#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
http://m000035.blogspot.com

[Robin Hood]

I succeeded in getting the cylinder head off, finally! :)

There was a little bit of carbon in the cylinder proper and on the
head, a bit more oil sludge on the cylinder head, and a TON of oil
sludge located in the general vicinity.

http://youtu.be/xXfQa-V7ZkQ

I need to buy some wire brushes and such to clean the heck out of the
surface where the gasket goes, as well as the area in general.

I pried back a piece of sheet metal so that I could get to some of the
oily area underneath it. I'll bend it back into place when I'm done.

I also uploaded the other night's video, where there was really
nothing wrong but a dead starter battery. That's Part 08.

The store brand oven cleaner seemed to do a good enough job. That
stuff STINGS when it gets on you.

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Robin Hood]

So I'm moving right along on my project. The cylinders and cylinder heads
are cleaned up nicely. The gaskets are drying after having multiple coats
of metallic spray paint applied. I am repainting the cylinder head covers
Smurf blue just to be different. I tried taking loose one of the exhaust
manifold bolts and the bolt just started to round off, so I stopped that
experiment. I might save the repainting of the intake and exhaust manifolds
for a later date, and simply concentrate on getting the Onan back into
proper running shape. Tom Phipps came by yesterday and brought me a spare
tire which was awfully kind of him. We went to Harbor freight and he
pointed out some tools that I would need and I took him to lunch. That was
a fun little outing.

I do have a question about the stainless steel muffler that Jim K sells.
How exactly does this thing connects to my existing exhaust system? My
exhaust manifold runs into a rusty pipe which heads down and at the end of
the rusty pipe is a clamp and there's nothing on the end of the
clamp. Both ends of that pipe have clamps. One Connects to the exhaust
manifold the other one does not connect anything.

While I wait for the assorted paint to dry I'm going to run to the auto
parts store and get a few quarts of oil and oil filter. I'm going to check
my various resources to make sure that I'll be getting the correct oil
filter and a sufficient quantity of oil.

[Rob Mueller]

Robin,

Congratulations!

You have taken a big step towards becoming a mechanic when you noted; "I tried taking loose one of the exhaust manifold bolts and
the bolt just started to round off, so I stopped that experiment." Knowing that you're probably going to screw something up if you
continue!

You need these parts from JimK:

http://www.appliedgmc.com/prod.itml/icOid/632

http://www.appliedgmc.com/prod.itml/icOid/956

Tom Hampton of Grandview Motorhomes also sells a muffler for the Onan, however, it's not stainless steel.

http://www.grandviewmotorhome.com/index.html

You can use the same oil you use in your engine which in my case is Shell Rotella T 15W-40. You need 4 1/2 quarts with a filter.

The filter part number is: Wix 51762 / Napa 1342 / Napa 1762 - There are two different height filters so take the old filter with
you to make sure you get the correct one.

Regards,
Rob M.


-----Original Message-----

Robin

[A.]

Robert Mueller wrote on Sun, 16 December 2012 16:25
> ...You can use the same oil you use in your engine which in my case is Shell Rotella T 15W-40. ...
You can but I wouldn't. My sister has been in the small engine repair business for about 15 years. She says use straight 30W oil, not multi-viscosity oil.
My MM mostly agrees with her, It says 5W30 or 10W40 ONLY when operating between 0 and 30F. Above 30F, it says use SAE 30 oil.
--
'73 23' Sequoia
UA (Upper Alabama)
"Time is money. If you use YOUR time, you get to keep YOUR money."

[Rob Mueller]

A,

Interesting, could you ask her why she doesn't use multi viscosity oil? Specifically what does using multi-viscosity oil hurt?

I am of the opinion that engine oil formulations have improved greatly since the MM was written over thirty five years ago hence my
use of Shell Rotella T 15W-40.

Regards,
Rob M.

-----Original Message-----

From: A.

You can but I wouldn't. My sister has been in the small engine repair business for about 15 years. She says use straight 30W oil,
not multi-viscosity oil.

My MM mostly agrees with her, It says 5W30 or 10W40 ONLY when operating between 0 and 30F. Above 30F, it says use SAE 30 oil.

[A.]

Robert Mueller wrote on Sun, 16 December 2012 17:50

> A,
>
> Interesting, could you ask her why she doesn't use multi viscosity oil? Specifically what does using multi-viscosity oil hurt?
>
> I am of the opinion that engine oil formulations have improved greatly since the MM was written over thirty five years ago hence my use of Shell Rotella T 15W-40.
>
> Regards,
> Rob M.

I have asked her, when we were talking about the 4kw Kohler in the 73 CanyonLands. And she explained it, but once I was satisfied that it made sense, I promptly forgot.
I will try to remember to ask again next time I see her.
I agree that today's lubricants are better formulations than was available 35 years ago, which is why I asked her why multi-vis wouldn't be better than straight 30W oil. And then again, the straight 30W oils today have a better mix of detergents and stuff than they did 35 years ago.
I do recall that one time my dad put some STP oil treatment in a 3hp lawnmower. It siezed up in a matter of seconds. The aluminum from the rod adhered to the steel crankshaft.

--
'73 23' Sequoia
UA (Upper Alabama)
"Time is money. If you use YOUR time, you get to keep YOUR money."

[Robin Hood]

http://youtu.be/XsnmnOxzzYA

That's 15 minutes of me messing around and learning things. I am
worried that I may have stripped the coarse threads in the block that
the cylinder head studs screw in to. I'm not 100 percent sure, though.

I got everything back together and tried to start it. I accidently hit
bottom Terminal 1 with my alligator clip while trying to prime the
pump by jumpering to bottom Terminal 9, and it blew the fuse. I think
I may have bent the fuse holder slightly. It would turn over, and
tried to fire. I was getting "blow by" where combustion was getting
past the gasket. This is after I had torqued the heads down using the
torque wrench.

I decided to torqe the heads down to 20 foot pounds. One of the nuts
wouldn't snug down. I think it may have backed the bolt out of the
block? I ultimately wound up taking the cylinder head completely off
again, ruining my layers of paint on the gasket (so that's gotta be
redone). I tried screwing the stud into the block. It was still loose,
like a tooth. I backed it out using just my fingers. I put a fresh
coat of antiseize on it, and screwed it into the block, and it feels
solid now, but I'm really not sure about it. I'm scared that when I
put a nut on it and snug it down that it's going to back out again...
I hope that it's not stripped; I know damn-all about helicoils and
really don't want to learn right now. :(

I need a muffler (in my video I say "exhaust" but I meant "muffler."
I"m not sure exactly how it's supposed to connect to what I have
already.

I did manage to break my exhaust manifold nuts loose. Six sided
sockets for the win. :) So, it will be getting repainted.

I appreciate everyone's advice and encouragement. :)

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Robin Hood]

I took another look at the stud, and it's official: the threads are
stripped and I need to learn how to use a Helicoil.

I think YouTube probably have some good examples hopefully I can learn from
that.

[Robin Hood]

http://www.youtube.com/watch?v=DNV2iqx9iiE

definitey need to get a helicoil or similar. In the videos I'm
watching, people are doing their drilling and tapping freehand with
battery powered drills. That looks doable...

[Charles Boyd]

Sir: my old eyes may be playing tricks but it looks like there is a heli coil there. In the bottom of the hole is there a piece of thread that goes across the hole? If there is get a pair of long hemostats or small needle nose pliers and see if you can get a holt of the cross bar and see if it will thread out. Heli coils are made to go in and bottom out then break off the tab. It might have been pushed in to deep when installing the stud?? If not I have had good results with a chemical thread restorer. It is 2 part like JB weld and has a releasing agent you put on the stud. Mix it up and pack the hole then apply releasing agent to stud and install and let cure. That flat head torque isn`t much. Heli coil kits are available at AZ for about $25 + drill bit.
You are doen good.. keep it up..





Robin Hood wrote on Mon, 17 December 2012 20:47

--
C. Boyd
76 Crestmont
East Tennessee

[Robin Hood]

Well first of all I'm amazed that you were actually able to see something
in the video. Now that you mention that there was something in the threads
of the stud when I pulled it out. I thought it was just fossilized
anti-seize because it was very brittle. I suppose it's possible that that
was actually an old helicoil coil that was wrapped up in the threads. I
will get in there and see if I can determine one way or the other.

On Monday, December 17, 2012, Charles Boyd wrote:

>
>
> Sir: my old eyes may be playing tricks but it looks like there is a heli
> coil there. In the bottom of the hole is there a piece of thread that goes
> across the hole? If there is get a pair of long hemostats or small needle
> nose pliers and see if you can get a holt of the cross bar and see if it
> will thread out. Heli coils are made to go in and bottom out then break
> off the tab. It might have been pushed in to deep when installing the
> stud?? If not I have had good results with a chemical thread restorer. It
> is 2 part like JB weld and has a releasing agent you put on the stud. Mix
> it up and pack the hole then apply releasing agent to stud and install and
> let cure. That flat head torque isn`t much. Heli coil kits are available
> at AZ for about $25 + drill bit.
> You are doen good.. keep it up..
>
>
>
>
>
> Robin Hood wrote on Mon, 17 December 2012 20:47

> > Fixing the Onan Part 11: Stripped cylinder head stud.<http://www.youtube.com/watch?v=DNV2iqx9iiE>

[Robin Hood]

Upon further investigation I do believe you are correct. Now that I watch
some videos and researched and know what to look for, I believe I see
about half of a helicoil in the bottom of this hole. This has been
repaired before.

[Charles Boyd]

Sir: please wear safety glasses. Clean the hole with carb cleaner and compressed air, be carefull.. Check to see if the threads are there to screw the heli coil out. Some times a pick will roll it out. There is a chance there has been more than 1 previous repair done. Crusty anti seeze lookin stuff might be the JB weld kinda stuff on top of the heli coil. You might have to clean that stuff out before the heli coil will come out.





Robin Hood wrote on Mon, 17 December 2012 21:28

--
C. Boyd
76 Crestmont
East Tennessee

[Charles Boyd]

Sir: when you get the hole clean and are ready to try to remove helicoil and you get a hold of the cross bar and it breaks instead of coming out ( it is made to break) you will need to take a very small screwdriver or a pick and get under the heli coil at the top and get it started out of the threads enough to get the needle nose on it and unscrew. Be carefull not to damage threads in the head if possible. It should wrap around the needle nose and come out. The stuff most heli coils is made of is fairly easy to bend.

This is a blind hole we are dealing with?? Is there a bottom in this hole??






C Boyd wrote on Mon, 17 December 2012 21:42

[Dennis Sexton]

[quote title=C Boyd wrote on Mon, 17 December 2012 21:01]Sir: when you get the hole clean and are ready to try to remove helicoil and you get a hold of the cross bar and it breaks instead of coming out ( it is made to break) you will need to take a very small screwdriver or a pick and get under the heli coil at the top and get it started out of the threads enough to get the needle nose on it and unscrew. Be carefull not to damage threads in the head if possible. It should wrap around the needle nose and come out. The stuff most heli coils is made of is fairly easy to bend.

This is a blind hole we are dealing with?? Is there a bottom in this hole??






C Boyd wrote on Mon, 17 December 2012 21:42
> Sir: please wear safety glasses. Clean the hole with carb cleaner and compressed air, be carefull.. Check to see if the threads are there to screw the heli coil out. Some times a pick will roll it out. There is a chance there has been more than 1 previous repair done. Crusty anti seeze lookin stuff might be the JB weld kinda stuff on top of the heli coil. You might have to clean that stuff out before the heli coil will come out.

Robin,

You may also be seeing the threads that have stripped from the aluminum block. If it is not a helicoil -- and you go the chemical route -- "Form-a-thread" is the brand name for the JB weld product. Works well in aluminum.
If you can rotate the Onan up on it's side it will be easier to put the mix into the stud hole.

Dennis

--
Dennis S
73 Painted Desert 230
Germantown, TN

[Mike Miller]

Robin Hood wrote on Sun, 16 December 2012 18:34
> ...
> I got everything back together and tried to start it. I accidently hit bottom Terminal 1 with my alligator clip while trying to prime the pump by jumpering to bottom Terminal 9, and it blew the fuse. I think I may have bent the fuse holder slightly. ...


There is a reason I suggested that you use a very short jumper between lower pin 6 and 9. If made from a single connector and a 1 or 2 inch piece of wire, it can be LEFT IN PLACE and you do not have the issue of hitting the incorrect pins and blowing stuff up. Pressing the start button latches voltage to pin 9. Pressing stop removes it. No arcs and sparks.

You just have to remember to press stop if you did not turn it off with the stop button. It also removes all safety features supplied by the board. But these same downsides apply to the jumper you are already using! (Plus more downsides.) :twisted:

--
Mike Miller -- Hillsboro, OR -- on the Black list
(#1)'73 26' exPainted D. -- (#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
http://m000035.blogspot.com

[Jim Bounds]

If you run a jumper from a power source at the starter to the positive side of the coil (the side with more than 1 wire on it), you can test operation of the generator the same as jumping the 2 pins on the PC board.  When you touch the jumper in place, you should hear the electric fuel pump fire up.  Listen for a number of seconds, the sound of the pump should change which means there is fuel to it.  Press the start button at that point, the generator should fire if you have spark.  If it does not, pull a plug wire, hold it near the metal case of the generator and hit the start button and look for a spark.  If you have no spark, open up the point set and work to get spark.
 
If the generator does fire, let it run for a minute then remove the jumper.  If it continues to run, let it run for a bit, adjust the screw on the bottom of the float bowl to it's smoothest run, load the generator down with the roof AC and again adjust for smoothest run.  If the generator dies when you remove the jumper, go to my web site http://www.gmccooop.com/ and on the "information" page scroll down to "Onan Prime Circuit".  Exchange the momentary button in the diagram to a toggle switch.  This will be the same as the jumper, you can run the generator this way.  You will not have a "low oil shut down" circuit so be sure to always know your oil level.
 
I have many people running their generator without having to replace the alternator windings or PC board.  Just be sure you do not run out of oil.  Opinions differ on running the generator this way, I just hate spending hours and big bucks trying to coax that old war horse to live a little longer.  Good $ after bad, it's an old beast, make it run until it will not then make it a boat anchor, they really work well for that-- be sure you drain out the oil before doing that though...
 
Jim Bounds
----------------------


________________________________
From: Mike Miller <m00...@gmail.com>
To: gmc...@temp.gmcnet.org
Sent: Wednesday, December 19, 2012 4:23 AM
Subject: Re: [GMCnet] So, about removing the Onan heads and looking for carbon...

[Mickey Space Ship Shuttle]

great info thank you - i needed that info.

happy holidays to the co-op and all here as well as there, and eveywhere

down there too, mickey

anaheim ca. next to disneyland where it snows all the time in the park.

77 palm beach.

[Robin Hood]

That is very good info. Thank you very much Jim! I hope someday that I will
be able to come down and see your operation, or maybe even get some work
done. I'm getting a real kick out of all of these hours I'm spending
working on just to the Onan, as well as all the help here.

Granger is shipping a helicoil extraction tool to my local Granger store,
it should be here Friday.

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Robin Hood]

Quick question. I can entirely remove the Electric choke that goes from the
exhaust manifold to the choke flap inside the carburetor correct? One of
the bolts that is holding the thing on is rounded off and just stuck to the
exhaust manifold. I have the exhaust manifold loose, but if this is a part
that I can just toss and not have to buy any special tools to remove this
bolt, I think that would be awesome.

[Mike Miller]

Jim Bounds wrote on Wed, 19 December 2012 04:06
> ... Exchange the momentary button in the diagram to a toggle switch.  This will be the same as the jumper, you can run the generator this way.  You will not have a "low oil shut down" circuit so be sure to always know your oil level.
>  
> I have many people running their generator without having to replace the alternator windings or PC board.  Just be sure...


A 2 inch wire and a crimp on connector between the lower pin 6 and pin 9 will do the same thing as the toggle switch without requiring you to install the "prime wiring."

It is cheaper, fully reversible and the use is completely transparent to the user. It works just like if everything was working properly. (Other than not having the safety features the board provides, but other jumper methods do this also.)

It is so transparent, my 1978 came from the PO with a jumper installed and I did not know it for almost a year.

I still do not understand why people still insist on using clips and hunting for the correct pins each and every time they start and stop the generator. (Other than quick troubleshooting checks.) I have heard of several boards being burned out from errors when using clips.

To make it easy:

1. Take a 2 inch piece of wire and strip both ends.
2. Install a single female spade connector on one end.
3. Connect this connector to the unused lower pin 6. (It is right next to pin 9.)
4. Disconnect pin 9 and place the stripped wire under the connector from pin 9 and reconnect the connector with the wire under this connector.

-- You are done.

The safety features of the board have been by-passed but the start and stop functions should work as normal. Be sure to keep oil in it and turn it off if you did not actually turn it off with the stop button.

No arcs, no sparks, no mistakes causing blown boards.


Robin, I do not want to tell you: "I told you so." :twisted:

[Emery Stora]

On Dec 19, 2012, at 5:32 PM, Robin Hood wrote:

> Quick question. I can entirely remove the Electric choke that goes from the
> exhaust manifold to the choke flap inside the carburetor correct? One of
> the bolts that is holding the thing on is rounded off and just stuck to the
> exhaust manifold. I have the exhaust manifold loose, but if this is a part
> that I can just toss and not have to buy any special tools to remove this
> bolt, I think that would be awesome.
>

Robin

You are going to need a choke for the Onan so don't throw it away. It might start without it in warm weather but if its a bit cold outside it will definitely need a choke.

The Onan choke is not an electric choke in the manner that you might be aware of for an automobile carb.

Hitting the choke with 12v is not going to pull the choke on. The coil in the choke is there to hold the choke in the on position until the bimetallic strip pulls it away from the hold position.

No wire goes to the bimetallic strip. A bimetallic strip is a
mechanical device which has two layers of metal that expand at
different amounts when heat is applied. That causes the strip to bend.
If you look at a typical house thermostat for a furnace you will see a
coil. This is also a bimetallic strip which coils and uncoils with
room temperature.

So the electromagnet holds the choke closed and as the Onan starts to
warm up the exhaust heat transfers some heat to the choke housing and
the bimetallic strip starts to heat up and expand which pulls the
choke metal plate away from the electromagnet and the choke begins to
open. When totally warmed up the choke is fully opened.

The choke gets it's 12 volts from the start relay on the control
board. It doesn't get any power after that when the Onan is
running.

Years ago when my choke wasn't operating right I saw the rusty bolts that hold it to the manifold and right away assumed that was getting a poor ground. So, I cleaned a spot on the side of the choke and soldered a length of wire to the choke housing and put a ring terminal on the other end of the wire and attached it to the Onan support frame where it wasn't getting heat as the manifold does. I have never had a problem with the choke since.

Emery Stora
77 Kingsley
Frederick, CO

[gene Fisher]

> On Dec 19, 2012, at 5:32 PM, Robin Hood wrote:
>
> > Quick question. I can entirely remove the Electric choke that goes from
> the
> > exhaust manifold to the choke flap inside the carburetor correct?

read here
http://gmcmotorhome.info/generator.html#choke

gene

Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Robin Hood]

Ok so I need A choke but not necessarily THAT choke in THAT location, and
only in cold weather. Im in MS, it was 70F today. I will terminate that
choke and bracket with extreme prejudice.

--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome

[Ken Burton]

Robin Hood wrote on Thu, 20 December 2012 04:48

> Ok so I need A choke but not necessarily THAT choke in THAT location, and
> only in cold weather. Im in MS, it was 70F today. I will terminate that
> choke and bracket with extreme prejudice.
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome

You are going to need it so do not destroy the parts when you take it off.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana