crossover and choke stove block off

[CB]

I'm just about to deal with the choke stove lines, and making a new blocking plate for that.  It got me to thinking, has anyone figured out something that could be poured into the crossover to block it.  Something that would harden in place, and provide a sure block.  Of course the risk is that if you over-fill it, whatever you pour in will make it's way into the heads, but leaving that out of the equation for the time being, . .  It would have to hold up to the exhaust temps, but if it were a total block, then the exhaust gases would not get to it too much down that dead hole I'd imagine.  Probably a dumb idea, but...

Any ideas?

By the way, wish me luck on removing those two bolts, they look to be very securely rusted in place.  I hope I can get them without having to drill them out and rethread the holes.  I've got them soaking in PB Blaster now and for the next day or two.

[George Beckman]

They fill them but not in place. The head port for the crossover has the valves right there. I wouldn’t want to “pour” anything down there. 

Back to filling the ports, a discussion of Hard Blok is here:  http://gmc.mybirdfeeder.net/GMCforum/index.php?t=tree&goto=200611&rid=0

On May 3, 2014, at 5:46 PM, CB <corle...@gmail.com> wrote:

I'm just about to deal with the choke stove lines, and making a new blocking plate for that.  It got me to thinking, has anyone figured out something that could be poured into the crossover to block it.  Something that would harden in place, and provide a sure block.  Of course the risk is that if you over-fill it, whatever you pour in will make it's way into the heads, but leaving that out of the equation for the time being, . .  It would have to hold up to the exhaust temps, but if it were a total block, then the exhaust gases would not get to it too much down that dead hole I'd imagine.  Probably a d

----

Best Wishes,

George

http://www.pggp.com

[dwayne jacobson]

Dick Paterson has a gasket with a metal plate specially made for this.

Dwayne Jacobson

White Rock, BC

77 Kingsley

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Dwayne Jacobson
White Rock BC
Cell: 604-644-8090

[Howard Nielsen]

No please remove the manifold and install the blocks

I have stainless steal plates in our 74 

Howard 

Alpine Ca

Morning Glory  Evening Grace. 

[CB]

No No, you are missing the point.  I was trying to think outside the box, of a way to block the crossover W/O removing the manifold.  We all know about block off plates, new manifolds cast W/O the x-over, filling a removed manifold, etc'.  But is there another way?  A way to do it without removing the manifold???

It seems to me that the entire passage does not have to be filled in order to stop air flow, and if you could stop air flow, you reduce heat tremendously.  What about a steel plate welded to the choke stove cover, that stick down into the passage, blocking air passage.  A high temp sealer might be used around it to further block air flow.

Think outside the box...

[Howard Nielsen]

You are not stoping air flow

It's exhaust gas and gets a little hot very hot.

I would not want to give it a try

I had a cross over get blocked on a 350 small block.

It over heated the exhaust manifold and turned the manifold to crystals 

It's not that hard to R&R the intake.

Howard

Alpine Ca

74 Canyon Lands

With blocked manifold running TBI

Morning Glory  Evening Grace. 

On May 4, 2014, at 7:35 AM, CB <corle...@gmail.com> wrote:

No No, you are missing the point.  I was trying to think outside the box, of a way to block the crossover W/O removing the manifold.  We all know about block off plates, new manifolds cast W/O the x-over, filling a removed manifold, etc'.  But is there another way?  A way to do it without removing the manifold???

It seems to me that the entire passage does not have to be filled in order to stop air flow, and if you could stop air flow, you reduce heat tremendously.  What about a steel plate welded to the choke stove cover, that stick down into the passage, blocking air passage.  A high temp sealer might be used around it to further block air flow.

Think outside the box...

On Saturday, May 3, 2014 5:46:51 PM UTC-7, CB wrote:

--

[CB]

I'm sorry Howard, but that makes no sense whatever. Guys are blocking off the cross-over all the time, and it does not cause the exhaust manifolds to overheat and turn to crystals.  Of course I realize that it is exhaust gases and not "air", and extremely hot.  The point is, if you can block it so it is dead space, the heat won't be carried into the passage.

To that end, I've  built a blocking plate that I've welded to my block off plate.  It sticks down into the passage blocking about 95% of the flow.  It's tricky to get it in there, because the passage was shaped such that you have to insert and turn it a bit, then bolt it down.  It is 1/4" thick, so should be up to the task. (My block off plate is 3/16" thick.)

[kdpotato]

based on the recs of other folks, I used furnace cement to pack our intake manifold, plus
 a set of Dick P's block-ff gaskets with the stainless plates.  Furnace cement is a thick black or grey
sticky paste you can buy at a lot of hardware stores for patching fireplace and furnace ducts, fireboxes, etc.
Generally comes in pint or quart sized tubs.

DickP said  filler isn't needed, but it was a belt-and-suspenders idea, in case there were cracks in the intake.
I left the choke stove cover loose for a while just in case the moisture in the cement needed a way out.

 I got to examine the cement when I pulled the intake to move it to the new engine.  It seemed to be holding
up just fine and was quite solid and well adhered to the cast iron, though it did expand more than I expected
(the stuff isn't supposed to expand...)  Out of paranoia, I had left an inch or so of gap by digging out the cement to
keep it back from the stainless plates, but it had expanded  all the way out to the plates.

So, I don't know how well it would work without the plates, but I did consider just packing some
in through the choke stove hole.  The problem is it might work itself loose and bang around in there.

jwid.

Karen
1973 23'
1975 26'

[kdpotato]

sounds good, let us know how it works out.  You might have a new product idea there :-)

[CB]

Here are a couple pictures of what I have...

 

[Howard Nielsen]

Sorry I'm only passing on what happen on a 350 sb

The heat riser gate froze closing off the exhaust and forcing the exhaust up and over through the intake.

Hope this sound a little clear 

Thanks

Howard

Morning Glory  Evening Grace. 

On May 4, 2014, at 1:34 PM, CB <corle...@gmail.com> wrote:

I'm sorry Howard, but that makes no sense whatever. Guys are blocking off the cross-over all the time, and it does not cause the exhaust manifolds to overheat and turn to crystals.  Of course I realize that it is exhaust gases and not "air", and extremely hot.  The point is, if you can block it so it is dead space, the heat won't be carried into the passage.

To that end, I've  built a blocking plate that I've welded to my block off plate.  It sticks down into the passage blocking about 95% of the flow.  It's tricky to get it in there, because the passage was shaped such that you have to insert and turn it a bit, then bolt it down.  It is 1/4" thick, so should be up to the task. (My block off plate is 3/16" thick.)

On Sunday, May 4, 2014 8:21:41 AM UTC-7, Howard wrote:

[George Beckman]

I think some have experienced this when one muffler plugged and most of one side was going through the crossover.

Best Wishes,

George
Sent from my iPad

[George Beckman]

I am intrigued with this idea. Gordon has mentioned that old school flathead guys left a little hole when blocking the crossover. We have had some EFI rigs that seem to want some heat. After all, we are trying to vaporize gasoline and a cold manifold and engine make that tough. 

I have an aluminum intake so this is not a choice for me but interesting.

Best Wishes,

George

Sent from my iPad

On May 4, 2014, at 2:27 PM, CB <corle...@gmail.com> wrote:

Here are a couple pictures of what I have...

 

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<P1040358.JPG>

<P1040360.JPG>

<P1040361.JPG>

[Howard Nielsen]

Well living in Kaliforina we can't change a thing from the Cat forward.
The car only had one exhaust


Morning Glory Evening Grace.

> On May 4, 2014, at 3:18 PM, George Beckman <gbec...@pggp.com> wrote:
>
> I think some have experienced this when one muffler plugged and most of one side was going through the crossover.
>

> Best Wishes,
>
> George
> Sent from my iPad
>

>> On May 4, 2014, at 3:09 PM, Howard Nielsen <hnie...@cox.net> wrote:
>>

>> The heat riser gate froze closing off the exhaust and forcing the exhaust up and over through the intake.
>

[gene Fisher]

then there is this

http://gmcmotorhome.info/radiator.html#PLUGS

erf

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

[CB]

Those plugs are a bad deal, because they are free to float around and wear.  Once they start moving, every exhaust pulse move them more and more, as they wear.  Mine is welded solid to the choke stove cover , and cannot move, hence it cannot cause damage like that.

Just what I think...

[CB]

Howard,  That is a whole different scenario.  I'm blocking the cross-over, similar to what your block-off plates do.  On the sbc, you forced all of one bank's exhaust through the cross-over.  Way different thing.  In that case, the Intake passage would overheat and eventually fall apart.

[Howard Nielsen]

C B

You are welcome to do what ever you like.

It's your rig.

Me I would not

Thank you

Morning Glory  Evening Grace. 

On May 4, 2014, at 5:00 PM, CB <corle...@gmail.com> wrote:

Howard,  That is a whole different scenario.  I'm blocking the cross-over, similar to what your block-off plates do.  On the sbc, you forced all of one bank's exhaust through the cross-over.  Way different thing.  In that case, the Intake passage would overheat and eventually fall apart.

On Sunday, May 4, 2014 3:09:49 PM UTC-7, Howard wrote:

[Ken Morris]

http://www.summitracing.com/parts/edl-2733/overview/make/oldsmobile/model/f85

 

This works well for the crossover block and I just made a steel plate out of 1/4" to block the choke stove.

--

[Ken Henderson]

Ken,

If you're using those abominations, be SURE to review this:

http://www.gmcmhphotos.com/photos/g3057-cylinder-head-damage-from-exhaust-crossover-plugs.html

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,

Manny Brakes & 1-Ton, etc., etc.

www.gmcwipersetc.com

[Ken Morris]

I agree that looks horrible

Ken, who installed the plugs? they don’t appear anything like what I installed, mine were from summit and look like the product photo.  Is there a hole drilled in them?

 

Whatever that is it obviously was not "fit" properly in the head from the photo it appears as if the plug was rattling around in there must have made a horrible racket.  It also appears that the head shown was a 455  I had to grind mine down to fit. 

The intake also holds them from moving about, I have about 15k since installation I also installed crossover blocking intake manifold gaskets to keep the BBQ pellets from forming in the valley tray and getting to the lifters. 

 

Ken M

--

[Ken Henderson]

Ken,

When I received the plugs directly from Edelbrock, they looked exactly like the photo from Summit:  As-cast iron.  I personally fitted them, very carefully, in accordance with the instructions (which did NOT recommend drilling holes in them).  I drove them into the ports with a ball peen hammer when they were "almost" there.   As noted in the album, the smooth, dark red, appearance resulted purely from their tenure in the engine.  They WERE NOT loose when I installed the manifold on the 455.  There was no obvious noise from the loose plugs, right up to the time I removed the manifold -- although my poor hearing is well known, others did ride in the coach without mentioning any strange noises.

 I had 20k-25k miles (I don't remember but it's probably in the album) on the engine when I decided to remove the too-high Edelbrock manifold.  JUST IN TIME!  If you've got 15k on your engine with them installed, I STRONGLY urge you to pull the intake an at least check the condition of those plugs.  I seriously doubt that there's any sign that you used intake gaskets without crossover ports cut into them -- the moving plugs have almost certainly worn the gasket material away.  

I've heard of several episodes similar to mine, one of which I'm personally familiar with, where the plugs wore through into the water jacket.  In the case I know personally, hydraulic lock and bent connecting rods resulted.  

As for drilling holes in whatever plugs are used, I can see the benefit of allowing SOME exhaust gases to pass, keeping the manifold warm.  The original Olds design would probably have never caused as many problems as it has if the passage had been a lot smaller.

Please don't ignore my experience and lose your engine.

 

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,

Manny Brakes & 1-Ton, etc., etc.

www.gmcwipersetc.com

[George Beckman]

I have a Rockwell aluminum and have not crossover ports but am curious. How do these plugs stay in? Do they expand faster than the cast head, there by hugging in place. There must be terrific force pounding those guys thousands of times per mile. The “crossover” term makes me think the gas, unrestricted is reversing path with every cycle.

On May 23, 2014, at 2:35 PM, Ken Morris <k...@aaaaimage.com> wrote:

I agree that looks horrible

Ken, who installed the plugs? they don’t appear anything like what I installed, mine were from summit and look like the product photo.  Is there a hole drilled in them?

[Reid]

As DickP once said; It is a good thing when were young, we didn't know
what we know now or nothing we built would have been attempted. :-)
Gordon

[Kosier]

I've put several sets of the iron plugs in, but you MUST properly weld them
in, or they WILL
beat the heads to death. It's been proven, time and again, even before this
internet group was formed, that this will happen. If you don't weld them
with the correct rod and procedure, it'll happen. Count on it.

Gary Kosier
77PB w/500 Cad
Newark, Oh

----Original Message-----
From: Reid
Sent: Friday, May 23, 2014 10:28 PM
To: gmcm...@googlegroups.com
Subject: Re: [GMCMH-EFI] crossover and choke stove block off

[Reid]

Absolutely correct. Been welding or brazing 1/4" steel plates in
forever. (55 years) I still have tubes of Castolin.
Gordon

[Ken Morris]

I will pull my intake and check with photos and post,  Who has the dimensions difference of the heads crossover port between the 403 and 455 crossover question how many of you have installed headers and have the 2- 1/2" exhaust going out of the coach, I have put in 3" out and the engine seems happy , IMO headers are counterproductive unless you can have true dual exhaust.  With this restrictive exhaust seems that it would increase pressure on the crossover port . 

 

I have also googled this issue and no reports of this problem other than Ken's in a GMC could this be based on the restrictive exhaust? has anyone communicated with Edlebrock about this issue?

 

I also have an aluminum  intake so if the plug becomes loose would it take the path of least resistance and wear the aluminum out before the steel while rattling about?

 

I agree the crossover was a poor design and causes a myriad of issues in the engine unless you drive your GMC in Alaska with a carb in the winter and need extra cabin heat .

[Ken Henderson]

Ken,

Since my bad experience with the Edelbrock plugs, I've followed Alex Sirum's example:  Make a 1/8" steel plug slightly larger than the crossover port in the intake manifold.  Either free-hand or using a jig, cut a recess in the manifold using a straight carbide bit in an ordinary wood router -- it works surprisingly well and the bit exhibits no unusual wear afterward.  The recess should leave the plug a few thousandths proud of the surface so the gasket holds it securely in place.  A little RTV will provide more security.

The engine in which the plugs damaged the head has been in service for at least another 40-50 thousand miles without disassembly after that mod; it's been in the GMC my son has for at least 25k of those and shows no need for service.  I kind of wish he'd open it up so we can see how those plugs are doing -- and how the head bolts exposed to exhaust gases are standing up.  But with it running so well, he's not about to "fix" it. :-)

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,

Manny Brakes & 1-Ton, etc., etc.

www.gmcwipersetc.com

[Ken Morris]

Thank you Ken for taking the time and sharing your experiences. I would also like to hear from the Edlebrock corp. as they have designed these plugs and see if they would stand by any issues caused by the product they supply.

[Gordon]

For interest sake, please let us know what you hear from Edlebrock?
Thanks,

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