[GMCnet] Remflex vs copper exhaust gaskets

[Bruce Hislop via Gmclist]

My driver's side exhaust manifold has a large crack so I am replacing it with a used but good condition cast iron manifold. It has a few small pit
clusters that are not deep and appears to have been plained but never used after that.

Two questions:
I have a new set of DaveL copper gaskets and a new set of Remflex gaskets. I'm wondering which would be the best. I know if it did not have any pits
I would use the copper gaskets, but I'm leery because of the pits. How much pitting can copper withstand? I would be installing them with some
Permatex high temperature copper sealant for exhaust manifolds. My worry about the Remflex is the higher temperature the manifolds run at due to the
poorer heat transfer compared to copper.

Second thing is the top center bolt for the manifold broke while trying to remove it. I read where some do not bother to install this bolt as it is
recommended not to torque it. So do I just leave the broken stud there as a installation guild, or do I need to remove it and re-install a new one.
They had been installed with never-seize, likely zinc based. I'll be using copper based this time.

Thoughts, ideas, experiences...?

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

[Charles Boyd via Gmclist]

Sir, my thoughts is if there is enough of the broken bolt to clamp solid a pair of vice grips, soak it and soak it and soak it @nd try to get it out.
I have had luck center welding a nut on the broken part to remove with a wrench. I know a lot recommend not even using the center bolt but it was put
there by GM.




RF_Burns wrote on Sat, 21 September 2019 11:03

> My driver's side exhaust manifold has a large crack so I am replacing it with a used but good condition cast iron manifold. It has a few small pit
> clusters that are not deep and appears to have been plained but never used after that.
>
> Two questions:
> I have a new set of DaveL copper gaskets and a new set of Remflex gaskets. I'm wondering which would be the best. I know if it did not have any
> pits I would use the copper gaskets, but I'm leery because of the pits. How much pitting can copper withstand? I would be installing them with some
> Permatex high temperature copper sealant for exhaust manifolds. My worry about the Remflex is the higher temperature the manifolds run at due to
> the poorer heat transfer compared to copper.
>
> Second thing is the top center bolt for the manifold broke while trying to remove it. I read where some do not bother to install this bolt as it
> is recommended not to torque it. So do I just leave the broken stud there as a installation guild, or do I need to remove it and re-install a new
> one. They had been installed with never-seize, likely zinc based. I'll be using copper based this time.
>
> Thoughts, ideas, experiences...?


--

C. Boyd
76 Crestmont
East Tennessee

[Matt Colie via Gmclist]

RF_Burns wrote on Sat, 21 September 2019 11:03

> My driver's side exhaust manifold has a large crack so I am replacing it with a used but good condition cast iron manifold. It has a few small pit
> clusters that are not deep and appears to have been plained but never used after that.
>
> Two questions:
> I have a new set of DaveL copper gaskets and a new set of Remflex gaskets. I'm wondering which would be the best. I know if it did not have any
> pits I would use the copper gaskets, but I'm leery because of the pits. How much pitting can copper withstand? I would be installing them with some
> Permatex high temperature copper sealant for exhaust manifolds. My worry about the Remflex is the higher temperature the manifolds run at due to
> the poorer heat transfer compared to copper.
>
> Second thing is the top center bolt for the manifold broke while trying to remove it. I read where some do not bother to install this bolt as it
> is recommended not to torque it. So do I just leave the broken stud there as a installation guild, or do I need to remove it and re-install a new
> one. They had been installed with never-seize, likely zinc based. I'll be using copper based this time.
>
> Thoughts, ideas, experiences...?

Bruce,

Two things...
If the pitting is not deep, the copper gaskets will probably do just fine. They will require multiple re-torques before they settle in. The Remflex
should not. Reflex are a clad graphite gasket and will have more compliance than the copper and should not gain much from a re-torque. At 7 #ft, how
would you know?

A word of caution...
The good copper anti-seize all contain lead as well. This can foul an O2 sensor and make it either slow or dead. This is not true of the nickel
based anti-seize. In fact that lead is why there is nickel based anti-seize.

A short lesson I have learned along this road....
If you get done working on an exhaust system and you do not have anti-seize all over you, then you did not use enough.......

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Richard Denney via Gmclist]

On the driver’s side, you get good access to the cylinder head surface if
you remove the inner fender well. There is room for a drill.

I had the same broken-bolt problem when I installed headers years ago. I
used a sharp 1/8” left-turning drill, which was part of an extraction kit,
and drilled all the way through the bolt. Going all the way through is
important. The center hole is open at the back, as I recall, so you can
also attack it with Kroil from the back side. Kroil also makes an
acceptable cutting fluid—also important. I enlarged the hole, and
eventually the left-turning bit pulled all the remains out.

I think the top bolt is needed to keep the manifold from rocking up and
down, but I may be the only one who thinks so.

As to the pitting, it depends on whether the pits create a tunnel around
the crush ridge on the copper gasket. You should be able to tell that by
inspection. If it might, then either plane it down more or use the Remflex
gasket. The carbon composite used by Remflex is a pretty good thermal
conductor. But copper is, of course, better. You can plane the manifold
with aluminum-oxide sandpaper laid down on a hard, flat surface, like a saw
table or even a smooth concrete floor.

Rick “whose manifolds were cracked, welded, and cracked again, making
headers an easy decision” Denney

--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com

[Ken Henderson via Gmclist]

Bruce,

Purely opinion, but I'd use the Remflex, leave the broken stud in place,
and use NO sealant.

Remflex because of its ability to conform to your still-pitted manifold.
Stud 'cause it ain't hurtin' nuthin'.
No sealant because Remflex doesn't need it and it would probably be the
weak link.

Ken H.

On Sat, Sep 21, 2019 at 11:04 AM Bruce Hislop via Gmclist <
gmc...@list.gmcnet.org> wrote:

[Bruce Hislop via Gmclist]

Well, checking the replacement manifold over after finding DaveL's instruction.. I found its not perfectly flat. Using a straight edge its out by
0.015" and looking at my micrometer the pits are upwards of that depth too. There is one area of pits that I'm thinking the copper will not seal
well.

I had these manifolds planed when I had the engine rebuilt. I swear the guy running the planer went for lunch break in the middle of the job because
he took so much off I had to flatten the dipstick tube to get it to fit in between. So I don't want to go down that road again.

Rick mentioned the Remflex had good heat transfer, so I think I'll go that way.

The broken bolt was a grade 8 with about 1/8" sticking out. I'm thinking that will be a hard drill-out. All the bolts are open at the back, except
this one. I have a small electric MIG welder, but I haven't welded much in a long time. I'm likely to do more damage with spater flying all over!

Without the center bolt, I worry that the weight of the front of the mufflers hanging from the manifold may put a twisting torque on it and cause the
Remflex's to open at the top.

I worry too much while others go ahead with blind abandonment and it all works out well for them! :roll:

[tonka6cuda6--- via Gmclist]

Bruce if you have an 1/8" of that bolt sticking out its going to be near impossible to drill as is....let alone grade 8. To get it out you have 2
choices: grind it flat to the head so you can center drill everything properly or weld a nut onto the end....i would choose #2 personally if i wanted
it gone.

So if it was me i would leave it alone....my opinion is the bolt was a production thing...a way to assemble the manifolds on the assembly line without
the need of guide pins etc to put it together....it really does very little to clamp anything properly in tjis setup.

As for gaskets....im fighting the exact same thing....front right cylinder blew out gasket so i put a nice copper one in with copper rtv spray to seal
up the pits.... i took a chance but it didnt work and honestly in my mechanics gut i knew it wouldnt...so i ordered a set of Reflexs and i should have
done that from the start.

Im actually starring at the gaskets right now but because i just got in from a business flight and go back to the airport tomorrow morning for another
the gaskets are going to have to wait another weeks.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

[tonka6cuda6--- via Gmclist]

As for the exhaust hanging on the manifold....you should have the spring bolts in there which allows all that to move and not nuts/studs....i think
that is how all this gets messed up in the first place.

[Todd Snyder via Gmclist]

0.015" is a lot! It's going to put a lot of stress on that manifold if you try to clamp that down that way. Time to get it milled (if it were
mine). I did one of mine on a Bridgeport one time for a 6.5L diesel.
--
Todd Snyder, Buffalo NY
1976 Eleganza II

[Matt Colie via Gmclist]

RF_Burns wrote on Sat, 21 September 2019 12:19

> Well, checking the replacement manifold over after finding DaveL's instruction.. I found its not perfectly flat. Using a straight edge its out by
> 0.015" and looking at my micrometer the pits are upwards of that depth too. There is one area of pits that I'm thinking the copper will not seal
> well.
>
> I had these manifolds planed when I had the engine rebuilt. I swear the guy running the planer went for lunch break in the middle of the job
> because he took so much off I had to flatten the dipstick tube to get it to fit in between. So I don't want to go down that road again.
>
> Rick mentioned the Remflex had good heat transfer, so I think I'll go that way.
>
> The broken bolt was a grade 8 with about 1/8" sticking out. I'm thinking that will be a hard drill-out. All the bolts are open at the back,
> except this one. I have a small electric MIG welder, but I haven't welded much in a long time. I'm likely to do more damage with spater flying all
> over!
>
> Without the center bolt, I worry that the weight of the front of the mufflers hanging from the manifold may put a twisting torque on it and cause
> the Remflex's to open at the top.
>
> I worry too much while others go ahead with blind abandonment and it all works out well for them! :roll:

Bruce,

Now where to start....
I agree that 0.015 is probably more than Dave's gaskets will like.

Remflex are metal clad flexible graphite and are not very good at heat transfer. (I used to make gaskets like this all the time at McCord.)
It will accommodate the non-flat much better than the copper.

Grade 8 should not be used in exhaust for lots of reasons that I will not go into right now. Do not worry about drilling it as it is not Gr.8 now.
If you want to try the weld a nut on, get a piece of aluminum flashing about 8" square and cut a 1" hole in it. Hang it on the valve gear cover with
tape so it stays out of the way. If spatter does get through the hole, a chisel should knock it right off.

If you haven't used this box in a while I suggest that you find something to practice on as you will be in a bad location and off-hand. Please have
someone else on hand with an extinguisher. (Just about every time I weld on an assemble vehicle, I set something I can't see on fire.) (Not DC... A
squirt bottle will do.)

When you weld, don't give it time to cool, have some ATF or PS fluid there in a pump oil can and cool it with that. (Be aware the any local First
Peoples may respond to this signal.) The reasoning (and proven) is that the hot joint will suck the lubricant in and the ATF is because it does not
like to burn or coke so it will stay liquid longer than most things.

The heating and cooling trick does work because on heating, the fastener expands and crushes the scale in the joint. Then the addition of any
lubricant sucked into the joint has a much better chance. Before I did the work on my own engine, I had four other 455 heads to get manifolds off.
Many broke, but I only had to play dentist with one in the final count.

Best of luck.

Are you hoping to make Mansfield??

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Thomas Phipps via Gmclist]

The top center bolt just holds the manifold in place so you can attach the other four bolts. Do not torque this bolt down, as it can pull the top
surface in and resulting in the bottom not sealing tight against the block. I did use and would use the Remflex. Follow their instructions carefully.
If there is enough of the top bolt protruding, I would consider leaving it alone and just hang from it.
Tom
--
2012 Phoenix Cruiser model 2552
KA4CSG

[Bruce Hislop via Gmclist]

I'm just going to leave the broken top bolt alone. There is enough of it left to use for gasket alignment.

I had a set of Remflex on before the engine rebuild... about 3k miles I'm guessing and they worked well. Just hope the higher manifold temps don't do
in my cast iron manifolds.

Thanks for the help guys.

Matt, What should I be using for manifold bolts? These were installed by the fleet garage that R&R my engine back about 10 years ago.

[Matt Colie via Gmclist]

RF_Burns wrote on Sat, 21 September 2019 16:33
> <snip>

>
> Thanks for the help guys.
>
> Matt, What should I be using for manifold bolts? These were installed by the fleet garage that R&R my engine back about 10 years ago.

Bruce,

Grade 2 is just fine. As I recall, Remflex calls for a final torque of 7.5#ft.
That is just fine with grade 2. Try to find them unplated.

And Again, if you do not finish the job covered in anti-seize, you didn't use enough.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[tonka6cuda6--- via Gmclist]

Matt Colie wrote on Sat, 21 September 2019 16:53

> RF_Burns wrote on Sat, 21 September 2019 16:33
> > <snip>
> >
> > Thanks for the help guys.
> >
> > Matt, What should I be using for manifold bolts? These were installed by the fleet garage that R&R my engine back about 10 years ago.
>
> Bruce,
>
> Grade 2 is just fine. As I recall, Remflex calls for a final torque of 7.5#ft.
> That is just fine with grade 2. Try to find them unplated.
>
> And Again, if you do not finish the job covered in anti-seize, you didn't use enough.
>
> Matt

The Remflex 11-001 i have for my 403 say 20ftlbs on the sticker.

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

[Rob via Gmclist]

My recent Remflex gaskets stated: "Suggested Torque 20 LB FT".

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

[Matt Colie via Gmclist]

Rob wrote on Sat, 21 September 2019 16:57

> My recent Remflex gaskets stated: "Suggested Torque 20 LB FT".
>
> Rob
> Victoria, BC
> 76 Royale - Rear Twins/Dry Bath

Good on both of you, I don't know where I remembered the 7-1/5 from, but it is way below Dave's 25 and many retorques.

[Bruce Hislop via Gmclist]

The sticker on my Remflex package says 14-18ft-lbs, but I've had them for a few years.

Matt, is there any issue with using the grade 8 bolts? I have them re-installed, but only finger tight. I have some plated 3/8" bolts.. with the 3
bars on top so they are grade 5 I believe.. TSC stores up here have switched to black phosphate bolts in their bins.

We are registered for Mansfield. I have a Chemo treatment on Tuesday so hopefully I'll be bright-eyed and bushy-tailed in about a week after that.

[Ken Henderson via Gmclist]

Bruce,

The last set of Remflex I used (for the Cad 500, not an Olds) had original
14-18 ft-lb with sticker saying 20 ft-lb. I think they had a change of
heart.

Ken H.

[John Shotwell via Gmclist]

Bruce,
IIRC, Remflex makes two different gaskets for the 455 - one for manifolds, and one for headers. I didn't know that when I put ours on about 10 years
ago. I think we have the ones for headers, but we have manifolds. So I don't think it matters much...
--
John Shotwell
Ridgeville Corners, OH
78 Royale Center Kitchen

[Bruce Hislop via Gmclist]

Ken, That's good to hear because my 3/8" torque wrench is rated for specs between 20 and 150ft-lbs... so I'm good with that.

John, would the one for headers have the center piece for the dual port center position? Mine is open there.

[Jim Kanomata via Gmclist]

https://www.gmcrvparts.com/product-p/gm12-030.2.htm

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Jim Kanomata via Gmclist]

Both Remflex gaskets states 20 ft. lbs.

[Matt Colie via Gmclist]

RF_Burns wrote on Sat, 21 September 2019 19:22

> The sticker on my Remflex package says 14-18ft-lbs, but I've had them for a few years.
>
> Matt, is there any issue with using the grade 8 bolts? I have them re-installed, but only finger tight. I have some plated 3/8" bolts.. with the
> 3 bars on top so they are grade 5 I believe.. TSC stores up here have switched to black phosphate bolts in their bins.
>
> We are registered for Mansfield. I have a Chemo treatment on Tuesday so hopefully I'll be bright-eyed and bushy-tailed in about a week after
> that.

Bruce,

Yes, there is a problem with Gr8 bolts in exhaust applications and there are actually two issues. Well three if you try to use them at Gr8 loads.
That last one is that as they are heat treated, they will actually unload (creep) at near normalization temperatures (~900°F). This is a time and
temperature problem that may take a while to show up.
The next problem is that the alloy of Gr8 fasteners is much more likely to cause transfer (aka gall) in a hot application. This is something you
really don't need.
A third issue is related to the first, but can get you even if they are not tensioned to Gr8 stress. As they are heat treated and with heat, they
will loose that temper, the frequently develop cracks at the thread root and so are prone to failure when any attempt to remove them is made.

I hope the Chemo does you well.

Hope to see you both at Mansfield.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

_______________________________________________

[Bruce Hislop via Gmclist]

Manifold Update,

I installed the driver's side exhaust manifold today. Some choice words were used as I eventually managed to get my torque wrench around the
obstacles.

The coach is much quieter, so now I can hear I likely have leaks on the passenger side too!

I have EFI and since the O2 sensor is on the driver's side, I suspect air was leaking into the exhaust as well. I hooked my computer up before
starting the engine. As soon as the closed loop mode was entered, the EBL was pulling fuel from the mixture and the engine was running much smoother.
I took it for a VE learn and every cell hit was removing -3 to -6.

Thanks everyone for their input!

[tonka6cuda6--- via Gmclist]

Now that your "experienced" your can do mine....lol. :d Just kidding of course and good to hear it worked well.

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

[Ken Henderson via Gmclist]

Bruce,

Congratulations on getting the job done. I can feel for you having
recently had to do the same job on my Cad500, which is even tighter in the
hole. On top of that, as sort of a warning to others, I had another
problem: During the previous installation I replaced the manifold bolts
with studs and double brass nuts. That wasn't such a bad idea because the
brass nuts came off easily. But the fact that I left some of the studs too
long was BAD. It meant I couldn't get the manifold off without removing
the studs. Despite liberal nickle anti-seize, most of them wouldn't budge
with reasonable torque. My final solution was to leave the manifold
hanging from the studs and modify the Remflex. It was easy to clean the
old Remflex residue from between the head and manifold. Then I extended
the Remflex's bolt holes downward so I could drop it into the head-manifold
gap. Cutting the gasket was something of a surprise because that was the
first time I realized they contained the metal screen reinforcement. Good
aviation snips made the task simple. The installation trick worked
amazingly well and I've had no sign of adverse effects -- yet.

Ken H.

[Matt Colie via Gmclist]

Ken Henderson wrote on Sun, 22 September 2019 21:57

> Bruce,
>
> Congratulations on getting the job done. I can feel for you having recently had to do the same job on my Cad500, which is even tighter in the
> hole. On top of that, as sort of a warning to others, I had another problem: During the previous installation I replaced the manifold bolts with
> studs and double brass nuts. That wasn't such a bad idea because the brass nuts came off easily. But the fact that I left some of the studs too
> long was BAD. It meant I couldn't get the manifold off without removing the studs. Despite liberal nickle anti-seize, most of them wouldn't budge
> with reasonable torque. My final solution was to leave the manifold hanging from the studs and modify the Remflex. It was easy to clean the old
> Remflex residue from between the head and manifold. Then I extended the Remflex's bolt holes downward so I could drop it into the head-manifold
> gap. Cutting the gasket was something of a surprise because that was the first time I realized they contained the metal screen reinforcement. Good
> aviation snips made the task simple. The installation trick worked amazingly well and I've had no sign of adverse effects -- yet.
>
> Ken H.

Ken,

I appreciate this information. The only time I saw a Remflex, I thought it was a metal clad graphite part. Now I know that at the very least some
are perforated core with flexible graphite surface.

If you think of it and it is REAL convenient and you are coming to Mansfield, could you save and bring along the little pieces you cut out?

Thanks again for being a valuable source of information.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Ken Henderson via Gmclist]

Matt,

I've already disposed of the material from the Remflex. However, Remflexes
are among the very few spares I carry, so if you'll remind me at Mansfield,
I'll drag them out for you to examine. I, too, was surprised to find the
"screen wire" inside those gaskets. I'm not at all sure that the earlier
ones had that reinforcement; IIRC, they were considerably more fragile than
the current ones.

Ken H.

[Todd Snyder via Gmclist]

Without resurfacing the manifold?

Let us know how that works out. 0.015" out of flat is a lot to ask any gasket to seal.

Also, since the heat transfer to the head is what keeps the manifold from heating up too much and warping, that extra layer of insulation is going to
make it heat up, warp and crack even faster.

Keep us posted either way!



RF_Burns wrote on Sun, 22 September 2019 20:29

> Manifold Update,
>
> I installed the driver's side exhaust manifold today. Some choice words were used as I eventually managed to get my torque wrench around the
> obstacles.
>
> The coach is much quieter, so now I can hear I likely have leaks on the passenger side too!
>
> I have EFI and since the O2 sensor is on the driver's side, I suspect air was leaking into the exhaust as well. I hooked my computer up before
> starting the engine. As soon as the closed loop mode was entered, the EBL was pulling fuel from the mixture and the engine was running much
> smoother. I took it for a VE learn and every cell hit was removing -3 to -6.
>
> Thanks everyone for their input!


--

Todd Snyder, Buffalo NY
1976 Eleganza II

[Bruce Hislop via Gmclist]

Actually I was using a straight edge and the high spot was near the center. I can't justify the $$$ for the actual equipment to measure this so I was
eyeballing it against my digital calipers. Since I was looking at the end of the straight edge, the actual high point would be closer to 1/2 that
amount so maybe 0.008 - 0.010".

I had the manifolds and heads planed flat when the engine was rebuilt, then used DaveL's copper gaskets. The manifold cracked anyway with about 25K
miles. Actually its been this way for a few years now.

Just trying to put off the inevitable cost of header's.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

[Matt Colie via Gmclist]

RF_Burns wrote on Mon, 23 September 2019 11:54

> Actually I was using a straight edge and the high spot was near the center. I can't justify the $$$ for the actual equipment to measure this so I
> was eyeballing it against my digital calipers. Since I was looking at the end of the straight edge, the actual high point would be closer to 1/2
> that amount so maybe 0.008 - 0.010".
>
> I had the manifolds and heads planed flat when the engine was rebuilt, then used DaveL's copper gaskets. The manifold cracked anyway with about
> 25K miles. Actually its been this way for a few years now.
>
> Just trying to put off the inevitable cost of header's.

The actual thermal conductivity of flexible graphite is pretty good, not like copper but way better the any of the other post-asbestos things that
have been sold.

The easy way for a typical person to measure flatness or straightness is with a set of thickness (feeler) gauges and a table saw. Most decent table
saws have a cast and ground table that came out of the box very flat.

Bruce, if you got that manifold back with the center high, that guy really screwed it up. I have never seen an exhaust manifold curl that way.

Matt - Break is over, back on the creeper.

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Bruce Hislop via Gmclist]

Matt,
To clarify, I did not get this one planed, although it looks like it has been gone over because the facings were shinny and same with the 2 casting
blocks. It had some pitting of the face as well, but just surface and maybe a couple thou deep.

It was in pretty good shape otherwise.

Thanks,

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

[Rob via Gmclist]

I just talked with Remflex. They suggested my still leaking Remflex gaskets might benefit from a little more torque than the specified 20 LB FT - perhaps 25 LB FT? I'll have to try that next spring...

I also asked about the earlier, lower torque specs. They mentioned the earlier gasket formulation was a fibreglass (?) core and the later gaskets had a steel core and could handle more pressure.

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

[Ken Henderson via Gmclist]

AhHa! I thought there was something different about the later Remflexes --
less fragile.

Thanks for posting that.

Ken H.

On Mon, Sep 23, 2019 at 5:10 PM Rob via Gmclist <gmc...@list.gmcnet.org>
wrote:

[Todd Snyder via Gmclist]

The parts diagram and maintenance manual don't show any gasket. GM didn't want one there apparently.

I would think that the heat transfer between one clean, flat, piece of iron clamped to another piece of clean flat iron is much better than anything
with 0.015" gap

<<The actual thermal conductivity of flexible graphite is pretty good, not like copper but way better the any of the other post-asbestos things that
have been sold.>>

--
Todd Snyder, Buffalo NY
1976 Eleganza II

[tonka6cuda6--- via Gmclist]

tmsnyder wrote on Mon, 23 September 2019 17:55

> The parts diagram and maintenance manual don't show any gasket. GM didn't want one there apparently.
>
> I would think that the heat transfer between one clean, flat, piece of iron clamped to another piece of clean flat iron is much better than
> anything with 0.015" gap
>
>
>
> <<The actual thermal conductivity of flexible graphite is pretty good, not like copper but way better the any of the other post-asbestos things
> that have been sold.>>

Very true but things have changed since the 70's from fuel perspective etc.....todays fuel has different additive etc so my opinion, not founded in
fact just visual, is the modern fuels burn hotter. (Cleaner combustion chambers = better fuel economy)

GM or Olds never wanted these things to run 40 years plus...they only had to make it till the end of waranty.

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

[Matt Colie via Gmclist]

6cuda6 wrote on Mon, 23 September 2019 21:53

> Very true but things have changed since the 70's from fuel perspective etc.....todays fuel has different additive etc so my opinion, not founded
> in fact just visual, is the modern fuels burn hotter. (Cleaner combustion chambers = better fuel economy)
>
> GM or Olds never wanted these things to run 40 years plus...they only had to make it till the end of waranty.

Rich,

Two things here:
Modern fuels really do not burn any "cleaner" than that of 40+ years ago. But even this is a little tough and this is comparing what was good fuel
then to most fuel now. The big thing is the removal of tetra-ethyl lead. Available octanes really have not changed much, but the marketing has. The
fact that combustion is cleaner is really a result of changing engines for emissions.

Maybe GM didn't want engines to last 40 years, but the Olds family sure did. This is why you never saw BB Chevs in industrial and pump service, but
Olds? They were a benchmark and only recently supplanted by diesels. If you talked to any of the first tier suppliers of the past, they will tell
you that Olds wanted the good stuff. The very best seals and bearings and if it didn't pass their validation, you would hear about it....

Matt - The refugee from Dyno-Land

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit