Vacuum Leak, Manifold footprint on graphite gasket

[NeverGiveUpYota]

Just layer the whole port holes w/ copper before mating the double gaskets?
I pulled everything again today and what I see is a clear impression on the remflex but the corners opppsite the bolt flanges on both outer intake ports are very smooth. At the bolt flanges the material pealed off when I pulled the manifolds away. So in my eyes I feel like it’s leaking at the smooth diagonal but maybe it’s opposite at the rough corners? (Middle section pulled away rough as well).
Left to right on the mani and gasket pixs.
Hand drawn pix self explanatory.

 

[Trapper50cal]

I would never use a remflex gasket ever again. The torque specs are so low that
the manifolds physically move around at the stated specs and tightening beyond
the specs just displaces the material out the gap like a play dough spaghetti factory.

Felpro and a properly flat manifold set...failing that, 2 Felpros.

My 2cents.

 

[OSS]

The bolt corners are going to clamp the gasket harder than the non bolt corners, so that probably explains why the gasket stuck to those manifold corners when it was removed. I don't remember if you tried the OEM gasket first before the Remflex. It has metal crush rings around each hole. If you've got a piece of glass you can place on the expanse of all the flanges/ports and it will reveal any unevenness.

 

[NeverGiveUpYota]

Yeah I had @OSS... More times than I want to admit.

 

[NeverGiveUpYota]

Spoke to a machinist (different from the one that had machined them way back) and sent him the photos and he had little to say of advice, other than to slap some copper on it and double gasket it and go. Guess I gotta move onto another. I've gotten conflicting stories on the flatness of glass esp if old... whether its as flat as we'd hope it would appear. I have a stretch of slate countertop but even that I am not 100% sure of. I might take a ride to the guy who did my valve job. I know he has a good flatedge and I respect his opinion.

 

[LAMBCRUSHER]

I burned thru 2 remflexes... fel pro seems to work fine on several engines. How much torque did you have them on? I feel like the reflex gives too much and then not enough, if that makes sense...the fel pro is almost oem, afaik, quality and fit-wise, IMO. Clean the mated manifold and inspect it with glass and glass and water. I did an es ton of work on my smogable 2f mani when I rebuilt the motor but it leaked like my head ( ...is like a sieve, by Cheech and Chong) after assembly, and I know it was flat before assemble... I got rash and hacked a spare intake to clear a set of 3fe exhausts in a fit of rebellion rather than continue to sink more money and time into it... years later and it dawns on me that the manifold was milled flat assembled, then jammed onto the head with the bolt holes barely if at all in a couple cases clearing the threads of the studs, then torqued to spec doing gawd knows what to the flatness...you need to have the manifold milled flat as an assembly, right? You need to assemble the rebuilt manifold with gaskets and heat shield in place loosely the faux to the head, the torque the es out of it all, in order to get all the holes to line up, right? So which do you do first, right? Or does this obscene gesture of rebuilding an archaic plumbing disaster actually necessitate the wasting of a manifold gasket, and cost 2 or more trips to the machinist?

I propose the correct fix for a manifold is:
1 remove, disassemble
2. Have a machinist tank, blast, crack check, and clean the exhaust body end horn bores
3. Assemble halves with gaskets and shield loosely, then mate to head WITHOUT the gasket on the head and torque halves
4. Have machinist mill for flatness and counter bore bolt hole faces
5. Mount to head with gasket and torque
6. Heat and cool a few bunch a times and pull it back off and have it milled for flateness and counterbore again and replace the gasket.
7. Retorque after a few heating cycles

My theory is it needs to twist back into shape after being reworked....

That or they just suck after 30 years... time to buy a tig and turbo...

Dumb question... you checked the head?

 

[NeverGiveUpYota]

Yes yes yes.
And seriously have done basically every friggen thing you wrote. It’s amazing really.

 

[LAMBCRUSHER]

Did you confirm those places were leaking before removing?

 

[White Stripe]

Sorry your having so much difficulty.

 

[NeverGiveUpYota]

I had a friend from the local group come by a few weeks back. We were able to get a pretty good image that it was leaking just about exactly on those two ports.
I picked up two gaskets, one oem and one felpro. I mated them yesterday w/ the copper and set them aside to dry then pulled everything off the truck again, for what seems like the twentieth time.
Was really hoping to not have to go the silicone route. In me it ticks me off but at this point like said above the amount of money I’ve blown going back and forth on this is pathetic.
I won’t say it.... this has gotta be the .... time at least till it’s my kids turn.

 

[BGarcia88FJ62]

Hate to hear your troubles. I had issues as well with my headers. Remflex seemed to have squashed my problems but I did torque everything down a few times well above their recommended values. Ultra copper may be the ticket. Double gaskets I've heard good and bad results.
Best of luck. May the Cruiser Gods be kind to you and acknowledge your efforts. The blood sacrifice of a live rooster may be in order.

 

[NeverGiveUpYota]

I did have an exciting moment yesterday as I had my son handing me tools to put in the bag... he knows his teens. He named off all correct as he gave me wrenches and sockets. Kid is not even 4.5, such smart little bugger.

 

[NeverGiveUpYota]

Hate to hear your troubles. I had issues as well with my headers. Remflex seemed to have squashed my problems but I did torque everything down a few times well above their recommended values. Ultra copper may be the ticket. Double gaskets I've heard good and bad results.
Best of luck. May the Cruiser Gods be kind to you and acknowledge your efforts. The blood sacrifice of a live rooster may be in order.

Well it’s a good thing I’ve gotta a little rooster to sacrifice!

 

[gregnash]

Watching this closely as I am having the same issue since I rebuilt the head and just have been living with the inherent high idle. Leak, using the carb spray method, is right at the locations you talk about, center mass intake ports. Was planning on doing the double gasket trick but may try the OEM with the copper first.

What I had heard/read some time ago was that when planing the manifold surface you are supposed to have everything together (end horns and everything) then align the bolt holes to each other and then tack weld the manifolds to one another. From there you then plane the surface as they technically SHOULD be aligned properly when you bolt everything up.

 

[Trapper50cal]

That's also what I remember hearing/reading about resurfacing...both
together, fixed in what will be the final mounting position.

 

[NeverGiveUpYota]

Yeah well it didn’t go exactly as it should have an I’ve been biting my own tail as a result.

 

[klinetime574]

I just want to share my experience. I did not machine my intake manifold. Got it from the junkyard, made sure it was flat. Paired it with my SOR two-piece header and slapped it on. Double gaskets don’t make much sense to me. Where else would you do that? I first used a kevlar (?) one from MAF. It was green in color. That one sucked. Didn’t last for a day. Swapped for a stock style. No leaks. It’s been too long but we may have used copper spray on the gasket. Just make sure the manifold flanges are close in thickness. Use one stock style gasket and factory torque specs. Check after a couple of heat cycles. Sounds like we got a case of MOTS (Mud Over Thinking Syndrome)

Happy Thanksgiving!

 

[gregnash]

I just want to share my experience. I did not machine my intake manifold. Got it from the junkyard, made sure it was flat. Paired it with my SOR two-piece header and slapped it on. Double gaskets don’t make much sense to me. Where else would you do that? I first used a kevlar (?) one from MAF. It was green in color. That one sucked. Didn’t last for a day. Swapped for a stock style. No leaks. It’s been too long but we may have used copper spray on the gasket. Just make sure the manifold flanges are close in thickness. Use one stock style gasket and factory torque specs. Check after a couple of heat cycles. Sounds like we got a case of MOTS (Mud Over Thinking Syndrome)

Happy Thanksgiving!

However, this was what I did after having it supposedly machined by a knowledgeable shop. Still leaks and i am sure is the primary cause of my high idle issue. Maybe the copper spray is the key to making things mate up properly. When I get around to redoing mine maybe I will try that as the first go round and then if that still leaks after a few heat/cool cycles then I will go with a double gasket.

 

[Spike Strip]

You have to use the Lacquer-based copper coat (if you're not). The paint on kind with a dauber, not the spray on stuff. The Lacquer-based carrier acts as an adhesive and actually bakes on, allowing the copper to stay in place and help distribute heat.

Use liberally on all surfaces, head, all gaskets surfaces, Int/Exh.

You can double up gaskets if necessary, but if surfaces are flat, not necessary.

If you've verified that both the head and manifold assy are within tolerances, then maybe the two-gasket thing will work for you.

Be careful removing the old gasket from the Aluminum surfaces as it will gouge easily. Best to use a plastic scraper or gasket remover spray.

 

[NeverGiveUpYota]

You have to use the Lacquer-based copper coat (if you're not). The paint on kind with a dauber, not the spray on stuff. The Lacquer-based carrier acts as an adhesive and actually bakes on, allowing the copper to stay in place and help distribute heat.

Use liberally on all surfaces, head, all gaskets surfaces, Int/Exh.

You can double up gaskets if necessary, but if surfaces are flat, not necessary.

If you've verified that both the head and manifold assy are within tolerances, then maybe the two-gasket thing will work for you.

Be careful removing the old gasket from the Aluminum surfaces as it will gouge easily. Best to use a plastic scraper or gasket remover spray.

I examined this can at a Napa Spike... it doesn’t say a specific temp or did it say 400* something or other?