IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: Scoobum on July 23 2017, 07:51:12 AM
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RJC sells shims that raises the compression ratio 4 points. Any other shims that are available readily to do the same thing? Seems to be a cheap and easy way to quicker spooling and better driveability. Steve...your site says they won't blow out...but they lose their sealing capability. Is this under constant high boost pressures...or is this with KR thrown into the equation? I believe it was a quote from Jim Beeler about the sealing. My engines never see any KR...so more compression with just a pair of shims sounds like good bang for the buck.
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My son's T appears to be seeping a little altho the water level has not gone down. I say this because, at times, it seems to be putting pressure in the radiator on cold starts. It started this after 18 years of hard running. Did not do it yesterday so I am not sure. Runs perfectly under boost but it has pushed a little water out in spite of the radiator appearing to be full.
The consensus that I have heard is that the silicone glue that is used with them on our cars begins to lose its grip after a number of years. Mine are the single 0.018 shims from GM that are no longer available. I think the hot air cars used two of these on each side. I have one on each side.
In all these years, I have never blown a HG. Knock on wood. I suspect that it would catastrophic if I did.
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Funny you should mention the hot air cars. I was having a discussion with Joe last week who's my friend/engine builder about head gaskets. He uses the hot air gaskets...whic h are readily available up here. I'll likely go that route the next time around. Thanks for the input.
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Now that is really interesting. Does he use the magic GE silicone industrial sealer that everyone tries to keep a secret down here?
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No...they go on dry. Forgot to ask him what he uses for a torque spec with them using ARP studs.
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I am pretty sure the factory went on dry as well but they stacked two....
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I am pretty sure the factory went on dry as well but they stacked two....
Steve, he said nothing about stacking. I'll call him tonite...if he has time. He's up the wazoo with marine engines at the moment.
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The factory stacked them on hot air cars. I used a single
You probably remember that in the old days, the factory used a single shim on sbc and such. We used to use aluminum paint on them right before we installed them
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I've read about guys spraying gaskets with some sort of copper spray. I'll get the particulars off Joe and post back.
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In the old days, spraying aluminum paint on shims and installing while wet was the trick. Then some starting using spray on copper coat. I have done both. Main thing with shims is the block and heads must be flat.
When LC and others started using single shims on IC engines to bump the compression over 9, they used a commercial GE silicone and rolled it on. With the high combustion pressures of a turbo engine, it really helped eliminate seepage. Shims will sometimes lift under high boost a slight bit determined by torque and type of head fastener. then they will sit back down and work again. A person with good ears can often hear the change in sound when this happens.
This is the weakness of the shim...no elasticity in the seal as compared to compound gaskets.
You probably remember a few vendors claiming they had a magic, private sealer that they would not tell anyone what it was or how they got it....It was/is the GE stuff. I believe this is what RJR still uses with his shims.
Same deal as the guys that ground the number off commercial fuel pumps and claimed they modified them to put out more than factory pumps...Shimmi ng the bypass with a piece of copper wire made these pumps extra special.
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I think some guys used the shims with copper coat or hylomar and claimed it worked well. I asked Billy about Cometics and he said he like to use Hylomar. It can be hard to find at times but I found some spray cans on ebay.
The secret GE magic silicone that some claimed to have worked directly with GE to develop is claimed to be GE 1200. I am completely convinced GE worked with a Buick guy to develop a secret turbo buick shim hg sealant...Yep, I completely believe that. Giant market out there of guys using shims and I know GE jumped all over the opportunity to develop a secret sealer for that business!
I will be interested to know what Joe uses. Some how, I doubt it is a secret GE product. :icon_lol: :icon_lol: :icon_lol: :icon_lol: :rofl: :rofl: :rofl: :rofl: :rock: :rock: :rock: :rock: :rock: :cheers:
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There's a pic of the GE sealant and a writeup who worked with the GE engineers to develop it. Did you know CNN is fake news...
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LOLOLOLOLOLOL
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The secret GE magic silicone that some claimed to have worked directly with GE to develop is claimed to be GE 1200. I am completely convinced GE worked with a Buick guy to develop a secret turbo buick shim hg sealant...Yep, I completely believe that. Giant market out there of guys using shims and I know GE jumped all over the opportunity to develop a secret sealer for that business!
Now I feel bad for using plain ole inexpensive copper paint that's works perfectly.
....he says sarcastically.
What brand shim gaskets are readily available up in Canadia?
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Felpros are readily available...an d that's it. You guys are incredible lucky down there for parts and cheap quick shipping.
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Shipping goes up everytime gas goes up. For some reason it forgets to go back down between spikes.
Shipping to Canadia wasn't that bad in the old days. I recall frozen hosers talking about the high price of freight, but when I'd mail over the border it was only a dollar or two more.
Now it's a pain in the ass. I shipped over the border a few times in the last year and I had to itemize every single part, what it was worth and what each part weighed.
Then, when I got done the label was too big for the box and I'm pretty sure it said all of it had to be on the same face.
What's bad is I can mail a small flat rate box with 70lbs in it to Hawaii or Puerto Rico for 6 bucks. If it goes over the border it's now 20US and can only weigh 4 pounds.
What's the part number on the Fel-Pro's you're looking at? The only name brand shim gaskets I know of here are the Cometics at 100 clams a piece.
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Earl needs to develop a pop off valve in the head of each cylinder to release any pressure spike from detonation then close again when it goes away...save a lot of work.
right now, it seems the rjr shim is the only game for me. too bad, he does not offer a thinner one
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How thick is the RJC gasket? Cometics can go down as far as .027"
It just sucks that I'm committed to running them after decking my block and machining my intake before I developed my pistons.
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RJC's are .035 compressed
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I thought the Cometic was for a Stage block? With a larger bore.
No, I am wrong. It's a 3.860 bore and will fit both standard/Stage http://www.cometic.com/i-24769025-buick-192-231-252ci-v6-027-mls-cylinder-head-gasket-3-86-gasket-bore-stock-stage-i-ii-heads-each.html (http://www.cometic.com/i-24769025-buick-192-231-252ci-v6-027-mls-cylinder-head-gasket-3-86-gasket-bore-stock-stage-i-ii-heads-each.html)
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True or false? I read the Cometics require a mirror finish to seal properly.
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Only if you believe them. But, if you look at all the stuff that users use...maybe not...
Cometics are made to go on without any sealer. they have a coating on them that should seal on a smooth surface. To obtain such a surface, the heads and block need to be cut with a grinder not a mill which leaves tiny grooves in the surface. The link I provide above says viton
so users, spray them with copper coat, or such. Some go to the hassle of separating the pieces and spraying each piece so coolant cannot seep between the layers.
Billy told me to try spraying top and bottom with Hylomar.
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Cometics should be good when using aluminum heads which move around a little on cast iron blocks due to temperature growth differential
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Norbs ran Cometics on the S1 block and TA heads he had. I crawled underneath with the engine warmed up and could see oil seeping between the block and heads. I know the block was milled...and the heads were as he got them from Nick Micale. I somehow think I recall Norbs said he sprayed the Cometics with copper seal...but I may be mistaken on that one.
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They seem to be holding on my Mopar but I have heard lots of complaints on Buicks....
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TECHNICAL SUPPORT
CAN MLS HEAD GASKETS BE USED WITH MOTORS SETUP WITH O-RINGS OR RECEIVER GROOVES AROUND THE CYLINDER BORES?
No. MLS head gaskets require smooth, flat and true head and deck surfaces to seal. Most of the time with o-ring setups the wire and groove fall where our gasket’s combustion seal is located; therefore, the wire will hold the gasket and not allow proper compression while the receiver grooves allow combustion gases to escape.
WHAT SURFACE FINISH IS REQUIRED TO US AN MLS HEAD GASKET?
A surface finish of 50 RA (roughness average) or finer, is recommended for a proper gasket seal. Anything rougher may conflict with the gasket design.
WHAT HEAD BOLT/STUD TORQUE DO YOU RECOMMEND WHEN USING AN MLS GASKET?
When using MLS head gaskets always refer to the manufacturer of the fastener to determine accurate torque values. Appropriate torque is critical when installing new gaskets of any kind.
WHY DOES COMETIC RECOMMEND MLS GASKETS TO BE INSTALLED DRY?
Cometic Multi-Layer Steel (MLS) head gaskets go on dry because they are coated with a sealant. Each MLS head gasket is coated with a .001" thick Viton rubber that is bonded to the outer stainless steel layers. Adding an additional sealer can hinder the performance of an MLS head gasket.
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The steel shim head gaskets used in LS engines are very forgiving when it comes to surface finish and straightness.
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TECHNICAL SUPPORT
CAN MLS HEAD GASKETS BE USED WITH MOTORS SETUP WITH O-RINGS OR RECEIVER GROOVES AROUND THE CYLINDER BORES?
No. MLS head gaskets require smooth, flat and true head and deck surfaces to seal. Most of the time with o-ring setups the wire and groove fall where our gasket’s combustion seal is located; therefore, the wire will hold the gasket and not allow proper compression while the receiver grooves allow combustion gases to escape.
WHAT SURFACE FINISH IS REQUIRED TO US AN MLS HEAD GASKET?
A surface finish of 50 RA (roughness average) or finer, is recommended for a proper gasket seal. Anything rougher may conflict with the gasket design.
WHAT HEAD BOLT/STUD TORQUE DO YOU RECOMMEND WHEN USING AN MLS GASKET?
When using MLS head gaskets always refer to the manufacturer of the fastener to determine accurate torque values. Appropriate torque is critical when installing new gaskets of any kind.
WHY DOES COMETIC RECOMMEND MLS GASKETS TO BE INSTALLED DRY?
Cometic Multi-Layer Steel (MLS) head gaskets go on dry because they are coated with a sealant. Each MLS head gasket is coated with a .001" thick Viton rubber that is bonded to the outer stainless steel layers. Adding an additional sealer can hinder the performance of an MLS head gasket.
There ya' go.
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For what it's worth. I run a RJC gasket, I didn't have a problem til I screwed up and overboosted at Summit a couple years ago. it was good for the weekend, we went into the car show, came back to the track. Next day we got rained out and headed home. We raced a couple times at Maple Grove and it spit compression at #4. Pulled the heads, discovered seepage at #4. Head gasket was still good, the heads passed at the machine shop, the deck was good too. I think what happened is what Steve said earlier, the head lifted. Additionally, momentarily broke the 3M seal and it took a few runs to show up. If I just ran it on the street it probably would have been OK or at least took a lot longer to show up.
In my opinion, a MLS gasket is used for aluminum heads to a cast block OR a condition where the head "walks" excessively.
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I have seen several shims get lifted and heard the motor boat sound when it happened. Retorquing seems to get you back in business most times.
BTW, what size of socket does it take on headbolts? 5/8"? or is 11/16?
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I use Cometics on my build. The block and heads were decked by me using a 14" cutter head with a CBN carbide cutting disk. Head speed is fixed but I have control over cutting depth and feed speed.
I'm pretty practiced at getting a good finish when the machines not in a bad mood. No idea on the RA. Since I have a 4.1 I counter sink the hell out of the head bolt holes, and do the same to the heads as well. Then when I'm done there I hit the surfaces with a flat diamond honing stone with WD-40 as a lube.
With the Cometics I pop out the rivet and copper coat all 6 sides and my hand. On the hard parts I smear a 1 molecule thick layer or Yamabond around the water ports. Since I have a 4.1 I also drill a pair of steam holes on the exhaust side of the head surface.
What I just described as had a 100 percent success rate with sealing and no fluid leaks. It works so well that I can bust a hyper piston with less than one second of leaning out due to a faulty clogged fuel filter.
It also works with reusing head gaskets. My enigne right now has a pair of used Cometics since I didn't want to wait for some .027"s when I was swapping my 2nd set of busted hypers for my forged slugs.
I don't think the surface finish is the more important factor like a lot of people seem to believe. Flatness is the important thing. If the head bolt holes are pulled up on the block a few thou, that's a deal breaker. If the head has a .004" low area between cylinders or leading to a water port, that's a deal breaker.
MLSs are squishy like composites. If you pull the head down on a raised area of the block, the fire ring does not have the proper clamp pressure, period. Couple that with our 4 bolts per cylinder and it's a recipe for a bunch of ''Cometic gaskets suck'' threads.