head gasket

[ryan77]

Im having im heads done what head gaskets should i use the stock ones look like there copper. autozone has felpro # 8723 pt-1 but ive seen people on here say to use felpro9441pt what should i use. The car is a 84 im going to run 42.5 injectors a chip and a little more boost nothing crazy though.

 

[2buicks]

Cometic is a good choice - C5691-040...Multi-Layered Steel.

 

[Jerryl]

I am going to suggest the stock 87 replacement Victor Reinz gaskets, if everything is set-up for them, i.e; You will need to verify all the lifter preloads and intake alignment.
Not need for the super duper failsafe HG’s for what you are trying to do

The question always comes down to; You want to replace a HG or the crank? Just my $0.02

 

[dr_frankenstein]

does anybody know of a good replacement though for the steel shim?

I dont like the loss of compression asociated with the thicker 86, 87 unit.

and the cometics, dont crush enough...

Any ideas gentel men?

A.j.

 

[stickybones]

I just ordered a set of stock steel shim head gaskets (~0.018" thick) from Nick Micale at ArizonaGN. This was just last week. In fact, I haven't even received them yet.

 

[FlaBoy]

I ended up doing the same thing. Even though GM hasn't made these in years, there are a few guys with stashes of NOS stock steel shim headgaskets. I ended up paying a little more than for the Fel-pro gaskets, but I'd rather have one that would last as long as I needed it to, and wouldn;t sacrifice compression due to being thicker (not to mention potentially messing up valvetrain geometry/preload). I just replaced the HGs on my car and spent a week or so looking at all the different options out there (2 different fel-pro versions, cometics, RJC steel shims, etc. etc.) and decided that the stock ones were what i wanted (just my opinion though).

 

[Jerryl]

I ended up doing the same thing. Even though GM hasn't made these in years, there are a few guys with stashes of NOS stock steel shim headgaskets.......

I had no idea these were still available, anywhere.
What did those cost for the set?

 

[FlaBoy]

I'll have to check my records but I think it was about 100 for the set... not cheap I know, but i seem to remember a set of the fel=pros would be about 70-80 or so, and I was willing to pay a bit extra to know I was getting a good set of gaskets that didn;t cause any issues I mentioned. I don't even know if going to a thicker gasket would change valvetrain geometry enough to be a concern, but i know using the stock ones certainly woudn't

 

[boostmaster]

Head Gaskets

I'll have to check my records but I think it was about 100 for the set... not cheap I know, but i seem to remember a set of the fel=pros would be about 70-80

Highway robbery for a set of gaskets that at best cost 16-20.00 a pair. IMHO for the price you'd be better off cost and performance wise with a set of Felpro 1000's. They stand up just as good as the stock steel shim and are only slightly thicker than stock so no geometry issues.

 

[BRAD_PADGETT]

Highway robbery for a set of gaskets that at best cost 16-20.00 a pair. IMHO for the price you'd be better off cost and performance wise with a set of Felpro 1000's. They stand up just as good as the stock steel shim and are only slightly thicker than stock so no geometry issues.

I agree with the Felpro 1000. Cost $42 pair at Summit. I have used my set for three and one half years all with knock issues and they hold up. Good Luck-Brad

 

[FlaBoy]

Highway robbery for a set of gaskets that at best cost 16-20.00 a pair.

While they may have been that cheap while in production, since there haven't been any made in years, and pretty much every GM dealer or GM parts dealer has been sold out for almost as long, it doesn't surprise me that the price has gone up so much. Would it be nice to get a set for 20 bucks? sure. After a week of trying, did I find anyone selling them that cheap? not nearly. As far as are they worth it, they were to me. I know they stand up to abuse (the IC guys used to use them doubled up before some of the pricier cometic and RJC gaskets came out) and they are the exact same thickness as what I pulled out, maintaining stock compression.

I agree with the Felpro 1000. Cost $42 pair at Summit

According to Summit's site, they are $42 EACH (says 'each' in part description, and under quantity says 'sold individually'). With shipping to me, that comes to $52 apiece. With shipping, the stock ones I got were $56.50 apiece. Spending 9 bucks more for a set of head gaskets that i know will work fine and are stock dimensions seemed like an okay deal to me.

I'm not saying theres anything wrong with the Fel-pro 1000's, and if Ryan77 decides to go with them, I'm sure he'll be fine, since many on here seem to be running them and are happy. To my way of thinking, and as dr. frankenstein said, I liked the idea of not having to lose compression due to a gasket thats about 0.020 thicker installed (not much of a difference, but every little bit helps) and not having to worry about valvetrain geometry (probably wouldn't have been an issue, and could be ameliorated by having 0.020 taken of the head deck when i got the valves/seals done, but this way it wasn't an issue). And if it cost me essentially the same as a set of the fel-pros, then it seemed a good choice to me.

In addition, when I called nick micale to place the order, i got some first-hand knowledge (from a man who knows his stuff) on installing the gaskets and a few tricks to make the job a little easier, quicker, and more likely to seal, which was nice.

Like i said, i'm sure theres nothing wrong with the fel-pros, but since the stock ones cost about the same, they seemed the better option to me. just my $0.02

 

[Nick Micale]

Highway robbery for a set of gaskets that at best cost 16-20.00 a pair. IMHO for the price you'd be better off cost and performance wise with a set of Felpro 1000's. They stand up just as good as the stock steel shim and are only slightly thicker than stock so no geometry issues.

Next time you think about saying something as stupid as above, check your facts.

The original GM steel shim gaskets for '84-85 NEVER sold for $16 each. Maybe a gasket for a non-turbo V-6?

Yes, I purchased a bunch of GM gaskets years ago when I was doing a head gasket job a week, and they cost MUCH more than you quoted.

A Felpro is twice as thick as the GM, and will have noticeable affect performance in an '84-5 GN engine.

I am sure you have some good info that you can post, so maybe next time we can see something of value.

 

[2buicks]

Not disputing any of the facts here...

Differences between the Cometic/Fel-Pro/Other .040" gaskets and .018" GM Steel Shim equate to a difference of about 4cc, or a reduction in compression ratio (if using .040") of about .3. (ie. 8.5:1 to 8.2:1)

Now, if all is stock (no machining-stock turbo-etc), yes you will probably see a minor reduction in low end (little/no boost) torque, but parallel deck block, surface heads, modified turbo, etc., etc....you get the picture.

..or just add about 1/2 lb of boost...

Just my 2 cents worth...:biggrin:

 

[gs462]

So whats the best gasket to use? and if the cometics are there any tricks to making sure they dont leak, ive heard coat each layer, remove the rivets etc.
Nick what do you suggest?

 

[Grumpy]

we have coated the Cometics, used them out of the box, and reused them on different cars over the past year.. Ya I had 3 or 4 jobs (way to much work for me !!) Also used the GM pellets with them.. We never had a leak:wink: I know I know they suck..they leak ..maybe time to just sell the car and move on

 

[Nick Micale]

So whats the best gasket to use? and if the cometics are there any tricks to making sure they dont leak, ive heard coat each layer, remove the rivets etc.
Nick what do you suggest?

Cometics will do fine too, if they are thicker than 0.018", you will lose some compression on the '84-5 block unless your block or heads are machined to compensate.

As far as performance, my experience is that no Buick factory block has ever been at advertised compression, usually 2-3 tenths of a point less. You cannot make up initial crisp response with 1/2 psi of boost. Will not happen from a launch. This is one reason we increase compression ratio on our race engines, and also a little for street builds too.

With the Cometics and steel shims, we use 2 coats of Permatex Copper Coat spray on both sides for installation.

 

[Nick Micale]

Not disputing any of the facts here...

Differences between the Cometic/Fel-Pro/Other .040" gaskets and .018" GM Steel Shim equate to a difference of about 4cc, or a reduction in compression ratio (if using .040") of about .3. (ie. 8.5:1 to 8.2:1)

Not to beat this into the ground, but the turbo Buick V-6 is advertised at 8:1, so with factory tolerances on the low side, and double the head gasket thickness, you could easily end up with a 7.5:1 ratio.

I have only done about 20 hot air cars over the years. When we increase the static CR over stock, the result is a MUCH better in response and in overall performance. So, I feel it is critical NOT to lose compression, especially in a hot air Buick.

Brent is not in this thread, but his low-11 sec. hot air build always puts a big grin on his face when driving at the track or on the street.

 

[ryan77]

Here we go again

Now who sells the stock shim type and how much are they? I might use the felpros and have .030 taken off the heads what do you guys think?

 

[etriebe]

I have bought RJC's bullet proof kit with .033 thick shims. Is that ok for A hot air car or overkill.

 

[stickybones]

I have bought RJC's bullet proof kit with .033 thick shims. Is that ok for A hot air car or overkill.

Wouldn't it be considered "underkill". Why not just buy the correct thickness gasket for your hot air car? Why would you want to lower your compression ratio with the thicker gasket that Jason sells? As I posted above, you can still get the thinner ones from Nick Micale at ArizonaGN.