Head Gasket Choices?

[jonnyb]

It's been a few years since I did a T3 build, and now I'm in the middle of two of them! For the hi-po build I was going to go with the stock thickness cometic headgasket, but I'm not sure what to use for the other motor which is a completely stock rebuild/overhaul. That motor is for my 93 IROC R/T which I'm trying to restore to OEM specs and was wondering if cometic is my only choice for this application, or are there still stock mopar and/or mopar peformance headgaskets available for the T3?

I looked around and couldn't find anyone selling any mopar headgaskets for the T3.

Thanks!

Jon

[ScottD]

Jon - I had this issue last year on my mostly stock 92 Spirit R/T. Even though I am only running 14lbs of boost, I ended up going with head studs and the cometic gasket. The reason I did this was after doing some research it seems the stock composite gasket likes to leak near a plug in the head. Over time the gasket deforms to the shape of the recessed plug. My R/T was leaking coolant and it was pooling on top of the trans. Sure enough, when I pulled the head, this failure spot that others talked about is exactly where my stock head gasket had failed. I've not had any issues since going cometic. I have some brand new stock T3 headbolts - if you are interested in them let me know, I will let them go less than what I paid for them. Hope this helps.

[jonnyb]

Thanks for the reply Scott. Why did you go with the head studs? Are they required/recommended with the cometic or did you just want something that was reusable?

[turbovanman²]

I modify an 8 valve MP head gasket and with studs, no problems. Takes about 15 mins to modify depending on your skill level and you need a set of cheap cut out punch's.

[ScottD]

Good question which jogged my memory. Both Pat C. and Jackson recommended that the clamping force with the head studs was more uniform than the head bolts, which you want with the cometic so that is why I went with the head studs. I really did not want to spend the $ on studs when I already had bought the bolts, but I did end up going with studs because I liked the idea of the cometic not developing that failure point where my prior composite gasket had failed.

Keep in mind the cometic is not going to be like a stock composite HG and pop (and possibly save you from bigger damage) when something goes not quite right. For me, since I was running lower boost, this wasn't an issue. But to clarify, I think if you are going to go cometic use the studs, if you are going stock composite you can use the stock head bolts.

[jonnyb]

I modify an 8 valve MP head gasket and with studs, no problems. Takes about 15 mins to modify depending on your skill level and you need a set of cheap cut out punch's.

MP006 Simon? What exactly do you have to modify?

[turbovanman²]

MP006 Simon? What exactly do you have to modify?

That one or the 005 which has since been superceded with other numbers which are still available but for who knows how long, :(

Some of the holes are bigger, in different spots so you need to add them or enlarge them, some of the end holes are also bigger. I'll see if I have one around and I'll post up pics.

[jonnyb]

Yeah - it would be nice to use one of the 2 "006" or the "005" that I already have in my spare parts bin as long it works. Nothing worse than having to redo a headgasket due to trying to save a few bucks!

[thedon809]

I wouldn't fear using regular head bolts with a cometic. Every Chrysler engine nowadays has mls head gaskets and torque to yield bolts. Studs would be better though.

[turbovanman²]

Yeah - it would be nice to use one of the 2 "006" or the "005" that I already have in my spare parts bin as long it works. Nothing worse than having to redo a headgasket due to trying to save a few bucks!

I've modded literally a dozen with the only failures caused by me, :banghead:

[wheming]

I wouldn't fear using regular head bolts with a cometic. Every Chrysler engine nowadays has mls head gaskets and torque to yield bolts. Studs would be better though.

To revive this thread, can you explain this a bit more?
Does using the bolts require more torque with the Cometic?
I've discussed with Jon a bit but I find myself in a pickle. I purchased Cometic gaskets for Slug and Mini and purchased bolts. Now I'm ready to go back together and the question was raised to me if I had studs.
Option 2 would be to find a copper shim gasket that I've used before along with an 006 gasket which I have some spare.

Does use of the Cometic really require a superfine mirror Polish finish?

[Turbo3Iroc]

I replied about the head bolts in your other thread. I don't think using a Cometic would make a difference. My machinist builds a lot of engines and exclusively uses Cometics. His machines don't get the surfaces as smooth as they require but it is smoother than a standard head surface. As far as a spacer, you would have to know how much they cut off the head and block. Did you get the STD Cometic or the oversize?

[wheming]

I believe it was like 0.084" or 0.086". It was one of the oversize options.
Both the block and the head *have not* been resurfaced. I was just looking to get the compression down to as close as where Gus had it with a single gasket.
I guess we'll see how everything goes.
Thanks Kelly.

[Turbo3Iroc]

If you didn't have either surface refinished, you may end up with some sealing issues. Some have used the copper spray for this but I have no experience with it personally.

[thedon809]

When talking with teachers at chrysler training school, they say not to use gasket spray on MLS headgaskets.

[wheming]

It may not matter much, if this gasket has to come back out right now. I'll probably just use one of the 006 gaskets I have along with the copper shim I ordered. But still have to wait for that to come in.

But thanks for the tip. Did they discuss a reason why not to use copper spray?

[thedon809]

Something about causing problems with the different expansion rates of cast iron block and aluminum head.

[ScottD]

I had the head resurfaced on my car but not the block. I used the copper spray on the cometic gasket. No issues to this point.

[86Shelby]

I had the head resurfaced on my car but not the block. I used the copper spray on the cometic gasket. No issues to this point.

Ditto. I even reused the cometic. Granted, the gasket has maybe 500 miles on it since June of last year.

[Pat]

While the block and the head can not be a disaster, I don't think the cometics are as sensitive to surface perfection as it's sometimes made out to be. I ran a many time used cometic on my GRM T-III motor in my Shadow. When I assembled that motor, I prepped the block deck and the head with sandpaper on a big --- sanding block. A bit of copper spray on both sides of the gasket, slammed it together and away it went. That motor held together for 2 years that way and was making 500ish at the wheels on nitrous (best ET 10.57, best mph of 137).

I do like the studs much more than bolts only because it does help to ensure a more even clamping force across the head. The TTY bolts only provide as much clamp force as the bolts allow due to stretch. If they don't stretch evenly, you don't get an even clamping force. With non yielding studs and the right lube, so long as you torque the nuts evenly, clamping force should be even across the head.