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desufnoC
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1,842 Posts
Discussion Starter #1
Ok, so I got my head back from the machine shop today and the guy said in order to make it 100% flat he had to take off 15 thousands. He said the head had never been resufaced prior, and it is ready to go.

This time around, I'm going HKS stopper, no more playing around.

Now, should I go with the 1.2 stopper, or the 2.0 stopper?

Thanks.
 

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Escaped from infinite lag
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1,103 Posts
I went with the HKS 1.2 beaded and its holding fine for me if he only took off 15 thou dont worry about it go with the thinner hg because more compression will help in the lowend for a larger spooling turbo
 

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desufnoC
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1,842 Posts
Discussion Starter #5
malloynx said:
is this the head i sent you???
Yes sir it is, and thanks for the killer deal.
Tony Mawad said:
One concern on gasket thickness is how much boost you plan on having & the new compression ratio. For what I plan on with my car, I want to increase the compression a little bit. There are 7M-GTE engines out there with higher compression that seem to be doing fine that were planned that way, not as a coincidence.
Thanks for the advice, I was aware of these things you mentioned. I was honestly shooting for the stock compression, and if anything lower compression.

So I guess my question is with taking .015" off a never before surfaced head, will the 1.2mm yield me stock compression? The 1.2 stopper is obviously cheaper than the 2.0, but if there is any reason to think with the 1.2 my compression will be higher than stock I'll bite the bullet and get the 2.0.

Thanks All.
 

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1,317 Posts
i just recently got my head and block done. i got 12 thousands off my head AND block so 24 thousands all together and the guy at the machine shop said to go with the 2.0 since that will make up for what was taken off.
hope that helps
 

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I don't want an MK4!
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1,727 Posts
No clue. The fatter HG will give lower compression and that is better if you want to run higher boost.

I know what I would do.

I doubt the small loss in compression would be that noticable.

My .02 only.

Good luck.
 

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desufnoC
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1,842 Posts
Discussion Starter #10
90Legend said:
No clue. The fatter HG will give lower compression and that is better if you want to run higher boost.

I know what I would do.

I doubt the small loss in compression would be that noticable.

My .02 only.

Good luck.
I hear you, If i cant get a definitive answer I'll just go with the 2.0 stopper. :dunno:

Just gives me an excuse to run more boost, detonation scares the crap outa me anyway.
 

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desufnoC
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1,842 Posts
Discussion Starter #11
Tony Mawad said:
If you really want a definitive answer you have to tell how much boost you plan on running, what type gas you plan on using. Those factors will give folks an idea on whether you should be worried. Suprra_Girl has a CR of 9.4:1 using pump gas & in one of HiPsiSupra's (Genna) builds (he had many), he had a "9.5:1 comp SP71, fully built w/ AEM" (he may have been on race gas though). Consider all the N/A models that get turbo'd that use the N/A's higher compression ratio.

If you really want to know for certain what compression you will have before & after you can use this calculator http://www.angelfire.com/fl/procrastination/motor.html
You will have to find out exactly what your piston's dome dish volume would be first though.

According to my machinist, the .020 I need taken off would not really change compression but would affect timing more.

Thanks to the link Travisimo provided, I can easily tell you that if your machinists took a total (both head & block) of .0315" off, a 2.0mm gasket would give you the same identical compression.
Hmm, well, I honestly don't plan on running race gas often @ all, so really, to be on the safe side, the lower the compression the better.

Since I had the block done over 10k miles ago, I dont remember what was taken off of it, but something must have been taken off, and if I know .015 was taken on THIS head, I guess Ill just play it safe and go with the 2.0.

A few extra bucks now to do it right, AND have peace of mind is worth it.

If this helps @ all, the 4 cyls that had good compression were all @ 155psi. This is with my current block and OLD head with a 2.0 Titan cometic.

155 is lower than the norm right?
 

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desufnoC
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1,842 Posts
Discussion Starter #12
Tony Mawad said:
That is something I am trying to figure out myself. The TSRM states 142 for a GTE, but some pistons have more carbon build up than others & may give more optimistic numbers. Do some of these people with higher numbers have carbon build up on their pistons? It is hard to compare compression #'s (I am thinking) to different cars when it can be unknown how much carbon build up there is in different motors. For me, I had A LOT of carbon build up on my pistons. I know it affected my numbers. I think one factor in which you can get carbon build up is from a turbo that once had bad oil sealing (my case most likely).

EDIT:
I just found out that I made 600 posts with this one but want to mention that I don't care one bit as it does not improve my car, or my skills necessarily, or anything at all really. Some do celebrate these occasions I have noticed. heheh
Oh, if thats the case, and I had fresh JE's put in with a full rebuild, and my numbers were as such with the 2.0 Titan MHG, then Im deff going 2.0 again.

Thanks Tony.
 

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***ified?
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1,087 Posts
I think you are oversimplifying this.

What is the head gasket bore and thickness? CC volume? Piston dish volume? Deck height? Some head gaskets have an 86mm bore - it DOES make a difference so you really need to know before you start buying shit.

Use an engine compression ratio calculator that takes into consideration all aspects of the engine. You might "estimate" a CR of 8.4:1 and end up with a 7.8:1 slug. Trust me.
 

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desufnoC
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1,842 Posts
Discussion Starter #14
p5150 said:
I think you are oversimplifying this.

What is the head gasket bore and thickness? CC volume? Piston dish volume? Deck height? Some head gaskets have an 86mm bore - it DOES make a difference so you really need to know before you start buying shit.

Use an engine compression ratio calculator that takes into consideration all aspects of the engine. You might "estimate" a CR of 8.4:1 and end up with a 7.8:1 slug. Trust me.
It's not that I want to over simplify this, It's just that a moron doesn’t know any better.

I just pulled out my receipt for the machine work done to the block (about a year ago) and it does NOT mention how much the block was resurfaced. All it shows is a charge for:

"resurface block"
"bore out 6 cyls"

That doesn’t really help me, and I doubt they are going to know if I call them.

All I know is:

I currently have a 2.0 Titan MS HG
Using same block
Using new head that was resurfaced .015"
Old head was also resurfaced, not sure how much though
I'm using .020+ JE pistons.

No sites list the bore of the headgasket they are trying to sell. I honestly don’t even know if they offer a 1.2 stopper, I thought I remembered seeing one, but now I cant find one on any of the major sites. I'm going to call Titan and see what they stock/know.

Either way, that’s the info I have, and unless you can point me in the right direction, that’s what I have to go on.

Thanks,

mMv
 

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1,087 Posts
all the HKS gaskets ive seen are offered with an 86mm bore, Greddy has some with an 83mm and 85mm bore. I dont know what cometic or any other gasket maker offers, but you should be able to find out before you buy it.

http://www.csgnetwork.com/compcalc.html

How much they took off the head is irrelivant - you need to measure the displacement of the combustion chambers on the head.

http://www.steigerperformance.com/docs/UniversalCylinderHeadCCKitInstructions.pdf#search='how%20to%20cc%20cylinder%20head%20head'
 
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