1mm Head-gasket on CA18DET - Bad Idea?

[ClasS13st]

Well I've blown a head gasket cause of a brief over-heat cause of a loose radiator hose.
I had a look at gasket sizes on ebay and the options for thickness was 1mm, 1,3mm (closest to 1,2mm - stock) and 1,9mm.

Without seeking out professional advice I decided lets go for slightly higher compression.
I thought it would give me less lag and running on lower boost would give me more reliability.

BUT now somebody said to me, despite having an electronic boost controller I'd still need a smaller turbo with the higher compression ratio.
Apparently the 0,2mm difference makes a big difference to compression.

The 1mm head-gasket was one of the top sellers so I thought why not?

Have I made a big mistake?
Has anybody else raised their compression?

I know I have Arias forgies and I think they lowered my compression slightly so maybe the gasket will compensate a bit?

I'm really worried. Any advice would be greatly appreciated!

[SonOfAnarchy ZA]

hey dude speak to PFB he built that motor so he will give you the best advice

[Grobblere]

The stock compression is at 8:5 to 1, if you run 95 octane it should not be a problem. Depending on your setup, I presume you bought a steel head gasket? The difference theoretically will not be that much, you might see a bump of 0.3 on the compression side at most...

We have run 10:1 compression motors with bigger turbo's (T3/4) with no problem, just keep in mind that you need to be gentle with the motor when cold and make sure you do not have any signs of ping. You can add octane booster or other wise ethanol to the petrol mix (pump fuel already contains 10% ethanol) but do keep this marginal to be safe.

[ClasS13st]

yea a steel one, cometic.
ok well thats relieving.
what kinda boost will be safe?
think i'll see a bit less lag? i'm not that sure how comp ratio affect spool up.

sonofanarchy - sent ash a message

[rat]

Arp studs as well.

No problem.

[ClasS13st]

oh yes. i was told you can't reuse arps cause they designed to stretch or something.
i'll order another set, thanks!

[Draco]

oh yes. i was told you can't reuse arps cause they designed to stretch or something.
i'll order another set, thanks!

Crap, you can reuse them plenty!!

The problem is that the ARP head studs don't allow enough thread to tighten on a gasket of only 1mm, I believe thats part of where my last problem came from.

[ClasS13st]

Damn.
Can I get shorter ones? Or maybe cut mine?

[Draco]

You need to go to a general engineer to cut more thread, it will cost you around R300 to cut the 10 studs.

[Pinkfluffybunnys]

I think the wrong question is being asked here, What needs to be asked is how hot did the motor get and what damage was done

The Engine was fitted with a Cometic HG and ARP bolts, If it blew through the Cometic HG, I suspect the head is no longer straight and the piston rings are shot (or will be shortly).

I will have the head checked for straightness and the valve stem seals replaced, Forged Pistons are not as forgiving as cast units on overheating they will tend to scuff the bores even with the extra bore clearance, destroying the skirt and the bore


As for the compression bump, the turbo fitted will be more than adequate and won’t need to be changed but depending on the damage a nice set of pistons might be on the cards and is the best solution

[ClasS13st]

Well it was fortunately a very short amount of time 2-5mins max. Very unfortunately it read all the way up to 150deg on the oil temp. i changed oil the next day
Cause i was in traffic and luckily down hill i just shut down the motor and free'd into the garage where i quickly filled up water and tightened the hose that came off.
Temp dropped quickly and all seemed fine.
The guy was worried that the head was warped but called me back saying it is only the gasket.
Somebody else had warned me that gasket and rings would go soon after an over-heat.
My guy claims the rings are fine. The head is off and the bottom end looks fine as far as he can tell. I don't know how thoroughly he's looked at it though.
He said I really just need the gasket.

Is it a big mission to replace piston rings? Should i do that just in case? Is it a mission just to check them?

I do have a spare set of stem seals that i got in the bucket of parts from you, thanks Ash! - Sorry you had to hear about this happening to your baby

Thanks for the help and advice 200SX Club.
Please tune me what you think and i'll advice the guy working on my car accordingly.