Where To Get Uprated Headgasket?

[ChrisB]

Fair points about coolant flow. But just to note that overheating (of coolant) won't be a sign of poor coolant flow through the head. If there is poor flow and poor heat transfer from the engine the coolant won't get as hot. The engine block/head would get hotter though (usually oil temperature is a fair sign).

If through back to back testing showed normal oil temp to raise from the Z20 gasket then I'd be questioning it. If normal coolant temp was higher, I'd be thinking the engine is dumping more heat into the coolant (which is of course, better).

[RDS]

My oil temps havent been above 94C either....result

[James W]

Fair points about coolant flow. But just to note that overheating (of coolant) won't be a sign of poor coolant flow through the head.

Why not, with the restricted flow the water will be spending more time around the cylider bores absorbing more heat instead of making its way to the rad.

[CavyTurbo]

The rivets, are they what i have highlighted in yellow on the above picture?

[Cavlad]

Why not, with the restricted flow the water will be spending more time around the cylider bores absorbing more heat instead of making its way to the rad.

Compare the Z20LET gasket to a C20XE/LET gasket, you'll not find much difference. The small holes you'll notice are all towards the pump end. There is a reason for this. The idea is that the coolant fully circles the block and head and therefore resists the chance of any 'hot spots' starting in any one place. Most headgaskets are like this, it is done for a reason.
The Z20LET gasket is more than adequate for your application. I have a Cometic one from SBD(bought before learning about the 'Z' one) and its nigh on identical. Drilling out the rivets also allows you to select the gasket thickness. We used a couple of gaskets and made one up to 1.9mm(spookily similar to the one Regal sell. ) for Phils astra.

[RDS]

The rivets, are they what i have highlighted in yellow on the above picture?

Thats right. You drill each one out *except* the one in the top right hand corner.

[CavyTurbo]

ok nice one, thanks for the help RDS, much apreciated and also everyone else that has given me info aswell.

[novavalve]

do spesso do 1.9mm gaskets?

[Jamie_F]

i fitted a 1.9mm cometic gasket to mine, very well made, and they are supposed to be reusable too.

[novavalve]

Jamie isnt your engine n/a and throttle bodied, how come you fitted such a thick gasket, surely you would want to higher the compression rather than lower it

[PhilM]

1.9 ish here too - made up of 2 Z20LET gaskets - cost me £30

[OllyHewitt]

how come you high compression/ na peeps are going for thicker HGs?

[Jamie_F]

Jamie isnt your engine n/a and throttle bodied, how come you fitted such a thick gasket, surely you would want to higher the compression rather than lower it

i wanted to keep the compression around the 11.3:1 area, with the pistons i have, if had used a std thickness gasket it would of been nearer 11.9:1.

i also could of had the picton tops machined down to give a lower CR but i wnated to keep them as is incase i want to do any furter mods in the future, which knowing what im like, i prolly will

[chip]

Anyone know just *how* re-useable the cometic ones are.

Ive taken one off after torque down but before the engine was run (last stud wrecked the thread in the block and had to be helicoiled) and then re-used it with no problems at all, but someone else i know who has run for a couple of K miles now is planning on taking their head off and back on, will they be okay to re-use it or should they be looking to replace instead?


Chip

[Jamie_F]

Anyone know just *how* re-useable the cometic ones are.

Ive taken one off after torque down but before the engine was run (last stud wrecked the thread in the block and had to be helicoiled) and then re-used it with no problems at all, but someone else i know who has run for a couple of K miles now is planning on taking their head off and back on, will they be okay to re-use it or should they be looking to replace instead?


Chip

my mate with a LET has used his twice and its fine

[chip]

Cool, good news indeed, cause at 100+ quid a throw its a shame to have to bin it!

[stt]

how come you high compression/ na peeps are going for thicker HGs?

Click Here! to find out!

[observer]

Rob u back tracking and using the z20let gasket??

cometic steel gaskets

Im used the spesso gasket, no problems with it even when running 1.5bra 304 bhp!!

Cometic one is a lot better! and aint a hack like the z20let one..they holes differ a lot!!

[elgan]

just noticed the original post was a gasket for a 20xe

i have a 20xe ready for my nova, i need to roder gaskets up, would it be worth fitting a Z20LET one?

cheers

[PhilM]

just noticed the original post was a gasket for a 20xe

i have a 20xe ready for my nova, i need to roder gaskets up, would it be worth fitting a Z20LET one?

cheers

No real point on a standard engine

[elgan]

will be pretty std originally, but looking at either 45s or TB's later this year

is there a point at a max 200 bhp later on??

[RDS]

I must admit Yunis looking at the gaskets originally the hole sizes were quite different. But after doing a little background reading its not a bad thing to have the smaller holes. The Z20 Block is essentially "supposed" to be an improvement over the C20 Block, but all stud points are the same and 9/10 water ways which does suggest that the differences in hole sizes was made due to better understanding of the original LET block. I don't mind back tracking Yunis, especially when the Z20 gasket does clearly work under lots of load.

[chip]

I use thicker gaskets on N/A engines to lower the CR to allow more nitrous, it does play a negative part with regards to squish though obviously if you go too far though.

Chip

[CavyTurbo]

Right just got the Z20LET headgasket through the post, it already has 4 rivet holes in it with like gold rings around them, do u mean drill 3 of the gold rivet rings out?

[chip]

Yes get rid of 3 of them, you can see which ones by offering it up and seeing where they touch the mating face when you try and put it together.

(or look on the diagram above)

Chip