g40 head gasket

jesseg40 · May 30, 2009, 03:15:57 PM

just wonderin if you can get an uprated head gasket anywhere, or is a gud standard 1 ok? cuz i think i popped mine 2 day, hopin its not the head its self

jez1272gt · May 30, 2009, 10:12:55 PM

Alot of people just use the standard G40 gasket from VW which is perfectly fine unless you run big boost. Those running higher boost often run a metal version from a mk4 polo 8v. The VW part number for the standard one b 030 103 383 r, is metal one is b 030 103 383 ah. Do note that the metal one is thinner so therefore will raise your compression ratio.

jesseg40 · May 30, 2009, 10:27:20 PM

thanx for reply, im not realy runin high boost about 14psi! most people use vw gaskets then?

jez1272gt · May 31, 2009, 11:58:51 AM

Dont think everyone gets them from VW, some use ECP or GSF.

hayesey · May 31, 2009, 04:02:22 PM

people use the metal gasket from a mk4 polo to slightly increase the compression ratio, it's not to do with strength. The normal headgasket is fine.

jez1272gt · June 02, 2009, 05:36:47 PM

The metal mk4 gasket would be better under higher boost levels though as it will be definately stronger, thats the main reason that you get metal and bi-metalic head gaskets! In the case of the G40 it might be that the standard gasket is strong enough to run even the higher boost levels but you would not get the same peace of mind from it!

Surely the main reason for using the metal mk4 gasket is not to raise the CR, especially on the higher powered Accralite 1341 bottom end as it is high enough anyway?

Robin · June 02, 2009, 09:43:51 PM

i did run a metal HG on mine but i am now in the middle of fitting a standard G40 one as i was getting too much det due to the higher compression ratio.

hayesey · June 03, 2009, 09:26:20 AM

but you have the higher CR Accralite pistons too don't you robin?

Robin · June 03, 2009, 01:07:44 PM

i do

jez1272gt · June 03, 2009, 05:21:55 PM

Yeah det will become a problem...!

A standard gasket is 1.5mm thick.
A mk4 metalversion is 0.4mm thick.

= 1.1mm difrerence.

If using the 1341cc 77mm Accralites the compression ratio will raise from 9.0:1 up to very nearly 10.0:1 by my calculations!

If you take into account the fact that the head has probably been skimmed at some point in its life then the CR could well be over 10.0:1. Not ideal to say the least.

Nick_S · June 03, 2009, 05:28:46 PM

Are the standard head gaskets ok to cater for the 77mm bore?
I thought they could only cover up to 76mm. The mk4 gasket can definatley accomodate a 2mm overbore to 77mm with it having bores of 77.5mm

My CR is 9.5:1 on the 1473cc with accralites. Same CR as a stock ABD lump.

hayesey · June 03, 2009, 05:39:37 PM

QuoteMy CR is 9.5:1

really?! fooking hell that's a bit high!

Nick_S · June 03, 2009, 05:47:32 PM

Yep, fortunately i don't need to run high boost though. Goes like stink even before boost zone is acheived.
Don't stock R5GTT run about 9:1 CR, albeit notorious for being unreliable and popping gaskets.

I'll look at running an ABU composite gasket if i want more boost, but it remains to be seen how well one of those will last.

Robin · June 03, 2009, 06:15:10 PM

The standard gasket is fine for the 1341cc.

The CR for the 1341 pistons on a standard gasket is 9:1, with the metal gasket it is 9.3:1 from what i have found out from various people.

Nick_S · June 03, 2009, 06:35:58 PM

I'm sure Beavis had the 1341 builds at 8.5:1 with a standard gasket.