Head Gasket Thicknesses - no waffle or guesses please!

I've struggled to find data on the compressed thicknesses of head gaskets for golfs.

So, I'm starting a thread, to collect data, and later it can be moved into the FAQs if it works out. So far, I've found the gasket to be much thicker than I expected.

Not the most exciting thread, but important if you're building an engine, and want to get the CR right.


So:

Elring gasket from a 9A head set (also fits other 2.0 16v). Composite type: 1.8mm compressed, measured at the fire ring. 1.6mm on the composite part. Been on the car for a year.

Measurement was with a vernier caliper.

Gasket set bought from GSF, Bolts were FEBI from VWSpares. 60NM + 2x 90 degrees.


More to follow.

 

New, uncompressed thicknesses.

Elring 9A/2E gasket - composite. 2.1mm at the fire ring.
Elring ABF/ADY gasket - multi layer steel - 2.2mm at the fire ring.

All measured with a vernier caliper.

 

for the steel gasket you should measure the thickness of the steel sheet away from the beads, add them all up and this will be the compressed thickness.

 

I was told 1.2mm (1.19379mm) for the ABF multi layer so I'd appreciate knowing (before I strip it )

I know Toyotec droped the comp on his ABF with two MLS's (quote "ABF motor had its compression dropped to 9.1:1 using 2 1.9mm metal gaskets")

I'm not doubting Toyotec, just looking for a definitive answer

Cheers

Simon

 

Just been having a sort-out and measured a Victor Reinz metal gasket: -

It's 4 element and measured with vernier (not mic'd): -

Top- 0.2mm
Middle - 1.1mm
Middle - 0.1mm
Bottom - 0.2mm

Measured as a whole (but NOT including the raised parts) 1.6mm

Bore is 84mm

Hope this is of use to someone

Cheers

Simon

 

Is that before or after it's been used?

 

Is it possible to safely remove the middle layer of the gasket and still maintain effective sealing?

 

Brand new

Don't know.... Looking at it, I would say "maybe" depending on if the 1.1mm middle part is "just" a spacer or if it's fulfilling some higher design purpose, it's pretty substantial.

You'd have to do a dry build with plasticine though, I'm pretty sure the piston would be damn close to the inlet side of the head, not to mention the inlet valves.

What were you looking to achieve?

Cheers

Simon

 

Higher compression without resorting to multiple skims and hc pistons. This is just a standard VAG part engine. How much would taking 1.1mm out of the gasket raise compression by?

 

1.1 x 84 = 6.0959cc's so circa a full point

Unfortunately as I said above, doing this without machining the pistons could quite possibly result in piston to head contact at the squish point (by the inlet valves), AND / OR the inlet valves.

The other issue (depending on what engine i.e. 9A, ABF etc) would be the possibility of contact between the edge of the piston and the rim of the head bowl (it's smaller than 82.5mm) and IMO most (all?) 16v pistons protrude to some extent.

I see were your coming from but I don't think you could do it without machining and if your machining then why mess with the gasket...

Cheers

Simon

 

I will check to see if, and by how much the piston protrudes above the deck, that will be the main determining factor I guess.

Being a kr block with standard pistons I suspect the chamber of an ABF head will be greater than 81mm so foulling should not be a problem there.

Regarding valve contact, a KR inlet cam does not open until 1 degree after TDC so unless the ramp opening the cam is particularly steep, the pockets in the pistons should be sufficient.

 

OK, so a KR, I suspect you are correct about the valves then.

According to Mahle the comp height of a KR piston is 33.4mm (it also has a 0.6mm dome and 3.34mm valve cut-outs).

Given a 220mm block, 86.4 crank, 144mm rods and the aforementioned 33.4mm compression height I would guess circa 0.6mm protrusion (plus another 0.6mm for the dome but I think the dome is under the exhaust valves and can be discounted).

If we assume the gasket is something in the region of 1.6mm compressed that gives circa 1mm squish, taking out the 1.1mm middle section would reduce squish to the point of piston to head contact.

Cheers

Simon

 

I am looking forward to measuring up, should be fun. If it looks tight, the first start could be a little nerve wracking!!

 

Don't run your squish too tight.

The tightest squish is found in two-stroke's, down to as little as 0.5mm BUT this is only at the very edge of the chamber, by 1/2'' in it's up to 0.8 - 0.9mm. Most four-stroke road car squish is in the region of 0.9 - 1.2mm with forced induction using the larger values.

In forced induction motorsport engines it's not unusual for squish to be opened out to 1.5 - 2.0mm or to run divergent squish (like a two-stroke but with larger values), I suspect this is why lowering the comp with double gaskets works so well to be honest.

Also, if it "nearly" touches when turned by hand it will touch at 7000rpm

 

KR/9A motors have domed pistons.
ABF motors have flatish pistons with a 1mm protrusion.
The the cylinder heads had different to suit the type of engine. This was covered sometime ago when Brookster had a bit of a small problem...

 

I remember the "collision". He was running HC 12:1 pistons though IIRC...

 

Edge of ABF hi comp piston hit edge of 2nd gen 051103373 KR head = Minor ABF system error!

 

1.4mm Group A head gasket:

http://www.autotech.com/prod_engine_headgaskets.htm#groupa

Two oil returns on the front edge means this is prime fodder for getting rid of 1.082cc, but without going the composite gasket route?

It's clearly a Goetze gasket. No need to get from the US?

For an ABF 16v on my maths, an instant compression rise from 10.5 to 10.73:1.

 

Has anybody sourced one of these autotech 10-198-026 gaskets in the UK?.
ps good thread
Jon

 

some useful info on this site;
http://www.volkswagenspares.com/page.php?page=headgaskets