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Re: 2L 16v is 10.8:1 (OttawaG60)

I don't consider this proof. The measurements and calculations taken in the other thread are much more meaningful to me. If VW told you the sky was green and they designed the sky would you believe them?
 

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Re: 2L 16v is 10.8:1 (vfarren)

No, I think it doesn't matter if VW quotes the correct compression ratio to their techs. It doesn't help them fix the car or even check compression readings. There's another VW tech manual for the Audi V8 that says they have forged aluminum rods. Not correct! But who cares if the manual has a few errors like that if it doesn't affect the tech's job.
The MEASURED compression ratio of the 2.0 16v is 10.4:1 as shown in the other thread about 16v compression ratio. It looks like VW did not account for thickness of head gasket when calculating 10.8:1 ratio.
And a link to the thread containing ACTUAL MEASUREMENTS: http://forums.vwvortex.com/zerothread?id=1211812
 

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Re: 2L 16v is 10.8:1 (billzcat1)

Quote, originally posted by billzcat1 »

The MEASURED compression ratio of the 2.0 16v is 10.4:1 as shown in the other thread about 16v compression ratio. It looks like VW did not account for thickness of head gasket when calculating 10.8:1 ratio.

You can't say this, because unless we have blueprints of the engine our calculations are only approximations. And besides if it is 10.4:1 then the PL has roughly a 9.6:1.
I sometimes get confused with you "anti-10.8" guys. Are you saying that the 9A doesn't have a 10.8:1 or just that the 9A and the PL both have a 10:1
.
 

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Re: 2L 16v is 10.8:1 (12 Inch Club)

Did you read the other thread? We don't need blueprints! You take the total cylinder volume and divide by the compressed volume. Where's the difficulty here?
Volume of the cylinder is (bore/2)^2 * pi * stroke. Add the thickness of the head gasket (bore/2)^2 * pi * thickness of gasket. Add volume of combustion chamber in head. This is the total volume of the cylinder. The volume of the chamber has been measured - using the graduated cylinder/plate method and a Bosch tri-electrode plug it is between 41 and 43cc. Add all these numbers up and hold on to it.
Just take the chamber volume and volume in headgasket and divide this by the number you just added above for total cylinder volume. You can measure things to see how large they are - who cares about blueprints?
As for the point: the compression of the 9A is not 10.8:1. The PL hasn't been discussed at length yet. Those who have experience tuning both motors say the 9A is more knock prone and therefore has a higher CR.
 

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Re: 2L 16v is 10.8:1 (OttawaG60)

and yes the pl is not 10:1. but it doesn't matter.
 

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In the other thread, the 9.6 compression ratio was for if you took the 9a bottom end and put a 1.8L 16v head on it.
 

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Re: 2L 16v is 10.8:1 (billzcat1)

Quote, originally posted by billzcat1 »
using the graduated cylinder/plate method and a Bosch tri-electrode plug it is between 41 and 43cc.

We need blueprints exactly for this reason, because there is a HUGE difference between 41 & 43.
 

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Re: 2L 16v is 10.8:1 (12 Inch Club)

Quote, originally posted by 12 Inch Club »

We need blueprints exactly for this reason, because there is a HUGE difference between 41 & 43.

Yes. The 9a being 10.8:1 or not boiled down to 3.632 cc's. Another words
a victor reinz head gasket has to compress 35.9% of its original height or
.0657cm .... or .... .657mm This is for a 2.0L cylinder head with a
bosh triple copper plug and combustion chamber of 43.4cc's
If you remove 2cc's of the combustion chamber for 41cc's then only
another 1.632 cc's needs to be removed for 10.8:1. I KNOW the head
gasket compresses that much...
Anyone care to prove how much a head gasket compresses?
 

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Re: 2L 16v is 10.8:1 (CrackerX)

ABA metal headgasket compressed to 1.5mm. Not sure about te 9a metal headgasket but I bet it is similar. If I remember, I'll measure it tonight.
 

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Re: 2L 16v is 10.8:1 (vfarren)

Quote, originally posted by vfarren »
ABA metal headgasket compressed to 1.5mm. Not sure about te 9a metal headgasket but I bet it is similar. If I remember, I'll measure it tonight.

So did you measure it by any chance? I'd be interested to know http://****************.com/smile/emthup.gif
 

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Re: 2L 16v is 10.8:1 (12 Inch Club)

Im pulling my head off tomorrow or soon anyways... I will be able to measure a victor reinz 2.0L head gasket when I do. However, even though the gasket is removed I suspect it should uncompress somewhat.
 

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Re: 2L 16v is 10.8:1 (CrackerX)

is there somewhere on the engine where you could measure the gap between the mating surfaces between the head and the block
 

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Re: 2L 16v is 10.8:1 (88Jetta)

I tried.... but the gasket is usually smushing a little bit outwards and measures larger than when uncompressed
 

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Re: 2L 16v is 10.8:1 (12 Inch Club)

I measured a used 9a metal headgasket at 5 different points I got an average reading of around 1.6mm. This is with the gasket off the car on my table.
Quote, originally posted by 12 Inch Club »

So did you measure it by any chance? I'd be interested to know http://****************.com/smile/emthup.gif
 

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Re: 2L 16v is 10.8:1 (vfarren)

Quote, originally posted by vfarren »
I measured a used 9a metal headgasket at 5 different points I got an average reading of around 1.6mm. This is with the gasket off the car on my table.

Interesting, was this right after it was removed from the engine?
CrackerX: What you might want to do is make a small mark on your block and one on your head. Measure the distance between those marks and then measure it again once you remove the head bolts. Calculate the difference.
 

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Re: 2L 16v is 10.8:1 (12 Inch Club)

No, this gasket has been sitting around for a few months. I would use 1.5mm as the correct, compressed gasket thickness.
Quote, originally posted by 12 Inch Club »

Interesting, was this right after it was removed from the engine?
CrackerX: What you might want to do is make a small mark on your block and one on your head. Measure the distance between those marks and then measure it again once you remove the head bolts. Calculate the difference.
 

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Re: 2L 16v is 10.8:1 (12 Inch Club)

Quote, originally posted by 12 Inch Club »

CrackerX: What you might want to do is make a small mark on your block and one on your head. Measure the distance between those marks and then measure it again once you remove the head bolts. Calculate the difference.

Yea thats not a bad idea, I will try to make it as accurate as possible. I think I will make a few marks in a few different places to check for precision.
I dropped the ps pump and took off the thermostat housing to drain the antifreeze.... everything else is off the head except for the nuts on the head studs. Should be able to take it off today unless when i get home I feel like working on my megasquirt project instead of the car.
 

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Re: 2L 16v is 10.8:1 (CrackerX)

Well I pulled the head off... and I had no way of accurately measuring within a thousandth of an inch... or even a tenth of an inch the change in height of the head after removing the nuts on the head studs. Even on the back of the motor with the exhaust mani off it was pretty much impossible to accurately measure it.
I did measure the gasket after pulling it off and I measured:
.165cm
Original height of different same brand head gasket was:
.183cm
.183 - .165 = .018cm
.018cm is 9.8% of the original height so in order for the 2.0L to end up at 10.8:1 compression with the calculations from actual measurements it needs to lose another 25% or so of the head gasket height. I do not think it compresses that much more when the head bolts are properly torqued.
I believe from all the measuring and calculations that I have done that the 2.0L head is closer to 10.3:1 compression. That is a synopsis from the other post and this one.
 
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