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Thread: Increasing W10 Avenir Compression

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Posts: 1-7 of 7
2008-03-16 11:18:34
#1
Increasing W10 Avenir Compression
(I've searched a fair bit and have mainly just have posted this up to make sure I have my facts straight so I don't blow my engine up)

Basically I'm thinking about raising my Avenir DET compression from the stock 8.5 to 9.0.
Not a big jump I know, but I like to keep things sensible , and it puts me between a DE and DET compression ratio, which I figure gives me a bit of both worlds
Since I already have a brand new stock head gasket in my possession, I don't want it to go to waste, so I'll probably get the head shaved.

So far I've found out I need to bring the head down .7mm.
(The great Mr Miko says 1mm = .7cr, so the maths says .7mm = .5cr)

What I'm having a tough time finding out though, due to conflicting info, is the thickness of the stock W10 headgasket.
Is it 1.2mm, 1.5mm or what

The other issue I'm worried about is valve/piston clearence when running cams.
With the loss of .7mm would I have any problems running JWT S3's or BC Stage 2's?

Thanks,
Clownie
2008-03-16 13:04:13
#2
Actually, I guess the gasket thickness doesn't matter if I shave the head
(it always pays to take a break, then come back later when something is messing with your head)
I feel stupid now....

I'd still like advice on the cam issue though
2008-03-16 13:32:48
#3
I run BC STG 2 cams, which I believe are rated for 11.5mm of lift, on a USDM DE. IF you're going for less compression than a DE, I don't see how valve to piston contact would be an issue.
2008-03-16 13:41:29
#4
Yeah that's what I though. I was just worried about the DET pistons VS the DE pistons so I just wanted to double check.

Thanks for your help
2008-03-16 15:24:10
#5
Yep! You shouldn't have any issues, as far as shaving a bit off the head in order to raise your CR.
2008-03-21 00:01:36
#6
Your mechanical timing may be slightly off which will change the location of the overlap between your intake and exhaust valves. You may want to get cam-gears to compensate for that. Stock head gasket is 1.2mm .
2008-03-21 01:15:37
#7
Originally Posted by SENTRASER
Your mechanical timing may be slightly off which will change the location of the overlap between your intake and exhaust valves. You may want to get cam-gears to compensate for that.
Didn't even think about that :o
Thanks for the input
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