How much effect does static compression ratio have on dynamic compression?

[Radar]

I tried I'll leave it now for the boys who know what they are doing

[Celica RA45]

the std head gasket doesnt make sense at all ,most new steel gaskets are .8 of a mm or 30 thou
,cant see how you had .02 of a mm std gasket

[DrNick]

Could we get on topic again please. If you read my posts I did not ask about the head gasket or anything to do with that. Its already done. I was asking about valve timing and how to calculate where its at now and the effect on DCR.

[Celica RA45]

well read what you wrote then and explain 0.2 head gasket more like .8 of a mm

its just that you are saying 0,2 of a mm and you went up to 1.3mm doesnt make sense here
could also be lower than what you think you have
most toyota pistons sit 40 thou down the block at tdc ,well most of the new toyota engines do and i would say the vvti 2jze would be the same

and head gasket has a lot to do wirth it as well not just pistons cams etc

[DrNick]

Where on earth did you get 0.8mm from. I said it was 0.2mm. The stock gasket is like a sheet of paper.

[Radar]

http://www.kb-silvolite.com/calc.php?action=comp
Type the std figures in and record the data it spits out (std HG size la la la)
then plug in your current config and record the date spit out (new HG size la la la)
Work from there to bring your current configuration back to somewhere close to original using the ABDC timing.
So say your inlet valve closes at around 72 degrees (no idea what the real ABDC is, just an example) originally and you get a certain DCR of something x.x:1.
Just advance or retard your inlet cam to bring it somewhere back to where you were before you put the larger head gasket in.? See if this fixes the problem
(No idea if it will work just makes sense in my head)
Make sure you apply this to both In and Ex cam other wise you'll start screwing with the LSA and you dont wanna do that unless you know what your doing.

[oldcorollas]

GT mentioned 0.4, others guessed 0.3 compressd in this thread
http://www.toymods.net//forums/showp...7&postcount=73

[andrew_mx83]

have you actually had the crank to true TDC and measured how far off the cams are? perhaps its less of a DCR issue and more of a "cam timing is off" issue

got adjustable cam pulleys?

[DrNick]

well obviously i've lined up the crank and cam timing marks when i put the head back on a few months ago. i would have to be a bloody genius to get it right without looking at the marks

they actually lined up perfectly.

i wouldn't really call it an 'issue' actually, it hasnt done it for days. its just once in a while, especially on a really hot day. im always keen to get things running as smoothly as possible so it got me curious.

thanks for the information guys, especially radar, that link is good. i have the specs for the head written down somewhere so i will play around with the different values and see what it comes up with.

[andrew_mx83]

i meant off by a degree or two, not by teeth