Engine compresion problem or is it normal
Hi guys

Have a closed deck block forged

Mahle pistons
Sti 8 conrods
V8 crank
Steel multi layer gaskets
V6 heads fully rebuilt skimmed etc

My engine builder has timed it today and when turning clockwise by hand with no spark plugs init it has some tight spots where you have to then apply more force to turn it....

Is this normal if not what seems to be the problem? Is it a sign of compression stroke .... And would i need thicker headgaskets?

 

You are probably feeling the cam lobes pushing against valve spring pressure. If the engine builder can't tell if it's normal or not then you'd better get a new engine builder. You can't feel compression stroke with plugs removed.

 

Even when we put the plugs in it was still getting toght spots when rotating

 

not being funny but surely the engine builder should be able to tell whats the problem, if hes unsure iam not certain id want his engine in my car !

 

A competent builder would not ask this question. Take it elsewhere.

 

I am not a competant builder hence me bein here!

 

how it is worded it seems you are asking because the engine builder doesnt know.

why didnt you ask the engine builder and as above its the tension on the cams.

nice set up btw same as me lol

 

Sounds like squirt jets & Mahle piston interference.

 

I'd take note of what Motors S GT says as he is one of the best engine builders around.

 

So to cure this would i need thicker gaskets say 1.6mm

 

So what does this mate x

 

If you have under piston oil squirters the Mahle pistons need to be modified to clear these. Gasket thickness is dictated by what CR you are going to run & this should be carefully calculated before the engine is built.

 

Try taking the cam belt off, make sure the valves are all closed and turn the crank, if you have tight spots you have a problem, either the pistons are fouling the oil squirters (very likely), the crank is bent, a bearing isn't seated right or something else! whatever it is, it needs stripping and re-assembling by someone who is an 'engine builder'.