400SE compression ration.

[TVRleigh]

Any one know what it should be on a standard 400SE (I know there is no standard )

[andymadmak]

10.5 to one.
Mine was found to be actually running 8.8 to one before the rebuild. NOW its running what it should

[TVRleigh]

yes I thought it sould be 10.5/1

why was your's so far out.

[andymadmak]

The pistons were running well down the bores. We ended up having to deck the block to bring it all up to where it needed to be. (tin gasket)
Just TVR being lazy really!

Andy

[TVRleigh]

do you remember if you had flat pistons.

also did you ever have it dyno'd or Rolling road'ed before or after.

[andymadmak]

TVRleigh said:

do you remember if you had flat pistons.

also did you ever have it dyno'd or Rolling road'ed before or after.

Pistons had little valve cut outs in them IIRC

Never dynoed or RR 'ed . Its faster now than it was before.......... and it was clocked at 155mph (roof down) BEFORE the rebuild

[Boosted LS1]

andymadmak said:

The pistons were running well down the bores. We ended up having to deck the block to bring it all up to where it needed to be. (tin gasket)
Just TVR being lazy really!

Andy

Well down the bores, .040" plus the thick tvr gasket. We took .030" off the block and then fitted the tin gaskets iirc. We had to machine the intake manifold to make it fit into the valley which had narrowed a tad .

Boosted.

Edited by Boosted LS1 on Wednesday 18th July 18:15

[TVRleigh]

Any one know what the calulations are to work out new compression ration.
as if you took of 60 thou to give you the correct 10.5/1 from 8.8 then its .3 for each 10 thou.
not sure how this would change with new style heads as I think they have a smaller compression chamber.

[Boosted LS1]

We cc'd the combustion chamber with oil and did the same for the piston at tdc. As for the gasket volume that's just mathematics. Then we worked out how to make the changes to bring the c/r up to a better level.

Boosted.