2.4 deck height

[NevenM]

Hi

I rebuilding a '73 2.4E to stock spec and have dry assembled the case to check the deck height, which is +0.4mm, So I'll need a packer of at least 1.7mm (to get a -1.3mm deck). Im mystified as to why I need so much the crank is the original (only needed polishing) The Rods have been reconditioned (which would generally make them shorter if anything) and the P/C are New Mahle, Which leaves the spigot height, I've had them machined
0.1mm. I'm going to get some 2mm steel 'gaskets' made up

Any comments

Thanks

Neven

[Tim Walsh]

Have your spigots been machined at all?

[NevenM]

Only 0.25mm

Neven

[Wayne 962]

2.4 pistons, not 2.2?

-Wayne

[NevenM]

Wayne

I assume so, purchased as 2.4 and they have a very low dome height.
The dome volume is 12.1 cc, Which with a head vol of 55.5cc and a deck
height of 1.3 would have give a comp ratio of 8.7 (which is about right
as I have taken 0.25mm off the heads)

Neven

[Tyson Schmidt]

Two possibilities come to mind.

Case halves machined at their mating surfaces for line-boring the main bearing saddles.

Rods incorrectly reconditioned with too long of an end to end length.

[NevenM]

Hi All

After a little investigation I think I have an answer. First the Machinist may have taken 0.5mm off the spigots. Secondly the new pistons are 0.25mm higher (from pin to top edge) than the old ones, thirdly I 'better'
measured the deck height with no copper gaskets in and it is +0.25

Which means with the original pistons, no spigot machining and gaskets
the deck height would have been -0.75mm. This Correlates with the
chain boxes, I set them up and at the same time and they are 1.1mm
out of centre (with no copper gasket and 0.25 machined off the heads),
With 0.5 taken from the case then this would be expectect to be 1.0mm
(so 1.1 is pretty good, I'd say the factory would accept this esp with a
compressable gasket at the base of the chain boxes)

I'm going to get some 2mm cylinder packers made, reassemble the
engine (dry), check the valve to piston clearance and then I can decide
(within limits) what comp ratio I want and set the engine to.

Thanks

Neven