Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   911 Engine Rebuilding Forum (http://forums.pelicanparts.com/911-engine-rebuilding-forum/)
-   -   2.4 deck height (http://forums.pelicanparts.com/911-engine-rebuilding-forum/145602-2-4-deck-height.html)

NevenM 01-25-2004 12:23 PM

2.4 deck height
 
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 01-25-2004 01:53 PM

Have your spigots been machined at all?

NevenM 01-25-2004 03:52 PM

Only 0.25mm

Neven

Wayne 962 01-25-2004 05:36 PM

2.4 pistons, not 2.2?

-Wayne

NevenM 01-25-2004 06:34 PM

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 01-26-2004 10:56 PM

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 01-27-2004 04:11 PM

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


All times are GMT -8. The time now is 09:13 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.