1972 911T 2.4 Build
 

I accidently posted this in the 911 Technical Forum yesterday....

I'm considering using the stock cast iron cylinders, bored to 85mm, and using JE pistons. I've seen this referenced in numerous threads but I have not been able to find much detailed info on the process.

- When boring the cylinders should they be bolted to some type of a torque plate fixture?

- Should I source the pistons and take them to the machine shop when I get the cylinders bored?

I attached a pic of #1 piston and cylinder. (#1 exhaust valve dropped. Head & piston were destroyed. I bead blasted the piston so it could be used for "desk art". The exhaust guides on the remaining cylinders are all very worn.)

- Do you think this cylinder will clean-up when bored to 85mm?


http://forums.pelicanparts.com/uploa...1551796029.jpg
http://forums.pelicanparts.com/uploa...1551796029.jpg

Yes first source the pistons. The cylinders have to made to fit the pistons. When using cast iron cylinders you have to take in account the material of the pistons. If you switch to forced JE pistons instead of the old cast pistons with inserts, the the cylinder to piston clearance needs to be made to compensate for the difference in expansion.

There are companies that specialize in air cooled motors and can bore the cylinders. It takes a special jig and machinery. If those are iron cylinders make sure you let JE know so they can supply the correct pistons.

I would go for a new set of P/C. JE 9.5/1 CR and Molly Nickicill cylinders. EBS will sell you the matched set. The extra compression will make a nice upgrade. This is the very heart of the engine.

Chris
73 E

Some more questions....
 

2.4T 4R case
85 or 86mm Ps&Cs
9.5:1 CR 40 Webers
Stock "T" heads/ports
Stock gear ratios (901)
Weekend Driver, some DEs and AX

What would be the best cam for this application?

(I asked this same question on the 914 forum and got the following)
(5) votes for "E"
(4) votes for "Solex"
(2) votes for "DC30" (one with recommendation for "S" porting

DC30 - see this recent discussion
http://forums.pelicanparts.com/911-engine-rebuilding-forum/1022738-1969-911t-e-cams-s-solex.html