Replacement cylinder height (delta) class
 

The specifications for the 2.2 liter motor say that cylinders come in two basic classes, 5 and 6. (What happened to 1 through 4?) There are different specifications for replacement cylinders in "R5" and "R6" classes, which I am guessing are intended as single replacements for an engine that still has 5, or fewer, of its original class 5 or class 6 cylinders. The specifications line up like this:

• Class 5, height 85.400-85.425
• Class R5, height 85.150-85.175
• Class 6, height 85.425-85.450
• Clase R6, height 85.175-85.200

My question is, why are the replacement cylinders shorter than the originals?

I am looking into this, because I have a single, new cylinder for a 2.2 E, marked class 5. The originals are class 6. Yet, when I mount two of the originals and the replacement class 5, I find that the class 5 cylinder is taller by over 0.05 mm.

I take it that single cylinders, these days, come out of broken up piston/cylinder kits. I am guessing that the R5 and R6 classes have long been unavailable.

I ve never seen an R class cylinder, only delta 5 or 6.
Bruce

Have you measured the heights of your "original" class 6 cylinders to find if they have been machined previously and are now in a class 5 deck height range.

I have come across this in many of the motors I've rebuilt over the years, with mismatched cylinders machined to fit the remaining cylinders in the set.

Tom,
The Specs booklets refer to R cylinders as "replacements", the '72 workshop manual as "reconditioned". The difference appears to be .25mm, the size of one cylinder base gasket. Like Bruce, I don't recall ever seeing one.

As Adam suggested, you should measure all your cylinder heights, preferably on a surface plate, and adjust them to match if necessary.

http://forums.pelicanparts.com/uploa...1317012020.jpg

I believe the "reconditioned " cylinder height refers to height targets for cylinders that are re-cut to true up either the upper or lower sealing surfaces during an overhaul.

Similar in concept to the undersize crank journal target sizes.

Have you ever assembled an engine with mixed 5 and 6 on one bank?

Mixing different height classes in a given bank of cylinders can lead to inadequate clamping on the short cylinder and a leak at the cylinder to head interface.

Cylinder heights should be checked to make sure all cylinders are within the allowable height variation.

I am more worried about misaligned camshaft bearings.

The heads will mate to the cam towers with no problem and the cam will spin nicely.

You need to be more concerned with the cylinder to head interface. I have seen several cases where heights have been mixed with resultant leaks and ruined cylinders and heads.

Thanks, Tom. Kind of hard to understand, with the heads being separately held by bigger fasteners, but those cam carriers are really rigid.

Are these numbers the same for 930 3.3 cylinders? I think I had a mix of 4s and 5s when I took mine apart.