2.2 vs 2.4 cylinder questions

I'm doing a budget rebuild on the neglected little '70 2.2E motor. So far, I have her torn down to the block. Two of the jugs are pretty corroded, meaning bore all and get a set of JE pistons, or find a set of usable jugs. Used jugs are preferred because of $$$. Haven't checked the pistons yet, but the motor was fairly low miles and they came out of the bores without fairly easily. Assuming p's are still good, I want to get my options. Couple of questions -

1. Can 2.4 jugs be used with 2.2E pistons and block? What other mods will I have to make with 2.4 jugs? What CR would it make?

2. Are all 2.2 jugs the same? Could I use T, E, or S 2.2 jugs as long as they are in spec and the same height group?
- Thanks

[Walt Fricke]

I believe these 84mm cylinders are dimensionally all the same (allowing for height groups etc). But the Ts were all cast iron, and hence less desirable.

The best replacements would be a set of Nikasil 84s. I don't think any 911 came with these, but they exist. I had a set for a while before reselling them when I gave up on that project.

Katrina engine?

Walt Fricke

Thanks Walt - no, this car was abandonded at a body shop for years and sat out in the elements.

[dtw]

Yes - the 2.2 and 2.4 jugs are the same, with exception of T jugs - both 2.2 and 2.4 'T' are cast iron vs. the composite birals.

Sometimes good in-spec 84mm jugs can be really hard to come by. One option is to take a junk set and bore them to 85 and match a set of JEs to them. Makes a 'true' 2.4 motor.

Thanks Dave. What questions do I need to ask when asking about condition of jugs? I'll make the following assumptions:

1. Are they birals(from an E or S)

2. What do the bores measure out at?

3. Have they been measured for roundness?

4. Are they all the same height group?

Anything else I need to ask?

[dtw]

1. Birals are easy to differentiate visually. Cast iron are all one-piece and the fins are virtually always rusty. Birals are two-piece: aluminum outer casting (no rust) and pressed-in ferrous sleeve.

2/3. Bores are 84mm, but yes, check tolerances - I can't find my 'Wayne' book lately or I'd tell you what the max run out is on bore/ovality.

4. Shouldn't be an issue - unless you need to replace some of the jugs. Make sure your replacements are compatible.

Anything else - since it sounds like you probably have biral jugs, carefully examine the aluminum casting where the sleeves are pressed in. Since they have different thermal expansion rates, many of the biral jugs I've seen have failed over time. The aluminum cracks, separating from the sleeve. This impairs the integrity of the cylinder as well as its ability to cool. The worst point, at least in my experience, is the absolute bottom of the cylinder - the cracks seem to propagate from here. In fact, I had a 2.4E cylinder fail from hydro (petro- ??) lock, and it was this bottom-most point at which the cylinder exploded. You can easily check yourself - make sure all the head gaskets are out and the jugs are nice and clean, then have a look.

Have you got the pistons also? I called Henry Schmidt with some related questions, and he noted that the cylinder bore measurement is not as directly relevant as the piston/cylinder clearance - that's the critical measurement.

Dave,
I don't have a set of replacements yet. I've located a set that the seller says are in spec, but I didn't know the specific questons to ask. I'll run these by him. Thanks

Originally posted by dtw


Have you got the pistons also? I called Henry Schmidt with some related questions, and he noted that the cylinder bore measurement is not as directly relevant as the piston/cylinder clearance - that's the critical measurement.

Just reread this part. The seller has 5 - 2.2E pistons that come with the deal, but I still have all 6 of mine that I think should clean up and be usable. Of course all still need to be measured.