I'd like a pic of the "fixed one"?? If it doesn't open a little while not just put the piston on the block/barrel straight away? and yes I've done it both ways so...
Do the books still say using vacuum hose on the bolts to guide over the journals to help?

The fixed compressors look like this: http://lnengineering.com/index.php/p...ssors.html?p=2

Hose trick isn't mentioned in the books, but others on here have brought it up. Thanks.

Yes - Ion and I started measuring the bores today. Here is cylinder #6.

First plane upper measurement.

http://i983.photobucket.com/albums/a...psubka3kfa.jpg

First plane lower measurement.

http://i983.photobucket.com/albums/a...ps9o6ts3gg.jpg

Orthogonal plane upper measurement.

http://i983.photobucket.com/albums/a...psnnbjzvq7.jpg

Orthogonal plane lower measurement.

http://i983.photobucket.com/albums/a...ps34qufoog.jpg

So the largest difference high to low across planes was 0.0020" which is 0.0508mm. I don't know what the spec should be for these engines. Looking around to find out.

EDIT: I just realized that I'm including taper in the out-of-round calculation. The max out-of-round at a single depth is < 0.0015", which is < 0.0381mm. Porsche max out-of-round specs that I was able to find (for other models) have been 0.03mm and 0.04mm, so I am right around there. I realize now that I would have to go back and do this much more carefully for a perfect reading. Temperature, I'm guessing, also plays a big part in this. As things stand, I now know that, as expected, the cylinders are not perfect, but probably a the high end of in-spec.

Today I also tackled some piston cleaning. After some research online, I found that this stuff should work pretty well.

http://i983.photobucket.com/albums/a...pspqobsavu.jpg

I have the #6 piston soaking overnight. During the day I made some progress, but it looks like it may have to soak overnight for a perfect cleaning.

Before:

http://i983.photobucket.com/albums/a...pshmyw1kky.jpg
http://i983.photobucket.com/albums/a...psdhjurton.jpg

3 hours later:

http://i983.photobucket.com/albums/a...pshibeacrr.jpg
http://i983.photobucket.com/albums/a...ps7vreieax.jpg

This is after minimal agitation. I will post some more pics tomorrow after the overnight soak.

That's amassing!! I was 1st shown this trick on my 1st rebuild in '66 (that's 1966 Talon, not 1866!)
Ok, got it. Tapered so as you push the piston w/rings installed down through the gismo the taper causes the rings to compress, thereby easing the install. Looks like it would work great on a specific size piston. the others work on a wide variety of sizes. Trick is to not tightened to much, but just enough to ease piston w/compressed rings into cylinder/barrel.

U pays your money etc. etc. I like tools!

Piston #6 is finally clean after an all-night soak. Five more to go.

http://i983.photobucket.com/albums/a...pss28omuoa.jpg
http://i983.photobucket.com/albums/a...pskyvr0chp.jpg
http://i983.photobucket.com/albums/a...ps6ilotfwy.jpg

Also cleaned the piston rings.

http://i983.photobucket.com/albums/a...pswhaf85bl.jpg

NICE!! Looks like the cylinder wear was acceptable. I have never been able to use those tools to get good repeatable measurements - more power to you! That Berrymans sure did the trick. One thing, did you keep the ring sets indexed to the pistons they came out of? You seem to be tackling this in a very precise manner so I assume you did. Question? Are one of the rings an "oil scraper" ring? If so make sure you have that in the correct orientation on re-assemble. I agree with Dave, those single piece ring compressors are slick.

I used that same ring compressor on my 944 engine. I don't understand what you mean by the "cone".

The problem I *did* have was that it got a little cockeyed and one edge of the compressor was a little higher so the piston ring slipped out and wouldn't go into the cylinder. I had to be very patient and make sure the thing laid flat on the top of the block the whole time. "shloook" and it was in. :)


I used some paint thinner I had left over from painting my motorcycle to clean up the pistons. It was still a PITA but seemed to work the fastest of anything else I tried.

A bit of a nit and I am not sure how you are setting up your your measurement planes but what you are looking for is not "taper" but "coke-bottle-ing". Your piston velocities are near zero and the tops and bottoms and highest in the middle so that is the wear you would be looking for = along with ovaling. (I think 3 measurements would do the trick but get one near the middle). Based on the assumption that the CB effect would be minimal at the top and bottom (of the cylinder), what you measured (at the top and bottom) should be truly due to the "ovaling effect" caused by combustion forces being apply to the rod as the crank rotates and therefore not in direct line with the motion of the piston and the center-line of the crank (piston slap I think). Piston slap or ovaling should show-up in the cylinders at a plane perpendicular to the crank. That's what I am thinking anyway! Interesting. Edit: Looking back at your pictures, and how you are measuring, it appears you may have figured this out already.

I had figured out that the worst wear would be perpendicular to the crank and thus got 2 measurements in that plane, but you're right 3 measurements at different heights would be better. I didn't get any measurements in the middle. I'll probably go back and do that too. It's easy enough.

Piston rings were kept in order. I can only dip one piston at a time in the Berrymans so I only removed the rings off one piston at a time, making sure to keep the original orientation. One ring set is indeed a scraper. I forgot to take a pic with the rings back on the piston, but will do that soon.