TheSamba.com :: View topic - which pistons for 2.0l type 4 CJ Did I buy the wrong ones?

Sun Feb 28, 2010 6:07 am

germansupplyscott wrote: ...the other advice i always give people who are buying engine parts is have the engine torn down and measured before you start buying parts...

your ignorance is nothing to be upset about. it's not possible to know things you don't know. but if you'd listened to the advice above, the purchasing mistake would not have happened. it's the first thing i said in the thread.

the flat top pistons are wrong for your engine anyhow.

Sun Feb 28, 2010 9:14 am

reko wrote: so anyway, I bought the barrels and pistons, they are not mahle, they are AA. Opened the box and found that the overall length of the piston is shorter than the original, and the distance between the top of the gudgeon pin, and the top of the piston is shorter (see photo of new and old piston on the same gudgeon pin) Is this because they are flat, or have I bought the wrong ones?

The new barrels are the same dimensions as the old ones

Why not use your old pistons? They dont look that bad, put them in some acid, clean them up nicely, put on new rings, and hone the cylinders you have if they are in good shape.

Sun Feb 28, 2010 9:42 am

Nica wrote: Why not use your old pistons? They dont look that bad

again, it has nothing to do with looks, a big part of engine building is about measuring. the measurements don't lie.

Sun Feb 28, 2010 11:01 am

top right in the photo - that piston is done in this lifetime.

Sun Feb 28, 2010 11:40 am

SGKent wrote: top right in the photo - that piston is done in this lifetime.
I dont know...One time while I was in Cuba I saw those kind of scuffs repaired with a piece of paper, some pencils, a razor blade, a grinder with a wire brush attachment, a sock, some grease, a Ciego Montero can, and a piece of aluminum foil.
Not that im saying that would last 100,000 miles(or even 20,000mi) but it can be used with a little elbow grease.

Sun Feb 28, 2010 12:01 pm

Nica wrote: I dont know...One time while I was in Cuba...

for sure.

they do all sorts of makeshift repairs in cuba because correct parts are completely unobtainable and labour costs peanuts. they have 70 year-old american cars that have pieces of 50 different models on them to keep them on the road.

if you don't live in cuba or some other marginal locale, if you can find the correct parts without going broke, if you want the job to be done well the first time, you buy the correct quality parts, fix it once and drive.

Sun Feb 28, 2010 12:24 pm

Nica wrote: reko wrote: so anyway, I bought the barrels and pistons, they are not mahle, they are AA. Opened the box and found that the overall length of the piston is shorter than the original, and the distance between the top of the gudgeon pin, and the top of the piston is shorter (see photo of new and old piston on the same gudgeon pin) Is this because they are flat, or have I bought the wrong ones?

The new barrels are the same dimensions as the old ones

Are you insane? Pistons are aluminum......ACID EATS ALUMINUM! DO NOT put these in acid.
Return the pistons you have they are for a 71mm stroke. Use a feeler gauge as per tom wilson to check skirt clearance to make sure teh skirts are not collapsed on your old pistons. If they are ok...use at worst a brass brush at low rpm on the piston tops only. Get new rings...clean them in clean solvent three times. Wipe with paper towels only....no rags.
Have the old cylinders honed very lightly if you cannot do this yourself....and re-install the whole set up. Ray
Why not use your old pistons? They dont look that bad, put them in some acid, clean them up nicely, put on new rings, and hone the cylinders you have if they are in good shape.

Sun Feb 28, 2010 12:26 pm

Lol yeah i just watched a special on Cuban cars.. quite interesting. They have to make replacement parts.. for everything.

Sun Feb 28, 2010 12:26 pm

SGKent wrote: top right in the photo - that piston is done in this lifetime.

Ah..I see it now. It not only looks scuffed...it looks like something dented it. Ray

Sun Feb 28, 2010 1:36 pm

germansupplyscott wrote: Nica wrote: I dont know...One time while I was in Cuba...

for sure.

they do all sorts of makeshift repairs in cuba because correct parts are completely unobtainable and labour costs peanuts. they have 70 year-old american cars that have pieces of 50 different models on them to keep them on the road.

if you don't live in cuba or some other marginal locale, if you can find the correct parts without going broke, if you want the job to be done well the first time, you buy the correct quality parts, fix it once and drive.

Agreed. The right way to do a rebuild would be to buy the parts from you, seeing that you sell Mahle p/c sets, which seem to be getting scarce. I cant tell you how many times I have been told and so called “reputable “ VW parts shops lately that I can use a Chinese p/c set and they will be “just the same “.Thats a load of BS, I trust 300 times more in a makeshift repaired Mahle piston then a cheap chinese piston that might not even get me down the street and back.

raygreenwood wrote:
Are you insane? Pistons are aluminum......ACID EATS ALUMINUM! DO NOT put these in acid.

No, my bucket of acid says that its safe for Aluminum :lol:

To be more specific....This stuff

Sun Feb 28, 2010 2:00 pm

I dont think thats acid cleaner, but solvent clenaer.

that said, here is a stupid idea that i feel stupid for not coming up with earlier. those pistons could be fine, and now that you know the wrist pin height (or gudgeon height as you call it) you can call up AA piston company and ask them what is the proper height. thier sales staff is awesome and smart and will let you know immediatly, and you will find out of your old pistons are simply 94s for a 1.7/1.8 crank, cause they sure look tall.

did you ever figure out what the stroke of your crank is? any pics of your rods?

Sun Feb 28, 2010 2:41 pm

as a former auto machinist I would not under any circumstances use the worn set of pistons. That one is in the process of failing at the crown.

Post photos of the heads and rods, have someone measure them to see what you have now. Then make a decision what you want and take the pistons back. Mahle sets are still available. Build yourself a nice engine.

This is photo from TheSamba of where your piston is headed to.