samana76

Hello everyone,

I am having the engine rebuilt on my 944 Turbo. It's a 1987 block that had been previously rebuilt. I had a great deal of work done to this block and have had sleeves put it. It's ready to be rebuilt, however, unfortunately we have run into a snag: it turns out that in the previous rebuild done years ago the balance shaft bores on the block were machined and genuine Porsche oversize balance shaft bearings, part number 944 121.06, were installed. Somehow two of these bearings have been misplaced and I am have having a hard time finding replacements.

Although it may seem strange, the technique used was to machine the bore in the block and not the balance shaft. In fact the inner diameter of the oversize bearing is the same as the new standard ones, but the outer diameter is larger. These oversize bearing are 2mm thick as opposed to 1.5mm, I believe, for the standard ones. I did try replacing the balance shafts with good used ones, but they are the same as my old ones confirming that the bore in the block has been increased.

Can anyone please help me with this issue. Anyone have two (or all four) oversized bearings on them I could buy? I know this is wishful thinking, but you'll never know if you don't ask... I would appreciate any leads anyone here can give me. Thank you all in advance.

Cheers Rennlist,
Igor

rlm328

Try Lindsey Racing, if they don't they don't have them they will know where to get them.
http://www.lindseyracing.com/LR/Parts/944BEARINGS.html

ramius665

Igor, you don't have a complete Porsche PN. I just checked PET and your PN for the bearings must be incorrect. PET does not have part numbers for oversize balance shaft bearings but the bearings for up to MY 86 motors is 944 101 121 07 and the 87+ motors is 944 101 121 10. There is no repair kit with oversize bearings listed under the "repair kits" tab either. I tried looking for a partial PN "944 101 121 06" which is the most logical PN based on your post and there is no part associated with that number.

Voith

Are you talking about the two part or front single part bearings?

If front, you can replace the housings with ones that use std bearings. Housings are replaceable.

samana76

Thank you all for your help.

These are the two part bearings in the rear of the balance shaft. I tried both the 944 101 121 07 and the 944 101 121 10 and neither of them worked - both of them are too thin.

Here are photos of what in theory would be the correct bearing for my engine (1987 year), part number 944 101 121 10, next to the over-sized one that was installed previously (and that I am trying to find). You can see my old one is a little thicker, 0.5 of a millimeter thicker to be exact.













I have written to David at Lindsay racing a few days ago, but haven't received a reply back yet.

Thank you all again for your effort in helping me out with this!

Cheers,
Igor

michaelmount123

I'll bet the earlier bearings will fit your block. You either have an earlier block, or perhaps there are some '87's that used the earlier bearing. They are larger on the OD than the later bearing, and the ID is the same.

samana76

Thank you michaelmount123 for your comment. However my mechanic said they had (accidentally) ordered the bearings for the earlier engines, part number 944 101 121 07, and these would not fit either. Now I have not seen them, however I trust what they say. In any case I will send the above photos I took yesterday to David at Lindsay so that he can check the size of the earlier bearings. I truly hope you are right - that would save me a great deal of problems.

michaelmount123

I just checked the early bearing and it's dimensions are the same as you need. They will fit without issue.

Voith

STD means standard (size), over sized bearings don't come with STD written on them..

samana76

michaelmount123 thank you for checking. That is great news! I cannot fathom why my mechanic would tell me he tried the older 86 bearings, unless he somehow made a mistake and only checked the new 87+ bearings, which are thinner. I, and my mechanic, have been searching everywhere for bearings with my same part number 944 (101) 121 06 with no results.

Does anyone know why there is a number difference between mine, 944 (101) 121 06, and the 86 and earlier bearings, 944 101 121 07, if they are exactly the same?

Voith, yes, just recently got the bearing from my mechanic and the STD didn't make any sense if they were supposed to be over-sized bearings. However I am not an expert and I was going by what my mechanic was telling me. I should challenge his affirmations a bit more...

I appreciate everyone's help here in solving this issue.

Cheers,
Igor

gruhsy

Where did your mechanic come up with the conclusion in your first post about previous work done? Not something I have ever heard of.....the part about balance shaft machining.