Help me select the correct bearings for my case

[Adrock]

Hi team,

I have a Japanese import 911 SC 1983 3.0
It comes with the engine case with part number: 930.101.104.5R

I'm just about to buy some rod bearings and in the parts catalogue I'm presented with 2 options.

1. Porsche 911 1978-1989 2993cc/3164cc
Part: H6 6B2462H

or

2. Porsche 930 1978-1989 3299cc / Turbo
Part: H6 6B2463H

My questions is, because my car/engine probably falls under both categories; do I buy the parts based on the size of the engine (#1). Or do i buy bearings based on the engine case number (#2)



Thanks!

[Flat6pac]

The rod bearings for 3.0 are larger than the 3.3 bearings
Not interchangeable
Bruce

[EdRogers]

I have not seen that company before, but short answer is 1. Long answer is, go to the engine rebuilding section here on this forum, and read about rod bearing problems. It will take you a while. The rod bearings need to be done right the first time.

[Adrock]

Originally Posted by Flat6pac

The rod bearings for 3.0 are larger than the 3.3 bearings
Not interchangeable
Bruce

Thanks Bruce. I figured they weren't interchangeable - given that the part numbers were different.

[Adrock]

Originally Posted by EdRogers

I have not seen that company before, but short answer is 1. Long answer is, go to the engine rebuilding section here on this forum, and read about rod bearing problems. It will take you a while. The rod bearings need to be done right the first time.

Thanks Ed.

I had already done LOTS of reading on rod bearing problems. Which is why I was looking for alternatives to Glyco bearings, I came across ACL. There are only a couple of posts on Pelican about them. Seems that not many Porsche people are aware of them. However, I've done lots of reading via google where other car enthusiasts rate them as some of the best bearings available. I'm willing to give them a go based on all of the good info I have read. I will measure them up prior to installation. They only make rod bearings - not mains.

So, just so I understand the differences between the 911 and the 930 rod bearings - is the difference in the crank journal size or in the rods?

[Flat6pac]

The crank rod journal size are different, that’s how the Carrera gets the .2 in 3.2
The mains are both the same, as is the nose bearing
The wrist pin size on Carrera is 1mm larger
Bruce

[Adrock]

Originally Posted by Flat6pac

The crank rod journal size are different, that’s how the Carrera gets the .2 in 3.2
The mains are both the same, as is the nose bearing
The wrist pin size on Carrera is 1mm larger
Bruce

Awesome, thanks for clarifying Bruce.

[juanbenae]

you can use a 996 era GT3 bearings as well. a bit more $ but ive used them in two motors now.

[DRACO A5OG]

You must insure the journals are straight where the bearings sit. A good machine shop that does Porsches can check and correct if needed ( do the oil squirters too )

Just as important or more important, you must MIC/measure the shaft to see how much wear has occurred, correct (requires shaving down, which I do not like but long as it will still be within spec afterwards, do it) and match bearings accordingly. Bearings come in three thicknesses -.25, STD, +.25. Yes, Porsche brand is more but they measure them for you to insure they are all within spec of each other prior to install.

If you are on a budget then get couple of sets of OEM manufacturer bearings, measure each one (expect non-uniformity), return the ones that are way off. If you find the shaft unevenly worn, place the thicker ones in order of wear on the shaft. Most likely, #7 & 8 portion of the shaft are bit more worn, put the thicker bearings there.

My take on the reason for uneven wear, the last two wear more due to POS's over tightening the fan belt coupled with over tightening of the AC belt if you have one, puts excessive leverage on those bearings ergo #8 wear and leaks.

I used Porsche Standard bearings made by Goetz (yellow packaging) for my 3.4L build. Yes, to my surprise they too were a bit non-uniform but not too far off, I placed the thicker ones at #7 & #8 as my shaft was worn there more than the rest ( my #8 was leaking ).

[Adrock]

Originally Posted by juanbenae

you can use a 996 era GT3 bearings as well. a bit more $ but ive used them in two motors now.

I had read that about the 996 bearings, but I wasn't sure what the benefit was? Other than they are just a different type of bearing that is likely to be delivered with better quality and within spec, in comparison to the stock Glyco versions?

My case and crank is currently at the machine shop getting measured, balanced and polished up.

I emailed the guys at EBS racing last night and asked if they have still been having problems with Glyco and if they are still getting dodgy bearings returned. They advised that they haven't seen any issues recently. But also did offer the 996 as an alternative.

Thanks for the tips as well Draco! I will ask them to do the oil squirters as well.

[juanbenae]

Originally Posted by Adrock

I had read that about the 996 bearings, but I wasn't sure what the benefit was? Other than they are just a different type of bearing that is likely to be delivered with better quality and within spec, in comparison to the stock Glyco versions?


I emailed the guys at EBS racing last night But also did offer the 996 as an alternative.

yir on the right track.