Main bearing specs - '71 2.2 T engine

[Optimusglen]

Hi all, picked up a set of main bearings for my 2.2T std/std build, I did get the Glyco bearings (made in Poland)

I've seen the threads on here about potential quality issues and I'd like to ensure they're within spec, and if not return them. I have the measurement tools already but in Waynes book I can't find the requirement for bearing thickness anywhere.

I will be installing and using a dial bore gauge as a next step but I was hoping to be able to do an initial check of the thicknesses.

edit: maybe that was a stupid question... I can infer the bearing thickness tolerances by using math can't I?

[Dmitry at Pelican Parts]

Hello - please feel free to give us a call at 888-280-7799 and one of our Porsche part specialists will be happy to help you out with the specs.

[DRACO A5OG]

Couple of things:

Did you measure and verify the shaft and case journals to insure they also are all within spec and straight? Let's assume you did.

The trick is to measure with a mic three points on each bearing like Porsche would before offering the bearings for sale, If I may suggest, make certain they are pretty close or better yet match the pairs and place in order of how the shaft measured some of the journals maybe worn more than others so you want to place the little thicker ones there.

I hope I am making sense. When I got the Yellow STD Goetz bearings I matched each bearing and I had several that were a bit thicker but within spec so I placed them at #8, #7 & #6 as those measured a bit worn more so then the rest of the shaft.

Probably not needed but I wanted the engine to have every little chance it can to wear evenly.

I know some builders when shaft is severely worn and not wanting to re-grind will mix and match bearings from STD to thicker bearings.

[Optimusglen]

Yes, crank journals are all in spec, high end of the tolerance window so I'm good there. Runout is also in spec.

[DRACO A5OG]

Good, then measure each bearing thickness and try to pair them to balance the journal out and mark them with a sharpie where they will go then you should be good to go. I know a bit OCD but I personally felt better when I did that.

[Trackrash]

You can measure the thickness of every bearing shell in three places. Center and near each end. If every measurement is identical you should be good. You can verify your clearances using plasti-gauge during a trial assembly.

BTW, I have not heard of any of the 2,2 main bearings being suspect. But it is a good idea to double check every thing anyway.

Personally, I would be more concerned with the case bores being straight. The old school check for that is to look at all the old bearings. If they all look evenly worn, and none looking way more worn than the others, you are probably OK. Again the 2,2 T motors do not have the most stressed cases.

[Optimusglen]

Originally Posted by Trackrash

You can measure the thickness of every bearing shell in three places. Center and near each end. If every measurement is identical you should be good. You can verify your clearances using plasti-gauge during a trial assembly.

BTW, I have not heard of any of the 2,2 main bearings being suspect. But it is a good idea to double check every thing anyway.

Personally, I would be more concerned with the case bores being straight. The old school check for that is to look at all the old bearings. If they all look evenly worn, and none looking way more worn than the others, you are probably OK. Again the 2,2 T motors do not have the most stressed cases.

Overall I think the old bearings were pretty good, here's a high res image, probably too big to post in the thread. It shows the bearings before I removed them from the case.

http://c1.staticflickr.com/5/4322/35777912632_b735575e68_o.jpg

I put the case together without any bearings, mating surfaces all clean and dry. Through bolts torqued to spec. And I measured the bores with a dial bore gauge. Most of the bores were actually under spec by 0.11mm on average (.0043 inches)

My assumption is that this is mag case squish and I probably need to send the case to Ollies but that's a tough pill to swallow. My cheap childcare (sister in-law) is moving several states away, so my car budget just dropped significantly.

[Trackrash]

After my last post, I remembered that I saw your bearings in your other post.

I agree, they looked fine. The odd wear on two of those bearings was probably due to some small debris when they were installed. Now if one of your main bearings looked like that IS bearing, I would be concerned.

My #1 bearing, in the motor I just finished, had a worn area, somewhat like yours. Believe it or not there was a small piece of metal under the bearing. They were the original FACTORY bearings.

If I was you I would do a trial assembly of the crank and main bearings in the case. If the crank turns freely, WTH, I would call the case good.

Then using Plasti-guage you could double check all your bearing clearances. If all your clearances are good, no problem, IMO.

You have case savers already, so, that is something you won't have to worry about.

[DRACO A5OG]

+1, the bearing are not horrible, #1 Thrust Side is worn as expected, #2 & #4 are wearing where they should as that is where the shaft sits prior to start.

Depending on your intended use, if Street only I would slap it together and call it a day but would not hurt to take that extra step of plastigauge and keep an eye on 1, 2 & 4. If obviously varied, send it out if not then move forward.

[Optimusglen]

Thanks guys, yeah currently just planning a stock rebuild of the 2.2, street driven, no track use.