3.0 SC Rod/Main Bearings
 

I see that there may be issues with the Glyco bearings. I see that some are using GT3 bearings for mains and rods. Do these bearing have to be dealership bought or are the Glyco GT3 bearings OK?

Cheers and thanks!

I've been told glyco mains are fine and bought the same. For rod bearing look at Automobile Associates set, they are around $380 for the set.

https://www.pelicanparts.com/catalog/SuperCat/0791/POR_0791_ENGMAN_pg3.htm#item8

Thanks for the reply.

I have spent a good amount of time reading and found these threads. Very helpful.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/541476-3-0l-stock-rods-bolts.html

http://forums.pelicanparts.com/911-engine-rebuilding-forum/825748-rod-bearing-controversy-5.html

http://forums.pelicanparts.com/911-engine-rebuilding-forum/723158-main-bearing-alternative.html

The dealership mains are very pricey - are Glyco mains still with issues?

maybe post in the 911 tech forum and see what is said. I have a set of Glyco mains and have not opened the box as yet. It claims I cannot return if box opened. So I wait in case I need something different (size wise). I was told by a knowledgeable engine builder that glyco mains are fine, as are the stock rod bolts for 3.0 SC.

Stock rod bolts are fine for a 3.0. Race/track may be different. You can upgrade for a little more with ARP.

I have sent an email to Don at EBS. Hopefully hear back soon.

There have been issues with Glyco aftermarket mains - not necessarily with quality, but with thickness. The ones I got, although they appeared to be made in germany and of consistent quality, measured between .0006" and .0008" thinner than the original factory 930 part number bearings in my engine from the last rebuild in 2002.

Adding .0012 to .0016" to the oil clearance would have taken me well beyond the acceptable limit.

In my case I was able to return them as defective.

I also purchased (and returned) a set of Glyco GT3 rod bearings that were dimensionally correct but I incorrectly thought they were too narrow:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/1017939-rod-bearing-alignment-edges-off.html

and also another good read:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/1028696-advice-main-bearing-clearance.html

Am I the only one who thinks the (lack of) availability of good quality, reasonably priced, bearings, for a run of the mill 3.0 or 3.2 is ridiculous?

Especially considering that we are on the forum founded by the guy who wrote the book on rebuilding flat six air cooled motors?

I can only guess that there's 100 times more money in selling bolt on parts to the water cooled crowd than catering to a bunch of DIY'er farting around with 40 year old motors. No doubt it's a PITA, but I feel like the ball has been dropped on this.

If you check the availability of main bearings on our hosts website there is a grand total of TWO options for std crank bearings. Of the two, one is unusable (so says 2 out of 5 reviewers yet no response from Pelican staff) and the other one is $828.00.

Save yourself a lot of frustration (and money) and call EBS. Of the 3 times I've called there, 3 out of 3 times Don himself answered the phone.

The GT3 main bearings being suggested are motorsports parts so not widely available, they come from PMNA.

GT3 rod bearings are available from Porsche (see some of my posts in the threads above) and are also available aftermarket from Glyco at a very reasonable price.

Here’s a better question... thousands of these sets are sold every year... so thousands of motors are being built with an extra thousandth of clearance, which must effect oil pressure...

Yet...they keep getting made...

Does no one else care? How is this not a huge issue mandating recalls?

No kidding!!!!!

The sale of defective parts like this is not acceptable when the practice is continued without correction or explanation.

When I measured the mains I compared them to the ones that came out of my motor with a ball end micrometer. I directly measured the thickness and compared them. I likely grabbed a few random samples from the package and a few random samples from my motor. I did not record my measurements.

I have since measured the oil clearance "properly" with the original bearings, installed in the clean bare engine block, using a dial bore gauge and micrometer. Oil clearance on these factory replacement 2002 date coded mains is on the "loose" end of the spectrum, in the .0028-.0030 range. This after 15 or 20K miles.

Had I used the glyco mains I would have had clearance in excess of .0040"

In reality this would probably be fine with the 20W50 dino goo that most people pour (slowly) into these motors but I can't bring myself to (A) put the motor together that way and (B) run the sort of oil you'd need to maintain pressure with those sorts of clearances.

I am really hesitant to include that last bit as I don't want to get into yet another oil discussion, but you can't really talk about bearing clearance without talking about oil. FWIW the last motor I built for my road racing car (NOT a Porsche) had main clearance of .0008" and runs 5W20 oil.

The OEM Gt3 mains and rod bearings are VERY pricey.

Don has responded to me. I really hope he does not mind my quoting him here;

original GT3 main bearings (1-7) along with German Glyco GT3 rod bearings as well as the USA made coated Clevite rod bearings. Any of these are superior options.

I will be getting the GT3 bearings - Original mains and the German Glyco rod bearings

I think they do this by design. Read the valve threads, the valve stems are thinner than stock too....

I have a theory...

Make a bearing or valve too tight, motor disintegrates, you get sued right away.

Make it loose, motor lasts 30k miles... no lawsuit...