Glyco vs clevite rod bearings - with data

onevoice · 06:41 AM

I ran into rod bearing problems when assembling a 1990 3.6 911 engine. All stock, crank polished, rods checked and sized. When I put the rods on the crank, several wouldn't turn. Disassembled and sent the rods back to the machine shop to recheck. They were in spec. After looking online, and finding posts about several "issues" with glyco rod bearings, I checked them all. Also obtained a set of clevite bearings, they are the darker ones in the photos. This is what I found:

First picture is both sets of bearings, I numbered the glycos as I took them out of the engine after the test assembly, the clevites are just numbered to keep track of them the same way:

This is how the measurements were made. The measurements at the parting line were all done with the pin the same distance from the edge. This is important because the the clevites have substantial taper to the edge. Exactly like a rod bearing is supposed to.

Glyco measurements. Note that the pin is 0.3745" and must be subtracted for actual dimensions. The right column is the flat side of the bearing, the left colimn is the side with the locating tang, and the middle is the middle.

Clevite measurements.

WOW what a difference

The glycos varied all over the place. A couple were probably ok, but some of the worst are positively ridiculous. There are a couple with 0.010 side to side difference. Also several with the parting line thicker than the middle of the bearing, opposite the way it should be. Rod bearings have eccentricity designed in, the middle of the bearing is supposed to be thickest, with a taper at the parting line to account for rod stretch. The clevites in comparison were essentially perfect given the limitations of my measuring equipment. They were all in the range of 0.0002

The glyco's were dated 05-14, and the box had a sticker Made in SAfrica.

I have always measured bearings when assembling engines, and can't recall ever finding any bad ones. Got a little lazy this time and it almost bit me, be careful. Also another reason to get good rod bolts, engines don't always go together the first time. It might also be of interest that the number stamped into the clevite bearings doesn't show up in any clevite catalog. I assume they are specially made. My conclusion is pay the money and get the good bearings. BTW, Mike @ Memphis Motor Werks did a great job helping me out with quick turnaround, and quality machine work.

boosted79 · 03-21-2015, 08:22 AM

Great info, thanks.

jhg41977 · jhg41977's Garage

Where did you get the glyco bearings? I've been told the ones that are from Porsche are better than the glyco not bought through Porsche.

Lyle O · Lyle O's Garage

I would like to know where you got the Clevite bearings. I have done some searches and have come up empty. TIA.

onevoice · 03-22-2015, 04:58 PM

Quote:

Originally Posted by jhg41977

Where did you get the glyco bearings? I've been told the ones that are from Porsche are better than the glyco not bought through Porsche.

The glycos came from pelican, the box had a label saying Made in SAfrica. Not sure how Porsche would get better glycos than others, unless they only get them from certain factories. The kind of inconsistencies in those bearings in my opinion point to much more than QC or random problems. Those bearings wouldn't have worked in a Briggs and Stratton

KTL · 03-23-2015, 06:32 AM

Quote:

Originally Posted by Lyle O

I would like to know where you got the Clevite bearings. I have done some searches and have come up empty. TIA.

Automobile Associates in CT has these made by Clevite. Note the decal on the plastic wrapper in the picture with all the bearings lined up.

Pelican has started carrying these too. AA Clevite 77 Rod Bearings

KTL · 03-23-2015, 06:33 AM

Forgot to say thumbs up for measuring the bearings. Your measurements are proof positive that those Glyco bearings are messed up.

jhg41977 · jhg41977's Garage

The ones I that came from Pelican were on a piece of cardboard and shrink wrapped to it. The Porsche ones were packaged better and cost more. The Porsche sourced ones also had very light caliper marks at several points along the edge on each one. My guess is that the Porsche ones have more strict quality control.

reclino · reclino's Garage

Has anyone tried to contact Federal-Mogul/Glyco with data like this? I realize that they will likely only offer to replace the bearings but at least this one example of bad bearings is before the engine has damaged the proof of one other there QA problems.
David

onevoice · 03-23-2015, 01:29 PM

Quote:

Originally Posted by jhg41977

The ones I that came from Pelican were on a piece of cardboard and shrink wrapped to it. The Porsche ones were packaged better and cost more. The Porsche sourced ones also had very light caliper marks at several points along the edge on each one. My guess is that the Porsche ones have more strict quality control.

My guess is that Porsche is not "inspecting quality into" the ones they sell in their own packaging. They surely don't sell huge numbers of them, an probably still get them from the same source they have for years, and it is a better production facility. If you look closely at the numbers, not a single one of the glycos had the conformity of the clevites. The numbers indicate a severe equipment/process/quality problem. Maybe only at a specific plant, possibility only at a specific point in time, but none the less, those bearings were so far out of spec that the rods wouldn't even turn. Everything I have been able to find out about rod bearings is that they should be consistent within one to two ten-thousandths, those were TEN thousandths, ie 0.0002 vs 0.010. A massive difference.

They are on the way back to pelican, they can try to chase the problem down with glyco.

The other point is to NEVER take anything for granted when assembling an engine. Accidents happen.

JJ 911SC · JJ 911SC's Garage

Quote:

Originally Posted by KTL

Automobile Associates in CT has these made by Clevite. Note the decal on the plastic wrapper in the picture with all the bearings lined up.

Pelican has started carrying these too. AA Clevite 77 Rod Bearings

The difference in price is not worth the problem that the Glyco may inflict.

My previous research did not show that the Clevite were available for 3.2

Thanks to KTL for the link and invoice for the research.

gtc · gtc's Garage

The Glyco-made Porsche bearings are not stamped with the same part number as the Glyco branded bearings. It was unclear to me which plant they were made in, but i'd bet it was the German plant.

It's a shame the Clevites are $53 apiece, vs $10-20 apiece for a similar type bearing on Summit, but i guess everyone needs to get their piece of the action. :\

JJ 911SC · JJ 911SC's Garage

Quote:

Originally Posted by gtc

... It's a shame the Clevites are $53 apiece, vs $10-20 apiece for a similar type bearing on Summit, but i guess everyone needs to get their piece of the action. :\

They list over 50 makes including Panoz but not Porsche???

http://www.summitracing.com/int/search/part-type/rod-bearings?sortby=Default&sortorder=Ascending&keyword=rod%20bearing&kr=rod%20bearing

jjeffries · jjeffries's Garage

Those measurements are so revealing. I wonder if the guys in Europe have any other choices (of bearings) available to them? John

Bird911 · Bird911's Garage

I had the same problem with the same batch of Glyco. They were also made in South Africa with the same date stamp, 05-14. Lot number 713427.

The bearings are just too thick on the edge. We were just hand tightening the rod bolt and the bearing would grip on the crank shaft. We tried all of these bearings with different in-spec rod combination, even with bran new Carillo rods, all gave the same results and the rods would just not turn.

I then ordered the original Porsche-Glyco bearing (at $60 each x 6) and these were fitting perfectly.

This is some of the glyco bearings pictures. Notice the mark that they show after trying them on. This is not appearing before you put them on the shaft. You don't even have to torque the rod bolt for the marks to appear on the bearing.

Bird911 · Bird911's Garage

These are the original ''Made in Germany Porsche-Glyco'' bearings I purchase in replacement of the S.African Glyco:

You can see the 6 quality control measurement marking on the porsche bearings. We measured a few, and the were all showing the same measurement, with a tapered edge of 0.0010'' thinner. The Glyco measurement were all over the place...