Glyco vs clevite rod bearings - with data

[porschedude996]

After searching around, I found another brand option. I bought this on ebay for $195.

[stownsen914]

Didn't realize they made Porsche bearings

[porschedude996]

Originally Posted by stownsen914

Didn't realize they made Porsche bearings

You got more knowledge than me. I’ve never heard of them. What is their primary target sales.

[stownsen914]

They were the other manufacturer of 911 cylinders in addition to Mahle. Not sure what they may still make for Porsche these days.

[PeteKz]

Originally Posted by porschedude996

I thank you Pete! I would appreciate a reply on the Clevite mains.

Dpmulvan was correct that my mains are not made by Clevite. I ordered the main bearing set from William Knight and he referred to them in our emails as German made "Motorsports." They were $675 for the set 2 years ago. That's all I have.

[porschedude996]

Originally Posted by PeteKz

Dpmulvan was correct that my mains are not made by Clevite. I ordered the main bearing set from William Knight and he referred to them in our emails as German made "Motorsports." They were $675 for the set 2 years ago. That's all I have.

Thanks Pete for checking.

I was not surprised the bearing were original, date stamped 1/83. I’ve been involved with motorsports for years and have never seen bearings like the ones i’ve pulled out of this ‘83. The are just plan dark gray and uniform across the whole surface. No specks of dirt lodged in the bearing. I was once told by a race engine builder to never look at the bearings upon disassembly, only look at the crankshaft. Meaning the bearings are made to tolerate contaminants to a degree and are never a pretty sight. “Don’t scare yourself with look of the bearings”. He was an American V-8 guy and probably never seen the inside of a boxster. The last 911 engine I had apart was many years ago and I recall the crankshaft being pretty clean and I only had it polished. I don’t recall bearing condition, I must not of set a negative synapse.

The IMS Bearings were a different story. One side was more worn and had copper showing. Nice and smooth, but not bad for 150k+++??? (Read Broken Odometer). The IMS bearing surface out of spec and given the bearing color it’s time to replace. Aha, what’s another $1,000. ;(

[PeteKz]

I agree with your friend who builds V-8's. I'm now of the opinion that you should NOT replace the main or rod bearings if the crank and bearings both look good. After all, they have already proved they work well, and have passed any "infant mortality" periods and have adapted to each other. Of course, put the same bearing shells back in the same place they came out of. With the poor quality bearing sets circulating in the aftermarket now, I'm even more inclined to leave good enough alone. I would check them with Plastigage, just to be sure, but otherwise, keep running them. I don't have the vast experience of the pro engine builders here, but of the half dozen aluminum case engines I've opened up (that didn't have a major failure), all the bearings were in excellent shape.

Yes, the Babbitt surface of the bearings is designed to allow small particles to embed into the soft surface so that they do not grind away at the crank journals. In the old days when oil systems were only partially filtered, or had no filter, the babbitt was thicker to absorb more of that contamination.

The IMS bearings quickly wear through the thin silver surface and "show copper," so after a few thousand miles, they look worn out. But it doesn't seem to matter because they keep on going for hundreds of thousands of miles. Go figure,