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there was an interesting thread a while back on the 928 side of the world showing the clear difference between Glyco branded and Porsche branded main bearings.
The Glyco box parts were of a completely different "oil drain" design and physically smaller....weird.
Porsche Glycos are measured again standard glycos are not. There are measurng tool marks on every porsche branded glyco bearing that are not present on glyco branded bearings.
My guess is the bearings are same but in porsche box you only get strict tolerance controlled bearings, in glyco you get anything that resembles bearing.
Btw: I have 2 OE Porsche glyco sets (for two rods) more than I need and will sell for cheap if anybody wants to go OE.
more to it than even that!
Porsche rod bearings are double-check measured and classified into tolerance groups - red, blue, yellow.
yellow is "mid range" tolerance, i forget which is which but red/blue represent "a little tight" and "a little loose".
regarding main bearing...this is a comparison of the Glyco brand (top/left) vs Porsche brand (bottom/right) main/thrust bearing from a 928 (should be same parts in 944).
I was asked to weigh in on this thread, so here're my thoughts:
The 951 rods are certainly long in the tooth, but still quite suitable for most applications. Given their age and cycles, always best to have them PROPERLY reconditioned which includes resizing the big end, checking/replacing the pin bushings, checking for alignment. I don't see any need to replace the bolts, but if it makes sleeping easier, have at it. New bolts always distort the big end, so reconditioning has to be done after the bolts are installed. Porsche specifies new rod NUTS every time, and I do this. It's so there is fresh serrations on the mating surface. Oh, if new pin bushings are installed, the rods MUST be aligned afterwards. Otherwise, the bushing won't be square with the big end.
Now, all this said, I'm a fan of the Molnar rods. The ones that have come through the shop are beautifully finished and dimensionally spot on. Few of the others are, some horrible.
There are almost never issues with 944 main bearings, whether Porsche bearings (yes, they're better) or aftermarket Glyco. No need to fix what ain't broke. Rod bearings, on the other hand, continue to be an issue. The ROD MOD using the Clevite 'H' bearing is hands down superior to any Glyco in performance applications. All the reasons are in my original Rod Mod post. New rods, old rods, Chinese, European or domestic, it's awfully cheap insurance. It's never fun to lose a rod bearing.
By the time you've done all that it could be 1/2 the cost of new forged rods, plus you'd get something for the old ones. I'm not sure every engine up to 89 had original forged rods either ?
I vote for new rods. Old is old, if you are going to stress them you will spend enough $ to test and recondition them that a new set makes more sense....and any aftermarket rod is way lighter than the factory tanks!
Chris, I guess that depends on the definition of stress...?
for my goals, 400 crank hp max, 6000 rpm limiter (yes i know), street car never tracked.
"refreshed" 951 rods A-OK or just bite the bullet and get Molnars ?
Chris, I guess that depends on the definition of stress...?
for my goals, 400 crank hp max, 6000 rpm limiter (yes i know), street car never tracked.
"refreshed" 951 rods A-OK or just bite the bullet and get Molnars ?
if it were me i would never reuse the stock rods. I was ok with that 10 years ago, but now they are all very old with decades of abuse (who drives their 951 like a little old lady?!).
testing old shows if they have started to fail....they could start to fail next week.
if it were me i would never reuse the stock rods. I was ok with that 10 years ago, but now they are all very old with decades of abuse (who drives their 951 like a little old lady?!).
testing old shows if they have started to fail....they could start to fail next week.
Agreed. The little extra you spend now could end up saving you a lot in the long run.
02-22-2017, 09:44 PM
