main bearing alternative
 

in the midst of rebuilding my 3.0 spec racer motor and have been researching main bearing replacement options. good info in this http://forums.pelicanparts.com/911-engine-rebuilding-forum/666971-new-glyco-inner-ims-bearings-unusable.html and other threads on how bad the glyco stock has been of late. concerned about ordering through our host or other suppliers due to the fact that tales of ordering multiple sets and poaching the best units and sending back the others... :(

i am being told that as with the rod bearings, a set of the 04-06 gt3 main bearing will drop in and work. the crank was in good enough shape to just be polish, balanced, plugs pulled and will not be cross drilled. has any of the brain trust here heard this option? at about 2x the cost of the standard 3.0l glycos, but a 1/3 of whats been suggested by sourcing them from a dealer.

any insight would be appreciated.

t

The jack shaft bearing thread is not bad quality. It's poor packaging by Glyco. My last set I ordered came with the pieces combined in one box, so they could beat each other up in transit. I think sometimes it can be a matter of reducing packaging to simplify shipping? Reason I say that is because if the bearings are supplied as purchased, one shell individually, then you should get tiny boxes for each shell.

The Glyco main & rod bearing saga is a matter of poor quality control and the surface of the bearings are not precisely finished. However the GT3 rod bearings are very nice, and individually packaged. No worries IMO about the GT3 bearings.

I have always liked the packaging of bearings by Clevite...(later Michigan)..they take extreme measures to prevent touching of one to another.
Bob

so, i bit the bullet ordering the standard glyco main bearings and am happy to report the packaging issues seems to have made it back to the manufacture. check out the new, more protective packaging!!:cool:


http://forums.pelicanparts.com/uploa...1355347974.jpg

Yep the main bearings come shrink wrapped nicely like that. It's the intermediate shaft shells that are loose flopping around in a little box.

When I last got the GT3 rod shells individually, they each came in a heavy mil plastic bag

#8 main bearing comes in a box and is a big hunk 'o alloy. No worries about messing that one up......

How are the gt3 bearings different?

I had no issues with the generic Glyco main bearing packaging or appearance but they simply were out of tolerance for my crank/case combo while the premium priced official Porsche bearing set from our local dealer was well within spec.

I have had the same problems for a couple years now.

I am using the Porsche Motorsport GT3 mains in my 3.2 per recommendation by Don at EBS. Upon pre-assembly they spec'd out perfectly. More expensive than Glyco mains but cheaper than stock 3.2 mains from the dealer. I bit the bullet and got the Calico coated rod bearings. The Glyco intermediate shaft bearings I'm using look ok.

Where do you get the mains & IS bearings, and how much? How much extra for the calico coating? What are you using for rod bearings?

those sound like the mains that were suggested to me. could not get a part number, and could not find them here with our host, that's what generated this thread.

can someone direct me to a good thread that walks through the checking of the bearing/crank tolerance prior to the dry run reassembly?

Do you have a bore gauge and 2-3" micrometer that reads to the fourth digit?

I ordered the GT3 mains from EBS Racing in Reno, NV and they were about $300 not including the nose bearing. The part number (Porsche motorsport?) on my invoice is 996 101 901 02R. The IS bearings should be readily available as they are just Glyco; I'm sure our host sells them. The rod bearings I'm using are from a company called Calico Coatings: Ceramic coatings, Teflon coatings, Thermal coatings solutions | Calico Coatings. They are the Calico Race Series bearing and were (gulp) $580 for the set. Still cheaper than the dealer supplied rod bearings. I hope I'm not violating any forum rules here by referencing other vendors but I don't think Wayne sells some of this stuff :o

Porsche Motorsport part number: 996 101 901 02R

You need a precision bore guage and micrometer to measure the main bearings as installed in the case then measure the difference of the crank journal dimension. Or you can use the simpler, cheaper, less sophisticated method of plastiguage as I did. I installed the main bearings in their bores, lined each bearing with plastiguage, dropped in the crankshaft, assembled the case halves, torqued the through bolts. Then disassembled and checked the plastiguage on each of the seven bearing shells. Each bearing was an identical .002in. clearance. I also mic'd the shells and compared this dimension with the stock bearings that came out of the motor (virtually identical). All the bearings fit snugly in their saddles and look to fit perfectly in this application.

http://forums.pelicanparts.com/uploa...1355644102.jpg

http://forums.pelicanparts.com/uploa...1355644151.jpg

http://forums.pelicanparts.com/uploa...1355644182.jpg

Here's what the Calico Rod bearings look like

http://forums.pelicanparts.com/uploa...1355644481.jpg

http://forums.pelicanparts.com/uploa...1355644626.jpg

http://forums.pelicanparts.com/uploa...1355644733.jpg

GT3 rod bearings have some sort of coating on them that is different than the mains. I don't know the specifics

I tend to think that the GT3 rod bearings should be plenty sufficient for our use, given the nature of the GT3 engine- high rpm. If it's good enough for a GT3 8000+ RPM motor, they're more than capable for our mildly modified older engines?

Thanks for the heads up on the GT3 motorsport mains. I'll look into those when I send Don my order next week!

WOW!!! Those look really nice! Kind of sick i get turned by these beautiful little bearings. :eek:

That looks like the same coating I have done by HPC.

There should be some markings on the bearing shells to tell you who the manufacture is.

I am pretty sure Calico does not manufacture bearings. They are a coating company (and a good one). Last I dealt with them - a couple of years ago - I remember that they could get you quick turn around if you sent them new bearings in the box, as they had already coated a number of bearings often requested by customers. So your new ones were more like a core charge. Doesn't surprise me if they decided they could also just sell new ones they coated directly - though taking something for their trouble, costs, and risks out of the deal beyond just the coating and their supplier's charges to them.

I was thinking the same thing.

I am building a 3.0 l SC motor and could use some assistance.

Could someone please confirm the part# for the GT3 Main Bearings? The number mentioned above does not come up with the correct part for me?

Also I would like a part# for the GT3 Rod bearings

Thanks

John

What is the deal with the colors on the GT3 crankshaft and main bearing sizes?

Porsche Motorsport lists 3 part numbers for 2004 GT3 #2-7 mains: 996.101.232.91 as well as numbers ending in a .92 and a .93

The .91 is for a Red marked crankshaft, .92 for a Yellow marked crankshaft and .93 for a Blue marked crankshaft.

The #1 bearing has a similar number/color scheme as well. 996.101.231.91 & .92 &. 93 for Red, Yellow, Blue cranks respectively

The Porsche street catalog only lists the .92 bearings for the #1 to #7 bearings, not the others.

Con rod bearings are 996.103.121.94 with no color references and is the same number in both street and motorsport books.

The #8 is the same old 964.101.138.01 number we know and love.



What is all this about?

Also, if one had in hand a fresh set of the Glyco bubble packed bearings that look very nice, would you go Porsche Motorsport bearings anyway with a GT3 crank?

Talking to Don at EBS, it seems that Porsche divides the GT3 crankshafts into size groups as they do cylinder groups and the bearing selections are for tighter control of the clearances.

My theory is that after production QC check that more cranks come out "nominal" in the middle = the yellow cranks and thus end up in street engines and the red and blue marked cranks are the plus and minus from nominal dimension cranks that are fewer in number and therefore go into the race engines and why only the .92 bearings are available from dealers.

So do we need red / yellow or blue for a street 89 930?
Thanks

What is the difference in measurements between Yellow,blue or red?
will these GT3 bearings fit a 1986 3.2 mains?
Thanks

I cannot locate thread tools on my iphone, sorry.

Bringing an old thread back...

Bought the glyco main bearings and also found them .0005 thinner than my old bearings...

So, do gt3 bearings work in a 88 930? Anyone use the calico bearings mentioned?

From what I understand the Glyco main bearings are fine to use in a street or track engines. It's the Glyco rod bearings that are not good for engines built for sustained high RPM track use. The right bearings are the ones made by Automobile Associates with the calico coating. These are available through pelican

My understanding is Glyco only had a short run of bad rod bearings. I took mine apart after 5 years, and they were totally fine. I'm 600 hp give or take, rev to 6750, so I've definitely put some decent stress on them. I'm sure 8000 RPM stresses more than hp, but no problems on my end.

Both the glyco main and Clevites rod bearings, which is what I have, look fine.

That's not the issue. They are thinner than the old bearings by 0.0005. Making my clearance .001 greater, putting it out of range for spec...

Why they are thinner I have no idea, but they are, as others have noticed... I kind of wonder if Porsche at the factory simply used bearings that were thicker depending on crank size.

Was going to use plastigauge to check case clearance today, but cleaning the case took waaaay longer than I thought....

The crank is in spec, on the low end of spec. Looks new, 55k miles or so. Not a scratch on it. With current old bearings all works fine... Putting in thinner bearings will lower oil pressure...

Ok... updates...

HM Elliot does do coatings, as Ollies posted earlier...

Cost is super reasonable. $5 a pair of rod bearings, $7 a pair of crank bearings...

Adds .0002 to .0004 to each bearing.

They do new and used bearings. The coating is a baked on Teflon coating...

They are doing this for a lot of cars whose bearings are NLA.

Cost is certainly reasonable... $30!


Anyone done this? Thoughts?

Teflon, as far as I know, is a hard substance... Risk to Crank?

Teflon is quite soft. No way it could ever scratch a crank, unless a foreign particle became embedded in it.

Really?! Gee my teflon pans are rock hard, can't scratch with a knife...