Main bearings 911 S oversized bore

[Fede44]

Hello again,

i´m having trouble searching for

Main bearings. Bore over size: 62.250
crank shaft undersize: 0.50

Porsche 911 S 1972 2.4l.

Are these bearings rare or difficult to find nowadays? Options and advices on brands, etc?

Thanks again,
Fede.

[ajwans]

Pelican Parts - Product Information: OEM-91110190175

andy

[mcfoo]

If you are looking for align bore bearings ,thats a tough one...and especially with second undersize .

They are like 'hens teeth" and could cost (if found$500-$1,OOO.

You can verify what I say by calling Ollie's or Competition Engineering.

You might try sourcing out a differnt case and/or crankshaft. Probably cheaper in the end when you might consider another re build down the road.
Tom B.

[Fede44]

Thanks for your replys,

ajwans: Those are std main bearings. The tricky thing here is the case has its bores oversized to 62.250 instead of 62.000 factory specs.

Just to complete the scenario, the crank shaft is 0.50 undersize.

mcfoo: I know they are not easy to find, but wonder how did they got the Glyco 62.250 0.50 that where in this block...

If they are not available nowadays i will have to rebore it to standard, machining both mate block surfaces....i would really appreciate experience from other workshops.

Fede.

[ajwans]

Originally Posted by Fede44

ajwans: Those are std main bearings. The tricky thing here is the case has its bores oversized to 62.250 instead of 62.000 factory specs.

Nope, the part number I gave is exactly what you asked for, standard are Pelican Parts - Product Information: 911-101-901-00-M41

andy

[chris_seven]

They are certainly the correct size.


Are the tangs on the correct side for the early engine?


I thought the 1974-77 engine had the tangs on the opposite sides.

[Fede44]

Andy / ajwans, looks like you found the hens teeth! Great.

Same question as chris_seven.

btw: how did you found those bearings? i can´t see them in the catalog even searching by 1974-1989 engines.

[Fede44]

Part number for standard bearings are the same from 1965 to 1977 according to the links below

Pelican Parts - Product Information: 911-101-901-00-M41

Pelican Parts - Product Information: 911-101-901-00-M41

[chris_seven]

Originally Posted by Fede44

Part number for standard bearings are the same from 1965 to 1977 according to the links below

Pelican Parts - Product Information: 911-101-901-00-M41

Pelican Parts - Product Information: 911-101-901-00-M41

I thought that from 1975 to 1977, which I believe were Carrera 3 - 6 bolt 3.0 litre , had tangs reversed compared to all other engines.

It is possible to re-machine the cases to take the opposite hand tangs.

The 91110190175 Part Number is NLA on the latest PET and updates to an earlier 901 set of part numbers which are showing in stock in Germany BUT at a cost of around $650.00 for the complete set.

As they have 901 part numbers they may be the correct tang.

Part Numbers are 901.101.131.75 x 2

901.101.132.75 x 12

901.101.138.78 x 1

[docrodg]

After having to find 1st oversize bearings and contacting multiple reputable machine shops about machining and line boring I will pass on what I learned:

The cases cannot be brought back to std size once linebored to an oversize, it requires too much material be machined from the mating surfaces.

The oversize bearings can be very difficult to find and are extremely expensive.

That said, you may try contacting a few of the machine shops as suggested above to see if they have the bearings. I could not find them but the shop I am sending my case to has them.

[Fede44]

Just to complete the story.........

inside Rod Diameter at Big End: 56.75 mm. instead of 56.000 - 56.019 factory specs.

still, rod journal at crank shaft is in 51.465, (when it should be between: 51.471 - 51.490)

so now move on searching this misterious bearings that fit the inside diameter to 0.50 but are AGAIN re bored to + 0.75.....

[ajwans]

Originally Posted by Fede44

btw: how did you found those bearings? i can´t see them in the catalog even searching by 1974-1989 engines.

I used PET. I can't see any oddball oversize OD rod bearings however. I can't even think why you would overbore your rods like that. They aren't prone to warping to the same extent that a mag case is.

You might be able to find something which suits a ford or gm vehicle in a 2" journal size and grind the rod journals down further.

Did the bearings you took out have 901 numbers stamped into their back sides?

andy

[4sd911]

Did you try a Porsche dealer to source the bearings? They should be able to get them. I bought 1st line bore and standard crank from a dealer.

[chris_seven]

Pelican just confirmed that they cannot supply 91110190175 as a bearing set as they are NLA at Porsche.

I guess that this means that the only supply is from a local OPC and wait for them to arrive from Germany. Expensive but available.

As Andy says the PET doesn't show oversize rod bearings and there are none listed in the Spec Book.

I think I would look for a set of good used rods.

[Fede44]

No, the number in the bearing si not a Porsche part number, neither the factory who built it. The symbol is an S inside a circle. I think it is SINTERMETAL a local bearing and bushing manufacturer. They did it probably because a rod was with big out of round issues and probably a bearing failure, lack of oil, temperature in the shaft, bearing and rod......that, combined with someone who wanted to show off his work and adapt a local bearing. **** happens.

I am going to need 6 rods, normal 0.50 bearings for the rods (or maybe 0.70 if available and grind and polish crank shaft) and bolts and nuts.

The real problem is still the search of the bearings, if anyone can help me naming users and/or dealers wich can help me solve the problem, i appreciate.


Main bearings. Bore over size: 62.250
crank shaft undersize: 0.50

Porsche 911 S 1972 2.4l.


I´ll post some pictures soon.

[chris_seven]

Originally Posted by Fede44

The real problem is still the search of the bearings, if anyone can help me naming users and/or dealers wich can help me solve the problem, i appreciate.


Main bearings. Bore over size: 62.250
crank shaft undersize: 0.50

Porsche 911 S 1972 2.4l.


I´ll post some pictures soon.

Part Numbers:

901.101.131.75 x 2

901.101.132.75 x 12

901.101.138.78 x 1

These are the update Part Numbers shown in The PET and my local Porsche Main Dealer tells me that they are in stock in Germany so any Porsche Dealer can order them using these part numbers.

They are 0.25mm oversize on the case and 0.5mm undersize on the crank.

They are shown on the PET on Illustration 102-00 for the 1972MY

The only problem is the price.

[Fede44]

Thanks for all your help Chris, i am asking for this parts and are available as you said in Germany.
Fede.