Hi, I know this has been discussed before, but I need to ask! LoL.

first some history:
my car is a 83 4.7 euro auto.
my # 1 main bearing is one piece 360 oil groove
# 2 is split with 360 oil groove
# 3 thrust is the larger updated one
# 4&5 or split with 360 oil groove

my question is can I use 944 main bearing on # 1,2,4, and 5. And buy the # 3 separate?

Reason is I already have a set of 944 bearings part # H006/5 std.
I will be measuring everything of course.

Thanks for your time!

 

If you want to retain the 360 degree oil grooves, you will need to buy 2 sets of 944 bearings....and throw away 6 ungrooved bearings.
You will have to have someone groove the #1 main bearing past the 220 degrees it is already grooved.
And yes, you will need to buy separate center thrust bearings (#3) for the wide flange crankshaft.

 

thanks, I’m not concerned about keeping the 360 oil groove, so I’m good to go! Thanks again for your help!

 

It has been discussed in length which oil groove length is optimal for the main bearings. It is considered by everyone that a 360 degree full groove is old fashioned and should be avoided. Today a simple 180 groove (only upper bearing grooved) is considered the best compromise.
https://www.mahle-aftermarket.com/me...dfs/tb2051.pdf
Åke

 

Thanks, I was just wanting to make sure the 944 bearings would fit, they are 180 grooved just as the later 928s are somewhere around mid 83 on. Thanks for your input!

 

Porsche has their current bearings for the 944 and 928 engines grooved 20 degrees into the plain bearing, on each side.
So, the total groove length is about 220 degrees.

That little "blurp" from Mahle is a bit surprising.
There's so much more involved than just the length of the groove in the bearing.
Little known, because it is such a tiny detail that not many people would notice, is that when Porsche changed to 220 degree oiling, they also significantly reduced the size of the drillings through the crankshaft, apparently to make sure that the crankshaft would have a completely filled cavity when using the 220 degree oiling.
The location of the oiling drilling to the rod bearing also becomes of extreme importance.

 

Main bearing modified for racing. 227 degree groove.
Åke