Shell Bearings - Help Required

J

Jonny's Cabbi

Junior Member
Hi I run an English 14.9hp 2.0 litre engine in my Cabi and travel a couple of thousand miles a year. The engine revs 400rpm faster than a 24 3.o litre standard engine. It seems the centre main is a weak spot as it has gone again and I am going to put shell bearings in for longevity. My Question is are there any differences in quality in the shells from differing parts vendors such as Brattons, Snyders Mikes etc?
 
Don't know, but make sure the crankshaft is not bent (at all). It needs to be straight or it beats the center usually.

Welcome to the barn, a lot of help here but I'm not familiar with that engine. How about a few photos it and the car for the Barn?
 
Jonny's Cabbi said:
Hi I run an English 14.9hp 2.0 litre engine in my Cabi and travel a couple of thousand miles a year. The engine revs 400rpm faster than a 24 3.o litre standard engine. It seems the centre main is a weak spot as it has gone again and I am going to put shell bearings in for longevity. My Question is are there any differences in quality in the shells from differing parts vendors such as Brattons, Snyders Mikes etc?
Click to expand...

Do understand that the center main bearing is NOT the weak spot. The weak link is your engine rebuilder. Correct that, ...and you will have an engine that will give you many, many miles of service. They gave many, many miles of trouble-free service when new, -and the capabilities of modern engine machinery and cast bearing materials today should equal that.
 
I saw your post on the MAFCA facebook page, it showed the cracking across the length of the bearing on the block side of the center main bearing. I'm not a babbit man, nor do I portend to be, pouring babbit is an art and a science.. but I have witnessed the process from start to finish. I agree with Brett, the center main bearing properly installed and maintained will give adequate service life. I'm going to guess that your failures have to do with your babbit mans process. Load failures occur on the cap side in my limited experience, block side failure for the most part are the installers.

That being said, correctly installed precision insert bearings will fix the root cause of the failure, but I also contend a properly installed poured bearing will fix the root cause as well.
 
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