Bob1958
Well-Known Member
Anyone grove there own bearing uppers either 3/4 or full.
Do you just use a Dremel like toolI groove my own lowers for my slants. Uppers come from the mfgr grooved.
I use a die grinder, with a cutoff wheel. Doesn't look pretty, but works for me.Do you just use a Dremel like tool
With a bit?
If you read the article, it states by full grooving it is bad for the main bearing, but good for the rod bearing. In my case/application, I had issues with rod bearing failure (particuly #5). The mains on a slant six, are the same size as a Hemi. Also rotation speed of the crank, has an effect. Once I started doing full groove mains, I had no more bearing issues, and I have turned some my 170CID engines 7,000 rpm. I am not arguing for or against full groove mains. Just stating what worked for me (in slant sixes), for over 40 years.
The bearing material is much softer than the crank. A vertical burr on a main bearing will not scratch a crank.What would worry me [ & why I wouldn't do it at home ] is how do you know if you have raised a burr? Cutting, grinding metal, raises the edge. The brg clearance is a little over 0.001" if you are running the customary 0.0025" gap. Any metal protruding above the surface will scratch the crank & I know of no way of the home builder accurately assessing that small amount.
Crank journals are hardened. The steel backing on main bearings is not, that is so the bearing shell will conform to the crank main bores in the block.The soft brg material is ultra thin & the steel backing which is cut into is thick & will be raised. Photo copy paper is about 0.004" thick. How do you tell that the 'de-burr' didn't leave raised metal that only has to be 0.001" high to cut into the crank. By eye? By feel? Good luck with that. Wouldn't trust either method to pick up 0.001".
Good discussion guys thanks for the infoCrank journals are hardened. The steel backing on main bearings is not, that is so the bearing shell will conform to the crank main bores in the block.
To inspect, add a chamfer. With a chamfer present, there can not be a burr.
The crank journals wether a steel crank or a cast crank are induction hardened.Bob,
Some BS creeping in here. There is no mention of your crank material, but since you are talking about increased oiling, I assume it is a performance engine & using a forged steel crank. These can be Tufftrided or Nitrided, both extremely thin chemical treatments that are gone if the crank is ground undersize; some have neither treatment & are just plain ole steel...Same with cast iron crank, plain ole CI.
The steel brg shell is as hard as the f/steel or CI. It is a 'springy', hard, steel, because when you insert it, & then remove it, it springs back into shape; mild steel does not do that.
Unless you have some method of accurately checking for raised metal, as I described earlier in this thread, you would be better of not attempting this mod at home.