Converting to roller crank bearings?
Converting to roller crank bearings?
(OP)
I am building an engine for a car that is being built with throttlebodies, large cams, etc and will be a screamer.
The biggest problem with high revs on these engines seems to be the failure of the lower end bearings. I would like to be able to find a company that can convert my lower end from 'plain' bearings to roller bearings in both the crank and rod bearings.
Any thoughts or ideas??
The biggest problem with high revs on these engines seems to be the failure of the lower end bearings. I would like to be able to find a company that can convert my lower end from 'plain' bearings to roller bearings in both the crank and rod bearings.
Any thoughts or ideas??





RE: Converting to roller crank bearings?
RE: Converting to roller crank bearings?
What kind of car and what engine. How much horsepower at what rpm are you trying to make. Is the oil film breaking down, or are the bearing caps flexing? Is it a bearing problem or is the crank flexing?
RE: Converting to roller crank bearings?
If you have an engine that is losing its lower end repeatedly, there is someting wrong with its design, construction, assembly, clearances, oil type, and the list goes on.
Roller bearings are no problem for high rpm, not not for high loading.
Franz
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RE: Converting to roller crank bearings?
Four bolt mains help this situation. In circumstances where two bolt mains are the only option, you can have a shop Dowel the main caps to the block. I have Doweled many blocks, one of which, a 736 hp, pump gas v-8. Good luck.
RE: Converting to roller crank bearings?
My experience with motorcycle engines is that singles always have needle bearings in the lower end (I guess it´s because it´s possible due to having built crankshafts, contrary to forged), whereas multicylinder engines use plain bearings.
Any thoughts why this is the case? Surely the hydro static "lube" system is the more sophisticated one!
RE: Converting to roller crank bearings?
Regards
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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Converting to roller crank bearings?
RE: Converting to roller crank bearings?
RE: Converting to roller crank bearings?
All off roaders who also used VW engines also have avoided roller cranks because of reliability problems and these units only had rollers in the rod journals not on the main bearings.
I would say forget the idea, besides I doubt that there will be enough "meat" to carve at the main bearing caps in order to fit the neadle bearings.
Cheers
SACEM1
RE: Converting to roller crank bearings?
The whole system is most likly very weak. And after all that expense you would end up having the same problem with rollers as well. Is the crank case iron or aluminum?
What is the crank material?
Maybe your cheaper and more affordable route would be to transplant an engine capable of generating the kinda power you want. The Chevrolet small block comes to mind.
And the after market speed equipment parts availability is mind boggling. If a V8 is not the answer then consider a V-6 Chevrolet.