The Care and Feeding of Your New Crankshaft
The Care and Feeding of Your New Crankshaft by Ohio Crank staff.
FIRST
Be sure you have the right parts, that they are what you ordered, that they weren’t damaged in shipment.
Then check that the parts are actually going to work for your application, that they fit your block, etc.
Oil Clearance
The final decision is up to the engine builder. We are fortunate that the race bearing suppliers have almost an unlimited amount of over/under size bearings to achieve nearly any clearance.
Our crankshafts are generally finished to the lower (smaller) side of the OEM specs, to allow adequate clearance for most application. Please call us to discuss clearances for your particular application. Oil clearance is affected by the diameter of the main saddles or rod big end sizes, the diameter of the shaft, and variations in the bearings themselves.
Bearings
The bearing is not actually round when torqued, due to bearing crush, and should be measured in several places.Cleaning The last thing to do, after all fitting, machining, clearancing, etc. has been done, is a thorough cleaning of the crankshaft. Be sure and run a small brush through all the oil passages.
Motor Oil
In most application we recommend a 20w50 racing oil. We do not recommend the use of heavy weight, single grade, like 50 or 60w. If these heavy oils need to be used, they must be pre-heated before starting. No types of “break in” oils should be used. There are many synthetic products on the market, but we don’t have enough experience with them at this time.
How Much Oil?
Good motors are ruined everyday simply because there was not enough oil in the pan. The oil in a wet sump pan is acted on by acceleration, braking, turning, etc. Also oil does not drain back to the pan as well under these conditions.
Drag race dry sump tanks are very small, after starting more oil may need to be added to these. Start with plenty of oil, a little too much is a whole lot better than not enough.
Oil Filters
Generally a high performance filter, mounted in the stock location is best. On Chevrolets we recommend the stock filter adapter not be modified. If a remote filter must be used, a lot of effort must be used to design a system that absolutely insures unrestricted oil flow. We do not recommend adding a “screen” to the filter.
Pans and Pickups
We suggest the largest pan suitable for the application. Pickup location is critical, the bottom of the pickup should be as close to 3/8″ off the bottom of the pan as possible. Many engines have been damaged when the bottom of the pan got pushed in a little and choked off oil flow.
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