I became aware of cam bearing honing while researching how to rebuild a 351 Cleveland engine. It's possible that due to the 351's oil passage design and Ford's technique of honing cam bearings on new engines, there's an oil pressure issue with rebuilt Cleveland engines. Then, last night while re-reading Doc Frohmader's series of articles titled Y notta Y-block? I discovered that Y-blocks have the same issue with cam bearing alignment. I'm in the middle of two y-block rebuilds and still have the chance to get the cam bearings honed if I can locate a service or tool to get the job done.



I did a little research on the googles to see if there are cam bearing honing tools available and found some, but the prices are usually out of my range. The subject is mentioned so seldom that there seems to be very little knowledge or understanding of the matter. I think this effects Fords more than Scrubs and that might explain some of the lack of knowledge; in the past more people worked on Scrubs than Fords or anything else.



With regard to the Cleveland oiling issue. My understanding is that the front cam journal is bored and then the rest of the cam bearing journals are bored from the back of the block. Because the bars on the boring machines are horizontal, gravity causes the boring bar to sag by the time it gets to the #2 bearing journal and that the #3, and #4 are likewise effected although to a lesser degree. The result is that the #5 through #2 journals are in alignment with each other but are not lined up with the #1 journal. To make matters worse on the 351 Cleveland, the boring is done with the block upside down so the journals are aimed high, above the #1 journal. If you resort to the usual truck of 'scraping' the bearings, this leaves excess clearance on the underside of the #1 journal.



Because the main oil passage that comes from the pump is routed by the underside of the #1 journal, this excess clearance causes a loss of oil pressure before the oil even has a chance to pressurize the system.



I don't know if this is the cause of the chronic oil pressure issues with Cleveland engines, but it can't be helping.



Does anybody have experience with this? Do people usually scrape their bearings?

Best regards,



Paul Menten

Meridian, Idaho