8SECONDSS Posted April 7, 2013 Report Posted April 7, 2013 I have a 47 Dodge 1/2 ton truck with a 218 flathead. I had an oil leak from the oil pump cover and replaced the gasket with a o-ring. I started it up and the leak stopped. I didnt noticed the oil gauge was on zero but i ran it for a while until it started to knock. I installed the old gasket and the pressure was back to 40lbs on idle cold. ordered a new oil pump, installed it, and the pressure was on 40 cold idle but when I drove it, the pressure was fluctuating from 40 to 10 lbs. When the rpm goes up, the pressure drops, and knocking under load. Without load no knock. I have the sealed canister oil filter on it. Drained the oil, but couldn't see any filings or bearing material. Was wondering if the filter could be plugged. The filter looks about 50 yrs old. Any help would be apreciated. Thank, Greg Quote
T120 Posted April 7, 2013 Report Posted April 7, 2013 (edited) Maybe check the oil pressure relief valve to ensure it's okay.Might be worth removing the oil pan to take a look,pickup screen...etc. Edited April 7, 2013 by Ralph D25cpe Quote
Barabbas Posted April 7, 2013 Report Posted April 7, 2013 The oil filter is a by-pass filter, filtering only about 10% of the oil at a given moment. If the filter is plugged the oil will still circulate in the engine and pressure will be maintained Quote
Plymouthy Adams Posted April 7, 2013 Report Posted April 7, 2013 it may be a good time to drop the pan and inspect for damaged inserts before you run the engine much more... Quote
8SECONDSS Posted April 7, 2013 Author Report Posted April 7, 2013 I'll drop the pan and check the pressure relief valve and let you know what I find, Thanks, Greg Quote
Dodgeb4ya Posted April 7, 2013 Report Posted April 7, 2013 I'd be looking at the rod and main bearings for sure. Quote
T120 Posted April 8, 2013 Report Posted April 8, 2013 This series of videos was referred to in another thread.This one on engine oiling is worth watching as it relates to this problem... Quote
greg g Posted April 8, 2013 Report Posted April 8, 2013 The clearence between the impellers and the body of the pump has a great deal to do with pumping effiency. When you substituted an O ring rather than the specified gasket you changed that clearence. Reverting to a proper gasket will likely return the pump to its former efffecacy. Quote
Don Coatney Posted April 8, 2013 Report Posted April 8, 2013 I'll drop the pan and check the pressure relief valve and let you know what I find, Thanks, Greg It is not necessary to drop the pan to check the pressure plunger. But like others I recommebd you pull the pan and inspect the bearings. Quote
8SECONDSS Posted April 8, 2013 Author Report Posted April 8, 2013 I drained the new oil yesterday and saw maybe 10 small copper dots on the bottom of the drain pan. i'll check the pressure relief valve first. Thanks for all the help, Greg Quote
8SECONDSS Posted April 13, 2013 Author Report Posted April 13, 2013 Pulled pan lots of bearing material on bottom of pan, pulled conrod cap and doesn't look good. The pressure relief valve was ok. Will pull engine. Thanks for the help, Greg Quote
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