blown oil pump gasket after oil change
blown oil pump gasket after oil change
I have a 1977 shovel head chopper. Everything was run and smooth. I went to an oil change and I warmed the bike up like I normally do emptied the oil took the filter off clean the area out put on a new filter added some more oil. Just like I normally do. Went to kick it over it started up, but then it blew a gasket in my oil pump. I replaced the gasket, checked all of the orifices in the cover of the oil pump. Everything works fine. All the lines are open and free-flowing. I blew air through all of them. The problem seems to be on the return line that pushes oil through the oil bag plumbing into the filter and then back into the oil bag. My oil bag has a spin on filter that takes an evo spin on filter. I removed the oil filter and ran air from the hose fitting on the return line of the oil pump through the oil bag and theres no restriction. I also pushed air from the hole where the filter spits oil back into the oil bag. No restriction. Im assuming my filter is bad and the cause of the problem. Ive never had a filter do this before and I dont know how a filter can be bad. Any thoughts or suggestions?
Stellar HDF Member
Joined: Aug 2020
Posts: 3,185
Likes: 2,228
From: College Station, TX
Not sure about your oil line routing and tank setup, but the return out of the pump usually goes to the oil cooler (if you have one) and then the filter before it goes back to the tank. I'd be looking at everything between there. With the filter being the primary suspect because it's the only hard part that was replaced.
I saw that you blew air through the lines, but did you do that from the return line out of the pump while the filter was still in place?
The pressure relief in the pump should release at 65 lbs. So check the oiln pump body and cover carefully for any scrartches or low areas. Use a good oil pump gasket, like Cometic.
Paul
I saw that you blew air through the lines, but did you do that from the return line out of the pump while the filter was still in place?
The pressure relief in the pump should release at 65 lbs. So check the oiln pump body and cover carefully for any scrartches or low areas. Use a good oil pump gasket, like Cometic.
Paul
Road Master
Joined: Mar 2012
Posts: 1,041
Likes: 997
From: Ohio
They are rare to fail. I know a man that had changed his oil filter and changed oil in his 302 F100 truck, so about a 1974 I think it was, he drove it about a day, then out of nowhere he lost all oil pressure. It was the oil filter that was the problem.
Stellar HDF Member
Joined: Apr 2016
Posts: 3,325
Likes: 2,115
From: Masshole
2 possibilities I see.
1. Like Max said, reverse routing of supply and return not allowing thru the anti drain back valve. The outside holes are the return from engine, goes thru the filter and the center is the return to the tank. It's possible you have been running it reversed for years and not have an anti drain back valve.
2. Defective anti drain back valve. This I have actually seen before, once, it was many many years ago tho. The "flapper" was essentially fused to the upper plate of the filter not allowing the oil to flow thru it.
1. Like Max said, reverse routing of supply and return not allowing thru the anti drain back valve. The outside holes are the return from engine, goes thru the filter and the center is the return to the tank. It's possible you have been running it reversed for years and not have an anti drain back valve.
2. Defective anti drain back valve. This I have actually seen before, once, it was many many years ago tho. The "flapper" was essentially fused to the upper plate of the filter not allowing the oil to flow thru it.
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I dont think so. I mean, the filter only goes on one way. And Ive been running this bike for 12 years with the oil lines hooked up the way they are. I triple checked, and all of these lines are hooked up the way they should.
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Joe Kucinski
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,939
Likes: 8,036
From: poway
If you still have the old filter, check to see if it has the back flow valve. If it don't then it's a possibility. The only other things are that the return line is some how plugged / crimped or the filter don't flow.
unfortunately, I tossed the old filter. Im going to the dealership after work to pick up a new filter.