First, I am a Engine builder with over 25 years of experience , but am always willing to learn something , humble enough to realize that I don't know everything ( www.kevinsmachine.com )
I have got a 304 that is whuppin my A$$ , rebuilt this 304 out of a 78' Jeep CJ last December for a friend of mine , we mainly do custom and performance ,so we meticulously do cleaning and machining , stock replacement's I usually order from ATK, LKQ , none were avail. at the time , so we did it ,
ran great for 6months , cust. called me with oil press issues , told him to pull it , tore it down ,sure enough ,bearing issues ,bad enough journals on crank were compromised , scratched my head to figure out why it happened
Even got on this site and did a lot of research about all the oiling issues these engines have ,especially after a rebuild
upon inspection noticed that the bypass valve for the pump was sticking , even after we had removed and deburred and honed the bore from the first rebuild , figured the aluminum housing got distorted while going thru heat cycles ,I just happen to have another 304 in the shop at the same time out of a 70 Javelin , didn't want to take any chances ,so i used the housing off it ( was in better shape) went thru all the setting end play on pump gears and addressed all other issues talked about on this site , reassembled put oil and filter (WIX) on , then primed it ,so the customer wouldn't have too
Now it's done it again , and the oil pressure is still around 50psi with no reporting from the customer ever loosing oil pressure ( mechanical autometer guage )
Bypass valve sticking. Was it any other color spring besides red? Was the spring broken? Bore should be .563-.565. If the bore is completely worn out that could be an issue as debris in the oil could be. I would make sure there is no fram on there first. Then I would drain the pan and take a look and from there take the oil filter adaptor off and bench test the valve using a rubber tipped compressed air nozzle on the filter side and use my finger on the other side. If it is physically holding it up then youll know why.
Well , I own a NAPA store so I know what filter was on it , red spring , bore looks clean from where we cleaned it last time , Ill set my dial bore gauge up in the morning and check the size , definitely not sliding as smooth as it did when i assembled it last time , do you have the nickel plated housing in ?
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