Good oil pressure but no oil in heads
- Thread starter fly_25
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Okay so I popped the valve covers off, poured some oil all over the rockers, and ran it till it was hot and eventually saw oil shooting out of the pushrods. Everything seemed to have checked out!
Seem to recall that the rocker shafts are hollow or drilled and that oil is fed to them through one of the pedestals? It has been more than just a minute since I last took a 231 rocker shaft assembly apart but I am still reasonably certain that the shaft can't just be set in place on a random basis; it has to be clocked or positioned on its pedestals in such a fashion that oil can flow from elsewhere can move through it.
What is puzzling me is that the dimples showing on the first two rockers for the pushrods seem to be drilled and that makes no sense if the oil delivery is through the shaft and the return is by drain back through the heads and down into the pan. I don't recall mine being drilled but that motor committed suicide back around 1990 with over several hundred thousand kilometers on it. (The metric measurement system is a crock of drool that our government foisted off on this nation around a half century or so ago MPITA)
Since you did manage to get circulation appearing at the top end the next step is to do an oil change to see what comes out of the oil pan now that the oil is moving more thoroughly. Take the old filter and cut the top off it and pull out the filter paper to see what is trapped in the pleats. What you find in the filter can give you a better idea of what might be lurking in the oil passages in you motor.
Nick
What is puzzling me is that the dimples showing on the first two rockers for the pushrods seem to be drilled and that makes no sense if the oil delivery is through the shaft and the return is by drain back through the heads and down into the pan. I don't recall mine being drilled but that motor committed suicide back around 1990 with over several hundred thousand kilometers on it. (The metric measurement system is a crock of drool that our government foisted off on this nation around a half century or so ago MPITA)
Since you did manage to get circulation appearing at the top end the next step is to do an oil change to see what comes out of the oil pan now that the oil is moving more thoroughly. Take the old filter and cut the top off it and pull out the filter paper to see what is trapped in the pleats. What you find in the filter can give you a better idea of what might be lurking in the oil passages in you motor.
Nick
The holes near the pushrod pockets and the big hole in the rocker shaft between the back two sets of rockers says this engines top end is lubed through the pushrods. Will have to research when they changed that.
First make sure you get the filter bypass valve repaired so it is using the filter, then follow nicks advice, If you find a bunch of junk in the filter keep changing the filter till it is clean when you cut it open.
Sometimes rock auto has real cheap closeout oil filters. I would get like six or eight and if it is real grungy change it every hour of operation. Just change the filter and top off the oil till it looks clean. Then you can do a real oil change with a good filter.
First make sure you get the filter bypass valve repaired so it is using the filter, then follow nicks advice, If you find a bunch of junk in the filter keep changing the filter till it is clean when you cut it open.
Sometimes rock auto has real cheap closeout oil filters. I would get like six or eight and if it is real grungy change it every hour of operation. Just change the filter and top off the oil till it looks clean. Then you can do a real oil change with a good filter.
Not just that but buick v6s are semi-notorious for the oil pump wearing a groove into the front timing cover.
Wonder what that looks like on this one given all the neglect
Pushrod Buick engines 1970+ all lube through the pushrods. Shaft oiling ended in late 1969. Your pushrods probably had some crap in them. Keep an eye on it. Before your next oil change pop a quart of atf or marvel mystery oil or something and let it idle for a few minutes from cold to warm. Drain the oil warm. Then change with a good quality non synthetic oil with zinc in it or a zinc addiditve added to the oil. And a wix, ac Delco, Napa gold, or Bosch filter. Something quality. Your oil pump.is probably about toast as well. It's only about 7ish little bolts and one behind the oil filter itself to remove the pump cover. Look at it next time.
Low hot idle oil pressure on an external oil pump Buick is usually a worn pump. Low across the board is wear or if a new build too loose bearing clearance. Buicks like .00175 -.002. Yes, that tight. Even the raciest engines stay on the high side of .002-.003. TA performance sells an oil pump shim kit to get proper .002 gear clearance as well as an adjustable regulator that goes in place of the big but on the pump housing to give you more cruise rpm oil pressure.
You'll know when the front cam bearing goes if the driver's lifters start ticking.
You'll know when the front cam bearing goes if the driver's lifters start ticking.
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I have since replaced the oil filter housing for one with a functional bypass valve, everything looked surprisingly clean with little to no wear! My oil pressure is solid when hot too so let's hope for the best
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