excessive oil pressure

[gregm]

About six months ago I replaced/overhauled the engine in my brother"s 1960 series I d17 allis chalmers. It ran great for about three months or so mowing his pasture and ditches. Then one day when he tried to start it, it blew the oil filter apart at the seam! I know that there must be a restriction and/or lack of but I do not know where to begin other than taking the oil pan off and start blowing through lines. As I mentioned before I replaced the block and did an engine overhaul. I blew every oil passage out when I overhauled it and being that the engine did not run odd when he parked it, I do not fill that it may have prematurely spun a bearing. The only thing I can think of is that the oil pressure regulator went bad, but where is it on this engine? The old block housed it next to the dipstick, which is easy to adjust or replace externally. The new block is the new style oil system with the internal threaded oil filter and this style does not have an external oil regulator . I have heard that the regulator is part of the oil pump on this system. Any help or suggetions?

 

[Gary in Mozarks]

I ran into the same problem in a 56 chevy engine. Blew the oil filter right off it. Oil pumps put out pressure in proportion to their RPM so to keep it from going above a certain level they put a spring loaded bypass valve in it to run excess pressure back into the oil pan. Your bypass valve is stuck and you need to change the oil pump. I replaced mine and its been fine ever since. Hope this helps.

 

[Mark]

just fix/change the bypass valve if possible. Obviously the pump is working fine! Who knows, it may have picked up something in the oil, sucked into the valve and stuck it closed.

 

[MSM]

Did you use the old oil pump on the new block? The old pump in the new block is unregulated and is probably building 100+# of oil pressure.You will have to install the correct oil pump,with the internal regulator.

 

[gregm]

I did reuse the old oil pump but if it was truly unregulated why did it take roughly 5 months for this problem to surface?