Chev 216 Oil Pressure

[Phil Waterman]

Hi Ken

Are you taking into account the camshaft turns at a lower speed than crankshaft, if I remember correctly. Don't have manual handy to confirm the difference.

Now as to oil pressure on 216 after rebuild I'll check my notes but the 40 psi sounds correct for drill prelube. Cranking the engine while using the drill is a good idea to be sure the engine is fully lubricated.

Did you use the heavy assembly lube as you put the engine together? If so that will increase oil pressure until it is washed out by the engine oil.

The splash/spray lubrication is a very high volume pump and the nozzles on the crank sprays will take care of most over pressure situations like a stuck pressure relief valve. My concern would be is the spray branch is blocked. If I remember correctly the spray can be confirmed by removing the fuel pump and looking in while priming with drill.

Please keep us posted on your progress.

Cheers Phil

[Ken Thomas]

Hi Phil, the speed of the camshaft and distributor is half the crankshaft speed and I allowed for this. I cannot understand that the relief valve can't limit the pressure to 15 PSI for whatever reason. I can only assume that for some reason the tightness of the bearings etc is causing some kind of pressure behind the valve ( I have seen this in other types of motors). I will push on for the time being until I have rebuilt the starter motor & then turn over the motor at the same time as spinning the pump. I will check the dipper sprays through the fuel pump mount. Will keep you all posted.

[Lynn Eades]

I don't fully understand what you are asking. How does the oil get past the camshaft? Often there is a cut out in the cam journal (or a hole through it) and this limits the flow to the valve gear. If the cam is in a certain position there is full flow, and in another position, no flow. The overall effect is a lower psi to the rocker gear (the rotation of the cam being a regulating device)

[Ken Thomas]

I am not sure what model Chev motor or oiling system you are referring to. I am referring to the output PSI of the oil pump and this PSI is determined by the relief valve which is integral to it and is irrelevant to anything further down the oil lines i.e. nothing can happen further down the lines to increase the pressure. It would seem that I either have a faulty relief valve OR as has been noted in this thread and is discussed in other Chev club pages etc. that a 216 motor with a new oil pump, ground crankshaft and cam shaft and all new bearings (all slippers, so the clearances should be correct) will give a PSI of 30 to 40 with a drill test driving the pump and even in an on road test. This decreases as the motor warms and "runs in". It appears to be understood that the "tightness" of the motor i.e. causing restriction to oil flow through the bearings, overcomes the flow capacity of the relief valve and it cannot bypass the volume of oil so that the PSI rises from 15 to 30+. Adding to this the crankshaft is not rotating in the drill test and is probably contributing to the lack of oil flow.
I will leave it now until I can fire up the motor, I should mention that the bypass filter filled nicely and there is flow to the rockers. The oil jets work well.