402 BB loosing oil pressure and some pushrods dont get oil

[dwhitley167]

i just dropped a new cam in the 402, and had the heads refreshed with new springs, valves, etc. we put it back together, and it cranked right up. we went to check the pushrods to make sure they were pushin oil, and bout 3 of them wasnt pushin oil. and when we were going to dial in the timing, oil pressure was droppin, and the distributor felt like there was something loose in the bottom of it. but its a brand new cam and distributor. i was thinkin maybe oil pump goin out. any suggestions?

[John Pasinski]

I have that exact problem w/ my rebuilt 402. New lifters, cam, crank, rings etc. I've checked, & double checked, & triple checked every possibility I could think of that may be causing this problem. I removed, reinstalled, & removed again the intake to prime the pump using an oil pump priming tool. ALL LIFTERS prime up perfectly. Yet when I reassemble it, NO OIL to the #1 push rod. Got so frustrated, I just started driving it (normally). Yep..... the lifter clacking is very annoying. I've got about 2000 miles on it so far. Still running, still bugging me. I was told to R/R the pushrods; that will cure it. I doubt it, they're all perfectly straight, the same length, & clear. I'm looking for MR. Spock to do a Mind Meld to this thing & tell me what's causing it! I've received LOTS of suggestions from the board members. They're a great bunch of guys. I'm sorry for the depressing news, but I'm not sure how to help you with this problem.

[dwaite72lnghrn]

Did you check the pump rod to distributor? There is a plastic sleeve on the original which over time cracks. Replacement short shaft has a metal sleeve on it. That might cause the shaft to bounce loose loosing oil pressure.

[Hottrucks]

by chance did you do something funny to the cam bearing??? scratch ding bend?? I dont do a cam with out doing bearings...

[dwhitley167]

i was leaning more towards the oil pump rod, because the distributor felt a little weird when trying to time it. i just didnt know if there was an easier way to make sure that it is def it. instead of buying stuff i dont need, and trying to plug and play. and i talked to the guy at the machine shop about the cam bearings, and he said that as long as you dont damage them while removing and installing the cam that i should be good and they looked pretty good when i checked them.

[dwaite72lnghrn]

Before you pull the oil pan and pump check the tension on the push rod and make sure it is not too loose which will not let the push rod pump oil up the rockers.

[mclairmo]

I would not suspect the oil pump drive shaft just because 3 push rods have no oil. My grand-dad (a professional mechanic) would often see push rods not flowing oil and would just take some pliers and twist them back and forth while the engine is running until the oil started flowing. Apparently, the channel in the push rod can get plugged over time or the end holes get plugged up with crud. However, in your case, you feel something weird with the distributor. As such, you should pull the distributor and check that oil pump drive shaft collar and replace with a metal one just in case. Also, make sure you installed the correct cam bearings. You could also easily pull the offending push rods and clean them out, as well as the rocker arms.

[jbristo67]

Sorry to hi jack your post but I am about to put a new oil pump in my 396. How do you prime an oil pump?

[mclairmo]

Buy a primer with the built in collar that seals off the distributor hole in the block so as to get oil to both heads. The cheaper ones without the collar will only put oil to one head.