Low oil pressure on my 429??????

[68swb]

Ok so i have a problem, my truck started to knock at hot idle, so i let it cool down and i installed a manual oil press gauge, started my truck up and it had about 10 psi of oil press., then i checked the oil and it was seemed a little thin, i changed the oil and filter and used 15w40, started the engine up again to check the oil press, it went to 50 psi great, thought the problem was fixed, well i let the truck warm, and as it warmed up the the oil press slowly dropped off. So there i am at idle with 10 psi of oil press, when i rev the engine up to 2000 rpm i get 20 psi and at 3000 rpm i get 30 psi, that still seems to low for me. all i can think of is when i built my engine, like a dummy, i didnt change my oil pump, i changed the main bearnings and rod bearnings, but they looked good, but i did change the cam bearnings cause they looked good aswell, so my question is with out pulling the oil pan, what else can i do to condim the oil pump, or find another problem,. Sorry fot the long post and all just want to let you all know the story. by the way it is a 76' 429 stock bore, stock bearning size, edle. cam, and edle carb. other than that all stock.... thanks for the help....

[Jake11]

Wore out pump. Rod bering loose now causing internal leak. Looks like your gonna end up pulling the pan and replacing
the pump and rod berings. Just my 2cents. The factory pumps are aluminum housing. They wear out.

[68swb]

well i kinda thought i was going to have to pull the pan and just inspect, looks like that is what i am going to be doing on sunday....

[fomocoguy]

I agree, pump and rod bearings. If it's knocking at low rpms with hot oil there is probably already enough damage done to the rod bearings that they will be bad in short order, if not already. While your in there you may as well change them!

[68swb]

when i have the pan down i will pull a rod cap and look at it, i hope that they are going to be ok, the knock is from the rocker arms, i dont have a lower end knock, but i will look and if i need to replace them i will, hope i will be able to pull the pan with out lifting the engine, but i will see... thanks again for the insite.

[Jake11]

Don't want to argue or such, but rockers clikkety clack/ rods knock/bang. Which is it? If you got a oiling pressure
problem it ain't no rocker arm causing it less it broke in half and flew off the rocker shaft/ball. If ya think yer leaks in the
upper end pull the distributor. Tape a thinwall 5/16" deep socket to a speed handle. Put it on the oil pump driveshaft
and crank it left. Take the valve covers off and see if lot's of oil sqirts out. If theres no bad leaks internal you'll get
tired cranking the speed handle pretty quick. Hook a guage up too! Should get 35psi or better. Jake

[68swb]

the rods are not knocking, but after the engine warms up, at idle the rockers clatter because the oil press. drops, i beleive that the oil pump is shot, started the disassembly process to get to the oil pump. so we will see when i get the pump out, i will measure it with feller gauge to see it the gears and/or housing is worn.

[68swb]

its been awhile since i posted this tread, but i guess i will give an update on it, so i got the engine out and pulled the pan, well the bearing all looked good still, i pulled the oil pump down and took it apart, and it didnt look bad either, had a line wore in it that you could bearly feel with your finger nail, bought a new pump anyways. i did notice that when i removed the pump it did not have the gskt between the pump and the motor. so i was looking thru the gskt i had from the rebuild and there it was the oil pump gskt .... i felt like i was forgetting something when i assembled the motor back when i did. well i have learned from my mistake and put the new pump on with a gskt. but while i had the motor out i done a few more upgrades, pwr steering, painted the firewall, will be adding a np435 instead of the 3 spd, since i am changing the coloumn to a pwr steering column.. will post a few pic this weekend after i get it all installed....