First Start-up problem after Rebuild ('67-327)

[Steve Vaughan]

After over a year of work including complete chasis/suspension and engine restoration, yesterday was the key milestone to restart my 327/350 engine. The engine started quite easily and sounded very good but oil pressure is too low. I would appreciate hearing thoughts on potential casues. All chasis/suspension work I did personally but the internal engine machine work I had done with a reputable machine shop.

The engine is a correct 327/350 that was returned from the machine shop bored .030 with new pistons/cam/lifters. The machine shop replaced the timing chain and timing cover/balancer. I installed a new Melling oil pump and prior to starting installed a modified distributor to drive the oil pump to pre-oil the engine. The oil pressure while driving the oil pump was lower than I expected but was about 30PSI. Watching the rockers while driving the oil pump showed a little oil coming through a few push rods, I manually rotated the engine two revs while driving the oil pump. The engine was then cranked without the coil hooked up and verified fuel filled carb. Coil was then connected and the engine started immediately but the oil pressure was only about 15 PSI at 2000RPM. I shut down the engine after a few seconds and removed the valve covers to check for oil in/around rockers. Seemed like adequate oil pumped into rocker area, so I restarted engine and let warm up for 5 minutes until oil pressure began to drop below 15 PSI. I installed a second oil pressure gauge and restarted engine the second gauage also read presssure below 15 PSI.

I then removed oil pan to recheck oil pump, everything looked fine. Any ideas what could be wrong??

[Clem Z.]

Re: First Start-up problem after Rebuild ('67-327)

check to make sure they installed the plugs in the oil gallerys behind the cam gear. also check to make sure the oil pump is tight against the rear main cap,look for any interferrance with oil pump body and main cap.

[Jim T.]

Re: First Start-up problem after Rebuild ('67-327)

Best recommendation I can give is to send retired race engine builder Clem Zahrobsky a e-mail for help.
I take a shot in the dark, since you have oil flow to the the lifters perhaps it could be the pressure relief valve in the oil system being stuck and not allowing pressure to build properly.

[Clem Z.]

Re: First Start-up problem after Rebuild ('67-327)

as jim posted the quickest test would be a different pump.

[Loren L.]

Sounds like the rear cam bearing is out

a position, allowing some of the oil to just fall back into the pan instead of circulating - if you don't have oil in the clutch area or in the timing chain area, you should be able to rule out galley plugs.

[Steve Vaughan]

Re: First Start-up problem after Rebuild ('67-327)

I think I have found the trouble. I removed the oil pump and made an adapter to mount to the pump outlet to mate with a flex line I submerge the pump pick up in a pan of oil and drove the pump with a drill motor. The pump put out a very strong stream of oil. Next we plugged the flex line with a pressure gage and the pump bypass opened at about 60PSI, I concluded the pump was not the problem. I next remounted the pump and without the oil pan in place held a small pan of oil up to the pump intake and drove it again with a drill attached to a subsitute distributor. It only took seconds for a gush of oil to come out of the bottom of the timing cover. It appears that Clem's first guess was on target, thanks Clem. My "reputable" machine shop apparently left out the lifer oil gallery plugs. Next I will disassemble engine front to confirm the missing plugs.

Is there anything special about installing these plugs, do they just install like mimi like freeze plugs??

[Mark F.]

Re: First Start-up problem after Rebuild ('67-327)

Steve:

Don't overlook that plug in the oil filter bypass system. If it's too far into the passage it will interfere with oil feeding into the upper part of the engine. Speaking from experience, 1/4 inch is a killer as far as this plug is concerned.

Mark