Upgrade to HEI, lost oil pressure

[Piece of Work]

I installed my new HEI distributor today, all went well. It started up easily, idled fine, oil pressure was good, throttle responses was good. Took it for a test drive and about a 1/4 mile down the road, I lost all oil pressure. Also making an odd noise from the engine. Any ideas on what happened? Where do I start to find the solution? Is possible the loss of oil pressure is related to the Dizzy replacement? All ideas are welcome and much appreciated.


-Mark

[67_C-30]

Its impossible to say w/o hearing it. Is it a knocking sound? Where does the sound seem like its coming from. I hate so say it, but if it has no oil pressure, I'd plan on taking it out and pulling it apart.

[Piece of Work]

The sound is not a knock, more of a fast tapping sound from the rear of the engine that rises and falls with RPM.


-Mark

[cdowns]

i'd plan on dropping the pan and changing the pump and pump rod might also want to pull the dizz to see if the end is ok

[68gmsee]

My .02 worth...

Before you drop the oil pan, remove the old distributor and check the shaft, gears and especially the underside where it engages with the oil pump. Make sure nothing is broken..

If all looks good with the distributor and shaft and you're sure that it was seated all the way down and engaged with the oil pump properly, then proceed with the other checks.

[Piece of Work]

Oil pressure issue resolved! The new distributor was not seated all the way in. I loosened the hold down clamp and turned the engine manually, until the dizzy fell in place. Tightened up the clamp, cranked it over and the oil pressure climbed while cranking. Now the timing is way off! so hopefully tomorrow I will be able to pull the distributor, crank the engine to TDC @ #1 and reinstall it properly, now that I know how it seats. With a little luck, it should fire up.


-Mark

[mnunn454]

You should be fine, but the vertical pressure that the incorrectly seated distrib put on the oil pump drive shaft couldn't have done the oil pump any good. My guess is it probably scored the surface between the gear and the machined cast iron bottom of the pump.

Hopefully the oil filter caught any of the tiny cast iron shavings. It wouldn't hurt though to change oil filter tomorrow and a couple of more times over the next week or so. Cast iron in the oil doesn't play well with bearings.

Also, while the distrib is out tomorrow, suggest you check the vertical end-play between the gear and the bottom of the distrib housing. The thrust surface there is usually only a couple of washers and they could have sustained some wear as well. Ideally you should have about .015" to .020" clearance (if memory serves me). If distrib shaft end play is more than about .030" then I'd pull it apart and shim it with some thicker shim/washers.

JMO.

[Piece of Work]

Thanks for tip! I never thought about the possibility of metal in the oil. Will check everything as you suggested. I really need to get another 20,000 miles out of this old tired engine.


-Mark

[Piece of Work]

Quick update.
I pulled it back out and there was no sign of any damage. Installed again, properly seated, put everything back together, and it started right up. Good oil pressure, smooth idle and good power. I have put 7000 miles on it since March and it has never run as good as it does now. Thanks to all for the help.


-Mark