Oh no not now

[mag162]

So we switched from a 2 bbl to a 4 bbl Edelbrock 1406. Along with replacing the floor pans and installing some buckets. Put in some aftermarket gauges also. All was good until my buddy took the wagon out for a test ride this evening. First thing was a loud thumping noise when pressing the brakes. Ok we will check the brakes later. Then the oil pressure dropped to 10 PSI an and he said he could hear the “bearing whine”. I wouldn’t know what that sound is but. They were able to limp it home. This motor doesn’t smoke at all. Not a single puff of smoke at all. Could it just be the oil pump? Is it worth it to just swap out the oil
Pump and see what happens or pull the motor and send it out for a rebuild?

 

[FURYGT]

I assume that you checked the oil level and checked for gas or coolant in the oil. Assuming that she was not low on oil and assuming that the oil pressure gauge installed is accurate it probably makes sense to drop the pan and inspect the bottom end and take it from there. Maybe you will get lucky and the pickup fell off the pump.

 

[furious70]

I would start with an oil change, then pump change, easy stuff on a BB. Sometimes you have to pop the distributor out in order to get the oil drive back in. Just watch that the drive fear inside stays indexed. I've had low idle psi cured by a new pump

 

[Davea Lux]

As noted above change the oil first. Pull the filter and drain the oil out of the filter over a dark cloth, do you see metal? If so pull the pan and inspect the lower end. If you have spun a bearing, you are at least headed for a rebuild (Usually a spun rod will not cause the oil pressure to drop). Do not forget to check the pickup screen on the pump, the screen may be clogged with debris from a failing timing chain or sludge.

Dave

 

[1970FuryConv]

Agree with @Davea Lux on oil change and check for metal particles. If there were no metal particles and If the oil pressure gauge was one of the aftermarket gauges installed, I'd consider grounding the gauge wire at the OP switch/sensor to see that the gauge is working properly. If gauge needle does not go from low to high, I'd consider starting the engine to listen for the "bearing whine." If gauge needle does go from low to high, I'd change the oil pump too, before test starting.
Sucks that it happened while a friend was driving. Hard to know what's going on.

 

[mag162]

My buddy that was driving is a diehard mopar gear head. So I go along with all he has said so far.
One thing that did cheer me up some was that he has offered to drop in a 70 383 out of a RR that he has stashed away for one of his own projects. He has a brand new set of 440 source aluminum heads to go along with the 383 also.
So who knows. I just wanted to be able to drive the car some before the weather turns to **** here in NY. I still have dreams of having a reliable, stout 440 built from a reputable shop this winter.

 

[live4theking]

Had you been driving the car prior to these upgrades? What was it driving like?

 

[mag162]

It’s been off the road since last fall. Before that it ran like a top not a spec of smoke at all!

 

[Big_John]

Pull the valve covers and check for an issue with the pushrods/lifters etc. A bent push rod or a push rod through a rocker arm will let a lifter can pop out and you will lose your oil pressure.

 

[twostick]

If it has a Fram oil filter, change the filter. It could have collapsed. Cut the filter open and see if there is any metal in it.

If no metal is in the filter and a new Wix filter doesn't cure it, the next cheapest cause could be the bypass valve in the pump is stuck open. Fairly easy to check on a BB as the pump is external so you can disassemble the bypass valve.

The pump itself could if it was completely worn out cause a loss of some oil pressure but if you only have 10 psi, I'd say the pump itself is not the problem. This is assuming it was 10 psi at speed not just idle.

If the bypass is OK, I'd pull the distributor out and then the pump drive shaft out. The hex on the end can get worn bad enough that it will still turn the pump but slip/jump over the flats so the pump speed is reduced to almost nothing.

I have no idea what this bearing whine is he is talking about unless it might be the noise of the pump drive shaft spinning inside its socket. The only noise most crank bearings make is knock, knock, come out.

If none of the above improves it, pull the pan and see of the pump pick up screen is plugged up with nylon timing gear teeth.

Kevin

 

[FURYGT]

I only run Wix or NAPA Gold oil filters (made by Wix) as there are far too many junk oil filters out there. I also only use oil with a ZDDP additive.