Well I'm not 100% sure but I suspect that we have had another oil pump gear failure. My son came home the other night and said the car lost oil pressure at low RPM while he was driving it. If he revved it up to about 3000 it had oil pressure. He drove it a short way home keeping one eye on the road and one on the oil pressure gauge. No noises were heard!!
I am just getting over a back injury so today was the first I was able to pull the distributor. I can see definite roughness and premature wear on the cam gear. I can only imagine that the oil pump gear is all but gone ?? Well I'm pretty bummed, as is my son! I certainly do not know what to do differently? If you have any ideas I'd certainly be glad to hear them? I'll let you know in a week or so when we pull the oil pump. I have to give my back a little more time before we tear it apart.

Just for the record: This is a completely rebuilt engine, Standard duty oil pump with a Dutra hardened gear, and using a Old Racer Brown cam I got from Slantzilla ,.460 lift. The gear was lapped well before it was run and we do have a cam stop in place. The engine has about 12,000 miles on it. It has only been run about 16 months. I can not see a new cam and oil pump every 12,000 miles. I love the slant and so does my son. But I'm not sure that we love it that much?

Rick

Frustration forecast - High today, expected higher tomorrow

sorry to hear that Rick, get well and keep us posted...you've got me curious as to what you find in the autopsy....


yipes,

-D.Idiot

I wonder if checking the tooth contact pattern with machinist blue - similar to the way a differential is checked - would help find potential problems?

Mitch

How exactly do you lap the gear?I just installed a Comp Cama 264 s in my slant and havnt started the engine yet.I have noticed that most of the oil pump gear failures occur on Mopar Performance cams and yours is a Racer Brown but havnt heard of a failure on a Comp Cams cam but Im sure someone has had it happen.
HyperValiant

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1960 Hyper-Pac Valiant(rolling test-bed)
1963 Valiant V2OO(Son's summer project,- he just turned 15 )
1972 Valiant 4dr(Daughter Kelly's repair in progress)
1974 Valiant (v8) daughter Kelly's work in progress

I installed the cam in the block and mounted the cam gear and bolt ( no chain of course). Then I installed the oil pump with a little bit of fine lapping compound on the teeth. I drove the cam for about 2 or 3 minutes with a cordless drill starting on low speed (400RPM) and finishing up on high speed(1200 RPM). I removed the oil pump and inspected the pattern to verify that it was centered on the gear and repeated the above steps 2 more times. The last time I lapped it with some oil in the lapping compound to try and get a finer lap out of it. I removed the pump and the pattern looked good, and it had the same light gray look as when you lap in the valves on a new cylnder head rebuild. I Cleaned everything up and put it together.

Rick

Ok, We pulled the oil pump off the Dart and much to my surprise the oil pump gear was not gone?? I would say it has some premature wear but it certainly was not the culprit. The cam gear looks to be worn more than the gear, but it has all the teeth as well. Now the question is, Why no oil pressure??? Need your help here. I didn't find anything in the oil pump, and all the passages were open and the Tee to the pressure gauge and the idiot light were all open as well. Pump turns freely too.
Thanks in advance.

PS. We did not pull the engine yet. We were considering just slamming on another new pump and running it for a little while. But that was when we assumed that the oil pump gear would be gone. Now that the oil pump looks Ok, I don't know? We really wanted to make it to Carlisle and the Pittsburgh races in July.

Rick

Rick, sorry to hear you're having trouble again. I ran the twin to that cam for a long time and the OP gear looked like new when we pulled it. CharlieS has it in one of his motors now.

Motor didn't spin a cam bearing did it?

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Official Cookie and Mater Tormentor.

Hi Dennis,

We didn't pull the motor yet. Is there something to be looking for as far as the cam bearings are concerned?? Or do I have to check them when the engines apart by actually looking at them?


Rick

I had the exact same problem with my Duster. When it would get hot, it would lose enough of the oil pressure to make the idiot light come on at idle, but it would go off when you revved up the engine a bit. I ran a can of engine flush through it, and then changed the oil. There was so much trash and goop that the oil was almost purple. I have not had a problem with it since. Another thing, A piece of trash left over from the engine rebuild may have stopped up the pickup screen for the oil pump.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

You should see some bearing flakes in the pan when you pull it.

Next question, was there a piece of junk stuck in the oil pressure relief valve in the pump or a broken spring? That would play tricks with the pressure.

_________________
Official Cookie and Mater Tormentor.

mine lost pressure at weird times, turned out the oil pressure sender switch wire was off and grounding against the fender wall
it later did start to flicker at idle, motor is currently sitting in a pickup-bed-turned-trailer with a spun rod bearing, hope you have better luck then i did, i also tried running some stuff through to fix it, but no luck, also, on a semi-related note, after the engine swap from the 74 to the 67 the engine made some noises and the idiot light would come on for a few seconds, changed oil/filter, hasnt done it since.... old oil was pretty nasty...

We have not pulled the oil pan yet but there was nothing in any of the passages that we could see. I pulled the sending unit and the tee for the oil pressure gauge and they were clear. The pressure relief valve was pulled and all was clear as well. The spring was in one piece. No junk was found anywhere in the pump.
We were running synthetic oil in it (after the first 1000 miles of break-in) and the oil was changed 3 times in less than 10,000 miles. This was a complete new rebuild, and all parts were new, so there should not be a reason to run a flush through this engine yet.


Thanks,
Rick

Make sure the oil pump's drive shaft is not spinning in the gear or in the impeller / rotor inside the pump. I have seen this happen on "no keyway" (press fit) shaft assemblies.

Rick, If you want to try a bronze drive gear, let me know and I will send you one. A bronze gear may solve the wear-in problem and should not trash your cam gear if it fails.
DD

I'll check that out tomorrow. I think this pump is one with a keyway? Is there a proper way to checkto see if the impellers are slipping on the shaft?

Thanks for the offer Doug, I'll let you know about the bronze gear

First, look for the key(s).
Some of the impellers have a roll pin installed to prevent slippage on the shaft.
I test them by taking them apart, if it comes apart easy and shows radial marks on the shaft, it is slipping.
DD