The worst has happened - no oil pressure

Eliems · #1 (**permalink**) 05-13-2005, 12:45 PM

I restarted this thread because I need your help. They are telling me I need a complete rebuild! The pressure releif valve was the culprit but the bearings are now toast! 450 miles on this car!

They are claiming low oil pressure before the oil change as I told them the guage read quite low at idle ( below 20 lbs ) but rises with RPM.

QUESTION: what should the oil pressure be for a 429 Cobrajet, 10 1/2 to 1 comp. mild cam, at idle and at 2000 RPM ... 3000RPM ?

Thanks Guys!

The original post:

Hello folks, great forum! I am two weeks into owning a beautiful Custom Cobra and loving it! Tight car and power unlike anything I have ever encountered.

Took her in for an oil change as only 350 miles on the rebuild but the car has sat for five years with only occasional sart-ups and the oil was 2 years old.

The mechanic took her for a test drive after the oil and brake-fluid and coolant was changed and noticed no oil pressure on the guage! Had it towed back to the shop!

Changed the filtre in case it had been faulty ... still no pressure! Tried their own guage and no pressure. Oil filtre remained cold and the transparant oil tube to the guage showed no flow.

Tommorow they try to operate the oil pump through the distributer, maybe the drive shaft has broken from the distributer to the pump. maybe the pick-up tube from the oil pan has fallen off, maybe the oil pump quit for some reason??????

Have any of you had this happen?

Thanks!

CobraEd · #2 (**permalink**) 05-13-2005, 12:52 PM

I had a pressure relief valve hang open once years ago because "crud" got into the engine and made it stick open. (don't ask).

Anyway, It was driven off and on for about a week with low/no oil pressure. Once I fixed the valve the car was fine for many years after that and in fact when I sold the car, I still had no problem with the engine. It was a GM 3.8 V6.

So, why not fix the relief valve and see how it runs. It might be fine. What is the oil pressure now?

Even if damage is done it will usually be the bearings. If that is all that is damaged and the oil pressure is truly low, just pull the pan and pop in new rod and main bearings right in the car.

Ed

427 S/O · #3 (**permalink**) 05-13-2005, 12:53 PM

What happen with the shaft drive?

Eliems · #4 (**permalink**) 05-14-2005, 12:26 PM

Now that the picture unfolds, things are becoming clearer. The oil pump is not faulty (althoughit is now scarred from running dry). The pressure relief valve, although weak was not the cause of the failure either.

The mechanic started the car several times after the oil change and there was no clattering of valves like there is now, the oil pressure seemed fine (although they did not check the guage).

When the test drive began the mnotor sounded fine and there was no reason to suspect anything. During the test drive the mechanic heard the clattering and noticed the oil pressure guage was on 0 but he thought the guage must not be working. He pulled over and then decided the rattling indicated no oil pressure and had the car towed back.

Turns out the builder of the car had extended the oil pan to increase the amount of oil for the big engine and he thought he had relocated the oil pump pick-up to the real of the pan but he had not.

Not sure, but I think what happened is that the mechanic put in less oil than was previously in there, (11 quarts is needed) and during the test drive the oil sloshed to the back of the pan and the pick-up drew air causing the pump to lose prime.

Now there is scoring (uneveness) on the crank at the end rod bearings and on Monday we will pull the crank to see the extent and perhaps have it turned/polished.

I wonder what more damage will have been done! The mechanic tells me he has put his flashlight on to the cam and everything up there looks perfect. Still, now there is metal filings visible in the pick-up screen and I suppose filings have travelled through the motor?

Some oil change!!!!!!

Any advice would be appreciated very much.

Someone asked about the drive rod ... it was fine.

Someone suggested priming the oil pump before restarting, How do you do that? Mechanic couldn't see how toget oil up through the pick-up without it just pouring back down. Is there some method to this?

Thanks Guys,
Greg.

Rick Parker · #5 (**permalink**) 05-14-2005, 01:19 PM

If you hve metal filings on the pickup screen, you would be best served to pull the engine completely apart, you can bet filings have traveled throughout the engine.

Sorry, but be glad the tech had the good sense to shut it down.

Rick

trularin · #6 (**permalink**) 05-14-2005, 02:55 PM

Wow, 11 quarts. That's one heck of a pan.

The engine is junk, better just give it to me and get a new one.

Eliems · #7 (**permalink**) 05-21-2005, 11:33 AM

So the way things have turned out, the engine was slowly grinding it's self to powder due to oil starvation and is now in the machine shop being rebuilt (1600 dollars can), but this may not have been the worst thing that could have happened as I will soon get the car back much better than it was before! Better clutch, better engine, better brakes, better suspension, better wiring, better handling ... all things identified and being redesigned or repaired by some people who know what they are doing.

For the most part they are minor adjustments but with major effect so I should be a happy boy once again!

The Lord is good, He sent me a $7,000 week of unexpected money as if to tell me ... "Stop whining!"

Can't wait!

Greg.

kevken59 · #8 (**permalink**) 12-31-2008, 09:17 AM

Hi. I'm new to this site. I am replying to this post, because it is closest to my problem. I bought a car with an origional 429CJ that appears to have been rebuilt in the past, but with few miles. When the car was delivered, I determined there was extremely low oil pressure(maybe 5psi). I have checked EVERYTHING except a so-called bypass valve. Is it true that there is some kind of valve where the oil pump screws on, and if so, how do I check/change it? I find it hard to believe there would be a moving/mechanical part in the

block. Thanks!! Kevin.

bobcowan · #9 (**permalink**) 12-31-2008, 09:54 AM

Just like a small block, the pressure relief valve is part of the oil pump body.

I would drop the pan, clean the pick up, and replace the pump. A pain in the neck to do, but relativly inexpensive.

Jac Mac · #10 (**permalink**) 12-31-2008, 01:12 PM

Quote:

Originally Posted by Eliems

The Lord is good, He sent me a $7,000 week of unexpected money as if to tell me ... "Stop whining!"

Greg.

Can you give us the contact details for this 'Lord' guy you speak/pray to.--@ 7k a week I have obviously been talking to the wrong guy for the past 58 years.

David Kirkham · #11 (**permalink**) 12-31-2008, 06:05 PM

I certainly wouldn't classify this as the "worst" thing that could happen to you. I know it stinks, but lots of guys around here can help.

David

RodgerH · #12 (**permalink**) 12-31-2008, 07:11 PM

Quote:

Originally Posted by Jac Mac

Can you give us the contact details for this 'Lord' guy you speak/pray to.--@ 7k a week I have obviously been talking to the wrong guy for the past 58 years.

Matthew 6:33

Clois Harlan · #13 (**permalink**) 01-01-2009, 04:29 AM

As David said it could have been much worse. This is a blessing in itself because things could have gone from bad to catastrophic (I have had that happen). I am sure you are replacing bearings, oil pump, and pick up on the engine. If you have an oil cooler throw it away too. Replace anything that moved your oil because you will never be able to get all the metal debris out of your oil lines or cooler. Cheap insurance for the future life of your engine.

Clois Harlan

jhv48 · #14 (**permalink**) 01-01-2009, 08:39 AM

Are you sure the mechanic didn't forget to put in fresh oil after he removed the old oil?

Wouldn't be the first time a mechanic got distracted and forgot to fill the crankcase with oil before driving it.

FWB · #15 (**permalink**) 01-01-2009, 07:03 PM

if anyone needs it try this guy, friend for over 20 years, have had several motors built by him, and they won't self destruct or have oiling issues.
here's what he currently has but he will build to suit. here's some ebay ads of his.........

http://cgi.ebay.com/ebaymotors/Fresh-71-460-030-ford-street-strip-engine-assembly_W0QQitemZ110****43760QQcmdZViewItemQQptZM otors_Car_Truck_Parts_Accessories?hash=item110**** 43760&_trksid=p4506.c0.m245&_trkparms=65%3A1|39%3A 1|240%3A1318

or call him 610-432-4645 his name is george

David Kirkham · #16 (**permalink**) 01-01-2009, 10:04 PM

I'd give Keith Craft a call and see what he has to say. He has built over 100 motors for our customers with very, very few problems.

We REALLY like him!

David

ps. Keith, you know where to send the goodies.

cdog · #17 (**permalink**) 03-01-2009, 05:34 PM

For any Ford engines, I would recommend Gessford Machine (George Anderson) of Hastings, NE. They are a long-time member of this site and really know their stuff.