Motor dies AFTER oil pump was primed

[iiiwildfireiii]

Hey guys!

Just finished my new engine build. Long story short, we started the motor and it was noisy as expected then quieted down and ran nicely. We ran it for approximately a minute to a minute and a half. While checking gauges, noticed on my electric oil gauge that I had little to no oil pressure (maybe a couple PSI). Shut the motor down, reprimed the pump as it had been sitting a few days since we'd primed it, and then started the car again. Car dies after 3-5 seconds. Oil pressure climbs to 50 psi when starting then the car immediately dies. Boost gauge reads ~10 in/Hg.

Does anyone have a clue why a motor would run normally with no oil pressure then die after having its pump primed?

We have spark, and AFPR is reading normal fuel pressure. Nothing else was changed from when we turned the car off to when we started it besides priming the oil pump.

Ideas?

 

[donniekak]

Did you re-time it correctly after taking the timing belt off to spin the pump?

 

[iiiwildfireiii]

Timing belt was not removed. I unscrewed the electronic oil pressure sender off of the oil filter housing and used a pump to push oil into the housing.

It had only taken 10 minutes or so to get the car turned off, jacked up, wheel removed, sender unscrewed, oil pump primed, sender and wire re-attached, wheel put back on, car lowered and then restart the car. That's literally all we did. Nothing else was changed.

 

[EclipticalGS]

woah, your telling me you didnt take the spark plugs out and fuel pump relay out after it was primed, and roll it over for 30 seconds, then let it sit for 5 minutes, then roll it over again for 30 seconds. Do this until you reach the right amount of oil pressure (4-5 times) because you do this to build oil pressure throughout the motor. Try this!! then put ## plugs back in and fuel pump relay and you should have you base pressure down.!

 

[iiiwildfireiii]

The balance shaft is removed. I thought that 50 psi on a cold start was a fairly standard pressure...at least until it warms up some? I can understand the importance of having consistent oil pressure throughout the engine, and I will try this, but why would it run prior with little to no oil pressure then stop running AFTER the pump was primed? That's what is really confusing me.

 

[lacroixdp]

Give it some gas to help it stay running. If you ran it with no oil pressure for that long, it's possible one or two of your cylinder walls doesn't have enough oil to get a good seal for compression. You can put a capfull of oil into each of your cylinders and see if this helps it out. I think it's merely a coincidence that it's not working just after priming the pump.

 

[iiiwildfireiii]

This isn't a bad idea at all. I'm definitely going to try this.

I was also just speaking to a friend who is a mechanic. I had prior issues with the crank not spinning freely by hand. It would be lose, then tighten up just a bit, then loosen up. While I had thought it may just be that the rings weren't completely seated and the tolerances were a bit tight, he thought that perhaps the bearings were too tight. With the oil pressure now hitting the bearings it could be binding the crank even further and causing it to shut down. I'm trying to get a hold of the person who built the block to see if he knows what bearings were used and what size they were but have not heard anything back yet. Anyone ever heard of excessive oil pressure locking a crank up?

 

[lacroixdp]

It depends... are you talking about the crank binding with the head off? It's going to have natural 'tugginess' with the cam belt on, not to mention the pistons compressing as well. If it's binding loose-tight-loose with the head off, then you probably need an align-hone. You could also have a bent crank, and yes, mismatched bearings could cause that problem. Regardless, if you have any doubts on the fit-finish of your bottom end, I'd stop where you're at before you cause more damage. If your friend thinks the bearings are too tight, I'd take the block with the crank to a reputable shop and let them take a look at it for you - let a machinist with the proper tools and know-how make that determination. It would certainly be cheaper than ruining your engine. When there's doubt like this, there's just absolutely no substitute for a good machinist, IMHO.

 

[EclipticalGS]

well it could just be the fact that 1 or 2 of your pistons need oil on them for compression, try that, if it still doesnt turn how it should at the crank, lacroix is right, take it to a machinist, maybe the person used oversized crank bearings when he built it and didnt turn the crank. You never know what some else does in there possesion so take it and have it checked out, most of the time you can catch a michinist that has time to do it, have him inspect. Good luck

 

[iiiwildfireiii]

I had just heard back from the person who built the engine. They said that they used standard sized ACL bearing in it. I've been out to see GI Joe so I haven't tried the oil yet. I'll get around to it sometime today.