No oil pressure, new build

[Racer2172]

Make sure the distributor is fully seated driving the pump
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[bowtiemanchevyman]

its a new motor right, when u got it back was it put together or did u put it together? one of the hole on the crank or the block side might be filled with stuff when they rebuilt the block. u might want to pull it apart and check all you oil hole befor u burn up a motor

[fast72beeper]

Originally Posted by Racer2172

Make sure the distributor is fully seated driving the pump
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Umm...OK?

[fast72beeper]

Originally Posted by bowtiemanchevyman

its a new motor right, when u got it back was it put together or did u put it together? one of the hole on the crank or the block side might be filled with stuff when they rebuilt the block. u might want to pull it apart and check all you oil hole befor u burn up a motor

Guess you didnt read my original post....

[bowtiemanchevyman]

It doesn’t say if u built it or they built. You might need to pull it apart and clean all the galleys in the block. If it start with oil pressure then dropped something moved in the oil galleys and is blocking oil from moving around.

[fast72beeper]

Galleys are clean...motor is torn apart...

[king-918]

This may or may not help. I did not finish reading

http://www.chevytalk.org/fusionbb/sh...hp?tid/192284/

[INSIDIOUS '86]

What's your journal and mains sizes on the crank? Then measure the main bearings
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[fast72beeper]

Originally Posted by INSIDIOUS '86

What's your journal and mains sizes on the crank? Then measure the main bearings
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All of the main and rod journals, main journals in block, rods themselves, etc measure fine. They have been measured empty and with bearings torqued. The issue is not bearing clearance.

[kalbert]

Have you tested the oiling system? Like with the motor on the stand sans valve covers and intake and stuff then run the oil pump with a drill and an old distributor and see what happens? I'd imagine you'll see the same pressure problem this way, but with visibility into whats going on inside. I'm thinking you'll see oil gushing from somewhere right away. Would also give you easy access to move the pressure gauge around to different ports and take readings in different places.

EDIT: Either you'll see oil gushing from somewhere or you'll confirm that there is something wrong with the pump, pickup, filter adapter, or filter.

[mrhino]

what about your oil galley plugs are they all in? and sealed including the "forgotten ones"

[INSIDIOUS '86]

Originally Posted by fast72beeper

All of the main and rod journals, main journals in block, rods themselves, etc measure fine. They have been measured empty and with bearings torqued. The issue is not bearing clearance.

Well if it builds pressure fine then at idle when engine is under load and warm there is a leak. Check the rear most cam bearing. Is it slotted or solid? Same with the cam.
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[85Bowtie]

When you spin the engine over, do you see oil coming up through the oil line?

I've had this problem before by being a cheap ass and re-using the stock pickup that I THOUGHT I got all of the debris out of. As it turns out, a few tiny (and I mean tiny) pieces of nylon had got sucked from the pickup into the oil pump, hanging up my pressure relief valve. I didn't catch this at first, since the pieces were so small. It did it a few times, sometimes it would go to 0 then shoot back up. I eventually had to pull the engine and replace all of the bearings and do it right the 2nd time....all because of a $25.00 part.

It would seem to me if it was a clearance issue you wouldn't be experiencing this problem more consistently, not building up pressure than going to zero.

[fast72beeper]

Originally Posted by 85Bowtie

When you spin the engine over, do you see oil coming up through the oil line?

I've had this problem before by being a cheap ass and re-using the stock pickup that I THOUGHT I got all of the debris out of. As it turns out, a few tiny (and I mean tiny) pieces of nylon had got sucked from the pickup into the oil pump, hanging up my pressure relief valve. I didn't catch this at first, since the pieces were so small. It did it a few times, sometimes it would go to 0 then shoot back up. I eventually had to pull the engine and replace all of the bearings and do it right the 2nd time....all because of a $25.00 part.

It would seem to me if it was a clearance issue you wouldn't be experiencing this problem more consistently, not building up pressure than going to zero.

Pickup is new.

[fast72beeper]

Took the whole thing to the machine shop that machined the block.


He is going to look it over and let me know on Monday.


Im really afraid the oil galley(s) is/are cracked. Hope Im wrong, but after talking with a few more guys, it seems like the only logical answer.

[mongoose]

is it just losing that much oil through the cracks it can't build pressure at idle? I'd think that would be a pretty big crack lol

[85Bowtie]

Originally Posted by fast72beeper

Pickup is new.

My post was directed more to sucking trash into the oil pump. If everything in this motor is new and freshy rebuilt, wouldn't cracks in the oil galley have been discovered when the block was magnafluxed?

[fast72beeper]

Originally Posted by 85Bowtie

My post was directed more to sucking trash into the oil pump. If everything in this motor is new and freshy rebuilt, wouldn't cracks in the oil galley have been discovered when the block was magnafluxed?

Ive spoke with 4 different machinists so far. They all say that cracks in the oil galley(s) dont usually show themselves with standard magnafluxing. They say wet magnafluxing will show the cracks. Very few shops do wet magging, at least in my area.

[bk2life]

keep us posted on the outcome..

i had a factory oil cooler take out 2 motors before relizing it was the culprit and tossin it..

[fleetweld47]

I had the same issue years ago on a 327 , turns out the the block was cracked due to the cam bearings being installed incorrectly at the machine shop .

[fast72beeper]

Well...motor is back together and running. The only thing that was changed is the oil pump. We did put new bearings in the motor, but same size. The old bearings were not beat up, just a little scuffed. Motor now holds 22 in gear and 30 in N. So, who knows...Machinist told me that he has seen it lately that he puts a motor on the dyno, oil pressure is low. Only change the pump and pressure will be OK.

[PAWS 72]

Being a stupid ... rite now but do you think it could be some of this china stuff that is soppsed to be good, is crap?

Which I'm starting to think all of this stuff we're putting on we have to do it twice to get a good part.