Vette sat too long?
Drifting
Joined: Mar 2008
Posts: 1,756
Likes: 0
From: Wichita KS
Oil pumps are gear rotor pumps (positive displacement). They are self priming so if it's turning, it's pumping. Problems could be:
Pickup tube has fallen out.
Oil pump bolt has backed out and the pump has either fallen off or is barely hanging on.
Oil pump drive shaft has sheered a drive tab or is not seated into the pumps drive socket.
One thread mentions the tab that holds the oil slug is prone to breaking. If this has happened, then the slug can raise up and allow the pumps drive shaft to come out. It wouldn't take that much lift if the slug has a broken bolt tang. Oil pressure in the past would have push it up and it can't fall back down into the distributor/oil pump drive hole in the block.
Of all the possible reasons, I'm leaning towards the latter. But the the intake manifold has to come off at the least.
Pickup tube has fallen out.
Oil pump bolt has backed out and the pump has either fallen off or is barely hanging on.
Oil pump drive shaft has sheered a drive tab or is not seated into the pumps drive socket.
One thread mentions the tab that holds the oil slug is prone to breaking. If this has happened, then the slug can raise up and allow the pumps drive shaft to come out. It wouldn't take that much lift if the slug has a broken bolt tang. Oil pressure in the past would have push it up and it can't fall back down into the distributor/oil pump drive hole in the block.
Of all the possible reasons, I'm leaning towards the latter. But the the intake manifold has to come off at the least.
Thread Starter
Racer
Joined: Jun 2004
Posts: 452
Likes: 0
From: Southern Md
Thanks Ryan. Never been into an LT1,except the 350/370's. So I can pretty much forget about the oil pump relief valve(in the pump) being stuck in the open position, building no pressure. I think I'll be looking at that intake soon. They just had to move the dist hole didn't they. There's a 69 c3 vert with a 502 sitting(about 2 years) in my garage next to it. 502 is a new crate motor and also has never been run. I can prime it maybe.
Last edited by bonehead2; Feb 19, 2009 at 03:21 PM.
Drifting
Joined: Mar 2008
Posts: 1,756
Likes: 0
From: Wichita KS
That's still possible. There's a roll pin that holds the pressure relief spring in the pump body. It's unlikely but possible for that roll pin to let go.
Sounds like you don't know much about this engine. Have you heard/seen it run? It's difficult to imagine an engine having oil pressure, then let it set for a few years and then no (zero) oil pressure. Anyone you know needed to borrow an oil pump but forgot to ask maybe?
Edit: Either way, the intake still has to come off. Meaning if the oil pump has a problem of any kind and needs to come off. The pump drive shaft has to be reinstalled from above to avoid missing the slot it fits into. Physically speaking, the old blocks VS LT1 blocks do have the distributor hole in the same place. On the LT1 engines the intakes don't have a hole for the distributor. Although I have seen where one member did drill his intake and runs a conventional distributor.
Sounds like you don't know much about this engine. Have you heard/seen it run? It's difficult to imagine an engine having oil pressure, then let it set for a few years and then no (zero) oil pressure. Anyone you know needed to borrow an oil pump but forgot to ask maybe?
Edit: Either way, the intake still has to come off. Meaning if the oil pump has a problem of any kind and needs to come off. The pump drive shaft has to be reinstalled from above to avoid missing the slot it fits into. Physically speaking, the old blocks VS LT1 blocks do have the distributor hole in the same place. On the LT1 engines the intakes don't have a hole for the distributor. Although I have seen where one member did drill his intake and runs a conventional distributor.
Last edited by Ryan59; Feb 19, 2009 at 03:40 PM.
Thread Starter
Racer
Joined: Jun 2004
Posts: 452
Likes: 0
From: Southern Md
Correct. I have never heard it run and the owner bought it out of a wrecked vette and never heard it run and sent it to an engine shop for a rebuild. I asked him if the dist dummy shaft is in place and he said he was sure of it and it has a new oil pan and hv pump. I put 6 qts in it and am getting a reading on the stick but he may have the wrong oil pump pick up on it for the pan. Pulling this engine to see about this will not be pleasant as I have repaired some "engine shops work" in the past. I am sure he researched everything about this engine, being the mechanical engineer he is.
Last edited by bonehead2; Feb 19, 2009 at 03:50 PM.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
Hopefully assembly lube will protect the bearings. Before you do any more cranking, take the plugs out and spray WD40 or preferably Marvel Mystery oil in the plug holes to lubricate the rings and cylinders which most likely are dry as a bone.
Safety Car
Joined: Nov 2008
Posts: 4,328
Likes: 15
From: Jacksonville FL
I am new to Vette motors but they are still in principal like any other. I put a 4 cylinder together and installed it without checking the oil pressure and ended up pulling it out as much as I hated it. I was rushing the project and forgot to torque the mounting bolts on the pick up tube.
I dunno what you want to hear but the advice given is the best way to start. Prime the engine directly with the oil pump if you get no results, I would then check the oil pick up, gasket and the oil pump itself as mentioned also. If there is any looseness and its getting air, the system will never prime. Most likely the "pro" shop made a mistake and forgot to tighten something or maybe forgot something else simple. I know you hate it but until you find out if these things are ok, your flogging a dead horse. The more you spin it, the more damage your doing to "dry" bearings. Go as far as you can with it in the car then pull it and start going thru the internals. Its probly something dumb and simple but you will never know until you pull it and look. I hate it for you but "Been there, got the Tshirt"
Good luck with it and let us know what you found.
I dunno what you want to hear but the advice given is the best way to start. Prime the engine directly with the oil pump if you get no results, I would then check the oil pick up, gasket and the oil pump itself as mentioned also. If there is any looseness and its getting air, the system will never prime. Most likely the "pro" shop made a mistake and forgot to tighten something or maybe forgot something else simple. I know you hate it but until you find out if these things are ok, your flogging a dead horse. The more you spin it, the more damage your doing to "dry" bearings. Go as far as you can with it in the car then pull it and start going thru the internals. Its probly something dumb and simple but you will never know until you pull it and look. I hate it for you but "Been there, got the Tshirt"
Good luck with it and let us know what you found.
Instructor
Joined: Apr 2007
Posts: 134
Likes: 0
From: new albany mississippi
Me and some of the guys'll be over Saturday to pull the motor, inspect everything, freshen up any bearings that may have scuffed, verify that everything is within tolerance AND (here's the kicker!) install a 'hot-cam' upgrade!
Not really, but I figured that might be an answer you'd like. Hang in there, man.
Not really, but I figured that might be an answer you'd like. Hang in there, man.
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Thread Starter
Racer
Joined: Jun 2004
Posts: 452
Likes: 0
From: Southern Md
Me and some of the guys'll be over Saturday to pull the motor, inspect everything, freshen up any bearings that may have scuffed, verify that everything is within tolerance AND (here's the kicker!) install a 'hot-cam' upgrade!
Not really, but I figured that might be an answer you'd like. Hang in there, man.
Not really, but I figured that might be an answer you'd like. Hang in there, man.
Last edited by bonehead2; Feb 20, 2009 at 09:26 AM.