First start up engine won't turn
Yes.
The shortblock was assembled, the customer took it home, called and said it "was locked up and wouldn't turn over". He brought it back assembled as a long block, as soon as the front cover was removed, we suspected it could be what it was- the oil pump was dead locked. We loosened the bolts, shimmed it, voila.
Never would have thunk it, but I was there.
The shortblock was assembled, the customer took it home, called and said it "was locked up and wouldn't turn over". He brought it back assembled as a long block, as soon as the front cover was removed, we suspected it could be what it was- the oil pump was dead locked. We loosened the bolts, shimmed it, voila.
Never would have thunk it, but I was there.
Thread Starter
Teching In
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Yes.
The shortblock was assembled, the customer took it home, called and said it "was locked up and wouldn't turn over". He brought it back assembled as a long block, as soon as the front cover was removed, we suspected it could be what it was- the oil pump was dead locked. We loosened the bolts, shimmed it, voila.
Never would have thunk it, but I was there.
The shortblock was assembled, the customer took it home, called and said it "was locked up and wouldn't turn over". He brought it back assembled as a long block, as soon as the front cover was removed, we suspected it could be what it was- the oil pump was dead locked. We loosened the bolts, shimmed it, voila.
Never would have thunk it, but I was there.
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Engine turned 360° with the rocker arms installed and before transmission was installed but now after removing the trans it dosen't? I find it strange to all of a sudden have an internal issue which leads to other questions like was the timing cover, valve covers, windage tray and oil pan installed at the time the engine was turning over by hand? I'm pretty sure that bolting a flywheel to the crank isn't going to keep it from turning over either and if so the problem would have been with the flywheel and visible. If for some reason the thrust is the issue this should have been verified before the connecting rods went on. Just as you should be checking for side clearance after rod/piston install.
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Verdad Gallardo Thread Starter
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Yeah it sucks but what can you do but learn and move on. Thanks hopefully when it's all done I can take it to some shows before the track!
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I assembled it 100% even took pictures every single step of the way for fun. I probably spun it 50 plus times just being excited seeing something I made turn over.
Did you try what n2xlr8n suggested? I've never heard of this before, but I suppose if a tolerance stackup was more unfavorable than usual, this could happen. You've been very careful about everything. I say that because this may happen more than we think, due to some guys just bolting everything together, turning the engine 10°-20° back and forth with a socket and ratchet to make sure its "free". They install the motor, then start it up. Engine power would force the engine to turn 360°, and we'd never know it. Interesting stuff. My 2000 C5 FSMs make no mention of even aligning the pump at all. I'm seeing guys now installing the pump bolts with finger/light hand tightening, then turning the engine over 360°-720° with a breaker bar and socket on the balancer bolt, rather than shimming. Apparently, this ensures nothing binds up by effectively centering the pump by turning the engine over. Then the pump mounting bolts are torqued last. I guess I'd try loosening the pump bolts. If it turns freely, you've got your answer. Maybe we've all learned something here today...
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The oil pump shimming thing is interesting.(not able to picture how that could happen)
not much could lock a engine up in either direction. Something inside a bore you should be able to spin in the opposite direction.
Have you tried a soft dead blow hammer on the front of the crank?
What was the throwout bearing clearance set at.
have you pulled the flywheel off to see if the engine spins.
The flywheel to crank bolts need to be a certain length. Those holes do penetrate into the block. Pressure plate to flywheel bolts could also catch the back side of the block locking a engine down. If they are long also.
not much could lock a engine up in either direction. Something inside a bore you should be able to spin in the opposite direction.
Have you tried a soft dead blow hammer on the front of the crank?
What was the throwout bearing clearance set at.
have you pulled the flywheel off to see if the engine spins.
The flywheel to crank bolts need to be a certain length. Those holes do penetrate into the block. Pressure plate to flywheel bolts could also catch the back side of the block locking a engine down. If they are long also.
Last edited by jasons69chevelle; Feb 4, 2023 at 11:24 PM.
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Did you try what n2xlr8n suggested? I've never heard of this before, but I suppose if a tolerance stackup was more unfavorable than usual, this could happen. You've been very careful about everything. I say that because this may happen more than we think, due to some guys just bolting everything together, turning the engine 10°-20° back and forth with a socket and ratchet to make sure its "free". They install the motor, then start it up. Engine power would force the engine to turn 360°, and we'd never know it. Interesting stuff. My 2000 C5 FSMs make no mention of even aligning the pump at all. I'm seeing guys now installing the pump bolts with finger/light hand tightening, then turning the engine over 360°-720° with a breaker bar and socket on the balancer bolt, rather than shimming. Apparently, this ensures nothing binds up by effectively centering the pump by turning the engine over. Then the pump mounting bolts are torqued last. I guess I'd try loosening the pump bolts. If it turns freely, you've got your answer. Maybe we've all learned something here today...
I’ve talked with Melling at length about the shimming procedure and it’s a farce. Here’s why…The crank is ONLY centered in the bearing journal when THE ENGINE IS RUNNING. It takes oil pressure to maintain the crank being centered in the bearing journal. Compression will always force the crank downward and as the engine comes to a stop, there’s not enough oil pressure to hold the crank up. The final compression stroke there will force the crank downward. It’s the same with building a new engine. The crank is never exactly in the center of the bearing journal until startup. So…what are you shimming to? Your shimming to an un-centered crank. Guess what happens when you start it up? Yup. I always use the method on the above posted Melling video. Takes 30 seconds, and is recommended by the best.
I’ve talked with Melling at length about the shimming procedure and it’s a farce. Here’s why…The crank is ONLY centered in the bearing journal when THE ENGINE IS RUNNING. It takes oil pressure to maintain the crank being centered in the bearing journal. Compression will always force the crank downward and as the engine comes to a stop, there’s not enough oil pressure to hold the crank up. The final compression stroke there will force the crank downward. It’s the same with building a new engine. The crank is never exactly in the center of the bearing journal until startup. So…what are you shimming to? Your shimming to an un-centered crank. Guess what happens when you start it up? Yup. I always use the method on the above posted Melling video. Takes 30 seconds, and is recommended by the best.
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From: Central Cal.
I’ve talked with Melling at length about the shimming procedure and it’s a farce. Here’s why…The crank is ONLY centered in the bearing journal when THE ENGINE IS RUNNING. It takes oil pressure to maintain the crank being centered in the bearing journal. Compression will always force the crank downward and as the engine comes to a stop, there’s not enough oil pressure to hold the crank up. The final compression stroke there will force the crank downward. It’s the same with building a new engine. The crank is never exactly in the center of the bearing journal until startup. So…what are you shimming to? Your shimming to an un-centered crank. Guess what happens when you start it up? Yup. I always use the method on the above posted Melling video. Takes 30 seconds, and is recommended by the best.
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Thanks for all of the replies! At the moment I haven't been able to dig into it with work sleep work sleep is the life ATM. I will definitely be looking into the oil pump as well. Thanks for all the advice and I'll report back as I go !
I’ve talked with Melling at length about the shimming procedure and it’s a farce. Here’s why…The crank is ONLY centered in the bearing journal when THE ENGINE IS RUNNING. It takes oil pressure to maintain the crank being centered in the bearing journal. Compression will always force the crank downward and as the engine comes to a stop, there’s not enough oil pressure to hold the crank up. The final compression stroke there will force the crank downward. It’s the same with building a new engine. The crank is never exactly in the center of the bearing journal until startup. So…what are you shimming to? Your shimming to an un-centered crank. Guess what happens when you start it up? Yup. I always use the method on the above posted Melling video. Takes 30 seconds, and is recommended by the best.
a) In the case of a newly assembled engine, assembly lubricant would take up some space b/t the crank and bearing
b) Once the pump is primed, again, the clearance within the pump gears themselves would change the fitment, as well
Whatever the case, I've seen a brand new (Melling) oil pump prevent the engine from turning over. All good- No b.s. here- just trying to help with facts.
