lt4 long block swap... no oil pressure
05-09-2008, 01:29 AM
#1
lt4 long block swap... no oil pressure like it says... just got the lt4 LB from GM swapped out and started up. ran for about 5-10 sec and noticed no oil pressure reading on the gauge.
so what could the problem be? when i went to prime the oil pump, all of the oil was coming out of the hole where the oil pump drive goes into. i know some small blocks need a plug or 2 put in them to route the oil the right way. any help would be great....
so what could the problem be? when i went to prime the oil pump, all of the oil was coming out of the hole where the oil pump drive goes into. i know some small blocks need a plug or 2 put in them to route the oil the right way. any help would be great....
05-09-2008, 02:32 AM
#3
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They should be the same I think. Like an old school dizzy you may have to turn the engine just a few degrees back and forth to get the drive to seat properly. Now... when you say this does that mean you started it w/ it sticking out of the block that far?
05-09-2008, 05:13 AM
#4
The prime tools need a bushing in that drive hole to properly route oil to send it to the whole motor.
If you think there is the slightest chance that the LT4 used a different drive then you have not done adequate research, then again the fact you bought an LT4 longblock and it sounds like new from GM is proof you have not done adequate research..
What are you basing the no oil pressure statement on?? Mechanical gauge, stock gauge, or watching the valvetrain??
If you think there is the slightest chance that the LT4 used a different drive then you have not done adequate research, then again the fact you bought an LT4 longblock and it sounds like new from GM is proof you have not done adequate research..
What are you basing the no oil pressure statement on?? Mechanical gauge, stock gauge, or watching the valvetrain??
05-09-2008, 12:49 PM
#6
SS RRR- yea i started it with it sticking out that far b/c i got it in there, rotated the engine some, and it dropped another 1/4-1/2 in. into the block... but was still sticking out...
96 Cap--the prime tool that the shop had that i used was an old SBC distibutor driveshaft... so nothing special. and i have no working knowledge on the LT engines.... ive built SBC's and an LS engine, but never got into an LT. Its a friends car and he wanted me to help after he bought a running car and got it in peices...
the oil pressure im basing off of the factory gauge and i felt under the valve covers after start up and there was no fresh feeling oil in there.
and yes the wire to the SU was connected... almost forgot it, but its on there. if it works i have no idea
96 Cap--the prime tool that the shop had that i used was an old SBC distibutor driveshaft... so nothing special. and i have no working knowledge on the LT engines.... ive built SBC's and an LS engine, but never got into an LT. Its a friends car and he wanted me to help after he bought a running car and got it in peices...
the oil pressure im basing off of the factory gauge and i felt under the valve covers after start up and there was no fresh feeling oil in there.
and yes the wire to the SU was connected... almost forgot it, but its on there. if it works i have no idea
05-09-2008, 12:55 PM
#7
well if its already together and unable to prime personally i would disconect the coil and let it turn over for about a minute or so, then id hooked it up and start it, it takes more then 10 seconds for oil to get to the top if it wasnt primed properly.
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05-09-2008, 05:40 PM
#9
Put another way, there is no chance that you need something different than the LT1, it is the same block even. The LT4 is NOT anything special and is frankly a poor choice unless you got an awesome deal and even then a mediocre choice.
05-09-2008, 07:10 PM
#10
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the oil pump drive gear needs to be in the same location that the old swapped out drive gear was. Flush with the mounting boss.
Yes the LT1 and LT4 oil pump drive gears are the same.
So if the drive gear was not installed all the way down then it was not driving the oil pump. Hopefully it's that simple.
Get that drive gear down further into the block as described above by turning the crank a few times while persuading the drive gear down gently as if it were an old style distributor.
hth.
Karl
05-09-2008, 08:50 PM
#11
but ya i got a great deal on it... $2k for the long block from a guy out here in hawaii...and the other engine was shot for reasons unkown, so we decided to just get that engine since it was a good deal...
and ill pull the intake off of it this weekend if i get a chance and see if i can get it straitened out.. thanks guys
and ill pull the intake off of it this weekend if i get a chance and see if i can get it straitened out.. thanks guys
05-09-2008, 09:19 PM
#12
Just pull the valve cover off and start it and see if there is oil coming out of the rockers. If there is, then during installation you broke the sending unit or it was faulty.
If there is NO oil making it to the top of the motor than it is probably a problem with the drive/shaft. And then you would pull of the intake manifold.
No reason to go through all that trouble of pulling the manifold just find out its a problem with the sensor.
If there is NO oil making it to the top of the motor than it is probably a problem with the drive/shaft. And then you would pull of the intake manifold.
No reason to go through all that trouble of pulling the manifold just find out its a problem with the sensor.
05-10-2008, 08:35 PM
#18
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This is probably the cause of no oil pressure.
the oil pump drive gear needs to be in the same location that the old swapped out drive gear was. Flush with the mounting boss.
Yes the LT1 and LT4 oil pump drive gears are the same.
So if the drive gear was not installed all the way down then it was not driving the oil pump. Hopefully it's that simple.
Get that drive gear down further into the block as described above by turning the crank a few times while persuading the drive gear down gently as if it were an old style distributor.
hth.
Karl
the oil pump drive gear needs to be in the same location that the old swapped out drive gear was. Flush with the mounting boss.
Yes the LT1 and LT4 oil pump drive gears are the same.
So if the drive gear was not installed all the way down then it was not driving the oil pump. Hopefully it's that simple.
Get that drive gear down further into the block as described above by turning the crank a few times while persuading the drive gear down gently as if it were an old style distributor.
hth.
Karl
If the pump drive is up a little that could mean the oil pump is not being driven. I wouldn't start the car unitil I was sure that the oil pump drive was engaged with the oil pump.
