Chevy Nova Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
49 Posts
Discussion Starter #1
(1963 chevyII, front sump pan) So, I decide to install a steel shaft collar in place of the plastic one. everything goes together fine, got the pump bolt snugged into place with the pump flush to the block. dowells are where they should be. time to torque it. I check the manual, and it reads 65 ft lbs. well, before the wrench clicks, the pump housing split around the bolt hole. 1) The manual is for 70's camaros, haynes. Is the spec different for the chevy II? 2) could the spec be altogether wrong? 3) should I get a new torque wrench?. Ordered a new pump, should be here by wednesday.
 

·
Premium Member
Joined
·
11,208 Posts
If everything was right it should not have broken. Either something wasn't seated properly or if you know everything was right and correct maybe the pump was cracked before so it failed when you torqued it. The torque number is for the bolt not what the housing can tolerate which should be much more than 70 psi. The bolt would fail or pull the threads before it broke a properly seated undamaged pump. JMHO, RM
 

·
Premium Member
Joined
·
8,405 Posts
The torque spec for the oil pump bolt is 65 ft/lbs. If the pump broke there may be reasons not readily obvious.
The front sump shaft is shorter than the "normal" shaft. If you used a steel collared rear sump shaft it will be too long. Also the front sump pump is shorter so there is less space for the collar. If you installed a collar on a short shaft it may not clear.
The M73 pump is not very robust so it's possible it was just old and fatigued.
 

·
Registered
Joined
·
1,908 Posts
Or your torque wrench is out of calibration.
 

·
Registered
Joined
·
590 Posts
Funny you mention this. Had a buddy at TNT last night make a good pass. Then when he went to staging for his second run he noticed he had no oil pressure.

After pulling the pan, the oil pump had "broken" around the bolt and the whole thing was in the bottom of the pan. He ran all year last year on this pump.

He went to get a new pump from the same place he got the first (knows the guys there) and they told him they had recently had a run of them having the same problem. I will try to find out what brand it was..
 

·
Premium Member
Joined
·
3,883 Posts
pump housing failures

...sounds familiar...melling 55?


steve
 

·
Premium Member
Joined
·
8,405 Posts
The new style Melling M55 and M55HV pumps are breaking at the neck when used for drag racing and that's the just one reason the PW pump project got started.

The problem with the front sump pump in the beginning of the thread is another issue.
 
1 - 10 of 10 Posts
Top