Technical Oil Pump wont spin

Good Morning

I am trying to prime the oil pump on a freshly rebuilt chevy 235. I am using a large flat screwdriver and the drill method. It won't spin, it feels tight. (drill is probably garbage) I tried it with another screwdriver and a wrench, and it moved but it was very little and very difficult to spin.

Any ideas from those of you more experienced?

Thanks in advance

 

is the engine in the car or on a stand? If it were mine I would be pulling the pan and then the pump to inspect the pump (pull the gear cover off the pump) to make sure it doesn't have any glaring problems. Also, is this a later 54 up full pressure 235? it will make a difference in the resistance the pump turning as the full pressure is a substantial upgrade in oil pressure compared to the earlier 235s.

I have smoked a cheap cordless craftsman drill trying to prime a small block Chevy with a regular stock type pump, so if you have an cheap no power drill that may also be part of the problem. there is defiantly some stiff resistance when priming an oil system with fresh cold oil and nice tight clearances, the oil weight makes a difference too. any more when I prime a system I use a 1/2 inch drive Milwaukie hammer drill and it makes it much less effort.

 

Sounds like you need to remove the pan and remove it. Once the pan is off check the locking bolt and nut that holds it in place in the block. The bolt may have been installed too tight jamming the pump drive shaft. You can also remove the bottom plate and check the idler and drive gears.

 

the motor is on the stand, and yes it is the full pressure system.

thanks

 

How did the pump spin/feel as you were installing it?

 

Take it off and check, do not p*** go.

 

This from the 1954 Chevy service manual but it should stand for any 235.

It's been Close to 60 years since I rebuilt one of those but that set screw has to go in the indent in the pump housing to hold the pump in it's correct spot but that shouldn't be an issue. Tighten securely doesn't mean overtighten though.

The Caution note on step 7 may well be the issue. Pulling the pan back off and start checking is a given, there is no way around that. First thing I would do after that is loosen up the oil line fittings and see if the shaft will turn then loosen the retaining lock screw enough to take pressure off it and check again. ONE check at a time.

 

I really think I tighten the retaining bolt too tight. it was nicely spinning before installation.

 

will do

 

Many times the ***embler will install the oil pump retaining bolt pointed end correctly then when securing the lock nut doesn’t hold the retaining bolt with a second wrench. Not doing that CAN cause the securing nut to tighten the retaining bolt. It doesn’t take much to squeeze the housing onto the oil pump shaft. The GMC 6’s are the same way.

 

Had a customer return a new oil pump. I took the cover off and a single strand from a wire wheel was stuck between the lobes.

 

Years ago a friend bought a new oil pump for a 351 Cleveland. Before installing it, he removed the cover for no other reason than to simply inspect it before installation. I was there. The cover came off and WOW ... a LOT of machining shrapnel inside. This was probably 30 years ago. I was shocked as I would never have thought inspection necessary before installation.

 

**Update**

Finally got a chance to get on this issue. We'll someone (me) forgot the gasket...... put a gasket on and fixed, spins smooth.

Thank you all for the input and advice

 

GMC 6’s don’t have gaskets…never used a Chev…good find.

 

Funny, I dropped the pan on a 235 to tighten the timing chain cover, I noticed some specks of something on the oil pomp screen, took the pump off, cleaned the screen, it it had a gasket I didn’t notice it.

 

Next time tap the two holes in the front main cap for 3/8”x16 and install header bolts with 3/8” head size….

 

All they got is gears ....

 

I don’t know, never took the over off, just wanted to stop the leak.

 

thats how i have mine set up.