BritishV8 Forum

Since I last posted about this, I have pulled the engine completely apart (Rover 4.0 with the front cover, etc, from a 3.5), had the crank re-ground and installed new cam shaft bearings.

Now, when I run the oil pump with an electric drill, I get up to 15 lbs. of pressure.  BUT, when I install the distributor, I get nothing. I HAVE checked to see if the distributor is, in fact, turning the pump, and it is. In fact, the engine starts and seems to run fine, although a bit noisy, because, no oil pressure (I have a professional oil pressure gauge hooked into the system.).

Understand that this front cover, oil pump and distributor are the SAME ones that worked fine, with plenty of pressure, on my old 3.5. The reason for the upgrade to the 4.0 was a bad block.

 -- moved topic --

So you're using the 3.5 cover?

Yes, I am using the 3.5 cover, which was functioning perfectly when the 3.5 was in use. I do have the special spacer for the crankshaft.

John, Is the relief valve stuck? Did you pack the pump with Vaseline?

Jim, since I'm nowhere near the expert you are ...
If he can spin the dizzy and get pressure, would he need to pack the pump?

John, how long did you let it run noting no oil pressure and how much time elapsed between the drill and the car running?

Don, I always pack the Buick/Rover pump with Vaseline. I use the drill too and usually have a lot of resistance and over 30 lbs oil pressure on the gauge. I also watch for oil up at the rockers. Maybe I'm a little paranoid. John are you running the closer bearing clearances the motor requires? .001-.0015 instead of SBC .002. Lots of info here and on V8Buick sight for improved oiling mods.

He's been posting his problems with the TWOA and really not having any luck.
He did say there that he's finding oil at the rockers with the drill.
I'm think that if he used the drill and got OP and then waited a while before he started it and didn't get any the oil was probably drained from the pump.
Other than that I'm clueless and will await the lots smarter people here

Check the shear pin in the distributor gear. If that goes there's no oil pump drive.

Jim

I had the crank re-ground to the tighter tolerances.

I have switched back and forth between the drill and distributor (I turn it with the starter.) The drill always gives OP, with the distributor, nothing. I KNOW the distributor is turning the OP because I can see the flange in different positions.

I have ordered one of those WiFi endoscopes to stick down through the Dist. hold down clamp hole. I tried renting one from Autozone, but the tip was too big to go down the hole. I think the WiFi tips are smaller, and should fit.

I can detect no slippage in the distributor shaft, but I am going to disassemble it just to check out the pins, etc.

I have posted this problem on other forums, in the hopes that something new will be suggested. I talked to the machinist today who did the bearing work, and he also insists that the problem lies in the dist. shaft.

Might have the drive gear and fuel pump cams switched on the nose of the cam.

Jim

I was just thinking the same thing as Jim!

Then why would the distributor be turning?

Then you need to look at the engagement between the end of the oil pump and the drive tang of the distributor.

Jim

How fast are you running the drill to get 15 psi? If you need the drill running at full speed to get 15 psi you might have an air leak somewhere.

I had a similar problem using an early front cover on a 3.9. I took the front cover off to make sure the oil pump was engaging properly. Everything looked to be working fine. I used a Buick 215 cover gasket instead of the one that came in the 3.9 gasket  set when I put it back together. With the drill turning the pump I got 50 psi and on start up 50 settling down to 30 psi idling at around 1000 rpm.

Unfortunately I ran the engine too long with little to no pressure. When I took the motor apart , all the bearings were scuffed up pretty badly so its rebuild time this winter.

Lorne, You may be on to something. Could be gasket where pickup bolts to block also. It may be cavitating and not priming. Try packing the pump with Vaseline.

To check for air leaks somewhere on the suction side of the oil pump, remove the relief valve piston and put the cap back.
Connect a hose to the output side of the pump that leads to the remote filter.
Run the pump with the drill. If the oil delivered to a container is frothy or intermittent in flow there is a leak on the suction side.

When you run the drill in reverse the oil should pump quickly and without a sucking sound back to the oil pan through the pick up.

After you solve the problem dont't forget to put the OP relief valve back in.

Not sure where a remote filter would hook in. This pump includes a mount for the filter.

I am running the drill at 1200 rpm to get 15 psi.

Other than the oil pick up in the pan, where else could their be a problem with suction?

Like Lorne says, wrong timing cover gasket?

Sorry my 3.9 is in an MGB. Couldn't make room for a filter on the front cover so I used a remote.

You may have a leak at the front cover gasket. If the mating surfaces are scored or not flat they will leak either air or coolant or both.
Also check to see that the gasket you use covers any passages on the front cover that doesn't match up to passages on the front of the block.

Have a look at the pics in this link. Hope it works I'm not that good at these things.

https://1drv.ms/f/s!AmTrxwF38OK3j0nSBfSbQGATm-5n

The gasket is correct, and the pin in the distributor is intact.

At this point I am wondering if I don't have a crack in the front cover. I think I will take it off tomorrow and get it checked out.

I am using up whatever wit's I had on this one. Got two waiting in the driveway to get working on.

Thanks for all of the input!!

if it works with the drill but not with the distributor, then logic dictates that the oil pump isn't being driven properly. Since the distributor is turning and the engine runs, the only thing left is the drive tang. Perhaps the distributor is not seating fully?

I had a similar oil pressure incident years ago when I had an Olds engine rebuilt.
 There is an oil gallery plug (similar to a frost plug) behind the front cover which wasn't staked into the block at the machine shop and it had subsequently popped out on engine start up and all oil pressure was lost.
.....just another possible  check for no oil pressure.

OK so the distributor is turning the pump but perhaps not very much.
Check the roll pin.

I had problems with a 3.5 a while back, wouldn't prime. Turned out the oil pump cover gasket was too thick. Got one from V8 Dev and it was fine.  
But that wouldn't prime with the drill and yours will,. So it has to be the dizzie.

Ivor

It is also possible for the drive tang to be twisted off up in the distributor gear.