Morris Minor Forum

If you buy from Mini Mania
likely you are buying good stuff John,

Likewise the Healey place in Southam.

What do you guys think is going on here? For some reason I'm not getting a good seal. That's quite a bit of oil leaking out. What's going on? Could the bolts be bottoming out? I bought some shorter bolts.

Is it necessary to put gasket sealer over the gasket when I put the oil pump in?

I would say yes to the gasket sealer. I like something called The Right Stuff. Also the short bolt in your photo seems too short to me. I would measure the depth of the blind holes and get (or cut to length) bolts that are the correct length but do not bottom out in the holes (which may be of different depths).

John F. Quilter
Eugene, Oregon USA

Ok, thanks John. Yea, I was going to use toothpicks and measure the depth of each hole. Then I was going to measure the the depth of the old pump and new pump to see if there was any difference. It could be that one of the holes was a tad bit shorter. I agree that the new bolts are a bit in the short side. I may have to grind the old bolts down a bit. I will find out more tomorrow. I will use some gasket sealer this time too. I believe that the torque for oil pump is 9 lbs. Would it hurt if a went a tad bit tighter or should I always go with what the manual says?

Sealer is essential in your case me Old China )

You also need to clean the old gasket off 110%

Torque according to the manual.

Blast the bolt holes out with air.

Clean the threada in the block with a bottoming tap.

Blast the bolt holes out with air.

One at a time
Without the gasket.
Without the lock washer
Run one bolt in through the pump and into the block.
to see if it holds the pump tight.

Mark that bolt for that hole.

When you've checked every bolt for length.

Fit the pump
using a new gasket
and gaskets seal.

Tighten to the given torque.

I just popped in to see what is going on and immediately came across your post. Having been in the business for many years, I can tell you that on reading about your problem, it is not an uncommon one to have. It really has nothing at all to do with the oil pump or gasket. The obvious clues are two things: 1) oil is escaping at the rear of the engine despite new lower gaskets, 2) You have "blow by".

Blow by indicates increased crankcase pressure venting outside. This is not good as it is caused primarily by poorly sealing piston rings and secondarily by poor valve sealing and loose guides. In both cases, compression is allowed to escape into the crankcase, which in turn vents out carrying oil vapour and unburnt fuels with it

Oil leaking at the rear indicates that the "screw seal", which is that half-moon shaped metal bit on the rear cover and sitting over the crankshaft, is a) not set at the proper gap to the crankshaft, b) is badly worn, c) the archmedes screw on the crankshaft is badly worn. The "screw seal" is set at the factory at the prescribed gap. Not often, but I have seen it on a rebuilt engines, the screw seal is improperly positioned, allowing for a larger than normal gap. Thus oil pushes past the screw which is not really a seal, but acts to keep oil in the crankcase by "scrolling" it back. That scrolling action is only made possible when the gap is narrow enough for the scroll on the crank to grab oil trapped between the crank and the ridges on the scroll seal.

It could be that your main bearings are also badly worn, but the fact that your oil pressure light goes off when running would indicate that they are good enough to maintain at least the minimum oil pressure required to extinguish the light.

I recommend that you pull the engine and do a complete refresh on it. In the end, you will benefit from a 948 running at its best and many more miles of fun driving with no embarrassing oil traces left on the ground. I recommend that you have the job done professionally. Not everyone is good at engine rebuilding. However, if you do this yourself, ensure that the scroll on the crank and the ridges on the scroll seal are in very good condition and that the gap is set properly on reassembly. If it is done right there is no need to fit the aftermarket seals. Those bits have their own problems.

Morry, please would you explain to me
how you get from,

"I had the typical blow by and
oil was leaking the same amount
as it was before I changed out
the old oil pump.
t didn't look like oil was leaking down
from the rear main, "

To advising Greg to
"pull the engine and
do a complete refresh on it."

I'm fully agog with puzzlement
to say the least

Very good advise provided here.

John F. Quilter
Eugene, Oregon USA

Crankcase blow by will tend to increase oil leakage by the rear crankshaft scroll. A positive crankcase ventilation system such as was fitted to the 1967 US spec Minors can reduce this. Here are a few photos of what the system should look like

John F. Quilter
Eugene, Oregon USA

Thanks Bob for the advise. I am by no means a mechanic. What turned out to be a fun hobby is now driving me crazy trying to figure this out. I guess your right...I'm gonna have to pull the engine and have everything checked out.

Is this oil pump leakage a problem common?

This series of exchanges really the first I've heard of as a source of leaks. It's usually the misnamed scroll "seal". I'd suffered from blowby there until I figured that one out.

I'm getting ready to tear down my 1275 engine to upgrade to a mild road cam and lifters, roller rockers, add a rear main seal kit, vernier timing gear, hardened valve seats, SS exhaust valves, and more bits - as long as I'm there sort of things. How about adding an A+ timing chain tensioner? Those parts are easy to come by.

I'm considering a Metro Turbo oil pump as one of those "there" things. Any thoughts? Oil pressure is fine right now, but it would just be added capability. (I have a Metro turbo, but that's not in the works for now, anyway)

Is lightening the flywheel worthwhile? I'm also converting to a 5 speed (I'm going with a T-50).

I'm also going with Sentra 4 wheel discs for improved braking.

The objective is a stronger street engine and better highway comfort, not more

Gene, as someone who has over-spent on his 948 - I say proceed with caution. Easy to go down the rabbit hole of spending on pretty parts - for only marginal gain. In your case, you already have an engine fitted to your Morrie that it never came with, with more power than it ever came with. "A" series engines have (relatively speaking) gobs of torque for what they are. It is actually easier to get Sadie rolling smoothly away from the lights than it is my daily driver Scion Xb (manual gearbox) - because that brilliant little Toyota motor has no torque at all until about 4000 RPM. Lightening the flywheel - other than skimming for wear - will most likely give you a lumpy idle and the need to slip the clutch a lot to get moving. Take what you would have spent there and add it to getting the complete rotating mass balanced at your machine shop (crank, damper, clutch and flywheel assy., along with careful balancing of the rods and pistons) and you will be a happy camper. You won't lose your torque - or the charming characteristics of the "A" series, and you will be able to rev higher when you need/want to. Hardened seats and some basic porting (which you can do yourself - although it's messy and horrible on your lungs (wear a GOOD mask - not the home improvement store dusk masks) are good ideas - as is a modest head-skim to increase your CR. Ask yourself how many hours a year do you get to drive your Morris and really sit down and justify the expenditure of all the other bits you mention. Most of it you will not feel in the seat of your pants - which is the only place is really counts.