Moss Motors, Ltd

1971 MGB 18GK engine

I lost the clutch in August of 2008 and it's taken this long to get things back together.  During the past year the engine has just sat on the engine stand - no work was done internally.  Now the engine and transmission are back in the car and I am trying to re-establish oil pressure with no results.   The crankcase is full of oil to the mark; Oil cooler lines have been topped up; the oil gallery from the oil pump has had 4 to 5 ounces of oil put in with a squirt can before the oil cooler line was refastened.  The engine has been cranked for several minutes in 20 second spurts.  The oil pressure gauge will go from below zero to zero when the key is turned, but no further.  (The pressure was good - 50 to 60 psi warm before the clutch went out.)  Please offer suggestions on how to restore oil pressure.

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Oh, to be as young as I think I am.

If you haven't, you should remove the spark plugs when turning the engine over.

Are you sure that your gauge is still good? Especially after all the work, you could have kinked or broken the tube somewhere. I'd buy another gauge (about $15) just to test it. Who knows, you might not have a pressure problem at all!

 

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On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"

'68 Sprite 1275
'76 Midget 1500

Thanks for the reply, Davey.  The spark plugs are out.  The gauge sender is electric, so the oil pressure line (steel braid armored rubber, about 1/8" inside diameter and about 7" long) goes from near the oil cooler supply connection on the back right side of the block to the gauge sender behind the alternator on the block.  If the engine is cranked over with the oil line to the gauge removed at the gauge, there is no oil flowing out of the line, suggesting that the oil pump is not putting anything out.  Since I didn't take the oil pan off, I don't think there is any chance of the oil pump drive shifting.  If the oil pump has prime, it should push oil through the system and force out any air that may be in the lines, no?  Of course it is possible that I do not have the gauge connected properly, which might explain why it does not read anything, but oil should come out of the gauge line if the oil pump is working, unless there is some sort of restriction in the oil gallery that does not allow any great amount of flow to the gauge, just the pressure.  Nothing is mentioned in my Bentley manual about a restriction but that does not mean that one does not exist.

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Oh, to be as young as I think I am.

When I last did this (earlier car with a working mechanical gauge) I was amazed at how long it took oil to fill the lines & block galleries in order for pressure to register, and when it did, I had 60 psi there and then.

I'd suggest a) checking the gauge works properly, as davey suggests, b) disconnect a line somewhere, e.g. into the cooler, arrange a suitable container (hold things in place with tape, just in case it moves, and see if oil comes through whilst cranking with the plugs out. At least that way you know the system is primed.

 Good luck,

Ed

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I want my MGB

Thanks Ed.  I will try it in the morning by taking off one of the oil cooler lines and see what happens, hopefully without melting the starter motor.

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Oh, to be as young as I think I am.

Ed is right. Try that, then if you still don't have oil flow, drop the sump and take a look at the oil pick-up.

 

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On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"

'68 Sprite 1275
'76 Midget 1500

Okay, the oil pump IS working.  Taking the inlet line off the oil cooler revealed that there is ample flow coming from the oil pump, so it would seem to be just a matter of time until the gauge starts to work.  I will hook up a booster battery and crank for a while, watching the starter temperature.  I will also make sure the right wires are hooked up to the right terminals in between cranking sessions.  Thanks for the advice guys.

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Oh, to be as young as I think I am.

WHEW!!!!

Cheers!

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On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"

'68 Sprite 1275
'76 Midget 1500

Hey Good news indeed!

Time for a or here too...

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I want my MGB

The good news - Oil pressure of 50 psi after only about 30 seconds of cranking.  Just gotta be patient, man.

The rest of the news -  Major oil leak in the area of the rear main oil seal that was not there when the engine came out.  A few minutes after the engine has been cranked to establish oil pressure, oil starts dripping down the mounting plate from the block side.  Yes, I did not change out the oil seal - it wasn't leaking (when the clutch went out)(well, maybe a little).

I decided to bleed the brakes and clutch before starting the engine.  A good thing.  The brake fluid was terrible looking.  It probably needed changing a couple of owners ago, but no one bothered.  Ran out of fluid when bleeding the clutch, which had leaked all its fluid out in the year of storage.  When I stopped, the clutch travel at the clevis pin was about 1/8" - I think it should be more, but I forget what was written several months ago.  I will go back and see if I can find the number from previous posts.

The engine and transmission may come out Labor Day weekend.  At least this time it will be a lot cleaner to work on.  I still have all the baggies with the labels on them.  Practice makes perfect.

Thanks to Dave and Ed for the advice and encouragement.

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Oh, to be as young as I think I am.

Mr. $pit-

I wonder if the rear seal took a bit of a set while the engine was sitting. It could be that when you restart the engine the heat will soften up the seal and the oil leak will return to it's previous minor state. On the other hand, it is a good feeling to just do it right  and get it over with by replacing the seal now, before you get too far into the re-install.

Just thinking out loud...

LCJUTILA 

Follow-up

 It only took 3 weeks, but the oil leak was fixed.  It wasn't the rear main seal at all, just forgotten paper gaskets on the engine mounting plate.  The engine went in yesterday without many hitches.  The rear stud where I had attached my leveler broke off when the engine was almost in.  The transmission fell about 4 inches, but was not damaged.  I used a jack to pick the transmission up and position it.  Other than that and neglecting to connect the coil wires and having the firing order wrong on the new distributor cap everything went fine.  Took some time this morning and set the timing, then took wife for a ride.  It sure is nice to be back on the road again.

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Oh, to be as young as I think I am.