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MG MGA - worried about my rebuilt motor

I assembled my motor 2 years ago, after it came back from the machine shop. New pistons, rings, bearings, etc. all checked spot on during assembly. Used liberal amounts of assembly lube. I rotated the crank with the block on an engine stand after each piston/con rod was installed, and after each main bearing was installed and torqued. When the entire engine was assembled, I was able to rotate the crank approx. 500 times using just a standard 14" breaker bar and socket on the crank pulley. I would say that it didn't require an unusual effort to do this, so I was satisfied all was good. I installed the motor/trans last summer, but have not yet completed the wiring so haven't tried to start it yet. I find now that I can't seem to be able to get the engine to turn by putting the car in gear and "bumping" it forward or reverse, as if one were setting valves (plugs were removed). I can't get a socket on the crank pulley as I have installed the harmonic balancer, and the crank nut is now too close to the steering rack. I can't imagine the starter motor having enough torque to turn the motor over. Any thought or comments are greatly appreciated!

George
George G.

Jack one rear wheel up, put her in 4th and have a go at it. You should have plenty of torque on the tire. You'll know soon enough.

If it won't turn, remove the starter and try, the dizzy and try. It could be that something's binding temporarily.

.....
MAndrus

If you really rotated it 500 times after assembly, you probably rubbed most of the assembly lube from the surfaces that needed it.

-Del
D Rawlins

Del, I meant to type "300 times". I was told that that helped to "bed in" the new bearings.
George G.

2 years. It's just a bit of haze on the cylinders. It'll go away once you run it.
MAndrus

Big adjustable will fit instead of a skt
mog

clutch cover dragging on bell housing?
B Suelzle

Go to Northern Tool & Equipment and buy a wrench that's the correct size to turn the crank. It's not very expensive.

Jim
JL Cheatham

B Suelzle - no dragging sound detected
JL - I have a socket and a box/open end 1 5/16 size, neither fits due to the harmonic balancer being closer to the rack & pinion steering housing than the original MGA riveted pulley.

Thanks for your comments!
George G.

300 or 500, the assembly lube that was there for lubrication until the oil pump provides circulation, is gone. If the crank journals are properly machined and the clearance is correct, there is no need to "bed" the bearings by hand turning the engine. I've never actually heard of that one before. That's probably one of the worst things you can do to a new or rebuilt engine that is going to sit for a while without running. Whoever told you that didn't do you any favors.

-Del
D Rawlins

Del, point taken. But isn't there always a film of lubrication on the journals given that there is a clearance between journal and bearing, albeit a very close clearance on the MGA...?
George G.

It turned once, it'll turn again. Convince it I'm right.

I once put oil and gas to a '53 Hudson that had sat for 37 years. We put 5,000+ miles on that car in 2 years without even looking under the hood for other than external maintenance.

If the rebuild was a good one... Once the oil flows it'll behave itself.
MAndrus

George,
Putting a car in gear and �bumping� it is not easy, try as it was suggested here
to jack one rear wheel and rotate it putting in 4-th gear. And don�t worry of your engine I�m sure it�s OK. 300-500 revolutions of the crankshaft were made by spanner with a very low speed. It couldn�t damage any parts and some lubricant is still on the journals. Assembly lube contains special additives which prevent from a dry friction for a long time.
Nick (mechanical engineer)
Nikolai Skliadnev

This thread was discussed between 23/07/2015 and 24/07/2015

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