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MG MGB Technical - Oil pressure priming


What's the best way to pime the oil pressure in the engine before start-up? ('64 mgb)
Doug P

If you're swapping in a new oil pump - before you
install, open up the pump and fill with oil. Some
folks pack it with a light grease instead of oil.

If you're installing a new oil filter, and/or oil cooler,
pre-fill them with oil, also.

In anycase:

1) Remove the spark plugs and squirt a 2-3
teaspoons of engine oil into each cylinder
and wait a half-hour or so for the oil to settle
down into the rings. Leave the spark plugs out.

2) Remove the coil wire from the center
of the distributor cap.

3) Optional: Disconnect the fuel pump wire.

4) If the car has been sitting for a long time,
remove the valve cover and liberally squirt
engine oil all over the valve stem tips and
rockers and rocker pivots. Replace the valve cover.

5) Drape a rag over the right side if the engine
in order to contain any oil from spurting all over
the fender, etc., when you spin the engine.

6) Switch on the ignition and spin the engine
until the oil press guage reads 30 lbs or so.

Sometimes, this can be relatively lengthy and
can stress the batteries and heat the wiring
- so consider spinning the engine for no more
than 15-30 seconds or so, rest a 15-30 seconds,
and repeat until you get oil pressure registering
on the guage.

7) Check for leaks, install the spark plugs &
reconnect all wires (don't forget the fuel pump).

8) Go, man, go!
Daniel Wong

Yep, excellent suggestions there from Daniel.
Apart from the rag over the head to prevent oil splattering all over the fender / mudguard that is exactly what I have done on every engine I have ever rebuilt both my own and those for others.

The only reason I didn't use the rag trick is because I didn't know about it. Wish I had it would have saved a lot of cleaning up!!

Cheers , Pete,
Peter Thomas

Daniel Says-

"2) Remove the coil wire from the center
of the distributor cap."

I had a problem with doing this once, I could hear the spark tracking over the coil insulator, and later when I had the car out on the road, had a misfire under load that started about 3,000 rpm. After going through all the usual with rotor, cap, plugs, ht wires - replaced the coil and all was well again.

It may well have been that the coil was faulty anyway, but I never had a misfire before the rebuild.

IMHO - It is better to disconnect one of the low voltage leads, or disconnect high voltage wire from distributor cap, and connect to earth.

Cheers
ian F
Ian Fraser

The best way I have found to disconnect the coil is to pull the wire from the coil to the distributor. This is done at the coil. Several people have noted the problem Ian mentions and have suggested grounding of the HT lead going to the distributor cap. However, disconnecting the wire going to the distributor has always worked best for me. Also a good idea if you are going to be having the ignition switch on for any length of time as when troubleshooting an electrical problem. I found that out when I did not do it, burned up the points and the wire going to the distributor. Do, however, remember to hook up any disconnected wires after getting oil pressure. Les
Les Bengtson

Packing a new oil pump with petrolium jelly helps aid in oil pump priming if you have the opportunity. It allows the pump to immediately create a strong vacuum in the pickup tube, rather than slowly pulling oil into the pump. Or you can prime the pump through the distributor hole, allowing fresh oil to circualte throughout the lower end of the block.
Jeff Schlemmer

I always pump with an oil can oil into where the rear oil cooler line comes out of the block this back fills the pump. Also I made a pressure feeder out of a 30lb freon tank. I put my four quarts of oil in the tank. Hook the tank to the input of the oil filter and put air to the tank. I regulate the air and fill the engine that way adjusting for about 60psi on the car gauge. Takes awhile but all my oil goes thru the engine on it's way to the pan. Even the rockers start oiling. Best way i've found. Bob Thompson/International Auto.
Bob Thompson

I know that this will cause an argument but I've never done this to an engine in my life after a rebuild. Put STP or Vaseline if you like into the pump. Build the engine and turn the key. DONT let the revs rise. The gauge will rise or the oil light go out if it's another make in two to three seconds.
Iain MacKintosh

This thread was discussed between 29/01/2005 and 31/01/2005

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