Hi,
Removed the oil pump cover (From End) on my 1942 G3L to check an oil leak. There are 2 holes for oil to flow on the pump cover. When I checked a spare cover I had there is just one hole for the oil to flow. Were there 2 types of these pump covers i.e. one with 2 oil holes and one with 1 oil hole?

P.S - The crank case also has 2 oil holes

Tavery

email (option): tavery.p@gmail.com

It would seem every front cover/oil supply union to rocker feed has only one hole in it.
this aligns with the oil pressure feed from the pump which viewed from the front is at 4 O'clock in the crankcase...this supplies oil to the rocker box via the tube..

the other crankcase hole located to the left of top feed center is normally blanked off by the gasket.

drilling a second hole in the cover to align with this hole assuming the hole in the cover goes into the cover oilway will supply oil to the pinion side main bearing and help lubricate it with a bit of oil pressure.

Given the pinion side main bearing was a plain brass bush and a perceived weak area on earlier engines, it may have been a service mod to introduce more oil in this critical area at the expense of rocker box lubrication which was well catered for anyway..or it may have been standard on earlier (G3 ) engines and then deleted, but i have never seen a 2 drilling front cover...we all live and learn such is the joy of the forum...

email (option): edd@abbottracing.com

The front end of the pump is the delivery (pressure?) end, the rear is the scavenge. The front supplies the timing side main bearing bush (assisted by a roller bearing) and thus the the big end bearing as well as the valve gear which with the exception of the valve guides never wears out. Therefore the more oil that gets to the timing side the better but of course it only does this at a pathetic rate compared to more modern machinery. However they still work very well!
Richard

Having looked at some early post war crankcases I have I have noticed that they to have the 2 holes that you refer to. I am not 100% sure but I thing the 2 holes may have been introduced when the brought in the double start oil pump and doubled the oil circulation. Are you absolutely sure you have post war cases? John

Hi,thanks so much for the wonderful responses. Here is an image. I am not very sure if the crank cases are post war but they have an oil hole on the top and no visible holes on the cylinder. I assume that this is for some sort of an oil circulation.



Tavery

email (option): tavery.p@gmail.com

Tavery, your photo shows a recent pattern part cast in brass and probably made in India. All WD period parts were cast in Mazak, which is an alloy of zinc and aluminium I believe. John

Yes, thats a piss poor part, hacked out of brass with a blunt file most likely, you can buy new ones via the AMOC spares scheme

Hello I understand about the part now. I have a spare which is genuine but has just one hole. Will blocking off the extra oil hole in the crankcase have any impact?...this part in the image that I posted was given a brass finish by the previous owner. Not sure why....anyways I am still afraid if blocking the extra oil way might harm the engine. Any thoughts?

Tavery

email (option): tavery.p@gmail.com

The upper oil channel is the oil feed to the crankshaft bearing and is blanked off by the gasket and the front cap.
The channel is in fact a leftover from drilling the connection between oil pump and bearing and certainly has to be blanked off.
I would stick to the original front cap if I were you.

This is how the oil pump works:
http://www.jampot.com/article_print.asp?id=519

1942 crankcases






Regards,
Peter