Devimead end fed crank...no oil return...

[COR274C]

Hi, just signed up.

I have a 1965 Lightning - owned it since 1977, threw the second con-rod in 1986 when I got SRM to build the engine and it was left in the garage as I moved over to a Laverda Jota.

The engine has some interesting bits - Devimead end fed crank, Devimead oil pump, SRM sump plate, Bob Joyner half-race cam and Carrillo rods.

Decided to finally try and get it to go in 2024 which was successful but after 100 miles it seems to have given up returning oil (it did when I first got it going)! I've taken the engine down as far as removing the oil pump and confirmed oil gets from the tank to the pump.

I dismantled the cast iron Devimead oil pump - the gears are intact and there appears to be no pressure leaks. The ball bearing and spring appear sound (although the spring seems quite 'strong' imho).

I removed the oil pressure valve and squirted WD40 down the oil pump exit gallery and WD40 appeared in the pressure valve housing (and vice versa) so I deduce the galleries in and out of the pump are clear. As oil didn't appear when I turned the engine by hand am I right to think the oil pump isn't pumping or at least isn't able to get past the oil pump spring?

Do I need to split the cases or is there anything else I should check?

Many thanks

[DAVE BRADY]

Hi,

After the 100 miles was there anything at all returning to the tank?  Unless you drained the sump there would be some oil sitting in there and the pump would scavenge this back to the tank as a constant flow and then, as you have a new and efficient pump, this will tend to be reduced to oil 'spitting' in to the tank.
Try putting about 1/2 pt. oil in the sump and see if it returns.  Turning by hand may not be enough so with the plugs out try some rapid kicking.

Dave.

[COR274C]

Hello Dave,

Thanks for the suggestion will get on to this!

Nick :-)

[JulianS]

Possible airlock in the oil feed from the tank to pump? Try loosening the 3 nuts holding the pump in place and see if oil emerges from the joint, if there is an airlock this should clear it.

[COR274C]

Thanks for the suggestion Julian. I read on other Forums about air locks so will pay attention to this. The other suggestion I've read is to spin the engine by putting it into 3rd gear without plugs and taking the bike for a walk (maybe I will make motorbike noises so I don't draw attention to myself). I'm a bit bemused because back in the past I never had to consider complexities like this to get the A65 going.

I know I have oil down to the pump and Dave's suggestion to put half a pint in the sump will show whether return is an issue i.e. does the engine scavenge. If both sides of the pump check out then I deduce pump issues.

I have ordered a replacement oil pump spring to compare with what I have.

Will report back on what I find.

Thanks again all.

Nick :-)

[DAVE BRADY]

Hi,

Assuming it is a cast iron pump, unless a colossal mileage has been covered or metal swarf has entered the pump there should not be a problem.  When fitting the pump gasket make sure that all the oil holes are completely unobstructed.  SRM do gaskets that ensure this.

Dave.

[COR274C]

Hello again,

I think I have positive news!

Tried pushing the bike round the garden with no success. Put half a pint of oil in the sump and again no success. So had a rummage in the shed and found another oil pump. I'm unsure of the history of this pump but it has a 'custom' end plate and bolts rather than screws. Anyways took it for a bigger walk down the road with the good wife adding a bit of 'heft' but still no oil return (met a nice chap who owns a 1950's Citreon DS walking his dog which provided a welcome break). On getting home checked the sump and this time oil had got past the pump so it was going downstream! Poured oil down the pushrod tunnel and back to pushing. This time oil came out of the top end feed! I carried on pushing and the wife walked alongside with her finger over the return pipe and bingo - of course this may be a false reading just showing that the engine is scavenging. I shall screw it all back together and see if when it starts all is well - at least it won't start dry.

I'm not convinced the Devimead pump is at fault here - it turns smoothly and pumps oil on the bench. What I did find was that the pressure spring I replaced is stronger than the part I got from Burton Bikes + on an original BSA pump the ball bearing sits deeper into the housing - which again means the spring isn't under so much tension. I wonder if the actual issue was an air lock which some of you advised me to be wary of.

Anyways thanks for all the help - I will report back again after it's started.

Nick :-)

[COR274C]

A quick update on the A65 - it's going and currently undergoing the 'road-hardening' process. It starts easily from cold and runs well off the pilot jets but these need to be set correctly. Ought to be simple - synchronise carbs, set tick over high then turn the mixture screw to when the engine runs quickest. Once both sides done just lower the tickover and job done...hmmm will probably settle for 'good enough'. Once I get to the end of the 500 mile road-hardening I intend to spend time on the cosmetics.

Thanks for everyone's help.

Nick :-)

[ChrisG]

Well done mate!

[V500]

Anyways took it for a bigger walk down the road with the good wife adding a bit of 'heft' but still no oil return (met a nice chap who owns a 1950's Citreon DS walking his dog which provided a welcome break). On getting home checked the sump and this time oil had got past the pump so it was going downstream! Poured oil down the pushrod tunnel and back to pushing. This time oil came out of the top end feed!

How many engine revolutions do you think your walk managed? 250 maybe?
Had you fired it up it would have achieved the same number of revs in maybe 15 seconds and you would've saved all that effort...

[DAVE BRADY]

Hi,

I must admit that I err on the side of caution.  15 seconds and then OK perhaps.  If all is working properly then turning with the kickstart should be enough and worth persevering with.

Dave.

[DAVE BRADY]

Hi,

Another thought.  After working on the oil pump etc. it is possible that the crank has pretty much drained of oil so before refitting the cover, position the crank at BDC and using an oil can, pump engine oil in to the quill in the end of the crank.  Put plenty in and then at least you know there is oil in the crank and it will have squeezed through the big ends.  They will now be oily for start up.

Dave.

 

[COR274C]

A good idea with the end fed crank to prime the quill - I will use that next time.

Yes just starting the engine would have achieved the same result in 15 seconds but remember before investigation the oil wasn't returning. I wanted to be sure that issue was fixed before starting. On the plus side it gave me and Mrs A some quality time together, we both burned a few calories and met a neighbour :-)

The road hardening had been going well until yesterday when it stopped charging or at least volts went up but only to a measley 12.75 @ 4,000 rpm. I suspect the alternator.

As ever thanks for all your help.

Nick :-)