Wet Sumping. .. a general query ..

[Taid]

Way back, 50s/60s, I don't recall hearing about anything which could have wet sumping.

Admittedly in those days, the bike was ridden pretty well everyday, so the oil didn't really get chance to drain into the sump.

So, was there originally a problem with oilpumps which is only now coming to light because of a change in usage, or is it wear due to age.which for some reason doesn't appear to be corrected on restoration?

[Groily]

You're right that daily use conceals the tendency Taid. Time standing idle is the enemy!

Most machines with gear-type oil pumps have the propensity to do it. It's inherent in the design. Some machines have spring-loaded ball valves in an effort to stop it - BSA in the crankcase / back of oil pump depending on model, Velocette in the oil feed line, etc. These can be very effective at preventing leakage past the pump.(Only machines with piston-type pumps, like Triumphs and Ariel singles, can't do it at all.)
How much oil a gear pump will let through is a big variable though. Wear is a large part of it I'm sure. I have only ever had one bike that never allowed a single drop to pass regardless of how long it was left standing. A minor miracle I used to think!

There have been several pump reconditioners over the years for our twins, incorporating O rings and seals here and there, and dressing the end-plates, to stop it happening.
On my own twins, including my Norton engines, I used taps on the feed lines, with an ignition cut-out incorporated for choice. They are of course 'marmite' and can cause expostulations and palpitations, but I'm happy with them. There was for a long time an advertisement by Mr Dove in the Jampot for such taps, but he has retired now. Others are now supplying a similar device in their turn.

[g80csp11]

wet sumping.jpg

All gear pumps will exhibit some degree of wet sumping as wear occurs . Twin gear oil pumps are worse than singles with plunger type oil pumps
Various attempts have been made over the years to minimise wet sumping , how ever once wear on gears , spindles and plates occur these have limited effect . Taps should always have a micro switch if fitted . it only takes minutes to trash an engine by starving plain bearings of oil.

[SPRIDDLER]

I guess pumps are older and more worn now than in the 50's and 60's when the bikes were newer and in regular use.
Some advocate leaving a single engine on TDC to reduce/prevent wet sumping although I've never bothered.
Various articles discussing wet sumping and attempts to cure it on singles and twins in the Technical Articles here........

https://www.jampot.com/article_search.a ... rch&num=10

[Taid]

Both my bikes had plain taps in the oil feed when I got them, but now both changed to combined switch to disable the ignition ..

Is there a difference in Vincent oil pumps ?
In 58 I bought a 1950 Comet which was my daily ride till 63 and then was put away in the shed till I sold it in about 81 (regret, regret, but needs must)
. After all this time it started easily, with no fettling, with no evidence of wet sumping, (and on the petrol that had been in the tank all that time)

Perhaps 13 years use isn't enough to wear the pump sufficiently to cause problems ..

[Andy51]

The singles (I have no experience with twins) wet sump because the bore in which they operate scores and/or wears. The handbook says you should send the crankcase half to have it sleeved, but that service stopped nearly 70 years ago! Some years ago I took the problem to a local machine shop who said yes, it could be done but he would have to charge me several hundred pounds just to make a jig to hold the crankcase half, then several hundred more to do the job...needless to say, I decided to learn to live with the problem. My G80 wet sumps after a few days, my 18S only shows signs after a 6 month layoff. Somewhere in Tech Articles there is a piece on making a 'TDC detecting plunger' to fit on the pump end piece - I spent several happy hours on the Myford, installed it....and found it pretty useless as you have to feel the plunger whilst turning the engine over which, unless you are a contortionist, is d**n near impossible! So, if yours leaks like my G80, two realistic solutions: run it regularly like they were intended back in the day, or drain the sump before using - the sump plug is only a simple bolt easy to undo - but make sure you tighten it properly afterwards! Now in theory the sump plug is not meant to be undone regularly as it screws into soft alloy, and I occasionally investigate drainage devices that could be fitted to the sump plug, but they are too large or too vulnerable in that location, and I haven't stripped the thread yet. Cheers, Andy

[Taid]

Thanks to all who have commented ..

I don't actually have a problem, but was wondering about history causes etc .. you've all been most helpful


Cheers, Taid

[jackstringer]

Over the past 15 years I have mine wetsump maybe 3 times. I never needed more than just a dump of the oil and put it back in the box.

Some have issues with it some don't. Some drain the oil out.

Back in the day it was common for people to fettle their bikes on a regular basis. Oil changes (top ups) twas common. It is only since Japanese bikes turned up with this whole idea of riding a few thousand miles before needing to do work to the bike and even then nothing drastic.

[shaunstaples]

Another factor that could be a big influence on it is using modern multi grade oil. I want to eventually end up using 20/50 with a detergent when I get a modern paper filter on oil feed rather than return. My Model 20 will wet sump after a couple of weeks using 40 grade, so I think 20/50 will be much worse.
As mine is draining oil tank quickly, I bought a gauge to check the oil pressure. If the pressure is ok then just a tap on the feed will do.

[Pharisee]

If, like me, you don't ride your bikes over the winter, It's much easier to drain the oil tank, rather than let it all flow down into the sump. The oil tank drain plug is more 'robust' and easier to get to than the sump drain plug.