The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: ronnierockets on 17.01. 2009 21:32

Title: Anti-wetsump device.
Post by: ronnierockets on 17.01. 2009 21:32
Hello to all,  just got my anti-wetsump device finished,(more uses for gas taps)

I've used a home made "L" bracket,a gas tap, and a push type horn switch,wired to the mags end, the same as the kill button.
so now when i'm leaving my bike for a few days,i turn the tap lever to the "up" position which turns the oil supply off ,and depresses the horn button, which in turn grounds out the mag.
So when the time comes to start the bike, if you forget to turn the oil on ,she wont fire up.
have a look and see what you think.
Title: Re: Anti-wetsump device.
Post by: stratcat on 18.01. 2009 09:20
A very tidy job. Well done.
Title: Re: Anti-wetsump device.
Post by: LJ. on 18.01. 2009 11:37
Well I must admit it's a very good idea to those who feel they need an oil feed shut off, i'd most certainly be the one to forget switching it on before starting. I think that if I were going to leave my bike unused for any length of time I'd welcome a wet sump because when turning an engine over with full sump everything is going to be well lublicated before draining and firing up, it has to be an ideal way of starting up after a period of disuse. But with using thicker oils, 50 mono in Summers and 30 or 40 monos for Winters I've never experienced wet sumps as all. Maybe an anti sumping valve device is much more desired for those who use 20/40 multigrades.

Congrats on a neat bit of modification though!
Title: Re: Anti-wetsump device.
Post by: a10gf on 18.01. 2009 12:07
Clever and safe invention!

But any wet sumping should only happen after a considerable long time. As Lj says, type of oil will influence what's happening.

See , check the oil retaining ball (part 23) (some recommend giving it a small punch to seat it properly), and check the spring tension (part 22). If these two parts are functionning properly, wetsump should only start to occur after weeks (I'd say many months) without starting the engine. Just some toughts, and this is how my gf is behaving.

Title: Re: Anti-wetsump device.
Post by: ronnierockets on 19.01. 2009 17:22
thanks for your comments fellas,
my bike wet sumps if it's left  for a period of 3-4 weeks, i'm running it on hd. 40 (detergent oil)
I'l do a check on the oil retaining ball as a10 gf suggested,and see if that makes any difference.
cheers for now ..Ronnierockets..
Title: Re: Anti-wetsump device.
Post by: groily on 19.01. 2009 21:33
Another nice one with the tap Ronnie - looks neat and great use for a horn button. Have to admit I've never left my A  standing for weeks. Very occasionally the oil trickles down a bit over a few days, but it almost always doesn't. Must be the ball I suppose - will have a look at some point. I tend to run on 20/50 for pretty much everything. It's been a bit thick of a morning while we've been enjoying the latest effects of global warming and temperatures have been down to minus 12C (weekend before last). But hey, it's nearly Spring again . . . snowdrops poking through here and there after a few warmer days this past week . . . feeling better already!
Title: Re: Anti-wetsump device.
Post by: ronnierockets on 20.01. 2009 09:28
hi Groily, glad you like the tap,
as you say the weather's certainly "different", It topped out @ minus eight here last week,  but it makes 
a good excuse for a hot whiskey, in front of a nice warm fire, on a very cold evening.
Our club's first run of the year, takes place on this coming sunday 25th.
If the weather dosent improve, i'll  have to dig out the longjohns, my "Biggles" helmet, and the fur lined williewarmer..
cheers for now..Ronnierockets..
Title: Re: Anti-wetsump device.
Post by: terryk on 20.01. 2009 14:16
Here in Queensland Australia its summer all year round. I haven't worn a coat in years.
Title: Re: Anti-wetsump device.
Post by: Daniel Toro (DT) on 15.06. 2009 00:08
Hey A10Gf, maybe this is my problem.

My bike was stopped for 2 years before I buy and maybe this ´22 spring´ doesn´t work correctly.

Tell me, have some easy way to check it?

On time, is this?:

Title: Re: Anti-wetsump device.
Post by: Josh Cox on 15.06. 2009 05:50
Nice job !!!!!.

Sorry to sound like a nay sayer, but I am not convinced wet sumping is caused by oil from the oil tank supply, let me explain.

If oil was to gravity feed from the oil tank to the sump, theoretically a very large proportion of the oil tank content would end up in the sump (two plus litres).

What if when you shut down the engine there was still a little oil in the sump plus a return line full of oil.

If the oil was to drain back from the oil return line / foot valve to the sump, it would be considerably less in volume,back to high school algebra: Pi times radius ( what 2mm ) times length of return line ( circa 400 mm), if someone with a scientific calculator could have a crack at that and work out the volume of the oil return line ?.

When driving with my Grandfather it was always noticable, when he turned the car off he would give the engine a little rev before shutting it down.

My theory is that perhaps what is happening is that we are not giving these engines that little rev before shut down and not giving the foot valve in the oil return line a little nudge shut. This would also give the float in the carby a little nudge shut also.

Perhaps I am talking though my rear end, but would logically explain this wet sumping issue in my head.

Has anyone out there fitted these anti wet sumping valves, and still gets the occasional wet start ?.

Perhaps if someone out there consistently gets wet starts would like to try giving the engine a little rev before shutting down to prove or disprove this theory ?.

Title: Re: Anti-wetsump device.
Post by: groily on 15.06. 2009 07:20
Well, the oil in the lines may well trickle back, but when the level in the tank has visibly dropped I'd say it's coming from there! Haven't done a tap like Ronnierockets on my A, but have 2 similar (not as pretty) on AMC twins, and can confirm that with them fitted, no 'wet starts'. (Plus no excess oil in the primary drive from the lack of drive side mainshaft oil seals on those particular engines, which makes a full crankcase worse to deal with.)

What's funny is that now, with a couple of bikes with taps and  others without, I'm paranoid whenever I start anything and look automatically for taps that aren't there on things that don't have them.
So the mental discipline does set in, which makes a catastrophe less likely, even if the switch fails because the carbon brush doesn't make good contact, etc. Cut-outs can't be 100% reliable for ever, without regular checks from brush to button. I have been thinking about a way of making the kickstart swing force the lever on the taps open in the event of mental lapse . . . . but not so easy to arrange.

The AMC sites similar to this one are quite full of tales of expensive woe from folk who forgot or otherwise made a horlicks, so the mental thing really does matter. The biggest risk moment is probably on starting up in the middle of a day if the tap has been switched off at a halt . . . best therefore to open it the once and leave open till end of playtime.
Title: Re: Anti-wetsump device.
Post by: olev on 15.06. 2009 12:27
Its not easy to change that spring.
You will have to strip the motor and remove a plug on the inside of the crankcase behind the oil pump.
You will also need a new plug as its punched and will be destroyed when you remove it.
I bought that kit off ebay too. It is cheap rubbish and looks nothing like the original spring.

Before you do that, I'd remove the oil pump and check the ball/spring operation through the hole with a probe.
Maybe its just clogged with poop and can be cleaned through the hole behind the pump.
Hope this makes sense,
Title: Re: Anti-wetsump device.
Post by: Daniel Toro (DT) on 15.06. 2009 14:57
Olev, this ball/spring operation at oil pump that you talk about doesn´t is the pressure release valve, right?(

So i need to remove the oil pump and put some probe trough the hole until reach the ball. What is the hole to reach this?

Title: Re: Anti-wetsump device.
Post by: rocket man on 15.06. 2009 20:36
well youve turned your oil supply off the pump is completly
empty ove oil so when you come to starting your bike
it carnt pump oil strait away because theres no oil in the pump
so for that short period no oil is getting to your bottom end
does that sound like a good idea i wouldent mess with the oil supply
better to be safe than sorry i would start your bike up once a week
to keep from wet sumping and also it stops the unleaded from blocking your jets up
Title: Re: Anti-wetsump device.
Post by: a10gf on 15.06. 2009 20:50
DT, correct, it is not the pressure valve, it's the spring + ball behind the oil pump, to renew it with new spring or ball the crankcase needs splitting. I do not remember if the ball can be reached\seen\pushed-in-to-check-function with only removing the oil pump (not been in there for quite some time...). Suggestions anyone ?
Title: Re: Anti-wetsump device.
Post by: bsa-bill on 16.06. 2009 19:33
DT andA10gf - cant recall which hole the valve is in but with the pump off you can see the ball ( might need a torch ) and it can be pushed gently off it's seat with some soft probe ( I use a cotton bud with the wool removed - well their for imortant little places)

Ronnierockets - thats one neat job and I say that even though I'd rather go with a valve which I did until I stripped the engine down, from then on I took the valve off assuming the original set up would work when all nice and clean - and it does.

Josh I can only say when my bike did wet sump the oil level in the tank did drop.

All the best - Bill
Title: Re: Anti-wetsump device.
Post by: trevinoz on 17.06. 2009 00:37
Josh, the complete contents of the oil tank will end up in the sump, I know from experience!
The problem arises from having a gear pump which has necessarily clearance between the gearset and the housing.
Oil will flow around the gears and should be stopped by the check valve in the crankcase behind the delivery port.
Over the years, the valve seat will have become pitted etc. and the spring will have lost tension therefore oil will leak past.
Another source of leaks is the pump body joints and possibly the mounting face.
The amount of oil in the scavenge pipe is negligible and if it leaks back it will not cause a wet sump.
So I guess the answer to the problem is to make sure the check valve is seating properly and has enough spring tension when the engine is pulled down. Otherwise, live with it or start the bike regularly.
Title: Re: Anti-wetsump device.
Post by: Josh Cox on 17.06. 2009 01:46
Thanks Bill, Trev and other,

If the tank level drops well, no argument from me.

I have purchased the SRM stainless oil pressure valve, how will this effect the pitted valve seat scenario ?.