BSA Owners' Club Forum

The BSA Workshop => Singles => Topic started by: TDub62 on 02 April, 2018, 12:37:04

Title: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 02 April, 2018, 12:37:04
Hello, I'm putting together a previously abandoned C15S project (1959). The engine was rebuilt by a previous owner (not the person I bought it from) so history of what has been done is a little vague. Last weekend I primed the oil pump by putting oil down the push rod tubes and have had a dribble of oil pumping back on the return pipe (on kickover). Today i retuned to the bike to find the litre of oil that I put into the tank is now in the sump. I removed the sump plate to look at the scavenge valve. All it seems to have is an open tube with no sign of a ball or spring. I can insert a rod 30mm into the tube before it reaches a restriction. Should there be a ball and spring in the tube?
Thanks
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 02 April, 2018, 14:59:20
The are two non-return valves (NRV) in the engine, one for the feed side from the tank and the other for the return side to the tank. The one near the sump should have just a ball bearing in it but no spring (works under gravity). However, this return or scavenge side NRV doesn't do a lot. The one that normally stops oil draining from the oil tank into the sump is on the feed side and is either in the outer timing cover (for end fed C15's) or in the RH crankcase for the earlier models.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 02 April, 2018, 16:52:58
Thanks for that I'll get back on it when I've warmed up a bit!
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 02 April, 2018, 17:10:47
Does that mean splitting the cases to check it out?
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 02 April, 2018, 18:14:09
Just noticed you have an earlier C15 which, unfortunately, means you would need to split the crankcases to get at the feed NRV - not one of BSA's best design features :'(
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 02 April, 2018, 18:43:43
Ouch not good news, is there any sort of test before i set off stripping it down. I haven't split one of these before is there a good manual anywhere?
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 02 April, 2018, 19:42:29
I wouldn't rush to take the engine apart - it's a lot of effort for a very small NRV. I would run the bike a bit and see how it performs over a longer period of time. In the meantime, you can always clamp the rubber feed pipe from the oil tank to stop it wet sumping over night.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: ducati2242 on 02 April, 2018, 20:09:48
you could think about one of these . www.ebay.co.uk/itm/6-8-10-12-14mm-BSA-Norton-Matchless-AJS-Vintage-Classic-Anti-Wet-Sump-oil-valve/181878137689?hash=item2a58c82359:m:m06-amOfqArhOMLO1gdGKAw . Not sure how good they are as I have never used one .
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: ANDY HIGHAM on 02 April, 2018, 20:16:07
Anything fitted between the tank and pump can cause engine damage, gear pumps are good at pumping but not so good at sucking
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 02 April, 2018, 21:04:22
Ive just put 500ml oil back in the tank and will see how much has drained from the sump in the morning. Not buzzing about splitting the engine but not convinced by the valves on the infeed pipe as there seem to be conflicting stories on their success rates.
Thanks for the info.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 03 April, 2018, 07:52:06
If the engine is wet sumping, it could be due to a problem with the feed NRV and/or it could be a problem with oil leaking from the oil pump before it gets to the NRV. The latter can occur around the mounting face due to distortion or a problem with the gasket. Once you've taken off the inner timing cover you can then get at the oil pump and check if it's leaking oil. In principle, with the pump removed, you can then more directly test whether the NRV is working ok and blowing through with an air line might clear any obstruction if you're lucky.

Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: GUY HUTCHINSON on 03 April, 2018, 13:16:18
Thanks for that, at least there is hope of a solution without splitting the cases. I'll take the inner timingcase off at the weekend and have a look.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 03 April, 2018, 13:29:45
If the engine hasn't been run very much, I would definitely put some miles on it first before coming to a final decision on whether the feed NRV is a problem. If you're lucky, it might even cure itself after enough oil has been pumped through the it.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 03 April, 2018, 22:03:24
Hello thanks for the help again. i stripped the oil pump which looks ok. i think the NRV bearing may have been stuck. Its free now. Can you tell me which hole leads to the inner NRV?

Sorry but another question. Before stripping the bike I checked to see if oil was going back into the tank. The pipe that i thought would let oil back into the tank appears to be a sealed tube that sweeps upwards and ends up inside the filler cap opening. I checked inside with a mirror but couldn't fathom out how the oil would return. No doubt I'm missing something obvious!
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 03 April, 2018, 22:03:57
the other pic
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: JulianS on 03 April, 2018, 22:35:31
The tube in the oil tank has a horizontal hole in the side just below the top.


You can see it on this service sheet.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 04 April, 2018, 08:35:01
Hello thanks for the help again. i stripped the oil pump which looks ok. i think the NRV bearing may have been stuck. Its free now. Can you tell me which hole leads to the inner NRV?

Sorry but another question. Before stripping the bike I checked to see if oil was going back into the tank. The pipe that i thought would let oil back into the tank appears to be a sealed tube that sweeps upwards and ends up inside the filler cap opening. I checked inside with a mirror but couldn't fathom out how the oil would return. No doubt I'm missing something obvious!
It's likely to be the hole closest to the inside of the crankcase. To check, simply blow down the other two holes and they should be connected to the inlet and output pipes to the oil tank. As indicated in Julian's diagram, the return into the oil tank is via a small hole in the pipe at the top of the tank. Just blow through the rubber return pipe to the tank and make sure it's unblocked.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 04 April, 2018, 21:19:40
Thanks again, I haven't had chance to get out after work tonight but will hopefully have a look tomorrow and let you know how things progress
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 08 April, 2018, 22:00:33
Oil pump checked and all seems ok in theory , i blew down the NRV hole but no idea if it did any good or not. Anyway all back together and and it turned over ok as previous. Checked valve clearances and the I put the plug in and turned it over gently to check compression. A hissing sound could be heard on compression which after much squirting and soaping around the head gasket joint I thought must be coming from behind the push rod tube. off with the head and sure enough a small fault and repair between the tube and the chamber with a small rectangular impression in the face. I;m going to see if i can get a better repair done and guess I will need it skimming as well. The bike has had a new high compression piston fitted and I'm slightly worried about adding a skim to this. I've read that you can get slightly thicker gaskets possibly from BSA singles in the USA. Anybody know of a UK supplier.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 08 April, 2018, 23:15:55
That looks like an odd bit of damage. Have you got a higher resolution pic of it and how do you think the damage was caused?
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 09 April, 2018, 12:41:08
I have better pics but struggle to upload them onto the forum. It looks like it may have been repaired previously as the pushrod tube opening has a slightly flattened surface near the damaged bit. The damage is like an impression of something but probably too deep for that. Sadly it came to me like that. Think I may take it to park engineering at Malton near where I am to see if they can repair it.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 09 April, 2018, 14:31:34
Just needs a bit of TIG Al welding followed by the milling machine.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: GUY HUTCHINSON on 24 April, 2018, 13:38:16
I've picked the head up, its been repaired with 'liquid metal' and a fine skim at our local classic machinery engineers. There was concern about heat distortion with a weld repair so close to the push rod tube area.
Next problem I can see is the gap between head and barrel being too great for the head gasket. To get around this I'm going to try a double gasket with copper spray to help seal it. Anyone else gone down this route or got views?
The oil pump seems to work pumping back to the tank (on kickover) but wont pump to the rocker union unless I put my finger over the tank return, might this resolve at normal engine speed?
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 24 April, 2018, 17:26:16
I don't think a double gasket is a good idea - the better solution is either to get one of the correct thickness or to skim the top of the cylinder to enable the gasket you've got to fit correctly with 4 thou or so compression.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: GUY HUTCHINSON on 25 April, 2018, 13:20:54
I'm wary of skimming the top off the barrel lip as I don't want to increase the compression, having said that presumably a thicker base gasket would counter that.
The new head gasket that I bought does feel a little thicker than the old one which may be enough with the copper spray that I also bought. I'll have a play this weekend.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 25 April, 2018, 14:01:47
According to my calculations, if you skimmed off 5 thou, you would increase the compression ratio by 0.5 which is nothing to worry about and could probably be viewed as a positive advantage. The best thing is to measure the head/barrel clearance using a feeler gauge with the head fitted without the gasket. This will tell you how much would need to be skimmed to leave you with 4 thou compression of the head gasket.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 14 May, 2018, 21:21:18
Ok so head repaired, camshaft outer bush changed and reamed and all back together.
I fed some petrol into the carb and tried to kick some life into the bike, nothing at all. I tried to choke the carb a bit (rag over the intake) which produced an engine ignition but also a massive kickback through the crank (ouch). Checked the timing (with a disc) which was spot on as per electrexworld 35.5 degrees. I retarded it very marginally. After the kickback I removed the footrests which get in the way with the U shaped lever and tried again. Same result, nothing until I choked it then bang a kickback (which I was more prepared for this time but still not good).
Any ideas what next? The fuel is from last summer which maybe doesnt help but how would that explain the kick back? I've checked the timing again and it looks spot on.

PS I seem to have created a second log on in the past with a different name on my work computer. TDub62 is me (Guy).
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 15 May, 2018, 07:08:54
It's probably kicking back because the ignition is far too advanced. Standard C15 advanced ignition is 33.5 deg BTDC but with modern fuels it's best to reduced this by a couple of degrees. I would check that the ignition has been set with the auto advance mechanism rotated fully to the advanced position. Also, if the fuel mixture is too rich it can produce the same effect as a more advanced ignition timing.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: GUY HUTCHINSON on 15 May, 2018, 12:41:59
Thanks I'll try retarding it to 33.5. I went by the figure given in the Electrexworld instructions which was 35.5 for a C15. Carb set up standard for the bike but I haven't got the air filter connected at the moment which I guess would make it more lean.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 16 May, 2018, 08:46:31
It takes a lot of effort to make a C15 kick back and it won't be the odd couple of degrees of advance that is causing this. I would double check the way you have set up the Electrexworld - are you sure the engine was accurately positioned at TDC before you tightened up the rotor? In terms of the missing air filter, it won't make much difference to starting the engine but it would be sensible to increase the main jet by 10 to compensate. 
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 16 May, 2018, 21:19:43
Thanks once again for taking the time to reply :).
I've checked the rotor again and timing as per the instructions from electrexworld looks to be spot on. I located TDC using a degree disc measuring either side of TDC and then finding the centre point. Stator fitted as their diagram.
I haven't tried to start it again as nothing has changed. I've fitted a temporary air filter so (waiting for side cover to arrive before I can fit vokes one).
I previously fitted an electrex on a Bantam that i had with no issues, its a real head scratcher this time.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 17 May, 2018, 07:09:58
Presumably, you are going to refit the rotor to set it to at most 33.5 degrees rather than the 35.5 deg wrongly quoted in the Electrexworld fitting instructions? I would be tempted to set it to 31.5 deg to compensate for modern fuels which would mean a 4 deg change on what you've presently got which might make the difference.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 17 May, 2018, 10:21:03
You can rotate the stator plate for fine tuning if not enough movement Iíll take the rotor off and move it slightly.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: TDub62 on 17 May, 2018, 20:54:17
Ok at last some progress to report. Timing backed off to around 31 degrees.  Bike fired and ran for a few seconds, as it stopped the kickstart gave a big rattle and clattered up into the awkwardly positioned high level pipe (runs outside the frame under the oil tank). This happened again the next time I kicked it. After a short break (whilst I tried to move the exhaust up slightly to reduce the kickstart problem) I re fueled the carb from my temporary bottle and pipe supply and tried again. This time nothing until a loud backfire through the pipe (no kickback).  After this I spent a few minutes kicking but nothing from the bike. A good spark, and plug ok. I'll try again at the weekend.
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: AWJDThumper on 18 May, 2018, 09:13:08
What happens with most singles is that the engine is stopped from spinning after the ignition is switched off by the compression stroke - that is, it doesn't have the momentum to carry it past TDC on the compression stroke. At that point, the engine can bounce back and rotate backwards. In principle, if the kickstarter is depressed at that point, the backwards rotating engine could cause the lever to rotate upwards. Not sure if that was happening in your case but, if it was, it is probably perfectly normal and nothing to worry about (unless it hits the exhaust system!)
Title: Re: C15S 1959 Oil Pump total oil loss from oil tank
Post by: GUY HUTCHINSON on 22 May, 2018, 13:28:42
Thanks for that, I've had it running again and ticking over. The kickstart is fine if I ensure it is fully returned (time for a new spring maybe).  Hopefully I'll get chance to have another play next weekend.