For now, I lumped all the pre-war cars together, I would LOVE for there to be enough demand to split it into groups (hint...hint, post here about your pre-war Singer)
Good and bad news: she seems to run OK although a lot of choke is required to keep her at it. Vintage Solex carburettors are not adjustable so I may need a larger main jet (hard to find). On the bad side I have a slight weep of coolant from one of the head studs although the cylinders on either side of it are dry, so I presume there is a small connection between the waterway in the head and the sleeve for this bolt. Its not catastrophic but rather a bit of a nuisance. This is not on the side of the head that Whitmores had modified so it is not down to them.
The other issue is one John Griffiths warned me about but I only saw the message after I had installed the engine. The timing chain is lubricated from the engine system and the oil returns to the sump via a small passage at the base of its cover. An oversized gasket can block this leading to a build up of oil which leaks out past the belt pulley. John discovered this the hard way and I seem to have exactly the same problem. It is impossible to get at this area without some serious dismantling with the most unattractive option being to take the engine out again. Fortunately the crossmember which supports the radiator and blocks access to the pulley is bolted in place, so I plan to drain the coolant, remove the radiator and this crossmember and deal with it this way. This will not happen for a week as I'm on Grandad duty from tomorrow and we will be taking six year old Freddie off on trips to North Norfolk and elsewhere. The engine has been such a saga I think a little break will do me good.
Really sorry to hear of your engine difficulties Colin. Mine's running quite a bit better & starts easily. I'm waiting for my pal to come & set up the twin SU's. I could do them myself but this is part of a 'deal' I did with him over some very early carbs he was looking for!! I've finally finished the wiring & it's all systems go - good oil pressure too. It's always a bit of a concern when the engine has been sourced from boxes of bits found in various parts of the country over a number of years. I'm chasing minor oil/water leaks at the moment so can sympathise
Enjoy your time off with grandson. I'm waiting for mine to return from Easter hols with his mum -he's my underneath the car man and loves it!!
Bill
Grandson back to Wales and I started the engine up today for the first time this week. While not yet fully tuned and with a few irritating issues it runs very smoothly so I'm confident that it will be OK.
I tried to get the bolt off the front of the engine to remove the pulley so I could get to the chain cover but it was so tight it would only turn the engine backwards even with it in gear. So I took off the sump as I thought I could get to the blockage in the oil return that way. Fortunately that worked and a piece of bent wire cleared the blockage and released a serious flow of trapped oil. The engine was finally ticking over nicely too after I found an air leak so I'm hopeful that after this is reassembled all the main mechanicals will be sorted and I can get on with the bodywork.
The extract from the manual shows the rather small oil return hole that had been blocked and you can see the healthy flow of oil coming out in the second picture. In addition the housing for the sump plug had moved when I tried to remove the plug to drain the oil (I think Whitmores did this up with an impact wrench!). I have repaired this with high-tin solder having first cleaned everything up, using the aggressive flux I used on the stainless brake cables. On checking this morning the sump is free from drips of any kind so I think this has worked. I will replace the radiator today so I can run the engine for a while to check that the chain case oil return is doing it job. Its such a messy thing to do that I really hope the sump doesn't have to come off again!
I forgot to mention an electrical issue I have - I had thought the engine was running on but noticed a little while ago that the ignition light was still on even when I had disconnected the battery. So it looks as if the dynamo is firing up the car without the battery being involved. On turning off the ignition the light started to burn even more brightly, I had smoke coming out of the rear of the switchboard and the engine continued to run. I smothered it with full choke and it stopped and I don't think I have any permanent damage.
My dynamo, while of the correct Rotax type, does not have a field wire as, according to Mel this is managed internally in this particular version. This means that it is not wired into the switchboard according to the wiring diagram. He has tested the cutout and that works, so I presume when I switched off the ignition I took the cutout out of the circuit and got the full 18v through the switchboard. It is a bit of a puzzle although John Griffiths tells me he had exactly the same issue on his car many years ago!
I will double check the wiring diagram but for the time being I have removed the dynamo from the engine and will just run it on the battery. I have another Rotax dynamo of the correct type that has both field and positive connections although this needs some attention as the bearings are shot. I will get this to Mel at some point.
In the meantime the radiator is back on, I have run her for a while and there is no sign of the oil leak by the fan pulley so hopefully I can get back on the bodywork.
I had the same problem with my Le Mans. When you switch off the engine reverse current begins to flow through the heavy coil in the cut-out. This opposes the current in the voltage coil and the contacts should open. If they stick for any reason, the current continues to increase and eventually overpowers the voltage coil and pulls the contacts closed. This causes the battery to discharge through the dynamo and smoke ensues!
Ironically, this also happened to my dad in his Singer Gazelle in the '60s which caught fire and was an insurance write-off.
The solution is to replace the cut-out with a semiconductor diode. You will need one that can handle 15 amps or so, and will need to be mounted on a small metal plate to dissipate the heat. I did mine almost 50 years ago and it is still working fine. If you need help I can recommend a suitable diode - they have changed a bit since I did mine!
Thanks Brian, that is definitely a solution I will consider so a recommendation would be really helpful. I wonder if I also have a fault in the switchboard as my multimeter shows a direct connection between the dynamo positive lead and the coil whether the ignition is on or off. Or is it the cutout that is supposed to manage this connection? The ignition switch works perfectly on the battery, switching it in and out with no problem. I am no expert on anything much, with car electrics being a particular mystery to me.
Thinking hard about the electrical problem and getting some useful information from an Austin 7 site I have one potential cause which is, of course, down to an error on my part.
As Brian points out, the current from the battery on the series windings in the cut out has to operate to counter the force from the dynamo on the shunt windings allowing the spring on the cut out to open the connection between battery and dynamo as revs fall. This is independent of the ignition circuit. When turning off the ignition the engine will die, the current from the dynamo will tail off and the battery will disconnect itself from the dynamo via the cut out.
I was stopping the engine by disconnecting the battery at the earth connection which I made using a jump lead onto the engine as I needed to be by the carburettor to manually handle the choke. Thus the ignition was still on but the battery was disconnected and was not countering the closing force of the current from the dynamo. This would lead to the contact remaining firmly closed leaving the dynamo to maintain the spark with its output not managed at all by the cut out leading to running on, the overload and near fire.
Does this sound plausible? The only flaw in the argument is that these old cut-outs are not regulators so far as I know and don't prevent the dynamo overcharging the battery so I don't quite know how the current surge would have been managed even with the battery connected. Its a puzzle.
To answer my own question, that seems to have been the source of the problem. Many thanks Brian for leading me to consider the root of the issue. The ammeter shows a good charge while the engine is running but everything switches off nicely when I turn the ignition off. I must get one of those Lucas spade keys as I'm currently using a penknife!
Hi Colin,
Your explanation sounds entirely plausable. It sounds like you have a dynamo with the field current resistors mounted on the end plate. Yes, the cut-out is just a cut-out and the current is regulated by the third brush in the dynamo. It works as a constant current device and when the battery is disconnected it tries to force the current through whatever is switched on - with alarming results!
I was once driving at night across the Yorkshire moors when this happened. All the bulbs went off like flash bulbs and I was left blinded in total darkness. I thought I had been struck by lightning. I managed to drive home using one main beam filament and the brake lamp bulbs.
If the output of your dynamo is fixed it might be worth considering LED headlight bulbs. I bought some from China but haven't tried them yet. They are available in the UK and get good reviews.
I am glad your dynamo is OK. I stopped using a screwdriver to turn on the ignition when one day the throttle linkage jammed open whilst doing 50 down Kingsway. Turning off the ignition was the only option!
On the subject of LED's; I'm using them everywhere on my latest project and so far with only one problem. Indicators work fine when the engine is not running, but as so as I start it up the flasher unit goes on to give continuous current to the lights. Apparently this is not unknown according to the supplier, but is unusual. I haven't had a chance to work on the car today, but sorting this one out will be my project for the week end. Any (polite) suggestions would be welcomed
Bill
Sounds like your electronic flasher relay is not immune to interference from the ignition circuit. There are a number of things to try:
1. Use suppressors on spark plug caps
2. Fit a different flasher relay
3. Fit a suppressor across the 12V supply at the relay
4. Go back to bulbs (Small-globe, 21W bulbs are available in 15mm cap and capless versions)
Regards
Brian
Indicators sorted today! As advised by the supplier, I moved the flasher unit to the rear of the car and wired a condenser in parallel with the power supply...don't ask me why but it worked!!
Bill
