cbjroms

Thanks guys, I am in Southampton. Anyone local who could lend me a generator and control box for fault finding purposes?

I have cleaned commutator, fitted new brushes and polarised. But arcing from back-end of the Dynamo is as bad as ever. Just checked the wiring to the Control Box (Large D to D, F to F) and checked that Ignition light is correctly on before start and off once engine running. Actually, when polarising the Dynamo I understood that it would only arc the first time the positive lead touched F. On mine it arcs every time. So either the Dynamo and/or Control Box are duff. If I change to an alternator then this should solve both problems. What is the best alternator to get (ie that will fit lower mounts) and is their a modified upper adjusting arm available? Will a Spitfire alternator and adjustable top bracket fit straight in?

Took the back plate off the Dymamo this afternoon and commutator looks fine. Both brushes seemed to be making good contact with the commutator but the lead to one of the brushes seems to have started to burn-out/fray. Cant understand why this should have happened but I guess that this would likely cause the arcing. Is there any reason why I should not be able to get away with just fitting a new pair of brushes?  

Ran the engine with the Dyanmo disconnected again this afternoon and no sign, whatsover, of a misfire. Then I put a jumped between the D & F terminals of the dynamo, put a voltmeter across D and earth and with the engine running measured 1.5 volts whereas I expected 14 volts? So then decided (having checked that D on Dynamo connected to D on Control Box and F on Dynamo connects to F on Control Box) to put the leads back on the Dynamo and run the engine again with voltmeter across the battery. With the engine running I was getting 14+ Volts across the battery but arcing in the back end of the Dynamo was very pronounced yet there was no sign of the previous misfire! So, in summary, on Thursday the misfire disappeared completely when I pulled the D and F leads off the back end of the Dynamo. When I ran the engine (for about 30 minutes) today there was no sign of a misfire, even after I can reconnected the D & F leads. With the Dynamo connected and engine at fast idle I am getting 14+ volts across the battery terminals but as I rev the engine harder there is significant arcing visible in the back end of the Dynamo. Does this make any sense?

I mentioned fitting the dynamo a few months ago but it was actually the wiring that I was replacing. In fact, up to that point the engine was revving without any misfire BUT the Dynamo was not connected. When I first connected the Dynamo the Ignition Light was not working properly and I found that the wiring into the Control Box was incorrect and so I swapped the connections around to get the Ignition Light working. I didn't polarise the Dynamo at all and so it could well be incorrect. Looks like my first port of call needs to be the Dynamo wiring into the Control Box and then checking the polarisation of the Dynamo.

Back out on the car this afternoon - first chance since the Christmas break. Conscious that my compression and misfire problems are unlikely to be connected, and before purchasing any new components, I decided to replace the female connectors on the end of the wires that go to the coil. Defintely 'clutching at straws'!! Ran the engine and the same misfire started occuring. But then I suddenly noticed a spark refelcted in the shiny vacuum unit which is attached to the distributor. First guess was that I have a crack in the distributor cap but, given I didnt have a spare to hand, I decided to elimenate the Dysnamo first. Unplugged the two female connectors from the Dynamo, ran the engine and misfire has disappeared. Engine sounds sweet under both low and high revs - albeit I am just running under no load in the garage. I had given the Dynamo a full test before putting it onto the engine a few months ago. So my first thought is that there must be something wrong with the wiring or the Control Box. But can anyone suggest how the Dynamo could be the root cause for a misfire under load? Could this be the cause of the weak spark leading to the "eight stroking" suggested earlier?

This afternoon I have adjusted all the valve clearances and redone the compression test. The results are the same as before BUT it has struck me that I should be getting 150psi per cylinder and yet I am only getting between 105 and 115psi! Just spoken to the guy who rebuilt my carb about adjusting the mixture. He pointed out that the carb will not operate properly at this level of compression, that I need to strip the head, check the exhaust valves and only adjust the carb mixture as a last resort. Now it could be that my compression tester is reading low - the consistency of the results  could suggest this? - but I do think the engine is running very rich and it doesnt even need any choke at all to get it running on the coldest of days. Grateful for your thoughts.

Yes, the engine was warm when I did the recording. It starts and revs alright for a few minutes but then starts misfiring when I rev it. At the moment I am running with just an open end on the rocker cover breather - no hose fitting so just venting to atmosphere. It is loud and thumpy but it is defintely not big-end; far more like a firing problem.

Really grateful for all the advice and it encouraged me to go back out this morning and check everything again. What I found is that the bolt through the bulkhead was quite loose and so I undid it, replaced the bolt/nut (the nyloc insert had burnt), rebuilt the connection with a couple of shiny washers and tightened it up. I also removed the in/out feeds from solenoid, cleaned the terminals, replaced nuts/washers and tightened. Then did the same to the starter motor postive post. This has resulted in perfect cranking and so I am dead chuffed! I still have the misfire as the engine gets warm and made a recording - Misfire It still seems to me that the misfire is not specific to one cyclinder as removing plug leads one by one makes little difference. But the more I test the less sure I become! I tested the compression on each cylinder and the results were fairly consistent (110/105/105/115psi). Does the recording suggest anything other than coil or distributor cap or rotor arm?

These are my leads. The positive goes from battery post to solenoid. The negative goes from battery post and is bolted (through the angle plate) to the bulkhead. I also have a braided cable bolted to sump and to chassis. So, without the jump lead, the only earth to body connection is through the black lead bolted to the bulkhead. The starter motor is then getting its earth from the gearbox/engine which is getting its earth from the braided cable connecting chassis to engine. So surely the jump lead (battery terminal to gearbox) should have elimanated an earth issue? The cranking has always been a little slow except when battery has just been fully charged (so the solenoid may well be causing a problem) but the situation has recently deteriorated and I have only just noticed the sparking at the bolted earth connection.  

Thanks again guys. The jump lead was definitely making a good connection to the gearbox flange and battery earth posts. Also, I fee that this slow cranking and sparking at the fixed connection point is something that has started recently and seems to be getting worse. So noting, but setting aside for now the possibility of fuel starvation, leaves me with the suggestion that the starter motor has a problem, or the engine has become excessively difficult to turn or the solenoid is introducing a huge resistance for some reason.  

Thanks guys, does the sparking (where the negative lead bolts to the bulkhead) indicate that the power cannot flow freely enough through the lead into the bulkhead? Why would the jump lead (negative attery post to gearbox) not provide a sufficiently low resistance path ?

I did some testing after dark and noticed that, when cranking, the negative lead from the battery to the bulkhead is sparking at the bulkhead end. The lead is bolted through the bulkhead with a tight and clean nut/bolt from which the spark appears to be coming. This, I presumed, was causing the slow cranking. What I cant understand is that putting a jump lead between the nagtive battery post and the gearbox, in addition to the negative lead, made no difference. Should this not overcome any poor negtive connection?

Thanks for the repsonses. I will do some more tests this afternoon. By the way, a couple of other things I have noticed. First the misfire seems to be getting worse over time. When it first started happening it was, by no means, as pronounced as it is now. Second, engine started quite easily from cold but having run for 10 minutes (and got warm) I switched it off. When I tried to start it again the battery could barely crank it over and starter solenoid positive post got very hot, very quickly.

I have replaced the electronic ignition unit with a new one and the problem is exactly the same. As the engine becomes warm the misfire starts and gets worse as throttle is increased. So plugs and ignition module have both been changed, leads are all brand new as is the coil (tested on a multimeter and looks ok). Could this be some sort of mechanical problem?

My Triumph Herald 13/60 is fitted with an Accuspark distributor and a Stromberg CD150 which has been professionally rebuilt. It has been running sweetly for some time but has just started to misfire when warm. When started from cold it runs fire and drives well until the engine gets warm and then it starts to misfire. Stopping the engine and allowing it to stand for 10 minutes results in it ticking over smoothly for a few minutes and then the misfire starts again. I have replaced all 4 plugs but this has made no difference. The coil does not feel hot and I have checked the timing. This does not seem to me to be a problem with a partcular cylinder as removing any one of the 4 spark plug leads when the engine is running has the same impact on the misfire. I have also run the engine with the fuel cap off in case there is an airlock but this has made no difference. Looks to be plenty of nice clean fuel going through the fuel filter. I would be grateful for any advice that you guys could give me.

Sorted it. I had these the wrong way round: Dynamo 'F' (big brown/green wire) should be to 'D' Dynamo 'D' (small brown/yellow wire) should be to 'F'.  

Thanks guys, I have wired-up the car with reference to the wiring diagram in the Haynes Manual. The Control Box has 5 labelled connections: E, F, D, A & A1. There is no WL? The letters are quite difficult to see on the diagram but seem to read as follows to me: Dynamo 'F' (big brown/green wire) goes to control box 'F' Dynamo 'D' (small brown/yellow wire) goes to control box 'D' Ignition switch (brown/blue wire) goes to control box 'A1' Ignition Light (small bown/yellow wire) goes to control box 'D' Ground (black wire) goes to control box 'E' Just to be clear, the Ignition has live 12v feed into one terminal of the lamp and the other wire is the one that goes to control box 'D'. So I am still struggling to see what I have got wrong?

I have a Herald 13/60 but I suspect that my plea for help will make sense to more than just Herald owners. The large connector (F) on my Dynamo is connected to F on my Control Box. The smaller connector (D) is connected to D on my Control Box. D on the Control Box is also connected to my Ignition Warning Light, the other terminal of which is connected to power. With the ignition key in first position the Ignition Warning Light is on, problem is it stays on permanently at whatever revs the engine is at! So, I have tested the Dynamo by removing fan belt, putting a jumper between its two terminals and applying power - it runs like a motor. I then put the fan belt back and ran the engine with a voltmeter connected to the jumper and was getting 20V at idle. So the Dynamo is working well? I am not sure what terminal D on the Control Box actually does but I am wondering whether it just provides a convenient way to 'splice' the wire from D on the Dynamo with the wire from the Ignition Warning Lamp. Or is my problem due to a Control Box fault?

An update on this. Frustration got the better of me and I sent the carb away for assessment and repair. It turns out that the leak was caused by the fibre washer supplied with the Grose Jet being inadequate. However, having left old fuel to stew in the tank for a couple of years it seems to have become extremely acidic and attacked the inside of the carb. I have been advised to clean out the tank, fuel lines and perhaps replace the fuel pump before plumbing-in the repaired carb. Are the copper and rubber fuel lines likely to have been attacked by the acidic fuel? 

That's a fair assessment! The Grose Jet that I fitted is designed for the 150CD so I thought it would be an easy replacement. Perhaps I should have ignored the specified 16mm and left the float as it was. Certainly one option would be to remove the Grose Jet and refit a standard needle valve. But worried that the bowl will still overflow.

I purchased a refurbished Stromberg 150CD for my Herald 13/60 a couple of years ago which ran beautifully. Having left it sat in the garage for a couple of years unused I now find that the needle valve has seized solid. I have removed the fuel bowl and replaced the needle valve with a Grose Jet in the hope that it will be more durable. To do the job (I thought) correctly I measured the height of the float having fitted the jet and adjusted the stop on the float to give me the 16mm between highest part of the float and the sealing surface of the carburettor housing.  Fitted a new gasket to the float bowl, reassembled everything and the engine started first time. Tweaked the accelerator and the engine would not pick-up and so I thought it needed some choke. Gave it some choke and petrol started pouring out of the fuel bowl overflow pipe. So the Grose Jet is not stopping the fuel bowl overfilling even though I set the float height correctly. Am I missing something here? I have a feeling that the float height on the refurnished carb was much greater than 16mm but maybe I have got this wrong.

I need a few blanking plugs for my 1360 U/Js and guess that I can use grub screws? Can anyone out there tell me what thread size and length to use?

Good afternoon, I am replacing the wheel studs on my 13/60 with the longer Freelander versions and understand that I will need to pull the hubs off to make the change. Don't know whether to buy a puller and then sell it on or borrow one. Anyone in Southampton area got one that I could borrow for a few weeks? Thanks Chris

I am looking for some 14" diameter wheels that have the corect PCD and offset to suit Triumph Spitfire/Herald hubs. Does anyone know where I might find some - either steels or alloys would be of interest. Thanks Chris