Coils

[Simonp]

Had a fun day sorting out the Simmond's Daimler engine which failed on Windermere yesterday. Getting wet with the hose in the cooling system etc!! It seems one of the float chambers had jammed open flooding one bank of cylinders but also the coil had failed which is why it wouldn't start. Like many my boat only gets used a few times a year and this must be the third coil that has gone. Should be pleased to receive any perceived wisdom on this. Is there a robust marine coil I should be using and should I have some kind of cushioned mount?

Thanks

SimonP

[Alacrity]

What voltage is the coil you are running? If it is a standard car one it may well be 9v which should only be used in conjunction with a ballast resistor. If wired direct to 12v it will not last. I have seen this often on boats where the ballast is done away with but the coil not changed for a 12v one.

Just a thought.

[solitaire]

re Coils - below is a brief account of my practical expierienc on this subject "may help!"
This used to be a massive problem "when I were a Thames aprentice"! Just about everything fitted with a petrol engine in an enclosed space would have at least one new coil per year, many slipper launches would have tandem coils on the bulkhead so the owner could switch them over, one enterprising engineer even made nice little water jackets for the coils by wrapping copper pipe around a scafold pipe (as a patern) and then running the cold cooliing water through the pipe to cool the coil! (It worked)
It seems the coils were overheating! - more apparant on a hot day - when boats were idling around waiting for locks to open and in a hot engine compartment with no airflow (after all, - these automotive coils are designed to have a bit of wind around them to cool them down!) - also more likely to fail on 6 and 8 cylinder engines and where the coil was mountred directly on the engine! (Morris veddets were the worst - where the coil is mounted on top of the hot dynamo)
I installed a couple of Jaguar XK engines in boats and and ran them Hot!! (as they should be with 90 deg C coolant and 125 deg C oil - " running cold boat engines is another 2 page story"!!!) ) sure enough the coils failed on a regular basis (we used performance coils (Lucas red Top and Bosch) and coils with resistors all failed - Matters improved when the coils were moved to a cool place with a fan - but in the end we went to Jacobs Ultra Coils from the USA (sold through Amazon) and never had another problem All my offshore racing career with Big Block 400+ hp chev's used Jacobs coils and we never had a failure

[Mirak]

I'll wade in with my £0.02:

Seen exactly the same problem with a certain Chris-Craft this year - switching coils didn't really fix the problem, the other one got hot and cut out.

Took engine and boat back to repair man who runs then it for an hour and half in the workshop without a problem. - however, one modification:
re-mount the coil upright with the electrics at the top - they are often oil filled (nearly) and if mounted on their sides, a hot spot occurs where the oil "isn't".

The Chris-Craft has been running fine since.

My Zephyr 6 engine has the coil mounted upright on the side of the engine and gets pretty hot, but has worked OK for some years - although I doubt its highly stressed. (that's probably jinxed it).

As to sticking float valves; blocked up carburettors and flooding engines - that's probably another forum thread's worth. All I can say, is that there was a lot of it about at the weekend. I suspect its the effect of the Ethanol in our wonderful modern fuel, acting as a solvent and cleaning the crud out of the fuel tanks and depositing it along the fuel lines. But before I start on that - I have to replace the trailer wheel bearing which collapsed at midnight last night, thankfully only a few yards from home...


S

[Simonp]

Thanks for the replies - it is always so good to know you are not alone in these matters. Tried to find source for Jacobs coils in the UK but no joy yet. For now we have put a friend's Bosch coil on which we took out of his Majestic Major (was a concours winner but now sadly a rusty heap!) - we also removed a few other ignition parts. So we should be up and running for Cardiff which was my main concern!

Coils in the Simmonds tend to get a bumpy ride (as I do) so not sure whether it is the heat or vibration - a combination of both I guess - think I will mount a second coil as I don't like breaking down out on water! Will try and source best quality 12V sports coil to feed the electronic ignition fitted.

The crazy thing is that I think the SP 250 has had the same coil in it for the last 25 years and I have probably covered nearly 100,000 miles in that time - no justice etc!! Think I did on one occasion borrow it for the boat which was handy.

On the float chambers - we have adjusted the prongs up a little - they were a little out of line and we retuned the carbs etc.

Another friend - David Plant - who is restoring a Boesch and also has a Simmonds ( and Daimler SP 250 car) is going to help me do a little rerivetting this winter ..................... and so the work goes on!

SimonP

[Healey75]

Definately check that's a non ballast coil ie 12v, I don't like them mounted on the engine as the vibration must shorten the life, suggest any coil is best mounted on the boat structure and upright to keep the oil in the right places and to keep it as cool as poss, I've used the Lucas high performance coil for Big Healeys and it s been fine. They used to about £15 each (+ the dreaded) from SC Parts at Crawley

[Simonp]

Mine is a non ballasted 12V - will get a best quality Lucas Sport Coil ( if that is not contradictory in terms!). I had the wrong coil on my MG for a long time and what a difference that made when sorted. It is currently mounted on the the cross brace away from the engine - should be reasonably OK there.

Thanks all

SimonP