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Hi all,

As some of you will remember my TR7 had head problems, well they are all behind me now, well nearly. The garage returned the car to me and the car starts easily and runs, but goes like a one legged chicken and will not rev over 4500, this is not what I expected. I spoke to the mechanic and he said there was an ignition problem, apparently my car is fitted with a ballast resistor and I had fitted a new coil, which was 12v ballast type, but after five minutes it became unbearably hot. this he concluded was a breakdown of the resistor, so they loaned me a 12v coil to get the car running. They also used their Autodata info for a TR7 8 valve engine to set the timing.My question to you is two fold, firstly can I leave the defunct ballast resistor alone and fit a 12 Lucas sports coil, and secondly is the timing right ,or is that inhibiting the engine from reving freely as it did prior to the head trouble.Lastly am I right in thinking the ballast resistor is a way of prolonging points life , or is there another reason they are fitted?



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Phil like you I have also bought a TR7 (due from the US in a few weeks) and am not able to help with your problem, but maybe your question should be aimed at the tech questions area.


I would like to know the answer too.

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Hi Phil,


no run of the mill garage is going to have data for a 40 year old engine - that's down to the owner.


Give the garage a fighting chance - without the proper data you're just wasting their time and your money.


You need a workshop manual for the TR7, and another for the Dolomite Sprint . . . . . and preferably parts books for both as well. The Rimmer catalogues for TR7 and for Dolomite would also help.


A 16V engine utilises a different dissie to the 8V, Lucas rather than AC Delco, and the coil would I think have been a Lucas 15C6 originally, 6v ballast coil.


Google ballast coil for more detail on the thinking behind the fitment . . . . googling will find the answer to most such questions, saves Forum folks reinventing wheels.





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