Possible aid to chronic failing ignition coils
#1
Possible aid to chronic failing ignition coils
I have a 1995 XJ6 that I bought new. The original coils lasted ten years. I replaced all six with Jag coils from Welsh Enterprises. Those lasted ten years as well. Since then the coils seem to last between one and two years. I've tried various ones.
One suggestion I had on Jag Forums was to leave the coil cover off which I did for a year or so. It was awfully ugly. Then I had the idea to just leave the gasket off the coil cover for ventilation which I did. I hasn't been long enough yet to tell if there is any benefit. I also thought about putting a spacer of some sort between the cover and where it mounts using longer fasteners but haven't done so.
I throw this idea out there for what it's worth if anything.
Comments?
bliving7
One suggestion I had on Jag Forums was to leave the coil cover off which I did for a year or so. It was awfully ugly. Then I had the idea to just leave the gasket off the coil cover for ventilation which I did. I hasn't been long enough yet to tell if there is any benefit. I also thought about putting a spacer of some sort between the cover and where it mounts using longer fasteners but haven't done so.
I throw this idea out there for what it's worth if anything.
Comments?
bliving7
#2
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Don B (03-26-2018)
#3
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Don B (03-26-2018)
#4
Item # 4 / option # 2 / 103.60 each
https://www.sngbarratt.com/us/#!/Eng....2/4.0%20LITRE
If the coils have already degraded closing the spark plug gap down to the original 0.035 inch may help for a while as a better spark as there already on the way out . 0.040 is for new coils to get them to last longer .
Jaguar TSB :
http://www.jagrepair.com/images/TSB/...cing%20MAF.pdf
https://www.sngbarratt.com/us/#!/Eng....2/4.0%20LITRE
If the coils have already degraded closing the spark plug gap down to the original 0.035 inch may help for a while as a better spark as there already on the way out . 0.040 is for new coils to get them to last longer .
Jaguar TSB :
http://www.jagrepair.com/images/TSB/...cing%20MAF.pdf
#5
#6
I think someone went so far as to wrap them in Kapton tape!
wrap them and report back? I’m not sure anyone found a way to make cheap coils last for a long time. 6-12 months seems to be the standard lifespan for other branded coils. There are always a few exceptions. A search would probably reveal one or two owners who have had success with cheaper coils.
wrap them and report back? I’m not sure anyone found a way to make cheap coils last for a long time. 6-12 months seems to be the standard lifespan for other branded coils. There are always a few exceptions. A search would probably reveal one or two owners who have had success with cheaper coils.
#7
I have a 1995 XJ6 that I bought new. The original coils lasted ten years. I replaced all six with Jag coils from Welsh Enterprises. Those lasted ten years as well. Since then the coils seem to last between one and two years. I've tried various ones.
One suggestion I had on Jag Forums was to leave the coil cover off which I did for a year or so. It was awfully ugly. Then I had the idea to just leave the gasket off the coil cover for ventilation which I did. I hasn't been long enough yet to tell if there is any benefit. I also thought about putting a spacer of some sort between the cover and where it mounts using longer fasteners but haven't done so.
I throw this idea out there for what it's worth if anything.
Comments?
bliving7
One suggestion I had on Jag Forums was to leave the coil cover off which I did for a year or so. It was awfully ugly. Then I had the idea to just leave the gasket off the coil cover for ventilation which I did. I hasn't been long enough yet to tell if there is any benefit. I also thought about putting a spacer of some sort between the cover and where it mounts using longer fasteners but haven't done so.
I throw this idea out there for what it's worth if anything.
Comments?
bliving7
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#8
My experience with aftermarket coils is that they are suitable for about one year.
When I bought the car 2 years ago, it had all coils original, 6 months later one coil failed, replaced with aftermarket from britishparts.co.uk. After another 6 moths others started fail.
Original old ones where at that half working state, some cracked but still worked. Whats interesting that misfires and other stuff happened mostly in winter time. In cold climate car was almost non driveable. In summer though coils did their job better. Cold and humidity for sure had a very negative aspect to them.
So decided to replace them all at once with cheap ones from ebay. Set of 6 coils round 80 Euro. Noticed that they hold one year. This year also bought another set and changed them all again without looking which is maybe still good.
I think 80 Euro per year is not so bad, compared to headache off constantly failing ignition , misfires and no joy while driving. Also compared to OEM coil prices this alternative is much cheaper.
When I bought the car 2 years ago, it had all coils original, 6 months later one coil failed, replaced with aftermarket from britishparts.co.uk. After another 6 moths others started fail.
Original old ones where at that half working state, some cracked but still worked. Whats interesting that misfires and other stuff happened mostly in winter time. In cold climate car was almost non driveable. In summer though coils did their job better. Cold and humidity for sure had a very negative aspect to them.
So decided to replace them all at once with cheap ones from ebay. Set of 6 coils round 80 Euro. Noticed that they hold one year. This year also bought another set and changed them all again without looking which is maybe still good.
I think 80 Euro per year is not so bad, compared to headache off constantly failing ignition , misfires and no joy while driving. Also compared to OEM coil prices this alternative is much cheaper.
#9
#10
When I bought my current x300, 3 years ago(~120k miles), out of 6 coils, 5 were cracked and cam cover badly burnt. I've fixed them by remelting the plastic and they worked fine for about a year and then 4 failed within a month. Replaced all with cheapo ones(from the old car where they worked for 2 years) and just had the third one fail a week ago, previous one failed last summer. Still have two spare ones from the old car, after which I'll try Lucas branded ones.
Original ones at over $110 a coil are way overpriced for what they are.
#11
#12
I believe this particular coil is unique to the X300 and also the late model XJS. I think a big part of the problem with these coils is their location inside the cam cover, the heat and vibration of the engine directly below them has to be a contributing factor for the short lifespan of some of these coils.
Most of the older cars with a distributor and a single coil usually had the coil mounted in an area where it was cooled by the surrounding air flow. Coils already run hot just by the way they work, burying them in top of the engine, I never thought was a particularly good idea. Most engines today probably use the c.o.p. design. I don't know how other car brands and models hold up with this design.
Heat is the enemy of any electronic component so maybe leaving the coil cover off or even modifying the cover with slots or holes for ventilation might be a good idea?
Most of the older cars with a distributor and a single coil usually had the coil mounted in an area where it was cooled by the surrounding air flow. Coils already run hot just by the way they work, burying them in top of the engine, I never thought was a particularly good idea. Most engines today probably use the c.o.p. design. I don't know how other car brands and models hold up with this design.
Heat is the enemy of any electronic component so maybe leaving the coil cover off or even modifying the cover with slots or holes for ventilation might be a good idea?
#13
#14
Join Date: Mar 2008
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In my experience, no advantage to the present-day Lucas branded units. They're just brand-X with a Lucas stamp and Lucas box...but no better than other brand-X.
Of course the original coil were made by Diamond Manufacturing with a Lucas label as well....but at least they lasted!
IMO, A) seek out (and pay for) the true Diamond coils or B) pick whatever brand-X is cheapest. Intermediate choices don't seem to have any advantage.
I wonder what Jaguar is selling these days?
Cheers
DD
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