Coil temperature

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Clifford Pope
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Coil temperature

#1 Post by Clifford Pope » Fri May 24, 2013 7:50 am

Interesting experiment and observation:

Some time ago I had problems with a faulty coil and poor quality contact breaker, all resolved satisfactorily.
However the question did come up about the normal coil running temperature, and whether mounting the coil on the engine block is really such a good idea.

Anyway, quite recently I decided to try mounting the coil on a bracket on the end of the battery shelf instead ( searching for any possible cause of the occasional hesitation, see other thread).
I had a spare coil so used that, but left the other coil in position so I could swap back if I had to or wanted a comparison.
Both coils work perfectly, established by swapping and trials on another vehicle, and they have the same measured resistance.

BUT I was surprised to find that whereas the coil on the battery shelf runs hot but comfortably touchable, the other unconnected coil becomes too hot to touch, ie just like the engine block. So I conclude that mounting on the engine block is largely responsible for the coil temperature. Does anyone think that matters? Are coils intended to run untouchably hot?

torque2me
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Re: Coil temperature

#2 Post by torque2me » Tue Jun 18, 2013 3:33 pm

Clifford Pope wrote:
<cut>

for the coil temperature. Does anyone think that matters? Are coils intended to run untouchably hot?
I've been pondering on this issue for s year or so now. Never moved my coil from the engine block and checks on it have shown it to be warm but never hot. However, people's perception of warm and hot are relative. I was going to purchase one of those infra-red temp guns (used for checking water temps in hoses) but have not got around to it yet.

Kev

Mike Stevens
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Re: Coil temperature

#3 Post by Mike Stevens » Wed Jun 19, 2013 11:41 am

torque2me wrote: I was going to purchase one of those infra-red temp guns
What a good idea. I've got one of those. The next time I have the PI out I'll use it to check the coil temperature and report it on here.

Interestingly, there is a thread on the SOC forum about just this. It seems that a problem of the car non starting hot can often be down to a hot coil. On the Stag the coil is mounted on the back of the inlet manifold, but if set too low in its bracket, the bottom of the coil can sit on the 'V' of the block. Heat soak then occurs and the coil stops working until cooled down a bit. Moving it up in its bracket so it doesn't sit on the block seems to help.

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

torque2me
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Re: Coil temperature

#4 Post by torque2me » Thu Oct 17, 2013 10:27 am

Mike Stevens wrote:
torque2me wrote: I was going to purchase one of those infra-red temp guns
What a good idea. I've got one of those. The next time I have the PI out I'll use it to check the coil temperature and report it on here.

Interestingly, there is a thread on the SOC forum about just this. It seems that a problem of the car non starting hot can often be down to a hot coil. On the Stag the coil is mounted on the back of the inlet manifold, but if set too low in its bracket, the bottom of the coil can sit on the 'V' of the block. Heat soak then occurs and the coil stops working until cooled down a bit. Moving it up in its bracket so it doesn't sit on the block seems to help.

Cheers,
Mike.
Mike,

Not had the pi out ;-0 since posting?

People are thirsting for this knowledge!

Kev

Mike Stevens
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Re: Coil temperature

#5 Post by Mike Stevens » Mon Oct 21, 2013 11:41 am

Sorry, too many other damn things to do. It's the usual story - remember to do to it when it's not possible and vica-versa!

I shall tie a knot in something to try and remember.

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

Forkie
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Re: Coil temperature

#6 Post by Forkie » Tue Nov 24, 2015 10:12 pm

What did you tie the knot in Mike :lol: :lol: :lol:
Member Number 7392 04/07

1975 TRIUMPH 2500S AUTO ESTATE IN BRG!

DON'T TIDY UP - LEAVE IT WHERE IT FELL!!

Mike Stevens
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Re: Coil temperature

#7 Post by Mike Stevens » Wed Dec 16, 2015 1:03 pm

Brain probably!

Sorry, we've been out out of the UK for 6 weeks and only just getting back into things. I was pleased to find that the PI started very well having been standing unused for over 6 weeks. Well, what did I expect? It's a Triumph!

It's MoT has run out so I won't be using it for a short while, but when it's next hot I will endeavour to remember to measure the coil temperature.

Who am I, Why am I here?

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

laurence
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Re: Coil temperature

#8 Post by laurence » Wed Dec 16, 2015 2:21 pm

From my experience the coil should never be too hot to handle, on my modified mk1 I've moved it to the strut turret here it gets good air circulation and is away from the block,before you ask,the battery has been relocated to the boot.
No doubting heat is the coils biggest enemy,
Cheers
Laurence
conifer green'68 Mk1, fastroad,rally car

royal blue'68 TR5,an overpriced toy, but still good fun, recently completed CT10'CR
wedgewood '67 Mk1 m o/d,the new addition

Forkie
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Re: Coil temperature

#9 Post by Forkie » Wed Dec 16, 2015 9:22 pm

Hey,my mentor Mike is back :lol: Was wondering where you have been,as you usually reply to my every post :lol: I thought you were ignoring me :wink: 6 weeks away from this location - lucky you! And yeah,i agree with the lapse of starts - mine gets fired up on average twice a year,( after 'dry' start up procedure of course :wink: ) and always keen to go! Nice to have you back in the UK!!!
Member Number 7392 04/07

1975 TRIUMPH 2500S AUTO ESTATE IN BRG!

DON'T TIDY UP - LEAVE IT WHERE IT FELL!!

pete lewis
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Re: Coil temperature

#10 Post by pete lewis » Thu Dec 17, 2015 7:43 pm

Just a thought,
if you have a balasted 1.5 ohm coil which is
re wired to run on 12volts you will get overheated as you have doubled the
current , burn points and have very high HT
which blows rotors and caps
a 12v coild has a 3ohm resistance

just a idea
Pete
Pete Lewis
Luton
also area organiser for herts and beds tssc.

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