High Tension electrical insulation question

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momec
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High Tension electrical insulation question

Post by momec »

Help guys ( Outback Trev are you there?)
Sorry this question is work related but the answer may be relevant to what we do on the salt

What material is best to insulate a rotor.
The problem I have is spark jumping across the side of the rotor to a mounting screw. We use a modified Mallory rotor with screws in a non standard position. I need the right material to both insulate these screw heads and the mid section of the rotor blade. This will save a major redesign of the distributor.

Thanks Chris
Acme Racing #251
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Greg Watters
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rotor

Post by Greg Watters »

How far is the spark jumping Chris ?

Is there excessive load at the end or in transit of the circuit?

May require some testing but a 2pack glue may be able to insulate enough to cover the screws if access is not needed or create ridges between the offending areas to increase surface area .

Because its tracking across now a new rotor may be required as there may be a carbon path already burnt into the surface.
outbacktrev
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Post by outbacktrev »

Chris,
Are the screws required to provide serious mechanical strength or could they be replaced with nylon or similar screws if they would be strong enough. :idea: There are several HT type insulation spray paints available. Could you give an indication of distance invovled and roughly what sort of voltage you are talking about and I will check out what's around. As Greg said once the tracking has started basically your rotor is stuffed as the tracking is impossible to fix/remove.
Cheers,
Trevor
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momec
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Post by momec »

Trev and Greg
OK voltage approx 50000 normal Motec Hei
Distance about 20mm

No we can't use nylon or plastic screws as there is to much at stake and can't risk it even if they would do the job.
Rotors are now be replaced each engine freshen which is 1500kms but will go to replacing each meeting if nessasary.

HT leads all tested perfect and plugs were less than 500 race kms
Rotor that failed was also 500kms old and after looking at lots of old ones around the shop found early signs on many of these but the one that stopped the car was roasted.

What two pak epoxys would suit. Would something as simple as araldite insulate well enough.? Spray on would be easier but the best result is our only objective and with the endurance rounds coming up soon I have to cure this problem.

Thanks for your help guys. Racings in two weeks at Oran Park.
This schedules a bit more hectic than our once a year deal.

Seeya Chris
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Greg Watters
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Post by Greg Watters »

Chris , 20 mm while not huge should be ok as the spark will look for least resistance, and always nice to treat the cause not symptom, so holding that thought.
What is the indexing like on the distributor, at full advance and cranking, i figure its not mechanical but the practice should be the same. At 30 whatever deg is the rotor in a good line with the pole on the cap

As for araldites its a thought not something i have tried you may need to check conductivity , and would probably need a mould
DON NOBLE
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Post by DON NOBLE »

Ooooh crikey ! Latest model Ford Falcon racing cars use distributors do they , dang dinasaurs still about . (come on bite )
NOW LIVE IN NEW ZEALAND
RED NISSAN WAGON 1986 # 281
2002 F/PRO 125.4 MPH RECORD
2003 F/PRO 140.2 MPH RECORD
2005 F/GC 137.9 MPH RECORD
2006 F/GC 141.1 MPH RECORD
1/4 mile ( drags ) @ Willowbank 14.15 @ 97.61 mph August 2006
outbacktrev
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HV insulating

Post by outbacktrev »

G'Day Chris,
Two part areldite (not the quick setting type) has good insulation values and as an insulator to screw heads at 20mm should sh!t that in. As Greg said 20mm is a long distance for 50k volt.
You could try areldite on a new rotor BEFORE tracking occurs. If you PM your work phone number I will give you some part numbers for various spry insulating paints and products we use in our industry which are very effective.
Cheers,
Trevor :lol:
momec
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Post by momec »

Thanks Guys
Yeah Trev I've pm'd my work # forgot the 07 prefix

Greg I think we have created the problem by making the phasing of the rotor adjustable and its this adjustment screw we now have to insulate.
The correct distance the spark is jumping is 13mm.
I think the rotor must have had a floor or something to set this off but know we no its a problem area we can't leave it to chance.

Yeah Don they got pushrods too.
Hows the wiring going on the blue wagon :lol:
Chris
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Greg Watters
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Post by Greg Watters »

Looks like Trev has you covered.
Somedays i miss the car raceteam stuff and others i don't :lol:
DON NOBLE
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Post by DON NOBLE »

C Hanlon wrote:Thanks Guys
Yeah Trev I've pm'd my work # forgot the 07 prefix

Greg I think we have created the problem by making the phasing of the rotor adjustable and its this adjustment screw we now have to insulate.
The correct distance the spark is jumping is 13mm.
I think the rotor must have had a floor or something to set this off but know we no its a problem area we can't leave it to chance.

Yeah Don they got pushrods too.
Hows the wiring going on the blue wagon :lol:
Chris

Pushrods , remember them in my 1st car FE holden . Ah the wiring , its happening . It really is good therapy unravelling a harness with 10 billion wires . Sitting on my little mobile mechanics seat , kind of like basket weaving , except lots of different colours
NOW LIVE IN NEW ZEALAND
RED NISSAN WAGON 1986 # 281
2002 F/PRO 125.4 MPH RECORD
2003 F/PRO 140.2 MPH RECORD
2005 F/GC 137.9 MPH RECORD
2006 F/GC 141.1 MPH RECORD
1/4 mile ( drags ) @ Willowbank 14.15 @ 97.61 mph August 2006
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Mopar Man
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Post by Mopar Man »

DON NOBLE wrote:Ah the wiring , its happening . It really is good therapy unravelling a harness with 10 billion wires . Sitting on my little mobile mechanics seat , kind of like basket weaving , except lots of different colours


I can relate to that Don, I thought I was the only silly bugger to pull apart a wiring harness and re-use the ignition wires :)

Recently did that on the corolla I'm building.....
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momec
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Post script

Post by momec »

As a conclusion to my own question I found a product called electrical potting mix (supplier RS components) that did exactly what I wanted.

Two pack epoxy specifically for electrical insulation.
Make sure it goes off 24 hours b4 use.
Seeya Chris
Acme Racing #251
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