RV8 rotor arm

[Sidecarbod]

Hi Everyone,

This thread sort of follows on from one I started last week when my car brokedown!

I finially traced the problem to the rotor arm (with the help of Jim Robinson of JVR.
Basically if I conected a strobe up to the centre HT lead on the dizzy I could see plently of "HT" going into the dizzy but when I connected the strobe up to number one HT lead (or any other) as soon as revs got past about 1500 the dizzy stopped distributing it and the engine would mis-fire.

The rotor arm was leaking the voltage to earth. (I got the arm from Real Steel but I believe that it is an Intermotor one).

I've now put a new one on obtained from Camberley Autofactors which is the same make, I've done about 50 miles and its starting to go the same way.

Jim has been testing some from a different supplier and I will get one of these but has any one else come across this and if so what did you do to sort it out? (Please don't suggest a Mallory dizzy as I've just spent all my money on a set of V8 Development heads!)


The dizzy is an SD1, 35DML8.

I need to sort this out as I'm starting not to trust the thing anymore!

Cheers!

[Happy Jim]

If the rotor arm is leaking to earth it must be going somewhere, normally you would be able to see the tracking marks on the dizzy cap? . . . . you have bought a new cap as well haven't you?

[slogger]

Originally Posted by Sidecarbod

Hi Everyone,

This thread sort of follows on from one I started last week when my car brokedown!

I finially traced the problem to the rotor arm (with the help of Jim Robinson of JVR.
Basically if I conected a strobe up to the centre HT lead on the dizzy I could see plently of "HT" going into the dizzy but when I connected the strobe up to number one HT lead (or any other) as soon as revs got past about 1500 the dizzy stopped distributing it and the engine would mis-fire.

The rotor arm was leaking the voltage to earth. (I got the arm from Real Steel but I believe that it is an Intermotor one).

I've now put a new one on obtained from Camberley Autofactors which is the same make, I've done about 50 miles and its starting to go the same way.

Jim has been testing some from a different supplier and I will get one of these but has any one else come across this and if so what did you do to sort it out? (Please don't suggest a Mallory dizzy as I've just spent all my money on a set of V8 Development heads!)


The dizzy is an SD1, 35DML8.

I need to sort this out as I'm starting not to trust the thing anymore!

Cheers!

I had the same problem but it was the cap tracking down! Fitted a new cap and rotor from unipart. About twice the cost of what the local auto shop could supply, but all was ok.

Sounds more like a pickup or amp fault to me if a new rotor and cap were fitted!

[Sidecarbod]

Hi Guys,

I've not fitted a new cap as its only about a 1000 miles old, I can't see any tracking on it. The reason that I'm sure its the arm thats causing the problem is that when I fitted the new one the engine ran fine for about fifty miles, it would barely run with the one in it when it broke down (which has probably one 100 miles in total).
I've fitted a brand new module today and Jim has sent me a second hand (but tested) one. I recon the HT was going through the rotor arm insulator and straight into the dizzy shaft.

The coil is also standard so there's not 50kV going into the dizzy!

The unipart arm sound interesting, I'll see if I can track one down (No pun intended!)