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A&R Power Amp, plug gap question(s).

Posted: Wed Jun 20, 2007 7:06 pm
by The Original Tom
As stated, I have the A&R power amp that RPI sell (with auto advance/retard).
I've been shocked by it, and know that it *$%£~#! hurts! I then shocked myself with a standard coil for comparison (call me an idiot if you like, it's accurate), and it's nowhere near as bad.
As with the standard setup, the plug gap should be 0.7mm, can I expand my gaps? I believe the unit is supposed to boost spark voltage to about 25kV (from about 12kV?).
It's been suggested on another forum that I could open my gaps to as much as 1mm without losing the spark reliability.
Normally I wouldn't bother, but I run LPG 99% of the time so I need all the help I can get.
On my old 4-pot I got specialist plugs with a 0.8mm gap instead of a 0.6, and I could tell the difference.

And for my second question... How can I tell if the auto advance/retard is working? I have a feeling it's not (or maybe just not enough?)

Answers on a postcard.
Tom.

Posted: Thu Jun 21, 2007 7:06 am
by ChrisJC
You can check the advance / retard by seeing if the mechanism is free in the distributor.

Or sticking a strobe light on it, but of course it's damn hard to see the marks on the pulley!

I'm not sure that opening up the plugs gives any benefit, maybe somebody will have a definitive answer on that one.

I use the standard LR ignition (amp on distributor) on my Landie, and it works perfectly. (on LPG)

Chris.

Posted: Thu Jun 21, 2007 8:18 am
by The Original Tom
Sorry, maybe I should have been clearer about which advance/retard I'm on about :oops: .
The A&R amp has a curcuit that retards the timing when you are running on petrol, eg so that your timing is at 6degs at idle.
However when you switch to LPG, a sense wire from the solenoid on the vaporiser goes live, and advances (or returns to normal) the timing by 8-12degs (user adjustable). eg giving 16degs adv at idle.

Guess I just answered my own question there really :roll: . But I can't see my timing marks, let alone know if they're right!