C2: Plug wire resistance

[Mark F.]

Can anyone advise me of the acceptable range of resistance in plug wires for my '65 300hp engine? The wires are almost new, but I'm down to them (and a few other things) to solve my 4000 rpm redline problem.

Also, a friend suggests that my premature redline may be due to a mismatched coil and condensor. I've never heard of such a relationship but, obviously, I'm no expert in automotive electronics. Is there such a thing?

Thanks,

Mark

[Dick W.]

Re: C2: Plug wire resistance

One item often overlooked is "point bounce". Lack of adequate tension on the point arm will allow the points to bounce. The quick and dirty way to check for this is to attach a dwell meter. Slowly increase the RPM's amd observe the dwell setting. You will see a minor change as the speed increases. If you see a major change chances are that your points are the problem. A good set of heavy duty points from an aftermarket supplier such as Accel will cure this.

I have seen points "double springed" by mechanics to aleviate this at very high RPM's. I do not recommend this due to the increase wear on the rubbing block and also to the distributor cam

[Dick W.]

Re: C2: Plug wire resistance

I have a one track mind. I got the point issue on my feeble pea brain and forgot your original question. Per a post by Bill Clupper earlier in the week the resistance should be 2500-4000 ohm per inch.

[Duke W.]

Re: C2: Plug wire resistance

As Dick said, you need to do a dwell variation check. Bring the revs up to 5000 and check for variation. It should be no more than two degrees.

The standard 19-23 oz. breaker arm tension points are okay for engines with redlines up to about 5500. Higher redline engines should use the 28-32 oz. points, particularly those with mechanical lifter cams.

If dwell variation exceeds two degrees, and the points are satisfactory the other causes of dwell variation can be excess dist. shaft end play, worn shaft bushings, or a worn, wobbly breaker plate.

Duke

[Mark F.]

Thanks, gentlemen. *NM*

[William C.]

Re: C2: Plug wire resistance

The ohms measurement quoted is measured per foot, just for clarification.

[Dick W.]

Re: C2: Plug wire resistance

Oops! The graying of this NCRS member has surely give me NCRS disease. I must have had a serious case of brain fade when I said inch Wonder where my very feeble mind was?