distributor cap rotors ?

1965lonewolf · Jan 4, 2015

I am replacing a rotor and it has a curved or hooked brass piece instead of a normal straight one like most rotor caps are - whats the difference ? why did they make one straight and the other one curved or hooked ?

Texasmark1 · Jan 4, 2015

If you are talking about flared out side to side means more contact area which may be helpful in ensuring that the plug gets a good hot spark somewhere along the length of it, but seems it would also advance your timing somewhat on the leading edge.

I have seen and used them but don't remember much else. Don't recall a timing problem. Setup the dist. with the timing light as always.

Other than that have no idea.

Mark

1965lonewolf · Jan 4, 2015

that's seems like it would work , its for a pulling tractor I am building and I bought the distributor and I open the cap and it has one of those hooked or curved rotors in it - what you said sounds perfect though

Steve@Advance · Jan 4, 2015

I've seen those in automotive applications. They were in V6 engines that had an uneven firing pattern. It allowed the distributor terminals to be spaced evenly and the rotor to "reach" the ones that fired slightly out of sequence.

mEl · Jan 4, 2015

Don't worry about timing issues with the rotor, the timing is set by when the points break not the rotor position.

I recently installed a electronic unit in a tractor and it started burning the rotor at a 45 degree angle at the rotor tip from spark trying to get to the cap contact when the spark was out of phase.

I sent the distributor out and the module was moved on the plate to properly phase the spark timing with the tower position.

Texasmark1 · Jan 4, 2015

Well I do and don't agree with you. Yes on the point break, but not
necessarily on the delivery part where the rotor has to get the juice
to the plug wire.

But the V6 comment on this thread makes a lot of sense. But again
I don't know.

Mark

Icuby · Jan 4, 2015

I have seen the AC tractors w/Delco dists. use that type of rotor. I have tried the straight ones on Ac tractors and found that the curved one is what they need.

sotxbill · Jan 4, 2015

Remember there is advance happening so the curved allows for more timing advance... less important on tractors, more important on higher rpm engines... seem to remember 23 degrees advance is normal vrs 18 degrees on tractors... too long ago and too much fog...

mEl · Jan 4, 2015

It is not necessary that you agree with me, that is your perogative. The fact is that spark is generated by the points breaking or in the case of electronic ignition by a magnet tripping a module. The speed that spark travels would make any difference in timing unmeasurable with any commonly used timing instruments and insignificant.

JK2 · Jan 4, 2015

If you are talking about a delco unit for a Minneapolis Moline, the V4 Uni-Tractor used a rotor with a fairly long curved tail so the spark could get to the evenly spaced tower terminals since the lobes on the distributor cam are not evenly spaced. That distributor won't run right on a 4 cyl inline engine.

1965lonewolf · Jan 4, 2015

I DID FIND SOME AT NAPA TODAY , ITS FOR A 6 CYC MOLINE/MASSEY 504 GAS MOTOR

Bob · Jan 4, 2015

Some Wisconsins with the cam lobes unevenly spaced use an oddball rotor, as well.

hd6gtom · Jan 4, 2015

Those were called an anti kick back rotor, supposed to be good when hand cranking your engine. Alan at R&R equiptment sold me 1 years ago, just after I overhauled dads WD45. I explained to him the starter didn't work, he recommended 1.

teddy52food · Jan 4, 2015

And how was it supposed to prevent a kickback???????????????????????????????????????????

distributor cap rotors ?

1965lonewolf

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1965lonewolf

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Steve@Advance

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mEl

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