Engine missing - can a rotor cause this?

[R N.]

Hello everyone,

Over winter I changed the rotor (extended tip K & B) on my '66 L72 and finally had the chance to get it out for its first run this year just last week. Upon start up I had terrible engine missing. At first I had thought I must of had one or more of my wires mixed up, but that wasn't the problem.

Since I had only changed the rotor, I thought I'd put the old one back in for the heck of it. I was really surprised that the missing stopped and the engine ran like it should with my old rotor re-installed

Being honest, I'd never heard of a rotor causing this sort of problem, so today I mentioned it to my buddy and he said he has seen it before, but it wasn't that common.

Could someone one explain to me how/why a "bad" rotor could cause an engine miss. Could it be because of the design of the extended tip of these K&B rotors that is at fault?

Should I stick to the generic rotor (NAPA) or try another K&B rotor?

As always, thank you for you advice and help.

[Ray G.]

Re: Engine missing - can a rotor cause this?

I believe the standard tip rotors cause the coil to build voltage to jump the gap between the rotor and the distributor cap contacts and fire the spark Plugs.
Also the extended tip rotors do not allow enough voltage to build and fire the spark plugs properly.
Don't have any written fact to back up the theory.
Have seen your condition many times and believe if everything else, spark plugs, wires, voltage, etc. are correct this problem will NOT happen.
In recent example whoever installed the spark plugs had excess anti-seize compound causing the plugs to have insufficient ground.

[Richard M.]

Re: Engine missing - can a rotor cause this?

Kurt,

Give Ken Anderson a call at K&B in the morning, or send him a email or PM here, as he's a active NCRS member. Ken's the main man at K&B and he'll help you figure out the problem, if it is in fact related to his rotor.

Ken is great to work with. He's helped me many times with TI and gauge issues, and most of his products carry a lifetime warranty. Can't beat that these days!!!!

Rich

[William F.]

Re: Engine missing - can a rotor cause this?

Would like to hear more about this. I bought 2 but haven't installed them yet. Idea of longer tip is to supposedly to get better, not less efficiency, I suppose you'd call it, out of ignition, especially in the higher performance, higher winding engine options. Some have said installing the long tip rotor cleared up previous high rpm misfires.

[Edward J.]

Re: Engine missing - can a rotor cause this?

Kurt, I have the K&B rotors installed on both my 63/72 with no issues. But it is possible that the spark is jumping to ground through the plastic in the rotor to ground using the dist., shaft. I have seen many failures of rotor burning through under the stainless tab on dist. rotors. Another thing to look for is a bad ignition wire or maybe a bad wire contact under the boots, When corrosion starts under the boot at the dist. cap end It will start looking for another grounding point generally under the dist. cap. Also make sure all the brass contacts on the plug wires are plugged all the way into the Dist. cap correctly.

[Duke W.]

Re: Engine missing - can a rotor cause this?

It's probably just a defective part. I'm not familiar with the name "K & B". Who manufacturers their parts?

Most common replacement brand ignition products, including "Delco". are manufactured by Standard Motor Product, which is an OEM supplier, so their replacement parts are built using the same quality standards that are in place for parts they manufacture for current new vehicle production.

Duke

[Richard M.]

Re: Engine missing - can a rotor cause this?

Duke, K & B in Alpharetta, GA is owned by fellow member Ken Anderson. Advertises in Driveline consistently. He manufactures many replacement parts, and high quality reproductions. His TI module IMO is the best on the market, and his warranty is unsurpassed IMO as well.

I have no affiliation, other than being a very satisfied customer. His customer service is excellent as well, and when I've had some problems with items in the past, he backs it up professionally and quickly.

I always like seeing his products on my restorations.

http://www.kandbcorvetteproducts.com/

Rich

[Dan A.]

Re: Engine missing - can a rotor cause this?

No issues with th K&B cap and rotor installed on my 72. It appears to be a stand up company and I'll bet they would exchange the possibly defective rotor for another one.

[William F.]

Re: Engine missing - can a rotor cause this?

Duke,
Did you miss a Restorer article several mos., maybe year or so, ago about longer lengths of rotors prior to the shorter ones that appeared in anti smog era? Said none you could buy had correct longer length so, Ken at K&B started manufacturing these with the longer dimensions said to provide better high rpm spark. Thought you would have tested some for your tuneup studies/advice.

[Joe R.]

Re: Engine missing - can a rotor cause this?

William,

To add to your post, I believe the article was by Bill Clupper.

Joe

[William F.]

Re: Engine missing - can a rotor cause this?

Exactly, as soon as I sent reply I realized it was Bill Culpepper who wrote the article. Sorry, Bill!

[Duke W.]

Re: Engine missing - can a rotor cause this?

Yes, I read Bill's article, but in my experience if the distributor is set up properly - proper end play and no breaker plate wobble, the ignition system will work properly with the short rotor and properly manufactured RFI wires, which are the same components that were used in the early emission era before HEI became standard in 1975.

The longer rotor, improved RFI wire design, and non-resistor plugs provide more ignition energy margin and will likely allow the spark plugs to last longer, but at the rate we accumulate mileage with unleaded fuel, spark plug life is not a big issue.

Duke

[Jerry B.]

Re: Engine missing - can a rotor cause this?

I made up a set of iginition wires using the Packard 440 spark plug wire. I also soldiered both wire ends for a good elertrical contact. Also, I plan on NOS AC 44 plugs. The applicaion is a stock 1969 350/350. Any forseen problems. Thanks

[Leif A.]

Re: Engine missing - can a rotor cause this?

I made up a set of iginition wires using the Packard 440 spark plug wire. I also soldiered both wire ends for a good elertrical contact. Also, I plan on NOS AC 44 plugs. The applicaion is a stock 1969 350/350. Any forseen problems. Thanks

My only suggestion would be to go one range hotter on the plugs AC R45T. I have found they perform better in our normal driving.

[R N.]

Re: Engine missing - can a rotor cause this?

Kurt,

Give Ken Anderson a call at K&B in the morning, or send him a email or PM here, as he's a active NCRS member. Ken's the main man at K&B and he'll help you figure out the problem, if it is in fact related to his rotor.

Ken is great to work with. He's helped me many times with TI and gauge issues, and most of his products carry a lifetime warranty. Can't beat that these days!!!!

Rich

Hi Richard,

I called earlier today for Ken, but they are closed for holidays until the 7th-July.