update on high rpm missing problem

[BarryK]

got my NGK B4 non-resistor plugs today and put them in.
Just got back from a test drive and was able to get in a couple nice high speed/high RPM runs.
took her up to redline (6500) in 1st, 2nd, and 3rd gears and up to about 4000rpm in 4th on each run and couldn't hear nor feel any missing at all while previously it was VERY obvious starting at around 4,000rpm or so.

It was a good friend that recommended I swap my R45's for the non-resistor plugs as he had a similar problem a while back himself and after going thru everything imaginable he switched to a non-resistor plug and it cured his missing problem.
his theory on this is that the original plugs were non-resistor plugs but the current plugs of the R45's are resistor plugs and that the resistor could be causing just enough of a voltage drop to cause the mis-firing.

Made a bit of sense to me so I tried it out as the first item on my list of parts to go through on my checklist to try to solve the problem and it seemed to have worked.

I'll give it a few more days of driving the car to make sure the missing doesn't come back before I reistall all the shielding pieces but so far the missing has disappeared.

 

[paul67]

Barry,
With respect I need convincing. I have used the R45S spark plugs for several years with no problems. And the Petronix Ignitor that you have chosen to avoid. But I wish you well! Hope your problems are over.

 

[BarryK]

Paul
I understand.
I can't fully expalin it and neither can my friend who is VERY knowledgable on these cars. I respect his opinions and advice as much as people like JohnZ, Duke, and others.
As mentioned in my explanation above he had the same problem and tried EVERYTHING to solve it ( new points & condenser, rebuilt distributor, new coil, new wires, rebuilt carb, etc) and changing out to a non-resistor plug was the only thing that solved it for him which is why i tried his idea first. His "theory" of a voltage drop from the resistor plugs was the only reason he could come up with but bottom line is that it solved his problem and it solved mine it seems.
Whatever the true reason is, it worked and that's good enough for me.
BTW, before he developed his mis-firing problem he also ran AC R45's (actually the AC R45S) for years with no problem. Ever since he switched to the non-resistor plug the misfire never came back and it's been a few years now he said.

I still have my fingers crossed for the next few days

 

[jims427400]

Hey Barry,I have to say that your thread on NGK B4 NON resistor plugs sounds like my next job on the 67..
Can you tell me if that is the same plug I would us on my BB?
Even though mine runs better than it ever has (for me)it still has a little miss like yours HAD..good job and thanks for the info. Jim

 

[BarryK]

Jim
I don't know what plugs the BB motors take but you want to find a non-resistor plug that is the same heat range that you are using now if the motor is running good.

 

[jims427400]

Barry, have been looking online where I can buy plugs,where did you pick yours up at?

 

[BarryK]

Jim

I got mine at the local NAPA store. They don't normally stock this particular plug but can get me most parts within a few hours or the next day if they don't stock it.
you may want to look here though:
http://www.clubplug.net/

 

[Marlar]

I actually found a set of non-resistor AC46 plugs at a local parts store. The box was dusty and looked to be 20 years old minimum. They don't work any better than the AC 45 resistors though, at least in my '65 327.

 

[BarryK]

Aren't 46's pretty hot to run??

anyway, I'm not trying to convince anyone to swap their plugs out to non-resistor plugs, especially if their cars are running fine. Mine ran just fine with the standard resistor AC R45's until recently.

i'm just mentioning what worked for me and seemed to have solved my misfiring problem.

 

[paul67]

Barry,
I think we get back to *4: a defective plug. But those B4s will not hurt. Enjoy the summer!

 

[Marlar]

Barry

I wish I had a place to reacg 4K rpms in 4th. Keeping legal, all I can get is 2500 rpms in 4th.

Does NKG have platinum? I realize that high mileage from plugs is usually way down the priority list for mid years, but the info might be a good thing to know.

 

[BarryK]

Barry

I wish I had a place to reacg 4K rpms in 4th. Keeping legal, all I can get is 2500 rpms in 4th.

Does NKG have platinum? I realize that high mileage from plugs is usually way down the priority list for mid years, but the info might be a good thing to know.

legal??!! I never said 4000 in 4th was anywhere near legal speed, even redline in 2nd and 3rd is past legal but sometimes you have to do what you have to do to check to see how the car is running!

actually, those test runs the other day were probably the second fastest speeds I ever put on the car. The fastest was last month trying to keep up with a Callaway and a bunch of C5's (fellow Corvette Club members) heading back from Carlisle, PA down the PA turnpike. My wife saw the speedometer at one point and turned white as a ghost.
Our club president called me the next day (he owns the Callaway - '87 B2K #3) just to say how impressed he was with my "old, 40yo car and that I was able to keep with with him

 

[magicv8]

Anyone running resistor plugs and resistor wires will probably overload an original coil. What coil do you all have in your cars?

 

[Marlar]

legal??!! I never said 4000 in 4th was anywhere near legal speed, even redline in 2nd and 3rd is past legal but sometimes you have to do what you have to do to check to see how the car is running!

actually, those test runs the other day were probably the second fastest speeds I ever put on the car. The fastest was last month trying to keep up with a Callaway and a bunch of C5's (fellow Corvette Club members) heading back from Carlisle, PA down the PA turnpike. My wife saw the speedometer at one point and turned white as a ghost.
Our club president called me the next day (he owns the Callaway - '87 B2K #3) just to say how impressed he was with my "old, 40yo car and that I was able to keep with with him

I know, I know. I was just jerking your chain. It is fun though....

 

[JohnZ]

Anyone running resistor plugs and resistor wires will probably overload an original coil. What coil do you all have in your cars?

Both my cars ('67 Corvette 327/300 and '69 Z/28) have resistor plugs (R45S), resistor wires, and factory-original coils, neither has ever had any ignition/miss/fouling problems.

 

[paul67]

*Message removed.*

 

[BarryK]

well Paul

I have some great tech info explaining the theory of why the non-resistor plugs could make a difference but i'm not asking you to "buy into" anything nor am I trying to convince you of anything.

Back-up tech info or not, all that matters to me is that my mis-firing stopped as soon as I put in the non-resistor plugs and that's good enough for me.

 

[paul67]

Thanks Barry. I've removed the message. It was rude. Glad you got matters sorted out.

 

[BarryK]

it didn't bother me Paul...........
I have a thick skin

 

[LUCKY13]

One big problem with these cars is the ignition system. The points and the weak coil (compared to today's high energy units) are hard on spark plugs. I converted my 65 to electronic ignition (installed kit in existing distributor) with a high energy coil and helped my plug fouling significantly.