use the 45, Bill.
Another Spark Plug Question...
Thread Starter
Heel & Toe
Joined: May 2009
Posts: 19
Likes: 4
From: CA
Another Spark Plug Question...
New to the CF with an original owner 1963 Coupe that I'm slowly bringing back to life...
No mention in the shop manual, but on page 43 of the owners guide there's a nice section on Spark Plugs. Currently I have one fouled AC 44 & I've been advised to switch to AC 46's. The CF threads I've read so far don't seem to mention AC 46's as a good choice. I plan to drive the 327/300hp several times per month, relatively short distances.
Any/all advice is appreciated...
Thanks...
No mention in the shop manual, but on page 43 of the owners guide there's a nice section on Spark Plugs. Currently I have one fouled AC 44 & I've been advised to switch to AC 46's. The CF threads I've read so far don't seem to mention AC 46's as a good choice. I plan to drive the 327/300hp several times per month, relatively short distances.
Any/all advice is appreciated...
Thanks...
Drifting
Joined: Jul 2005
Posts: 1,977
Likes: 194
From: Putnam Valley, New York. Amateur Radio Operator K2NS
New to the CF with an original owner 1963 Coupe that I'm slowly bringing back to life...
No mention in the shop manual, but on page 43 of the owners guide there's a nice section on Spark Plugs. Currently I have one fouled AC 44 & I've been advised to switch to AC 46's. The CF threads I've read so far don't seem to mention AC 46's as a good choice. I plan to drive the 327/300hp several times per month, relatively short distances.
Any/all advice is appreciated...
Thanks...
No mention in the shop manual, but on page 43 of the owners guide there's a nice section on Spark Plugs. Currently I have one fouled AC 44 & I've been advised to switch to AC 46's. The CF threads I've read so far don't seem to mention AC 46's as a good choice. I plan to drive the 327/300hp several times per month, relatively short distances.
Any/all advice is appreciated...
Thanks...
46 is too hot---Use R45S---Best all around heat range. "S" identifies the extended tip---no problem for a 300 HP with the flat pistons.
RON
Last edited by rongold; May 25, 2009 at 02:56 PM.
Race Director
Joined: Apr 2005
Posts: 11,265
Likes: 2,131
From: Bowling Green, Kentucky
The AC 45 are long discontinued. Still can find on E-bay or at swap meets......but a set of eight will cost between $25-40.
I personally like (and run) the old AC 45's.
Larry
Advanced
Joined: Feb 2009
Posts: 87
Likes: 1
From: Riegelsville PA
spark plugs
Melting Slicks
Joined: Jul 2004
Posts: 2,865
Likes: 195
From: Maryland
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Pro
Joined: Jul 2008
Posts: 622
Likes: 24
From: Clermont Florida
The extended tip places the spark further out in the open, and also improves firing of the air/fuel charge.
AC R45S, Champion RJ12YC, Autolite 24, will all work fine in your car.
BTW when pulling wires to check spark or to gap wire to temporarily improve spark, you should pull plug wires from cap and not plug, and coil wire from coil and not cap. This reduces chance of you getting bit by spark, as it has someplace to go other than you.
Pro
Joined: Jul 2008
Posts: 622
Likes: 24
From: Clermont Florida
Those are cold plugs, and would be for racing. I am assuming the N60 is a variation of the N6. RN9YC would be OK. If you are just putting around, you could use RN12YC. If you intend to use those 435 ponies, go with the 9.
Race Director
Joined: Apr 2005
Posts: 11,265
Likes: 2,131
From: Bowling Green, Kentucky
Resistor plugs have a gap inside the plug shell that requires more voltage to jump across. Thus the spark at the tip will be stronger. It is like when you pull a wire out of the cap, and let the spark jump to it. Doing so will clear a fouled plug most times. Pulling the coil wire out of the coil and making it jump a 1/2" gap will very often fire a flooded engine that normally would not start without pulling the plugs and cleaning them. Resistor plugs give you a better, stronger spark, and resist fouling.
The extended tip places the spark further out in the open, and also improves firing of the air/fuel charge.
AC R45S, Champion RJ12YC, Autolite 24, will all work fine in your car.
BTW when pulling wires to check spark or to gap wire to temporarily improve spark, you should pull plug wires from cap and not plug, and coil wire from coil and not cap. This reduces chance of you getting bit by spark, as it has someplace to go other than you.
The extended tip places the spark further out in the open, and also improves firing of the air/fuel charge.
AC R45S, Champion RJ12YC, Autolite 24, will all work fine in your car.
BTW when pulling wires to check spark or to gap wire to temporarily improve spark, you should pull plug wires from cap and not plug, and coil wire from coil and not cap. This reduces chance of you getting bit by spark, as it has someplace to go other than you.
An excellent answer/explanation. My reply was more "you can't readily buy AC 45 plugs, but can get R45S easily and they work well". I think "Eddie1349" now has BOTH sides of the story to make an informed decision.
Larry
Burning Brakes
Joined: Jun 2008
Posts: 801
Likes: 19
From: Moose country Vermont
AC45S longer plug
So just so I understand the info here, and it is clear to all. We can not use AC45S plugs in our L79 engines(to long). I have AC44's in our L79 and have fouled 2 of them, most likely due to short trips!?! It will be hard to find AC45 plugs at our local parts store. So what is available and best in our L79? We plan on longer trips as Summer is here, and do not push the car hard(no stoplight drags anymore, well maybe once in a while
). Thanks for all of this good info. Keeping these old cars on the road is a group effort.
). Thanks for all of this good info. Keeping these old cars on the road is a group effort.
Race Director
Joined: Apr 2005
Posts: 11,265
Likes: 2,131
From: Bowling Green, Kentucky
So just so I understand the info here, and it is clear to all. We can not use AC45S plugs in our L79 engines(to long). I have AC44's in our L79 and have fouled 2 of them, most likely due to short trips!?! It will be hard to find AC45 plugs at our local parts store. So what is available and best in our L79? We plan on longer trips as Summer is here, and do not push the car hard(no stoplight drags anymore, well maybe once in a while). Thanks for all of this good info. Keeping these old cars on the road is a group effort.
). Thanks for all of this good info. Keeping these old cars on the road is a group effort.AC 45 or AC R45 (without the extended tip) are available on E-bay or other swap meet sources. A new set of these plugs should go for years or thousands of driving miles. If you don't want this (too much hassle) you can buy Denso W14-U or NGK B4 plugs. These are currently produced/available plugs that are equivalent to the non-resistor AC 45. I have not personally tried them, but other have, and reported good results and no issues.
Larry
Burning Brakes
Joined: Jun 2008
Posts: 801
Likes: 19
From: Moose country Vermont
R45 plugs
Thanks for making it clear to me. I just called our local parts store and can get R45 plugs for $1.59 ea. I told them to hold 8 for me. I am also going to install new wires since I am going to the effort of replacing the plugs...seems to not be an easy job removing all of the shielding and feeding the wires thru the motor mounts etc. and the AC. It's called a labor of love. I still do not have brake lights, Traced it to the directional/flasher harness on the steering column. as I have all directionals/park lights and flashers front only. Going to order an new one. Looks like $75 at L.I. Corvette. Anyone have dealings with them? Are they a good place to get parts..quality/delivery? Thanks again, and enjoy the day, go for a drive.
Drifting
Joined: Nov 2001
Posts: 1,658
Likes: 25
From: Rochester Minnesota
The 8's will be way, way cold. Stock AC's crossed to RN10 which were also too cold for everyday driving. I finally settled on RN12's. They didn't foul up every 500 miles and you could still put the boot to it occasionally without them melting down.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
One time when extended nose plugs were relatively new, I installed a set in my '65 with an untouched 327/365 L76. The plugs ran worse than the AC 43s that I had pulled out. I then put in another set of 43s and the problem was solved. My conclusion was that if the plug gap is too close to the piston (the L76 piston has a flat 1/8 inch dome), that the turbulence may be too much to fire reliably. With the stock recommended plug, the tip is further away from the piston top.
In the last 35 years I've been using non-extended tip plugs, except for one more try - again, the results were the same - the engine ran poorly!
YMMV
In the last 35 years I've been using non-extended tip plugs, except for one more try - again, the results were the same - the engine ran poorly!
YMMV
Racer
Joined: Dec 2006
Posts: 264
Likes: 0
From: Bernardsville New Jersey
Has anyone tried the Champion C61C/CX? I believe it's still a 14mm/.750 reach but with a 5/8 hex, non extended tip and the CX has a side/cut back electrode(more clearance in a tight hi-comp. chamber.
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan