C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Cold Spark Plug

Thread Tools
 
Search this Thread
 
Old Nov 29, 2005 | 11:45 AM
  #1  
Tpls 69's Avatar
0Tpls 69
Thread Starter
Former Vendor
 
Joined: Oct 2003
Posts: 90
Likes: 0
From: Houston Texas
Default Cold Spark Plug

Need help with a p/n for a colder spark plug. Driving a '69 350/350, and use R35S plugs.
Reply
Old Nov 29, 2005 | 12:24 PM
  #2  
djgrelli's Avatar
djgrelli
Racer
 
Joined: Dec 2003
Posts: 304
Likes: 0
From: Pasadena Maryland
Default

The correct AC spark plug for your application should be a R43S plug. I could be wrong but this is right out of my old chilton manual.
Reply
Old Nov 29, 2005 | 01:31 PM
  #3  
big_G's Avatar
big_G
Le Mans Master
15 Year Member
 
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
Default

and I wouldn't go any colder, unless you on the juice or running a blower...
Reply
Old Nov 30, 2005 | 09:25 AM
  #4  
Tpls 69's Avatar
0Tpls 69
Thread Starter
Former Vendor
 
Joined: Oct 2003
Posts: 90
Likes: 0
From: Houston Texas
Default

I goofed on the spark plug number. You're right it's a R43S plug that I'm using. I'm getting extreme detonation, after installing a new distributor. I've got the timing down to 8 degree's, and have the plugs gapped to .045.
Reply
Old Nov 30, 2005 | 12:55 PM
  #5  
PureSilver's Avatar
PureSilver
Racer
 
Joined: Mar 2003
Posts: 268
Likes: 0
From: Mechanicsville VA
Default

Not to ask dumb questions, but did you change your wires? Had this problem with my GMC one-ton van after doing a 'tune-up'. Wires looked fine, but weren't.
Reply
Old Nov 30, 2005 | 01:46 PM
  #6  
pws69's Avatar
pws69
Melting Slicks
20 Year Member
Conversation Starter
All Eyes On Me
Liked
 
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Default

Originally Posted by Tpls 69
I goofed on the spark plug number. You're right it's a R43S plug that I'm using. I'm getting extreme detonation, after installing a new distributor. I've got the timing down to 8 degree's, and have the plugs gapped to .045.

Sounds like that "new" distributor needs some setup - those plugs should be fine. Try Lars' papers on distributors and timing. I wouldn't eliminate the carb/vacuum from the equasion either.
Reply
Old Nov 30, 2005 | 05:06 PM
  #7  
Tpls 69's Avatar
0Tpls 69
Thread Starter
Former Vendor
 
Joined: Oct 2003
Posts: 90
Likes: 0
From: Houston Texas
Default

Originally Posted by PureSilver
Not to ask dumb questions, but did you change your wires? Had this problem with my GMC one-ton van after doing a 'tune-up'. Wires looked fine, but weren't.
I did change the wires, but I'll check them again. Thanks,
Reply
Old Nov 30, 2005 | 05:09 PM
  #8  
Tpls 69's Avatar
0Tpls 69
Thread Starter
Former Vendor
 
Joined: Oct 2003
Posts: 90
Likes: 0
From: Houston Texas
Default

Originally Posted by pws69
Sounds like that "new" distributor needs some setup - those plugs should be fine. Try Lars' papers on distributors and timing. I wouldn't eliminate the carb/vacuum from the equasion either.
I stayed with the larger springs on the distributor, and I installed a new gasket when the carb was reinstalled. However, I will check out Lars paper. Appreciate the suggestion.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-1

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-2

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-3

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-4

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-5

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-6

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-7

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-8

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-9

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
Old Nov 30, 2005 | 10:50 PM
  #9  
marshrat99's Avatar
marshrat99
Melting Slicks
15 Year Member
 
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Default

Originally Posted by pws69
Sounds like that "new" distributor needs some setup - those plugs should be fine. Try Lars' papers on distributors and timing. I wouldn't eliminate the carb/vacuum from the equasion either.
Pull and block the vacuum going to the distributor. Timing should'nt be more than 36* at 2500 RPM. If more then need to change the distributor springs or weights. Since most distributors are usually shipped setup on the conservative side, I wouldn't think this to be your problem unless you've adjusted it. However when you ask about a "colder" plug, it makes me think that you're seeing a plug looking like its getting too hot. This would sound like a possible vacuum leak screwing up you air/fuel mixture causing a lean condition.
Reply
Old Dec 1, 2005 | 08:41 AM
  #10  
Tpls 69's Avatar
0Tpls 69
Thread Starter
Former Vendor
 
Joined: Oct 2003
Posts: 90
Likes: 0
From: Houston Texas
Default

Thanks I'll try that.I'm also going to re gap my plugs back to .035 from .045 ( as per Lars paper).
Reply
Old Dec 1, 2005 | 11:21 AM
  #11  
pws69's Avatar
pws69
Melting Slicks
20 Year Member
Conversation Starter
All Eyes On Me
Liked
 
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Default

Originally Posted by Tpls 69
I stayed with the larger springs on the distributor
Larger (stiffer) springs cause the advance to come in later which definately could contribute to your problem.

One down...
Reply
Old Dec 1, 2005 | 05:08 PM
  #12  
Tpls 69's Avatar
0Tpls 69
Thread Starter
Former Vendor
 
Joined: Oct 2003
Posts: 90
Likes: 0
From: Houston Texas
Default

Originally Posted by pws69
Larger (stiffer) springs cause the advance to come in later which definately could contribute to your problem.

One down...
Thanks.
Reply
Old Dec 1, 2005 | 06:05 PM
  #13  
dennis's Avatar
dennis
Drifting
25 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Sep 1999
Posts: 1,970
Likes: 91
Default

May be a mute point ,but my 70 L-46 uses a R-44. I believe 69 is the same. Lt1 uses a R-43. I actually went the other way with a R-45.

Your timing should be 4 degrees, all else being equal. 1970 uses 8 degrees, but then there's no advance at idle. (Good old TCS system)
Reply

Get notified of new replies

To Cold Spark Plug





All times are GMT -4. The time now is 04:16 AM.

story-0
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-1
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-2
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-3
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-4
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-5
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-6
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-7
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-8
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-9
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE