Spark Plugs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

LOW DOUGH · 07-19-2007, 05:51 PM

Hay yall,

I was hoping someone could tell me how to pick a hotter plug then what I have. I am not trying to do this. I am just curious. How do you tell if it is a hotter plug?

rambler · 07-19-2007, 05:56 PM

just have the parts store look it up for you, they should know by the book and the part numbers on the plug. I typically go to a hotter plug on a older engine that is using oil... (which is usually all of my vechicles...)

ChevLoRay · 07-19-2007, 06:03 PM

For AC plugs, I have simply gone by the numbers on the plug. If the book calls for an R45TS, an R46TS is the next hotter plug. A 44 would be one range cooler than the 45.

Back in my Mustang days, I think their numbering went by tens. Seems like I remember a BF32 as the colder version while a BF42 was the correct plug.

As in all my posts, I reserve the right to be wrong without any warning.

JimKshortstep4x4 · 07-19-2007, 07:37 PM

Reaper 71,

Here is a link to the AC spark plug information that explains the codes on the plugs including the heat ranges.

http://www.acdelco.com/parts/sparkpl...tification.jsp

Jim

LOW DOUGH · 07-19-2007, 07:57 PM

Thanks JimK, that was good info.

I put in an 85 Chevy Truck and got AC spark plug R43TS. Does anyone know what heat range the 3 indicates in the AC part number?

What would the heat range be for R41TS - R49TS, if there are such part numbers?

68gmsee · 07-19-2007, 09:23 PM

Not sure if you are asking how you can tell the difference by looking at them but theoretically the more the ceramic part sticks out of the plug the cooler it is-the gases/air cools the plug faster. The more recessed it is into the plug the hotter it is-not as much gases/air gets to the ceramic part.

68gmsee · 07-19-2007, 10:13 PM

Ooops, reread my info on plugs and I remembered it wrong. Its the recessed lenght of the insulator inside the plug that makes it hotter.

Here's a pic that explains the hot vs cold.

This is the site I got this from site:
http://www.dansmc.com/sparkplugs1.htm

Aarons72s · 07-19-2007, 09:17 PM

Jim thanks for the great link.

LOW DOUGH · 07-19-2007, 10:48 PM

More good info! Thanks 68gmsee

manimal · 07-20-2007, 12:16 AM

AC plugs suck IMO! As well as Champion. Autolite plugs are the way to go. But again thats JMO.
-Lance
If you use AUTOLITE,the parts store book will have a cross-reference in the back and it will put you in a specific heat range,then you can go up/down from there.

lbpd719 · 07-20-2007, 12:22 AM

I have had better luck with Bosch and NGK's than Autolite, Champion, or AC..

bult I will agree Champion and AC plugs tend to suck! they just dont wear the electrode efficiently..

But if you are having problems with plugs dying out, and you DON'T think it's oil related, pick up one of the Color-Tune kits. they can really tell you how "on" your setup is on the fuel side, without a whole lot of guess work. They also tell you if you are leaning out to quick and need to do some jet swaps..

A "must have" for the weekend tuner who doesnt want to invest in a gas analyzer.

LOW DOUGH · 07-20-2007, 11:52 AM

Thanks for the comments guys. Anyone with some more info?

07-19-2007, 05:51 PM	#1
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Spark Plugs Hay yall, I was hoping someone could tell me how to pick a hotter plug then what I have. I am not trying to do this. I am just curious. How do you tell if it is a hotter plug? Last edited by LOW DOUGH; 07-19-2007 at 07:39 PM.

07-19-2007, 05:56 PM	#2
rambler MOVE OVER Join Date: Jun 2002 Location: Warrensburg, MO Posts: 5,470	Re: Spark Plugs just have the parts store look it up for you, they should know by the book and the part numbers on the plug. I typically go to a hotter plug on a older engine that is using oil... (which is usually all of my vechicles...) __________________ No matter where you are..... There you are... Buckaroo Banzi

07-19-2007, 06:03 PM	#3
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: Spark Plugs For AC plugs, I have simply gone by the numbers on the plug. If the book calls for an R45TS, an R46TS is the next hotter plug. A 44 would be one range cooler than the 45. Back in my Mustang days, I think their numbering went by tens. Seems like I remember a BF32 as the colder version while a BF42 was the correct plug. As in all my posts, I reserve the right to be wrong without any warning. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

07-19-2007, 07:37 PM	#4
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Spark Plugs Reaper 71, Here is a link to the AC spark plug information that explains the codes on the plugs including the heat ranges. http://www.acdelco.com/parts/sparkpl...tification.jsp Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

07-19-2007, 07:57 PM	#5
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Spark Plugs Thanks JimK, that was good info. I put in an 85 Chevy Truck and got AC spark plug R43TS. Does anyone know what heat range the 3 indicates in the AC part number? What would the heat range be for R41TS - R49TS, if there are such part numbers?

07-19-2007, 09:23 PM	#6
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Spark Plugs Not sure if you are asking how you can tell the difference by looking at them but theoretically the more the ceramic part sticks out of the plug the cooler it is-the gases/air cools the plug faster. The more recessed it is into the plug the hotter it is-not as much gases/air gets to the ceramic part.

07-19-2007, 10:13 PM	#7
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Spark Plugs Ooops, reread my info on plugs and I remembered it wrong. Its the recessed lenght of the insulator inside the plug that makes it hotter. Here's a pic that explains the hot vs cold. This is the site I got this from site: http://www.dansmc.com/sparkplugs1.htm

07-19-2007, 09:17 PM	#8
Aarons72s Registered User Join Date: Apr 2006 Location: oklahoma Posts: 10,669	Re: Spark Plugs Jim thanks for the great link.

07-19-2007, 10:48 PM	#9
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Spark Plugs More good info! Thanks 68gmsee

07-20-2007, 12:16 AM	#10
manimal Registered User Join Date: Oct 2006 Location: Southern Kalifornia Posts: 3,066	Re: Spark Plugs AC plugs suck IMO! As well as Champion. Autolite plugs are the way to go. But again thats JMO. -Lance If you use AUTOLITE,the parts store book will have a cross-reference in the back and it will put you in a specific heat range,then you can go up/down from there. __________________ ------------------------------------------------------ -Lance 2000 Chevy C2500, 5.7, 4L80e 1999 Suburban K2500, 7.4, 4L80e 1980 Camaro..son's car...PROJECT

07-20-2007, 12:22 AM	#11
lbpd719 Zappaphile! Join Date: Apr 2007 Location: Los Banos, California Posts: 228	Re: Spark Plugs I have had better luck with Bosch and NGK's than Autolite, Champion, or AC.. bult I will agree Champion and AC plugs tend to suck! they just dont wear the electrode efficiently.. But if you are having problems with plugs dying out, and you DON'T think it's oil related, pick up one of the Color-Tune kits. they can really tell you how "on" your setup is on the fuel side, without a whole lot of guess work. They also tell you if you are leaning out to quick and need to do some jet swaps.. A "must have" for the weekend tuner who doesnt want to invest in a gas analyzer. __________________ 1969 C20 LWB Camper Special - The Beater.. 1998 Cheyenne V6 - 4/6 Drop - For The Son Last edited by lbpd719; 07-20-2007 at 12:25 AM.

07-20-2007, 11:52 AM	#12
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Spark Plugs Thanks for the comments guys. Anyone with some more info?

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