hotter spark plugs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**kidatheart** · 11-26-2019, 08:36 PM

I am wanting to put a hotter plug in a 76 farm truck-never gets warmed up to really clean up the plugs. It calls for an AC Delco R44T. I can't locate any R45T locally, but have found some R45TS. The are about 1/8" longer from the tapered seat to the tip. Can anyone tell me it these will work without hitting the piston, or should I just order the R45T and wait? Thank you.

SunSoaked · 11-26-2019, 11:00 PM

I'm not sure that engine temp correlates to the spark plug heat range. The heat index refers to the insulators ability to pull heat out of the plug itself. Unless you've altered the factory compression ratio, I don't know why you would want a hotter plug?

Dead Parrot · 11-27-2019, 12:03 AM

Guessing the OP is having a carbon problem since the average farm trail doesn't encourage speed driving. Hotter plug might help some. Leaning the idle mix a bit might help also. Plus leaning the choke as much as possible and still get a good cold start. Bumping the initial timing might help as well.

To OP: what motor?

**kidatheart** · 11-27-2019, 10:55 PM

Quote:

Originally Posted by Dead Parrot

Guessing the OP is having a carbon problem since the average farm trail doesn't encourage speed driving. Hotter plug might help some. Leaning the idle mix a bit might help also. Plus leaning the choke as much as possible and still get a good cold start. Bumping the initial timing might help as well.

To OP: what motor?

It is a 350 with a quadrajet. You are correct about the low speed driving. The truck gets up to operating temperature just fine, but a lot of putting around and idling. The plugs aren't clean-burning, like they might be if I was running the highway some. It has always been my understanding that a hotter plug might help with that-fire through the "crud".

geezer#99 · 11-27-2019, 11:01 PM

Give it the 6 ounce tune up!
Dribble some water into the carb at high idle and it’ll clean those plugs off pronto!

Loco83 · 11-27-2019, 11:59 PM

My 83 came with R45TS plugs in the 305 with no problems

**Getter-Done** · 11-28-2019, 12:28 AM

Auto-Lite plugs are a good brand for your
application.
They work well in a (Also an oil burner) truck
that does not see the Hi-way often.
I have had Great luck with this.

.

**kidatheart** · 11-28-2019, 11:19 AM

Thanks for all of the thoughts and suggestions! Doug

11-26-2019, 08:36 PM	#1
kidatheart Senior Member Join Date: May 2012 Location: Assaria, Ks Posts: 465	hotter spark plugs I am wanting to put a hotter plug in a 76 farm truck-never gets warmed up to really clean up the plugs. It calls for an AC Delco R44T. I can't locate any R45T locally, but have found some R45TS. The are about 1/8" longer from the tapered seat to the tip. Can anyone tell me it these will work without hitting the piston, or should I just order the R45T and wait? Thank you. Last edited by kidatheart; 11-26-2019 at 09:09 PM.

11-26-2019, 11:00 PM	#2
SunSoaked Registered User Join Date: Dec 2011 Location: Yuma Arizona Posts: 1,525	Re: hotter spark plugs I'm not sure that engine temp correlates to the spark plug heat range. The heat index refers to the insulators ability to pull heat out of the plug itself. Unless you've altered the factory compression ratio, I don't know why you would want a hotter plug?

11-27-2019, 12:03 AM	#3
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,627	Re: hotter spark plugs Guessing the OP is having a carbon problem since the average farm trail doesn't encourage speed driving. Hotter plug might help some. Leaning the idle mix a bit might help also. Plus leaning the choke as much as possible and still get a good cold start. Bumping the initial timing might help as well. To OP: what motor?

11-27-2019, 11:01 PM	#5
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,749	Re: hotter spark plugs Give it the 6 ounce tune up! Dribble some water into the carb at high idle and it’ll clean those plugs off pronto!

11-27-2019, 11:59 PM	#6
Loco83 Registered User Join Date: Nov 2018 Location: Cali Posts: 324	Re: hotter spark plugs My 83 came with R45TS plugs in the 305 with no problems

11-28-2019, 12:28 AM	#7
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 8,448	Re: hotter spark plugs Auto-Lite plugs are a good brand for your application. They work well in a (Also an oil burner) truck that does not see the Hi-way often. I have had Great luck with this. . __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build

11-28-2019, 11:19 AM	#8
kidatheart Senior Member Join Date: May 2012 Location: Assaria, Ks Posts: 465	Re: hotter spark plugs Thanks for all of the thoughts and suggestions! Doug



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