Detonation Sucks
09-13-2008, 11:33 AM
#42
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The autolite AR 3910 is what I would use. It is a nascar style plug with a cut back ground srap that is a little stronger, so they will take 2 runs to really show the heat, I would start off with the #8 ngk plug because it will show heat after one run alot better, but once you know your tuneup is good then go to the autolite plug, they don't seem to foul as bad, the tips aren't protruded, that type of thing.
I don't know what ya have for compression, but I look at it like this:
11 to 1 or over n/a #6
11 to 1 with 100 shot #7
11 to 1 with 200 shot #8
11 to 1 with 300+ #9
once you get to 13 to 1, I'd go to a #7 n/a, and for 100 shot a #8, 200 a #9, etc.etc.
Personally, I'm on a 13.5 to 1 compression motor, and am running a 150 shot, I run a #9 plug. I'm gonna start playing with the jetting a little, therefore I got some #10 plugs for a little added safety net.
Each heat range you go down lowers the combustion chamber temps by about 100 degrees (rough rule of thumb) so that may be enough to save you from some damage. Noone ever hurt anything from running too cold a plug, ya just foul them out easier.
I gap everything at 35, gap them too tight and the car gets a little harder to start and whatnot, plus this is a way to be consistant to see what just the plug change does.
I dunno about running different plugs in different heads, I'm running ET heads and am running the AR 3933 normally, and have some AR 3932's to go to for my next outing/testing session.
I don't know what ya have for compression, but I look at it like this:
11 to 1 or over n/a #6
11 to 1 with 100 shot #7
11 to 1 with 200 shot #8
11 to 1 with 300+ #9
once you get to 13 to 1, I'd go to a #7 n/a, and for 100 shot a #8, 200 a #9, etc.etc.
Personally, I'm on a 13.5 to 1 compression motor, and am running a 150 shot, I run a #9 plug. I'm gonna start playing with the jetting a little, therefore I got some #10 plugs for a little added safety net.
Each heat range you go down lowers the combustion chamber temps by about 100 degrees (rough rule of thumb) so that may be enough to save you from some damage. Noone ever hurt anything from running too cold a plug, ya just foul them out easier.
I gap everything at 35, gap them too tight and the car gets a little harder to start and whatnot, plus this is a way to be consistant to see what just the plug change does.
I dunno about running different plugs in different heads, I'm running ET heads and am running the AR 3933 normally, and have some AR 3932's to go to for my next outing/testing session.
09-13-2008, 12:22 PM
#43
What is the general feeling on a plug being colder but projected?
It would be nice to change the stickie to include a breakdown of plugs by temp and all the part numbers for projected and non projected. It appears some part numbers are missing? This is a good thread. To think I almost didnt start it. Thanks to all that participated!
09-13-2008, 12:54 PM
#44
I'd try to stock with non projected tips, being that the electrode is much closer to the head there's alot less of a chance of the glow plug effect, regardless of te plug's temp rating.
Autolite my friends.... non projected and the ground strap is cut back some already on top of it. They don't melt, and are available in the cold heat ranges we need to be running.
Autolite my friends.... non projected and the ground strap is cut back some already on top of it. They don't melt, and are available in the cold heat ranges we need to be running.
09-13-2008, 01:01 PM
#45
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I'd try to stock with non projected tips, being that the electrode is much closer to the head there's alot less of a chance of the glow plug effect, regardless of te plug's temp rating.
Autolite my friends.... non projected and the ground strap is cut back some already on top of it. They don't melt, and are available in the cold heat ranges we need to be running.
Autolite my friends.... non projected and the ground strap is cut back some already on top of it. They don't melt, and are available in the cold heat ranges we need to be running.
are they the same part numbers that are in the stickies? if not can you post up some part numbers with the heat ranges?
09-13-2008, 01:23 PM
#46
Autolite AR 3934 #8 heat range
Autolite AR 3933 #9 heat range
Autolite AR3932 #10 heat range.
Guys with street cars will complain that the #8 idles rough and starts a little harder then they're used to with the hotter plugs, but with these the chances of a plug turning inot a torch are alot less.
I run the 3933 with a 150 shot, but have some 3932's for the next outing
Please keep in mind I"m running alot more compression then the average guy on here with 13.5 to 1.
Autolite AR 3933 #9 heat range
Autolite AR3932 #10 heat range.
Guys with street cars will complain that the #8 idles rough and starts a little harder then they're used to with the hotter plugs, but with these the chances of a plug turning inot a torch are alot less.
I run the 3933 with a 150 shot, but have some 3932's for the next outing
Please keep in mind I"m running alot more compression then the average guy on here with 13.5 to 1.
09-13-2008, 01:57 PM
#47
Well, I just bought a set of these for the 175 shot. I hope its good to go!
MFG Recommendations: approx 11:1 compression
Heat Range: 8
Gap: Consult ignition mfg.
Plug: NGK R5672A-8 (stock number 7173)
I also bought a set of these as well incase the car does not like the #8's
Nitrous (two steps colder)
Heat Range: 7
Gap: Consult
Plug: NGK BR7EF (stock number 3346)
But, from the info above, it says one has a reach of .75 (3/4") and the other is .70. Does this make any difference?
MFG Recommendations: approx 11:1 compression
Heat Range: 8
Gap: Consult ignition mfg.
Plug: NGK R5672A-8 (stock number 7173)
I also bought a set of these as well incase the car does not like the #8's
Nitrous (two steps colder)
Heat Range: 7
Gap: Consult
Plug: NGK BR7EF (stock number 3346)
But, from the info above, it says one has a reach of .75 (3/4") and the other is .70. Does this make any difference?
09-13-2008, 02:42 PM
#48
I'd try to stock with non projected tips, being that the electrode is much closer to the head there's alot less of a chance of the glow plug effect, regardless of te plug's temp rating.
Autolite my friends.... non projected and the ground strap is cut back some already on top of it. They don't melt, and are available in the cold heat ranges we need to be running.
Autolite my friends.... non projected and the ground strap is cut back some already on top of it. They don't melt, and are available in the cold heat ranges we need to be running.
If you melt an NGK there is a 50/50 shot you might be OK.
NGK's are much easier to read also......I run NGK's FWIW.
09-13-2008, 03:48 PM
#50
But, once you have your tuneup set the autolite plug IMO is a better way to go.
I just got a bunch of #10 plugs today, 4 sets of autolites and 2 sets of NGK's, NGK will get the first couple runs.
09-13-2008, 05:47 PM
#51
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from what i have noticed the plug chart for the ngk-8 r5672a 7173 is a projected tip plug ,the plug you need is a ngk-8 b8efs 1049 it has a non projected tip but it is also a non resistor we hit a couple of cars with 300 shots with c16 in a stand alone and never had any problems
09-13-2008, 08:15 PM
#56
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Really? I've been running the gasket ones, one of my spark plug holes has a helicoil in it, so my machine shop guy told me I had to run a gasket style in there and he said it was ok to run them in the others so I didn't have to buy seperate plugs, is there any problem with running them in the stock casting heads?
09-13-2008, 08:43 PM
#58
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Really? I've been running the gasket ones, one of my spark plug holes has a helicoil in it, so my machine shop guy told me I had to run a gasket style in there and he said it was ok to run them in the others so I didn't have to buy seperate plugs, is there any problem with running them in the stock casting heads?
