Need opinions on plugs.

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Need opinions on plugs.

Post  70FB on Sat 20 Aug - 3:20

A429 headed 522. 13:6:1. 730 lift. 733 on dyno at 38 with 114 at 6800.
It's went 6.02 this year in bad air.... 3300da and bad humidity.
I've been running a 100 shot delayed on a leash board .08-1.2 delay off the line for 5.90 class.
Plugs have looked good and we brought 2* back in based off the plugs and mph.
Changed plugs every run. Towed to lanes,etc.

i ran a 6.0 class on motor with 38* back in it two weeks ago.
Question is.... Why are #3 and#7 rusted looking??
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Re: Need opinions on plugs.

Post  70FB on Sat 20 Aug - 3:24

6.0 class was all motor on 114 with 38. Then the car sat for two weeks. Compression check tomorrow.
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Re: Need opinions on plugs.

Post  BBFTorino on Sat 20 Aug - 4:41

Rust means there is moisture somewhere.
Compression check and pressurized coolant system check.

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Re: Need opinions on plugs.

Post  DaveMcLain on Sat 20 Aug - 7:42

Some fuels can cause stuff like that to rust VERY quickly if there is any moisture. That moisture can come from the air itself if the engine sat for a couple of weeks.


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Re: Need opinions on plugs.

Post  70FB on Sat 20 Aug - 9:23

Last it ran was on the 13th after a race. I had 112 in it at the time. Cranking compression last night all came in between 249-255. It just strikes me odd those are the only two cylinders like that. Garage is insulated. Open headers.
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Re: Need opinions on plugs.

Post  Curt on Sat 20 Aug - 21:51

IMHO, you are running to cold of a plug for racing fuel only. They might work well with N2O, but I think a 7 would serve you much better if you're running it all motor.
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Re: Need opinions on plugs.

Post  cool40 on Sat 20 Aug - 22:11

3&7 exhaust valves were probably open wile it set. I had some issues with copper head gaskets leaking that looked like that before. Any missed coolant?
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Re: Need opinions on plugs.

Post  70FB on Sun 21 Aug - 13:44

Those are #9s. I run some index races with a 100 shot delayed 2.2 seconds and also run 6.0 index on motor. I change from 120 to 114 when I do.


Maybe 1/2" of water loss after 8- 10 passes cool40.
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Re: Need opinions on plugs.

Post  cool40 on Sun 21 Aug - 14:13

Keep an eye on them two cylinders but being on opposite banks it's not likely an issue,IMO. Even if it's putting a little water through it you can use a block sealer and fix it.
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Re: Need opinions on plugs.

Post  jbozzelle on Sun 21 Aug - 15:23

I'd check the torque on the head bolts if you're digging into it. May as well cover all the bases before you decide what is wrong.

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Re: Need opinions on plugs.

Post  70FB on Thu 25 Aug - 10:01

Thanks guys. I'm going to race it at YBN and then probably pull it before hunting season starts. Well over 350 passes. I'm sure she is getting a little tired.
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Re: Need opinions on plugs.

Post  Scott Foxwell on Thu 25 Aug - 13:55

Curt wrote:IMHO, you are running to cold of a plug for racing fuel only. They might work well with N2O, but I think a 7 would serve you much better if you're running it all motor.
X2 big time! 9's way too cold. I agree on the 7's.

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