Hot hot hot too hot

[Tinman22]

Has anybody ever had any experience with very hot exhaust temps .i.e 2000 plus 4 in. Out 800+/- 6 in. Out these are measurements out from the header flange at 2000 rpm. Ignition is set at 10* with 34* total all in by 2100 rpm with an msd 6t box and a Holley 750 with 68 mains they were 72s . The 72s blew a hole in no. 7 tube (it has the tightest radius) 68s run a bit cooler. And no it's not running lean! Mixture screws out 3/4 of a turn good idle 600 or so. no pops ,misses, stumbles, just really hot exhaust! 6.5 power valve hmmmm.

 

[csuengr]

The mixture screws only control mixture at idle. At 2000 rpm, the idle circuit is out of the picture. So you could be running lean. Anyway, I think your temperature measurements are all wet. At 2000*, something would be cherry red and/or melting. The highest temps I have personally seen were on a diesel, at those were 1600*+.

 

[Tinman22]

Yeah hot 2037 to be exact that was the part where it blew a hole in my new supercomp headers! Correct on the mixture screws but 580 degrees at idle (on the screws) is also high

 

[Tinman22]

And yes very red and net looking says my 13 year old daughter

 

[csuengr]

Enrich the mixture and see what happens.

 

[Tinman22]

Ok just took screws out too 1.5 and put 72s back in it got hotter quicker but I did see something else , a spark . Turned off the lights and wow what a neet display of lightning! Around every plug boot ,every cap boot and any where the wires meet anything ! Grabbed the timing light hooked it up and it still looks like good clean spark? Wires are new and not solid core guess i need better wires huh. I wonder if this has anything too do with it? Think I'm going to rewire back to duraspark and see what happens.

 

[csuengr]

Your plug wires are shot. You are probably getting weak spark at the plug and are burning leftover gas in the headers.

 

[Tinman22]

I think you might be right. I'll go change wires back in a 10 min

 

[Tinman22]

Ok took off new wires and put on new new wires then got smoked by the msd box itself !!!! Started jeep same..test light to box.. light on...bad !! Going out and swapping 6t for 6al and put boots on this time! Back in 20.

 

[Tinman22]

Wires test at 260-320 ohms per foot,old set and new set. (belden wires from napa) old set of a accell wires 90-170 per foot put them on same results. Swapped 6t box for 6al box. Wife reminded me that it was midnight and the neighbors probably don't care if the jeep is running right or not guess well find out tomorrow.

 

[Les]

Wires test at 260-320 ohms per foot,old set and new set. (belden wires from napa) old set of a accell wires 90-170 per foot put them on same results. Swapped 6t box for 6al box. Wife reminded me that it was midnight and the neighbors probably don't care if the jeep is running right or not guess well find out tomorrow.

You could always leave the jeep running late into the night, and test to see just how hot the neighbors can get as well.....

Good luck!....

 

[Tinman22]

6t box same result ....called msd ....discharge from wiring is normal electrical aura ...exhaust heat is caused by weak spark at plugs and msd box shorting itself out are both caused by insufficient ground needs to be direct to batt. O.k. I'll try it when I get home.

 

[Tinman22]

Sorry les didn't see your post funny ..neighbor has a pretty hot 55 Chevy he's been working on for 10 years.. I think I'm gaining on him lol.
Anyway new msd box , first set of wires , 8* on dizzy dialed 32 total and viola !!! 600* at 1800 rpm and 350 at idle! at last a 440 that's not a hot air popcorn popper too!! As for the msd 6t ? My father in law says "free stuff costs too much" good thing I paid 20 bucks for the 6al!!!

 

[csuengr]

Hot air popper? I was thinking more of a killer burrito warmer.

 

[73CJ]

The old 70s Artic Cat Wankel 303 header glowed cherry red for 10". . . .

 

[Tinman22]

He said wankle.