Holy Sheet the headers are red!!!!

[justaZcarguy]

Morning.

FINALLY have redone the '74.

Was tuning 'er in the d-way last night and at a 2k sustained rev the headers will begin to glow red.

Get out the wenie sticks people, the bar-b-q is ready.

No.

Granted, the spark is "hopped up" and hotter. I figured she was "a bit" advanced in the timing and retarded the timing. If the timing gets any more retarded it's gonna be on the short bus and no change in the glow.

I had a friend tell me that this may be expected due to the triple mikuni / hot spark / thin header (compared to stock) combo....

Hmmm as I watch the dandruff fall as I scratch me head.:stupid:

I am not sure about that opinion. They do not glow at idle, just at rev.

By the way - motor is holding steady at 190 degrees.

Does not seem to be running lean as I know that this would be a key factor...

Below is a crappy pic of the headers....

Suggestions?

~Brian

[justaZcarguy]

And here's the engine...

[LanceM]

If the exhaust temps are that high I would have to say that the engine is lean, the only other thing I can think of is restriction in the exhaust system.

[Gav240z]

I tend to agree with Lance, your water temp might not rise but the internal workings of your engine could well be higher than that. I've never seen glowing exhaust systems on a NA car only on a turbo.

You can quickly check your spark plugs and let us know if they look grey, brown or black that would help. but you probably already know this.

[Gav240z]

Had a second read of your post, the headers are unusual are they coated in HPC coatings? Maybe try another header they look slightly(How do you say on the polite side) cheap?

They do seam unusually thin for what purpose I don't know.

[justaZcarguy]

Hey Gav - Morning all,

I have no idea aout the quality of header - this engine was built by some guy in Texas for a friend of mine that I bought the car from...

According to the previous owner, he dumped a ton of $ into it, and it would be weird to do all the high dollor stuff to this engine that has been done and then put cheap headers on it, but these things can happen.

However, the glow is gone, I adjusted the pilot screws on the Mikunis and this helped. It's the only screw that i have been afraid to mess with in the past. Trying to find d tuning guisde on these Mikunis is like trying to find a needle in a haystack... I ahev noticed that after they sit for a bit (over three months) with out being ran, they get a bit pissy and need to be tweaked here and there.

So, after the "adjusting" which was mostly guesswork :stupid: , which consisted of adjusting the pilot screw a few turns, the glowing disappeared with the exception of number 6, and looking at the brake booster vac line I found a hole, after patching it, number 6 cooled down also. Vacumn leaks make it run lean Brian, duh.

So the good event to all of this is that I learned a bit more about the Mikunis.

Too bad it still runs like crap about 3k plus under demand... I'm sure that's a pilot screw / timing / pump nozzle issue...

That's next, but first I gotta clean the garage...yuk!

If anybody out there needs the specs of the Mikunis (44 PHH), lemme know, I did find some info on them if it can help anyone out...

Have a great Sunday!

~Brian

[Chino 240Z]

Did you say the engine was new to you and you just installed it? I have seen new headers get cherry red hot when they are first fired up. After they go through a couple heat cycles they don't seen to glow like that any more. Breaking in new headers seem scarey. I was standing next to a guys car while he broke in the headers and the heat burned the plastic clutch line and release the clutch and the car jumped foward with the throttle about 2500rpms and stalled at 15 ft. out! Lucky no one was infront of the car. That's on of my rules when someone has a hood up and firing it up, I always stand to the side, and also out of line of the fan, just incase the fan decides to let go and the blades take flight!

Well hope the headers are cooled down some. You can have your headers coated at Jet Hot Coatings. They will coat them for a couple hundred, and they look nice too, rust and all! Headers in my Formula Firebird have been coated and you won't believe hot much cooler they run and how fast they cool off sooner so you can work near them faster. The stuff really works! Next time the Z headers are off they are goin in too!