Thread: Red HOT Headers - Literally

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Engine:
350 Chevy bored 30
B&M Cam designed for the 144 Blower that is on the engine
Hydraulic lifters
750 manifold referenced Holley

I recently had problems with my engine, per this thread. I replaced my lifters, and 2 bent push rods, 2 broken rocker studs, and 1 pushed through rocker arm - for a total of 5 valves that weren't working (engine still ran though

With that all happening, I did have some backfires through the carb, so I replaced the power valve on it as well.

Now that it is together, it is running Great!

However, both headers (Sanderson block huggers) are literally red hot in the center, where all 4 tubes gather. I had this in the past and came to a conclusion on something, and I seemed to fix it.

But I don't know why it would be back now.

I'm not offering what I had done, as I'm interested in what you folks here think, without my planting any ideas. If what I had done in the past was it, I wouldn't think I would have it now.

What do you think?

Appreciate your thoughts.

how many pounds of boost are you running and how big is your jets? it sounds like the motor is running lean.

It's either real lean or the timing is retarded.

I thought this was interesting...

http://www.users.qwest.net/~j5/sande...er_problem.htm

I thought this was interesting...

That IS an interesting article.

I too think I am lean, and thought so last time as well. After that article, I'm left wondering if the headers are the problem, and not a lean condition.

On the other hand, I think it is probably lean. Although, I'm not sure why, after doing the work on the engine, it is all of a sudden lean. The engine is running very smooth, so I doubt I ended up with a vacuum leak under the manifold or around the blower.

Currently my jets are stock. I have some larger ones, and will put them in today and see if that helps.

I've had times I'd like to have one of those laser temp guns (per the link). I may break down and get one.

Interestingly, the last time they were red, I had called Sanderson, and they told me the same thing: too rich. Everyone else told me too lean.

With regard to the question of boost: When I am WOT, it is 7#. But, at idle, while I watch the red hot headers, it of course is not pushing boost, and is running at just barely over 10" vacuum.

Timing is set at 10 degrees advanced.

If they are red down by the collectors, it could be rich. Red right from the heads means lean. Can you uncork them and see what kind of plume they make?

That's interesting. They are red at teh collector, not at the heads.

I could uncork them. but that is a pretty big pain. As well, the exhaust pipe they collect into pretty much stays in place, so seeing the plume would be an effort, for sure.

I wonder if it is possible to take it to a shop of some kind and have something shuffed up the tailpipe (that brings an unpleasant visual)...and get readings on lean vs. rich.

It is pretty easy to change the jets. I could do that, and if it doesn't fix it, maybe that tells me something.

BTW...I have a 45 powervalve in the carb. My vacuum, currently, is at just over 10. According to Holley's specs on lower vacuum, I should divide my vacuum by 2, and shoot for that. So, my opening hg should be 5, and the 45 is 4.5. They don't make a 50 powervalve, but I did see a 55.

Do you think there would be any value to getting an instrument to measure the temp at the header?

Interested in comments on my several thoughts above.

Thanks for your input, everyone!

I can tell you from experience with that blower if there is any? then go rich first. 750 carb, 7 lbs. of boost and stock jets sounds lean to me. with the same boost, same carb. it took me 90 jets in the front and no jets in the rear to get through the 1/4 mi. (without burning a hole in a piston or blowing a head gasket) and that was shifting at 5500 rpm.

Thanks. I'll put the larger ones in. I need to see what size they are, I don't remember.

I've been fussing with getting the lean vs. rich setting on my carb. It had been running rich in the past. But, I think I am definitely lean.

I'll post back how that comes out.

I'll still be watching here today for more comments.

BTW, lt1s10, have you experienced the red hot headers when you ran lean?

Of course, based on R Pope's posting, I could be rich.

If I could get a reading from a shop, I'd feel better.

[EDIT]
I just called Holley and spoke to their tech dept. They think it is rich. They gave same symptoms for red hot that R Pope did. They suggested advancing my timing. I'm going to check out the timing. and I'm going go change the jets to larger, and see if either of those fix the problem. If not, I may try to figure out how to lean it up and see what happens. Not sure how to do that, other than going to smaller jets.

By the way, another tidbit of info: my engine is tending to run a little hotter. I think that also points to lean. (Gee, there should be and easy way to tell.) Oh plugs...brand new, and maybe 13 miles on them...they are white on half of the porcelain, and med brown on the other half.

the red hot header pipes ive seen was on cars with c. converters. if the car ran rich the gas would collect at the inlet of the conv. and burn the excess fuel up. a lot of the ford cars header pipes would run red hot at the conv. and catch the grass on fire. with open headers ive never seen them get red at the collector, but if you get enough gas in there i guess it could. i belive it would show up as a rich exhaust first. i had a lot of them run red at the or just off of the head from being lean. i ran blowers on the st. every day for 15 yrs and one thing i learned is you're better off rich than lean. if i was gonna do it again id look into the o2 sensor that you can put into the exhaust pipe with a light inside the car that will tell you if you are lean or not, if that works sure would have saved me a lot of money, you said you didnt have but 10 in. vac. thats not enough. do you have power brakes?

Yes, I have 4 wheel disks, and power. I have an electric vacuum pump for them that puts out 18" vacuum. Darned thing is loud.

I just edited my post above. Not sure you saw that. Take a look at the [EDIT] section at the bottom. Even edited it, re: plug coloring.

what kind of cam are you running. the vac. on you blower motor should be the same as on any motor. i ran 6-71 blowers and power brakes with 16 in. of vac. should not need a cam that big for a blower. you can do what you want on the jets, but i cant believe holly is telling you to down jet a blown motor with a 750 carb. stock jets. the first blower i had was a 4-71, 6 lb. boost, blower cam, 7 1/2 to 1 comp. 750 holly 72 jets in the front and like 80 in the rear. trying to drive it on the st and drag race it i burnt holes in pistons or blew head gaskets 20 times before i got it right. right was 90 jets in the front and no jets in the rear. i started off doing what somebody that was suppose to know told me.

My cam is a B&M cam that was recommended to use with this blower in teh 1999 timeframe. Specs:

Lift: Intake 488 Exhaust 510
Advertised Duration: Intake 282 Exhaust: 292

I have stock jets in it now, which I estimate to be 85s in front and 74s in the back. I'm estimating that based on a set I have in front of me now, which are 87 and 76. I had tried to jet it up in the past, and I seem to think that I went up 2.

Interesting that you mention no jets in the back. I've never heard of that concept. Of course, I haven't been around a race track for years.

So, I'm going to put in the 87s in the front, and see what happens.

I'm waiting on new aluminum collector gaskets to come into the auto parts this morning. I had one blow out on the right side. As soon as I get that in, I'm going to experiment with advancing the timing more, and the jets.

talking about red headers the first predator carb. i ran i didn't know they want made for the st.(at the time they didn't have a st. carb.) so i bolted it on a 350 4-71 blown motor and took off up the st. run good, so i came on back to the shop and raised the hood and like to have fell out. the headers was so hot they was yellow, im talking top to bottom, you could see through them, I knew I had cooked the motor, so I called predator and they told me there was no idle circuit and would run lean if you drove it on the St. didn't hurt the motor though.

Originally posted by ewingr
My cam is a B&M cam that was recommended to use with this blower in teh 1999 timeframe. Specs:

Lift: Intake 488 Exhaust 510
Advertised Duration: Intake 282 Exhaust: 292

I have stock jets in it now, which I estimate to be 85s in front and 74s in the back. I'm estimating that based on a set I have in front of me now, which are 87 and 76. I had tried to jet it up in the past, and I seem to think that I went up 2.

Interesting that you mention no jets in the back. I've never heard of that concept. Of course, I haven't been around a race track for years.

So, I'm going to put in the 87s in the front, and see what happens.

I'm waiting on new aluminum collector gaskets to come into the auto parts this morning. I had one blow out on the right side. As soon as I get that in, I'm going to experiment with advancing the timing more, and the jets.

no jets in the rear is about the same as putting the biggest jets you can buy in. just save the price of he jets. i think 92's are the biggest.