Ok. This is ongoing. I have a friend that has an Atkins supercharger on a 4 port 13B. The rotating assy is GSL-SE as are the rotor housings. The steels are 12A. The porting is very aggressive street. The car is running stock distributor and a Holley 650 or something around that.
Here's the problem:
The headers are glowing right around the bend. The Headers are RB chrome (maybe ceramic) plated. You can see a glow in the bend about 5 in from the exhaust ports if the shop is dark. He has installed an Autometer AFR gauge, and it shows the mixture to be OK (as far as you can tell w/o being wideband. It's 4 lights into rich) We've tried base timing at idle and 5500RPM timing to get past the advance. Nothing seems to work. The headers are still glowing. Does anyone else notice their headers glowing? Is this common? Can anyone recommend a timing procedure and give us some numbers? We even took the s/charger and carb off, and installed my other friends Dellorto, and the headers looked the same. Atkins told us that headers are supposed to glow. WTF???
The steel sleves were knocked out of the exhaust ports by the guy that did the porting. Could this have anything to do with it? I was also wondering if the exhaust ports could have been ported too far DOWN. Any ideas on that? Here is a link to another post I made in regards to this problem.
https://www.rx7club.com/forum/showth...s+supercharger
Any help would be really nice, as atkins isn't really going out of their way to support their product, and he wants his car to be in Nashville next month at the gathering. Thanks guys.
Don.

 

GSL-SE is 9.4:1, so your friend should be using 92 octane. If the headers still glowed with a Dellorto, then it's not the SC that's at fault. What did the AF guage say about the Dellorto? Maybe the exhaust ports really do open too early. By the way, how did you mark the new pulley? Did you carefully rotate the engine to TDC with the old one, then replace it with the new one without turning the engine at all and mark it with paint or something? Have you needed to retard your timing at idle just so it wouldn't end up advancing too much above 4000RPM? How old is the SC kit?

 

Oh, ok I just went through that other thread. My friend and I just installed a 7" SC on his GSL-SE engine and the main drive pulley has two sets of holes. One set is for pre '85 (that's what we're using) and the other is for '86+ I would guess. It looked like one set was spaced further apart than the other. We didn't have any '86+ parts to compare it to. Anyway, that's why I asked how old your SC is. Atkins recently hired a new machinist who is really paying attention to the little details that Camden originally glossed over. One of the differences is the Holley carb that they're using. It now comes jetted for the SC (or at least my friend's did). He also already has an AF guage that should show how close to stoich the mixture is. He needs a throttle cable bracket and air filter, but it should be running really soon.

 

Jeff,
My main concern is timing. The blobs of paint that are on the pulley are probably 3-4 degrees. We've centered those up as good as possible. Unfortunately the engine didn't come with a SE pulley. The guy ported and built it and slapped on the newer pulley. The car has been driven down the street gently (as you can no full throttle and below 5k RPM, and it feels very strong. Everything still looked the same with the dellorto on it. I'm starting to think the ports were cut too low or the missing steel inserts may be part of the problem. Good luck with your project, too.
Don.

 

Hey, thanks!

My friend and I finished a 5" SC on his 1st gen last year. It used an Edelbrock right out of the box. The entire kit is the old style that Camden out of Texas was selling (aside form the carb) for the last 10 years or so. We had to do quite a few custom things to get it to work on his 4 port 13B. He used '86 NA rotors cut for 3mm apex seals, (has to use 92 octane), ported 12A side 'plates', ported '74 rotor housings, retarded the timing 10º during SC break-in, then adjusted it to 5º retarded and it's been that way ever since. With locked advance, we could probably advance the timing to maybe 5º or 10º at idle, and it would stay that way to max RPM (around 6500-7k on a 5" SC). It has enough power to break 'em loose on dry asphalt in gear with two adults together weighing in at around 300LBS+ in the car at 10º retarded.

We never noticed if his header glowed or not. Personally, I'd say after you've exhuasted all pulley information, to just drive on it for a while. As for me, I'm currently asking about pullies in a different thread because I'd like to know the difference too:

https://www.rx7club.com/forum/showth...92#post1018592

 

out of curiosity, how's the driveability and top end power. Also the torque, does it dive down at high rpm? I really considering this for an RX3

 

I wish I could tell you. We've only cruised it down the street and back being very gentle.
Don.

 

My n/a GSL-SE headers will glow sometimes. I wouldn't be too concerned with it unless it is at idle. When my car had injector problems and ran very lean the headers glowed at idle.

 

They glow slightly at idle. I don't exactly know what they do at cruise... it's hard to run beside the car with the hood up We had a Peripheral that would glow slightly at idle. The AFR gauge is showing a little rich, but it's not wideband. It was installed just to give us an idea.
Don.

 

I thought headers were saposed to glow.

Metal+extreme heat=GLOW

you look at the exhaust on any car that has been running for 20 mins it will glow. Now I would think headers would glow more consitering they are higher flow and lighter and not as thick as a cast iron exhaust manifold. I think you are worrying to much. With a SC I would think there would be even more glow because

more air + more fuel = MORE HEAT also more power.

The more power an engine has the more heat it generates and a large portion of that heat is expelled through the exhaust. Point stated I will now step down from my seminar podium.

 

don't trip protlewski.

my headers don't glow after 20 mins of running....hell not even after 20 mins of driving. they do when i'm rollin down the interstate around 135mph and i get out to look, and then it's only a faint glow.

 

ok well I may have exagerated alot but still I made my point. Metal glows when it is hot end of story.

 

I understand that. The point is.. how hot is too hot? The only other headers I've seen glow like this were on a peripheral port, and it had a mad idle with lots of unburned fuel and air dumping into the exhaust. This car idles solid. I guess we'll have to wait for the EGT gauge.
Don.

 

Then you'll need to protect your investment by rigging up some exhaust heat shields.