New Chrome Pipes but #8 is turning blue

[Scott Dallas]

Sorry to bother you guys with what is probably an old question but I have a 350 with a tunnel with newly installed Holley 390's. At the same time a new set of headers from TP were coated on the inside with some Blue Shield from a custom Harley shop. Well, the driver side bank headers seems to be holding up well with only a light shade of yellow. But the shotgun side back one is turning a very deep blue and the ones next to it are a gold. Header bolts are tight. Could the back carb be not feeding enough gas. Just need a little help to keep from screwing up something else while I am trying to fix this. Got this from Michigan and having the time of my old life. The Harley just sits and my '64 Elky only gets out every so often.
Probably an ole story but when I brought the T home and opened the garage I swore the Elky whispered " that better be a new lawnmower"
Thanks in advance guys

Scott Dallas

 

[kcfatdawg]

I might be wrong but I think it's running lean on the cylinder. How late do you have the back carb coming in on your linkage? What heat range on your plugs? If you had more than 1 turning blue it could be to much timing advance. Chevy's like about 34 dergrees total. Plus you could put a little more jet in the carb for that corner. Then again they could have just screwed up the amount of plating.

 

[putz]

This is why om a fresh rebuild you should get a set of test headers. There are some on this site you just have to pay shipping when someone is done with them.

 

[Scott Dallas]

It not a fresh engine. I just decided to downsize the carbs from 450s that were on it to 390s. The engine sounds like it might have a little up-cam but certainly nothing radical. The linkage is set so the back carb comes in a little before the front. Plug looks ok on that hole. Like it was mentioned it might be weak plating on that side. They certainly weren't the most expensive out there. The old headers looked fine, just old. I might have to work on that back carb some. Gonna find a Ir. temp. gun and see if the temp readings are different on the tubes. Then again,maybe the coating I put on it didn't do what it should. Does anyone make a nice set with the Harley aftermarket concept of inner and outer tubes. On the other hand, it sure is a pretty blue. Maybe I'll paint the car blue and call it part of a master plan.
Thanks again, everyone. I'm learning a lot on this site.

Scott

 

[LumenAl]

I've looked for double wall headers like on my Harley but have not seen any... after messing around with two sets of chrome header, I just went ceramic...

 

[Scott Dallas]

Just picked up a infared temp gage and lo and whatever, 8 pipe is running hot. Bout 100 degrees. Just on a hunch, next weekend - if we have 80 degree weather in Dallas like yesterday, I think I will flush the cooling system. The gage runs cool but it pulls the temp from the front of the engine. Just maybe the back part is not getting cooled down enough. Sounds like a longshot but so were a couple of marriages. They bombed so maybe I'm due a longshot. Does this sound like a possibility if it's clogged somewhere? That gage is also cool to play with.

Scott

 

[putz]

Make sure when flushing you pull out the block plugs.

 

[tfeverfred]

Hell, I liked it when mine turned blue. Verified the fact that it was "driven".:welcome:

 

[Mike]

Try kcfatdawg's advice. Stick a bit more jet in that corner (1-2 steps) and then try your infrared gun again. There's nothing uncommon about having to stagger-jet to make up for an intake's flow characteristics.

 

[Ted Brown]

You will most likely find it lean on that cyl. no matter what happens, remember this, whenever you make a change that could make the engine run different, try and always put t he old headers back on to get all the bugs worked out, so no unwanted coloring will mess with your NEW pipes... We have inserted the next size down tubbing into the first 10 inches or so, on some new chrome headers. PS, never let them copper your headers before chrome.. That is for show chrome and will Blue instantly.

 

[T4TWO]

I've looked for double wall headers like on my Harley but have not seen any... after messing around with two sets of chrome header, I just went ceramic...

Hey LumenAl your ceramic's didn't turn color did it? I will be getting ceramic headers for my build.

 

[Nas T]

I might be wrong but I think it's running lean on the cylinder. How late do you have the back carb coming in on your linkage? What heat range on your plugs? If you had more than 1 turning blue it could be to much timing advance. Chevy's like about 34 dergrees total. Plus you could put a little more jet in the carb for that corner. Then again they could have just screwed up the amount of plating.

back two cyl. will always run hotter on a chebby, I ran water lines to the rear of my intake to take care of that problem, I am running 2400 cfm of fuel through my headers and they still turn blue, so lean is not an issue. It is just getting hot there is not much you can do except buy a supply of bluejob and keep cleaning, or run water lines to the rear of your motor. running a little rich is SO much better then running a little lean.:dummy:

 

[LumenAl]

Hey LumenAl your ceramic's didn't turn color did it? I will be getting ceramic headers for my build.

I was a little to quick to take off my break-in headers and was running to lean... they glowed red at night! So they discolored just a little... I was just to quick to get'r done! So if you are patient, they will look just as good two years from now as new!

 

[kcfatdawg]

You know Nas T your right about the heat in back of block. I forgot all about when I bored my 454 out a .100 that I drilled out the back and middle of block deck to match the type of head gaskets I'm using to keep cylinders cooled down. It was 3 years ago. slept since then.

 

[excrewchief]

Hey Guys
With out sounding like an a$$ the problem is To rich When you run to rich with the exaust scavaging pulling the raw fuel out it hasen't burned all the way causing more heat and slow burning ( ie choke for cold start ) will cause header blueing every time. On most tunnel rams they have poor fuel distribution and tend to run fat on some cyl. if your carbs set sideways instead of front to rear it is worse. alot of times you need to stager jet. some manifolds never will work right. retarded timing also will make it worse and headers glow the good thing is if you have good chrome Flitz will take the bluing off very nicely. Hope this helps ( by the way i learned this 25 years ago when building motorcycles at dealers the first fireup we would use the choke for about 10 seconds then turn off to keep this from happining good luck

 

[Screaming Metal]

Hey Guys
With out sounding like an a$$ the problem is To rich When you run to rich with the exaust scavaging pulling the raw fuel out it hasen't burned all the way causing more heat and slow burning ( ie choke for cold start ) will cause header blueing every time. On most tunnel rams they have poor fuel distribution and tend to run fat on some cyl. if your carbs set sideways instead of front to rear it is worse. alot of times you need to stager jet. some manifolds never will work right. retarded timing also will make it worse and headers glow the good thing is if you have good chrome Flitz will take the bluing off very nicely. Hope this helps ( by the way i learned this 25 years ago when building motorcycles at dealers the first fireup we would use the choke for about 10 seconds then turn off to keep this from happining good luck

You Da Man!!!!!!!! PSSSTTTTTT.......I think this guy knows his stuff.....carbs sitting sideways have a tendency to screw up.....just the way fuel sloshes, etc. Hey want to keep your headers from turning blue?????????? Get a big gog of gease and smear on inside each header tube.......it'll form like a burned glaze on the inside and act like a insulator......used to work in the old days......don't know about this crap now........worked great on zoomies and drag bikes......