88 na exhuast glowing red on new rebuild
 

well guys i didnt do this rebuild...now the car will start with some 2 cycle oil and it will run around 2k but the exhust wil start to glow red after 2 mins runnig .. the engine does not over heat or anything...its a fresh rebuild and has zero hours of running time...whats causing this ....i have done few rebuilds myself and never had this happen to me...thanks for the help guys

Usually a glowing exhaust on a rotary is a rich mixture. Are you using the stock ECU?
If you are idling at 2k with a rich mixture you are going to get a red exhaust. It could be a number of issue. Did you have your injectors professionaly cleaned? Are you sure the timing is correct?

Brian

Is the CAS stabbed correctly? Extremely retarded timing will cause the exhaust to glow.

What about clogged exhaust components? pre-cats,cats,etc. I assume its glowing at the manifold...?

isn't it a lean mixture that burns hotter and produces hotter exhaust temps and a rich mixture will cool the exhaust down. with a rich mixture you don't do a complete burn and gas will enter the exhaust. with a lean mixture it does a full burn and the temps rise. and yes aaron cake is right if the timing is extremly retarded it sparks so late that your have the combustion come out the exhaust ports.

also what part of the exhaust is glowing??

is it just the exhaust mani or does it go on farther??

Well glowing exhaust could be many things. Check your timing first, its probably a fuel issue creating the glowing exhaust..remember rotaries do produce higher EGTs than piston motors.

In rotaries, a rich condition will allow unburned fuel to enter the manifold/header and burn causing the red glow. It basically makes a flame thrower.

Brian

**rx7tuner**

off topic. is that racing beat exhaust in your sig??
if so how did you get it to hang so nice?? mines all low and cocked weird.

Timing is off.

If you switched front hubs/pullies on your rebuild then the marks can be off as a result...you must always keep the hub (the metal chunk that is held onto the eshaft by the big bolt on the front) and the pulley with the timing marks, together. Even though other pullies will bolt onto your hub, the timing marks can then be off, due to the way mazda referenced/drilled the pullies and then made the marks.

I recommend finding true TDC and making your own timing mark, and then resetting it if this is the case.

It is an older version of Racing beats exhaust. It has a presilencer for each tube. The newer version tends to ride lower and has one large presilencer that keeps each runner seperate.

You could try buying different sizer rubber hangers. Play with the differente sizes in different locations to get it to sit better. Is it possible you have a bent header?

Brian

For the OP-
FWIW - Mine glowed due to clogged pre/main cats (97k on a 1990 S5 TII). Popped on RB downpipe and presilencer- no more glowing. Kind of a scary moment as the grease on the new parts burned off/white smoke the first run, but since it's been nothing but good times.
steve

13b
 

thanks for the help guys...i will have to do some timing work on the car...just for everybody els info the car has no cats...and the exhust mainfold was where it was glowing red...