Well I finally got around to starting her up after rebuilding the lower end and having Lloyd provide his LE2 magic on my heads. It immediately started right up and sounds great, good throttle response no problems while keeping the rpms around 2000 to 3000 however it searches during idle. I pulled the car out of the garage and continued running it in and on a whim turned off the flashlight to check for arcing wires (night time) when I noticed the headers on both sides were glowing slightly red (after about 12 minutes of running).

My question is, would this be normal for a fresh motor being broken in?

Motor details

95 Lt1
355 bored .030" over
LE2 Heads
224 230 Comp Cams Cam (from Combination Motorsports a few years ago)
Pro Mag 1.6 rockers
1 5/8 mac headers fully ceramic coated
stock injectors (looking to pick up a set of 30# this winter)
stock throttle body
madz28 mail order tune (cam only tune from 2 years ago, does not take into account the new heads)

I have all winter to play around with the tuning, right now I just want to run it some more to finish breaking it in. I'm wondering if the motor might be running lean due to the tired stock injectors, or if a new tune would be in order..


Next time I start it I'm going to scan it with the laptop. Until then, anyone have any thoughts?

 

I'd say its time for the 30#ers and a fresh tune

 

sounds like its time for those injectors

 

Its probably running lean.

-B

 

Thanks for the replies. Like I mentioned earlier, I just want to finish breaking it in and plan on adding in the injectors and a retune later this winter.

It's really nice to hear it purring again, unfortunately I have to wait till March before I can put it back on the road (took it off insurance for the winter!! on reflection that was a bad idea)

 

Check that all of your vacuum hoses are hooked up also. That would cause a lean condition.

 

had same problem. valves were a tad tight causing unburnt gas into the headers and reigniting

 

you aren't running lean at idle with stock injectors. the glowing headers are normal. exhaust gas is hot. the metal on header primaries are thin. it'll happen. ever see a turbo housing at night? it's a fantastic site. the searching for idle can be because the pcm may need to learn before the idle stabilizes.

 

Running an engine at 2000-3000rpm without air flowing over the engine will usually cause the symptom you describe. It will also blister the coating on many aftermarket headers as well.

There is no need to break in motors in this manner if you have a roller cam. Just vary the rpm & preferrably the load (as in driving the car) to help seat the rings. Holding 2000rpm plus was needed to spash lube a flat tappet cam during break in. It serves no benefit otherwise.

 

Lonnie is my hero.

 

Hey guys, sorry to post this in a domestic forum, but I just had to post it.........Glowing headders on an Evo. I'm still laughing at that damn car.

I also found a pic of a SBC........kinda cool......



Joe

 

Thats fantastic!!!

Thanks for the input Lonnie, SS RRR, I agree that the computer hasn't had time to learn all the new ST and LT block multipliers. Guess I'll finish putting on the front bumper and clip along with the hood and sneak it out for a drive around the plan this Saturday (took the insurance off for the winter so I can't go too far)

As for the other suggestions:

Vacuum: Checked it again last night, all vacuum lines plugged in and in the correct place. Even went back to my service manuals to verify

Tight valves: Don't think this to be a problem I went through and double/triple checked the lash while the motor was on the stand.


I guess I'm just being too cautious on my first rebuild. The glow was very dim and a dull dark red, you had to look at them directly to really see it (again this was at night)

 

Don't worry, the slight glow sometimes shows on a fast idling engine with the hood shut.

An engine at cruise (14.7:1) can exhibit EGT's in excess of 1100deg. It worried me the first time I actually checked one, but noticed this is common on computer controlled cars. Quite a contrast to my old Carbed Camaro that I routinely check if all cylinders are firing, by licking my fingers & tapping a header tube to see if they are hot..... don't try this on your FI car, or your fingerprints may come off.

I mistakenly did an o2 sensor test sitting in my car using a GM Tech2 scanner. Held the rpms just as the tool asked & then noticed a wierd smell. Jumped out & opened the hood to see my $800 custom headers glowing brightly (like in the picture) through the Jet-hot coating. Fortunately after cooling they went back to normal. Live & learn.....

As for break-in, the rings like a load to properly seat. It is best to vary speed & load with light to moderate acceleration through the gears..... Driving it is the easiest way. Hope tihs helps.

 

Glowing headers are generally caused by one of two things: a rich fuel mixture (not lean like others were suggesting) or overly retarded timing. I fought this problem with my 396 and it turns out my crank reference angle was off quite a bit, causing the timing to retard and turn the headers a glowing red. You won't have this issue because you're using the stock pcm. Does it smell like it's running rich?

 

An overly rich mixture will not be hotter.... rich mixtures will burn slower & often burn into the exhaust causing glowing headers. This directly relates to the retarded timing issue as a rich mixture will require more advance to prevent this.

Fact is, that as you lean the car (from say 12:1) it will cause a hotter burn as the mixture leans out towards stoich. Deping on the actual engine configuration, peak temps are somewhere in the mid14:1 range. Go leaner & it will then start to cause an additional drop in temp as well.

This is why most cars stay at 13:1 or richer to prevent engine damage under full throttle. Thats why they say lean is mean. It will generally run the best on the verge of damage.

Get an EGT & wideband, the results are very factual.