New engine, glowing header tube

[Gregsenne]

My engine is brand new, and I tried breaking it in, and the #8 cylinder header tube was glowing. I have a couple ideas of what it might be...
Its a 350, 40 over, carbeurated.
Anyways, can I break the engine in, at 2000 RPMs, with the header tube glowing cherry red? I want to get the engine broken in, and then I'll mess with why it's glowing. But I want to make sure it will be okay to leave the truck running 2k rpms for 20 minutes with that tube glowing.
Will I have to worry about damage to the headers? More importantly, will I have to worry about cracking the head around the exhaust port?

Thanks.
Greg

[chebyshortbox65]

Pretty normal its unburned fuel igniting in the tube
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[Gregsenne]

so it will always do it even after its broke in? and it doesn't have any consequences?

[INSIDIOUS '86]

There is something wrong going on there. Check the valve lash for that cylinder. Make sure your timing and firing order is good. Sounds like the cylinder is way lean and running hotter than the rest
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[86c20]

2x on the valve lash on the exhaust. would be hung open and spiting the flame out the cyl. i would not run it as you may burn the valve then have to replace it.

[chebyshortbox65]

It's petty normal especially breaking in a cam your sitting still running it above 2000 rpm and you have no airflow around to cool the exhaust ever watch an engine on a dyno you will see the same thing often
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[INSIDIOUS '86]

Originally Posted by chebyshortbox65

It's petty normal especially breaking in a cam your sitting still running it above 2000 rpm and you have no airflow around to cool the exhaust ever watch an engine on a dyno you will see the same thing often
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The dyno engines glow all the tubes evenly though
If this was a prob with no airflow over the headers then they all would be almost even in heat right?
So something's wrong
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[ElGracho]

I've seen it too on new engines. Hasn't caused a problem for me. Keep an eye on it and checking your valve lash can't hurt, but don't go tearing heads off just yet...

[Dsquared]

check for a vaccum leak. i had a broken bolt in the valve cover rail near the intake. didn't worry bout it cause it didn't leak oil. after i rebuilt the motor,i had the heads done and apparently some one had tried to drill it out and went all the way through to the intake port. caused that one cylinder yto run lean....hense the glowing header tube i had.

[lilpoindexter]

I think that cylinder is lean.

[Gregsenne]

Thanks for the replies.

- I will check the valve lash.

- I know there's no leak in the heads, I had them magna fluxed, and then I ported & polished them myself. It could be a leak in the intake gasket, I'll try spraying some carb cleaner around it when its running to see if I can hear a leak. I started up the engine last night, and a few minutes in I was getting a loud high pitched whistling noise, so I'm thinking there may be an air leak.

- As far as it being normal and no cooling, it's happening to the header tube furthest away from the fan, so it's probably the hottest anyways, right?

-My header tubes are a bit on the small side compared to other headers I've seen on other trucks. It's (true) dual exhaust , with a flowmaster muffler on each pipe. The pipes are 3" pipes. I was thinking maybe I have a restriction in my muffler, or the tubes are too small for the ported heads? I did notice more exhaust coming from the left bank than the right.

This is my concern...
The engine has been started a few times at idle speeds for adjustments. I tried to break it in once, it ran for 5 minutes at 2k and caught fire due to a wire touching the header, so I shut it off. Tried to break it in a second time, and after 5 minutes noticed the header tube glowing, so I idled it down and shut it off.

I'm concerned I'll loose my opportunity to break in the engine if I keep trying to fix the problem. Should I go ahead and break it in with the tube glowing? Is it okay to try to fix the problem at low RPMs and not worry about losing my chance to break it in?

The engine has never seen above 2200 RPMs yet. And has never ran for more than 10 minutes.

[INSIDIOUS '86]

The test of an engine is if it dies in the first ten mins. Those ten mins are crucial. The reason for 2k and alternating rpm Is to whip oil onto the camshaft and break in the cam.

If the engine isn't throwing parts in the air in the first ten mins then it's good. So you just need to break in the cam.

You said you Ported the heads yourself, did you Lapp the valves afterwords to make sure the valves seated right?
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[Gregsenne]

Yes, I lapped all the valves. I did reuse the old valves, springs, and retainers. New seals though.

The cam in this engine was broken in in a different engine. After break in, the cam, lifters, and pushrods were moved over to this block, with new cam bearings. The engine does have new rings and the cylinders honed. Since the cam is already broke in Im more worried about seating the rings.

In between each start, there was at least 8 hours. Plenty of time for the block to cool back down.
First start: At least ten minutes, at 700 RPMs, for valve and carb adjustment
Second start: Between 5 and 10 minutes at 2k RPM, until wires caught fire.
Third start: Between 5 and 10 minutes at 2k RPM, until header tube was glowing.
Fourth time: Around 3 minutes at 700 RPMs to readjust timing

[406 Q-ship]

Originally Posted by Gregsenne

Yes, I lapped all the valves. I did reuse the old valves, springs, and retainers. New seals though.

The cam in this engine was broken in in a different engine. After break in, the cam, lifters, and pushrods were moved over to this block, with new cam bearings. The engine does have new rings and the cylinders honed. Since the cam is already broke in Im more worried about seating the rings.

In between each start, there was at least 8 hours. Plenty of time for the block to cool back down.
First start: At least ten minutes, at 700 RPMs, for valve and carb adjustment
Second start: Between 5 and 10 minutes at 2k RPM, until wires caught fire.
Third start: Between 5 and 10 minutes at 2k RPM, until header tube was glowing.
Fourth time: Around 3 minutes at 700 RPMs to readjust timing

Running the engine at 2000 RPM is only for the cam not the rings. If the engine was broken-in another engine and the lifters were to that cam are kept in their original realtionship to the cam lobes. Then you should not need to do a cam break in. To seat the rings you drive the vehicle in a lower gear and run it up to 3000 RPM and then use engine braking to help seat the rings. When running an engine at a high idle to break-in the cam is common to have a glowing header tube....it is the reason that header coating companies tell you not to break-in a cam with ceramic coated headers .....unless you want the coat to die an early death.

[INSIDIOUS '86]

Alright well double check your lash. You soaked the lifters in oil right? It may be possible if you didn't that even if the cam is broke in. Not all the lifters pumped up while you lashed the valves. So after it ran at high rpm a whil maybe that one lifter was sticky and pumped up and and the exhaust valve isn't seating all the way now?

I'm assuming you did a running valve lash too?
Do a running lash on that cylinder again just to rule out that issue otherwise take it down a highway with no traffic for an hour and seat your rings
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[Gregsenne]

Yeah I adjusted the lash with the engine idling. Ill check it again when I can fire it up.
I can't drive the truck right now, still need to do the brakes and get my driveshafts back from the shop.
And yes the cam was broke in in a different engine, all lifters in the same spot. I soaked them in oil for a day or so, but then it was another month after I installed the lifters until I fired it up the first time. Should I be adjusting my lash when the engine has warmed up? I did it first thing the first time I started it.

I was worried about glazing the cylinder walls and then the rings wouldn't be seated all the way and leak oil. Is it okay to fire it up in the garage a few times before I go drive it? Is there a way to seat my rings without driving the truck?
Thanks!
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[Gregsenne]

Just wanted to update everyone, I adjusted lash on #8, and I believe my problem is gone away. As I was adjusting it I could hear the engine sound better (although I thought it sounded fine before). Gave it a bit more power from what i could hear.

i am still unsure of how I'm going to break in the rings. So many people have told me completely different things. Everyone I know whose done it before says 2k for 20 min, even if the cam is broke in. On here Im hearing drive it in high rpms for an hour, and drive it bringing it to 3k then slowing using engine braking. Ive heard the decelerating engine brake method before, and if I'm not mistaken, that's how the GM shop manual for that truck says to do it.

[INSIDIOUS '86]

If gm has a method then try that. You know for fact they studied methods thoroughly
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