Tonights Adventure...Grrrr
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Well, yes, any new (er) engine is tighter, and all those happy parts need get along with each other, so they fight it out untill happy again...
turn over a new engine is an experience....turn over an old engine, can be done by hand.....
both with the plugs pulled, obviously....
and so for any extra internal friction, generating extra HEAT, requiring more FUEL to burn at any given RPM and IF it's a mechanical fan, only so much airflow...yeh, everyone is under max stress....
which is why I highly recommend NO t stat in place for break in...
the damn things have a habit of sticking shut....don't ask please....
turn over a new engine is an experience....turn over an old engine, can be done by hand.....
both with the plugs pulled, obviously....
and so for any extra internal friction, generating extra HEAT, requiring more FUEL to burn at any given RPM and IF it's a mechanical fan, only so much airflow...yeh, everyone is under max stress....
which is why I highly recommend NO t stat in place for break in...
the damn things have a habit of sticking shut....don't ask please....
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
And no new CHROMED headers for the "break in" cycle
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
eh, go to any cruise night or hotrod show, any type car, and look around, tons of shows in Florida, hotrod heaven.....and see the ones with chromed headers....not one set is chrome silver still....not if it's been driven at all, that is....they all blue/yellow/green tint looking off color....honestly, it's part of the game
two types of chrome headers, those that are discolored from heat, andthose that WILL BE discolored from heat, assuming it's DRIVEN....
two types of chrome headers, those that are discolored from heat, andthose that WILL BE discolored from heat, assuming it's DRIVEN....
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Did you find the problem yet? I guess it may be normal to heat the crap outta the headers on a decent engine, but an L81??!!!!! 
When I broke in my L81's new cam there were no problems like my (new) headers glowing due to the heat (my problems were a serious fuel leak at the carb that was spraying neat fuel everywhere!).
The only time I've heated exhausts to cherry red within a couple of mins from start-up was due to retarded timing. It wasn't a SBC but the principle is the same (mixture is burning in the exhausts rather than in the cylinders). I'd check the timing before anything else.
Have you still got the computer hooked up? I was wondering if a sensor had buggered up, but if one had then the computer would probably set itself to "limp home" mode. I can't see GM designing "limp home" mode to turn the exhausts red with heat, so it's probably not that. There again, anybody who put the fuse box where it is obviously had a twisted sense of humor....
When I broke in my L81's new cam there were no problems like my (new) headers glowing due to the heat (my problems were a serious fuel leak at the carb that was spraying neat fuel everywhere!). The only time I've heated exhausts to cherry red within a couple of mins from start-up was due to retarded timing. It wasn't a SBC but the principle is the same (mixture is burning in the exhausts rather than in the cylinders). I'd check the timing before anything else.
Have you still got the computer hooked up? I was wondering if a sensor had buggered up, but if one had then the computer would probably set itself to "limp home" mode. I can't see GM designing "limp home" mode to turn the exhausts red with heat, so it's probably not that. There again, anybody who put the fuse box where it is obviously had a twisted sense of humor....
Instructor
Joined: Dec 2002
Posts: 222
Likes: 0
From: Leander TX
I broke in my solid cam, fresh built bb 427 on a test stand. The Headman ceramic coated headers had a "ceramic coating void warranty warning", so I borrowed a set of full length battered and abused hookers.. The infrared temp gun I had registered roughly 950 F within 2min of starting the engine as all the paint on the headers turned to ash.. and I burned one of my MSD wires. After breaking it in, with a bit of a timing adjustment and the ceramic coated headers on, it never got above 350F at 2500 RPM. I know I still have a some to go with jetting the carbs..
-F
-F
Thread Starter
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Hey Paul. I was breaking it in with the computer disconnected and neglected to concider that when I ran he rpms up I didn't get any advance, AND the carb was set to lean. So with the two together I roasted my new headers AND fried a plug wire and dammaged 2 boots
Intermediate
Joined: Jul 2006
Posts: 43
Likes: 0
From: Claremont Ca
I am to understand that the reason exhaust temp is soo much higher when breaking in an engine is because the rings haven't seated so there is a lot of fuel/air mixture blow by that then burns once it renters the exhaust.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
If the rings hadn't seated and he was getting blow by wouldn't that be burning oil not extra fuel? The air and fuel are in the cylinder whether the rings are seated or not.
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
), but the owner had just fitted new chrome ones & I had to buy him a replacement set after turning them bright blue with a hint of yellow. This is why I know retarded timing causes huge amounts of exhaust heat. Doing a mate a favor ended up costing me $200 so I'm not gonna forget that one for a while
