Burning on sign on Engine.

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,082
Re: Burning on sign on Engine.

Ayuh,.........

That's the exhaust cross-over,...... Perfectly Normal.....

Btw,.........
I see a picture of your Distributor,......
It's a all in 1 Delco, which is Probably Not Marine compliant......
That's Why your other threads have gone So Wrong.........
 

tigerhack

Petty Officer 2nd Class
Joined
May 7, 2007
Messages
157
Re: Burning on sign on Engine.

Ayuh,.........

That's the exhaust cross-over,...... Perfectly Normal.....

Btw,.........
I see a picture of your Distributor,......
It's a all in 1 Delco, which is Probably Not Marine compliant......
That's Why your other threads have gone So Wrong.........

Bond i was worrid , i thought i might have to lift that head off again,and knowing my luck.just thought i have damage something when fitting the engine up.
 

magster65

Commander
Joined
Sep 1, 2002
Messages
2,573
Re: Burning on sign on Engine.

Bond i was worrid , i thought i might have to lift that head off again,and knowing my luck.just thought i have damage something when fitting the engine up.

Lift the head off again?
 

Lakester

Chief Petty Officer
Joined
Nov 17, 2007
Messages
428
Re: Burning on sign on Engine.

Ayuh,.........

That's the exhaust cross-over,...... Perfectly Normal.....

Btw,.........
I see a picture of your Distributor,......
It's a all in 1 Delco, which is Probably Not Marine compliant......
That's Why your other threads have gone So Wrong.........

hello,

the sbc has a port off the center exh ports that runs to the intake side. it is to help warm the intake manifold to aid in atomization and reduce fuel pooling. as bond correctly comments; quite normal, given all else is normal.

your's to me does look a bit hot. many will just darken. but also they will burn the paint off. if u know the air/fuel ratio of the carb and ignition timing are fine, then i would not worry about it. what does the other side look like? is it similar?

that intake manifold should have a plenum divider. so if other side just dark blue and this is running that hot, one side may be a bit lean. with a flashlight and some snooping... u can see what cyls are fed from which plenum side which could indicate which side of carb is running lean. if it is.

what did it look like before you redid the head install? i assume u have had the heads off?

what is the conditon of the exh manifolds? is the paint sill on them? what about area where they bolt up to the head? at night is it running bright red or dull red or not red at all?

if brite at night, would indicate to me a lean condition. exh manifolds can run dull red to red, as most do... but bright red suggests a bit lean.

fine tune as u see fit. :)

regards
lakester :cool:
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Burning on sign on Engine.

lakester, you might want to read some of his other posts. Near as I or anyone else can tell, there is a LOT more wrong with that engine than just a little burned paint.
You can tell by the picture of the intake that it's an older style manifold with the crossover, and the do get hot and they will burn the paint.
He also has an automotive distributor and who knows what else on that engine that he now has. (Look at all his pictures in the link in original post)
 

sarantis

Chief Petty Officer
Joined
Feb 4, 2007
Messages
436
Re: Burning on sign on Engine.

It reminds me my problem.In my first thread (gm 305 but with the same crossover at the manifold) i was wandering why these points were so hot .Some time later at high speeds i had exhaust fumes from one side of the intake.After much search i m sure my problem is clogged exhaust possibly because of destroyed shutters.Have you noticed increased temperature at high rpms? or hesitation of the engine at WOT?In 2-3 weeks i'll when i 'll pull my boat out i'll let you know if my assumption come true.
 

tigerhack

Petty Officer 2nd Class
Joined
May 7, 2007
Messages
157
Re: Burning on sign on Engine.

It reminds me my problem.In my first thread (gm 305 but with the same crossover at the manifold) i was wandering why these points were so hot .Some time later at high speeds i had exhaust fumes from one side of the intake.After much search i m sure my problem is clogged exhaust possibly because of destroyed shutters.Have you noticed increased temperature at high rpms? or hesitation of the engine at WOT?In 2-3 weeks i'll when i 'll pull my boat out i'll let you know if my assumption come true.

engine temperature is fine at high Rpm ,but i do get fume off the engine.(Fume Doh) excessive.
 

Coors

Captain
Joined
Dec 8, 2006
Messages
3,367
Re: Burning on sign on Engine.

What is all that way-too-thick sealer on the intake? Looks like hi-temp rtv.
 

sarantis

Chief Petty Officer
Joined
Feb 4, 2007
Messages
436
Re: Burning on sign on Engine.

The only two things i can suppose if you get fumes from these two points (in my ocasion i had fumes only from the one side of the intake manifold are a)restricted exhaust system which will also cause problem to the breathing of the carburator b)bad surfaces at the points where the intake gasket is attached (so they need planning) or the first problem caused the second .
But did you try just tightening the screws?
 
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