Why is my intake burned?
01-20-2018, 10:22 PM
#1
Instructor
Thread Starter
Why is my intake burned?
Can anyone provide any insight concerning the paint damage to the driver's side of my intake? It is limited to the driver's side and is not on any of the numbered intake runners. It's a low compression 1975 L48 which is all original and to my knowledge has not been taken apart. Car has 84K and runs really well, but maybe slightly rich. Your help is appreciated.
Edit: Car has aftermarket dual exhaust with no converters and the smog/air pump has been removed. I also took the EGR off and cleaned out the built up carbon but it is still in place on the passenger side.
Edit: Car has aftermarket dual exhaust with no converters and the smog/air pump has been removed. I also took the EGR off and cleaned out the built up carbon but it is still in place on the passenger side.
Last edited by Highlander1732; 01-20-2018 at 10:26 PM. Reason: Added information
01-20-2018, 10:25 PM
#2
That's where the exhaust cross over port is.
01-20-2018, 11:02 PM
#4
01-20-2018, 11:53 PM
#5
Team Owner
If you did not use high temp (800+F) paint on the engine, those aresa WILL burn the paint. It happened on them when they were new, and it still does today.
Many intake manifold gasket kits have some little block-off plates that keep the hot exhaust gasses from going thru the manifold and minimizes that paint damage. Of course, doing so also lengthens the time it takes for the carb to warm up (that heat riser system is there to do just that); but if you don't drive that much in cold weather, who cares?
Many intake manifold gasket kits have some little block-off plates that keep the hot exhaust gasses from going thru the manifold and minimizes that paint damage. Of course, doing so also lengthens the time it takes for the carb to warm up (that heat riser system is there to do just that); but if you don't drive that much in cold weather, who cares?
Last edited by 7T1vette; 01-20-2018 at 11:54 PM.
01-23-2018, 07:47 PM
#8
On the bright side, they all did that, because the factory did not use/have high heat engine paint.
SO, I would "assume" it's NCRS correct, since every one I saw as a young man was burnt like that.
SO, I would "assume" it's NCRS correct, since every one I saw as a young man was burnt like that.
01-23-2018, 07:50 PM
#9
Race Director
I would assume that blocking it off may help to keep heat from increasing under the carb and help keep the engine getting vapor lock???????
Don't know for sure, but it seems possible.
Don't know for sure, but it seems possible.
01-23-2018, 07:52 PM
#10
Yes, unless you live in very cold climate, and drive the car in that cold, it works better blocked off.
01-23-2018, 07:59 PM
#11
Team Owner
Member Since: Jan 2007
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St. Jude Donor '22
yup, that cross over gets hot and blisters paint,
i have seen block offs and plugs with small holes
in intake kits.
i just put in what i find or don't find under the mani.
generally i leave it open. choke works quicker and
i don't get vapor lock.
i think the gas gets atomized better with heat.
gas flowing will cool the things it runs thru.
so i tend to leave them open.
i have seen block offs and plugs with small holes
in intake kits.
i just put in what i find or don't find under the mani.
generally i leave it open. choke works quicker and
i don't get vapor lock.
i think the gas gets atomized better with heat.
gas flowing will cool the things it runs thru.
so i tend to leave them open.
01-24-2018, 12:02 PM
#12
Le Mans Master
Cast iron intake would like to have it open.
Aluminum intake heats up pretty quickly so there you can make a stronger case for blocking it off on at least one side (side away from choke stove, if you have one)
Aluminum intake heats up pretty quickly so there you can make a stronger case for blocking it off on at least one side (side away from choke stove, if you have one)