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SAAC Forum => SAAC Forum Discussion Area => Topic started by: Bob Gaines on May 09, 2024, 08:58:19 PM

Title: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 09, 2024, 08:58:19 PM
I am trying to get a take on how important the metal pan is under the CJ cast iron intake.I have a chance to buy a cast iron CJ intake at a reasonable price unfortunately it is missing the sheet metal heat shield pan. I understand the pan is Cobra jet intake unique so I can't substitute one from a 390.What say you?
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: pbf777 on May 10, 2024, 11:32:40 AM
    As you obviously realize, without the shield, well, it's just not going to be "correct"; but of coarse once installed who would know?  ::) 
    The actual purpose of this shield is to reduce the sum of splashed oil that might come in contact with the exhaust heat cross-over passage section of the casting located on the bottom; this intended to reduce the sum of that oil which might be "damaged" by the excessive heat exposure and even worse will tend to "coke", even becoming a solid contaminant suspended in the oil.  ;) 

    So, if ones' vehicle is just driven off trailer to the display parking spot, or just never allowed to get hot (for fear of burning the engine or manifold paint  :-[ ), or even just never run hard producing elevated exhaust temperatures, or best, the intake manifolds' cross-over passage is blocked (reduces the burnt paint on the top of the intake issue, or is done to reduce the tendency for fueling vapor-lock  8)) it probably really isn't a necessary component (that is as long as you don't tell anyone its' missing!  ::) ).

    Scott.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 10, 2024, 12:12:55 PM
I suppose I will just fabricate a makeshift shield or block off the cross over. Thanks.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Coralsnake on May 10, 2024, 05:55:01 PM
Close but no cigar

https://www.ebay.com/itm/NOS-1966-1967-1968-1969-FORD-FAIRLANE-GALAXIE-MUSTANG-390-428-INTAKE-BAFFLE-PLAT-/392769646463
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 10, 2024, 06:07:34 PM
Quote from: Coralsnake on May 10, 2024, 05:55:01 PMClose but no cigar

https://www.ebay.com/itm/NOS-1966-1967-1968-1969-FORD-FAIRLANE-GALAXIE-MUSTANG-390-428-INTAKE-BAFFLE-PLAT-/392769646463
I can do a awful lot of fabricating before spending money on something like that which would have to be modified anyway to work given the CJ one is shaped different. I have decided to go the block off of the heat riser route given the car will not be cold weather driven but thank you for thinking of me. 
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Royce Peterson on May 10, 2024, 07:32:26 PM
We used to stuff the intake crossovers with crumpled up aluminum foil when I was young and poor. It worked pretty well.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 10, 2024, 09:41:46 PM
Quote from: Royce Peterson on May 10, 2024, 07:32:26 PMWe used to stuff the intake crossovers with crumpled up aluminum foil when I was young and poor. It worked pretty well.
I could see how that could work for awhile but would be concerned about burn through at some point . Come on Royce I am waiting for you to give me a better alternative then that. ;D 
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: J_Speegle on May 10, 2024, 10:05:12 PM
They make cross over block off plates for SBs never seen  or at least recall seeing them for sale for BB of any kind. Might be a small market for someone that wanted to get crafty at home in the garage,  With a couple of patterns I would start with a chunk of hard wood, trace the pattern and relief out with a bur head or drimmel tool then shape some plates and hammer them for a depression to hold them in place. SB ones are fairly thin metal so that they don't get in the way of the posts sealing (too thick of sheet metal)

Just a thought about a possibility
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 10, 2024, 10:13:50 PM
Quote from: J_Speegle on May 10, 2024, 10:05:12 PMThey make cross over block off plates for SBs never seen  or at least recall seeing them for sale for BB of any kind. Might be a small market for someone that wanted to get crafty at home in the garage,  With a couple of patterns I would start with a chunk of hard wood, trace the pattern and relief out with a bur head or drimmel tool then shape some plates and hammer them for a depression to hold them in place. SB ones are fairly thin metal so that they don't get in the way of the posts sealing (too thick of sheet metal)

Just a thought about a possibility
Thanks for the input. I am leaning towards a .030 piece of stainless in the gasket cut out for the heat riser port just enough oversize to keep from falling in and silicone the plate in with the gasket . At least until I hear a better procedure.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: vtgt500 on May 11, 2024, 04:26:18 PM
In the late '70s while working at Ford T&C I spent my free time hanging out at a couple of the more successful engine builders in Livonia.  Was told the benefit of using the turkey pan was to keep the intake charge cool as possible.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 11, 2024, 05:01:28 PM
Quote from: vtgt500 on May 11, 2024, 04:26:18 PMIn the late '70s while working at Ford T&C I spent my free time hanging out at a couple of the more successful engine builders in Livonia.  Was told the benefit of using the turkey pan was to keep the intake charge cool as possible.
I think you are mixing up two different pan terms. The Turkey pan is normally used to describe a enclosure around the carb which resembles a thanksgiving turkey pan. It is seen mostly used on competition Cobras to keep the cooler air from the hood scoop near the carb . By contrast the sheet metal heat shield underneath the intake is to keep oil away from the high temperature at the bottom of the intake heat riser crossover. The bottom of the intake becomes so hot (not cool)from the heat riser crossover that the oil can break down and burn leaving a coke deposit residue.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: roddster on May 11, 2024, 08:46:30 PM
Have you checked at Mansfield Mustang parts?
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Royce Peterson on May 11, 2024, 09:17:03 PM
When we used to stuff the ports with aluminum foil the foil would get coated in a sooty carbon like goo. It eventually plugged the port pretty well. The foil never went away, it just became gooey.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: 68stangcjfb on May 11, 2024, 10:24:02 PM
Quote from: Bob Gaines on May 10, 2024, 10:13:50 PM
Quote from: J_Speegle on May 10, 2024, 10:05:12 PMThey make cross over block off plates for SBs never seen  or at least recall seeing them for sale for BB of any kind. Might be a small market for someone that wanted to get crafty at home in the garage,  With a couple of patterns I would start with a chunk of hard wood, trace the pattern and relief out with a bur head or drimmel tool then shape some plates and hammer them for a depression to hold them in place. SB ones are fairly thin metal so that they don't get in the way of the posts sealing (too thick of sheet metal)

Just a thought about a possibility
Thanks for the input. I am leaning towards a .030 piece of stainless in the gasket cut out for the heat riser port just enough oversize to keep from falling in and silicone the plate in with the gasket . At least until I hear a better procedure.

That's pretty much exactly what I did with mine. I used Permatex Ultra copper gasket sealer to hold them in place. That was back in 2012 and to this day the paint still hasn't come off the intake manifold so I assume they're working pretty well.
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: JohnB on May 12, 2024, 02:39:36 PM
http://mansfieldmustang.com/02-110.jpg


http://mansfieldmustang.com/EngineMechanicalp1.html
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 12, 2024, 07:17:06 PM
Good to know and thank you for the input. I will not need the pan. I have decided to block off the heat riser cross over and hoping to eliminate the tendency for the BB to boil the gas on a hot summer day under a cramped Mustang/Shelby engine compartment. 
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: vtgt500 on May 13, 2024, 03:31:10 PM
Quote from: Bob Gaines on May 11, 2024, 05:01:28 PM
Quote from: vtgt500 on May 11, 2024, 04:26:18 PMIn the late '70s while working at Ford T&C I spent my free time hanging out at a couple of the more successful engine builders in Livonia.  Was told the benefit of using the turkey pan was to keep the intake charge cool as possible.
I think you are mixing up two different pan terms. The Turkey pan is normally used to describe a enclosure around the carb which resembles a thanksgiving turkey pan. It is seen mostly used on competition Cobras to keep the cooler air from the hood scoop near the carb . By contrast the sheet metal heat shield underneath the intake is to keep oil away from the high temperature at the bottom of the intake heat riser crossover. The bottom of the intake becomes so hot (not cool)from the heat riser crossover that the oil can break down and burn leaving a coke deposit residue.

I've seen the carb insulator barrier you describe, not knowing what it was called.  The lifter galley pan used on Clevelands and FEs was also called a turkey pan within Ford engine manufacturing plants.  Combined with blocking off the crossover is effective in reducing intake manifold temperature.  Objective being, an attempt at
 suppressing detonation.  Today, air gap intake manifolds seem to fill that role. 
Title: Re: 428 Cobra Jet heat shield pan under intake
Post by: Bob Gaines on May 13, 2024, 04:03:56 PM
Quote from: vtgt500 on May 13, 2024, 03:31:10 PM
Quote from: Bob Gaines on May 11, 2024, 05:01:28 PM
Quote from: vtgt500 on May 11, 2024, 04:26:18 PMIn the late '70s while working at Ford T&C I spent my free time hanging out at a couple of the more successful engine builders in Livonia.  Was told the benefit of using the turkey pan was to keep the intake charge cool as possible.
I think you are mixing up two different pan terms. The Turkey pan is normally used to describe a enclosure around the carb which resembles a thanksgiving turkey pan. It is seen mostly used on competition Cobras to keep the cooler air from the hood scoop near the carb . By contrast the sheet metal heat shield underneath the intake is to keep oil away from the high temperature at the bottom of the intake heat riser crossover. The bottom of the intake becomes so hot (not cool)from the heat riser crossover that the oil can break down and burn leaving a coke deposit residue.

I've seen the carb insulator barrier you describe, not knowing what it was called.  The lifter galley pan used on Clevelands and FEs was also called a turkey pan within Ford engine manufacturing plants.  Combined with blocking off the crossover is effective in reducing intake manifold temperature.  Objective being, an attempt at
 suppressing detonation.  Today, air gap intake manifolds seem to fill that role. 
Here is the picture of the enclosure that looks the part of a turkey pan that the carb sits in on top of the intake.