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Phenolic Spacers

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IB Sorgn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IB Sorgn Quote  Post ReplyReply Direct Link To This Post Topic: Phenolic Spacers
    Posted: Jun/19/2021 at 6:57pm

Wanted a way to reduce the heat soak on my carburetor so I decided to give a Phenolic Spacer a try, although I have never read anything concerning their performance.  I thought that I would share my findings with you all for what it might be worth.  First let me describe my intake setup and the temperatures I recorded before installing the spacer. 

I run a pretty common setup.  My intake manifold is a Edelbrock performer, running a performer series Edelbrock AVS2 carburetor, iron heads, and ceramic coded headers,  should that make a difference to some. 

Ran the motor until I got to a operating temperature of 185 degrees and shot the intake manifold at various areas until I decided that 160 degrees was a good representation.  I then shot the carburetor, trying to stay away from the bowls, and got a representation of just a little over 140 degrees.   With temperatures dancing around a bit, I decided that a 20 degree difference was as close as I was going to get with this unscientific test. 

I then removed the carburetor and installed a 1" phenolic spacer sandwiched between to gaskets (cellulose/nitrile/rubber composites).  I then warmed the motor back up to operating temperature and reshot the same areas with my laser gun and got approximately the same temperatures for the intake manifold but the carburetor showed a drop of over 20 degrees at 117 with the fuel bowls dancing around 3 degrees cooler.

 I should add that my testing was conducted with the air cleaner off and the motor running mostly at an idle.  The only thing the spacer forced me to do was readjust my idle circuits.

 I have no idea if these spacers increase my motor's performance but it's claimed they do.  I do know that this material definitely reduced my  carburetor's temperature by over 15% which would suggest it would lower problems caused by heat soak.  Whether these spacers would continue to hold these lower temperatures when a motor is running under load and/or for extended periods of time will be a test for another day.

 

 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jun/19/2021 at 7:37pm
Back in the day I used a MrGasket adjustable multi plate spacer for heat soak. Mostly because it was needed to space my carburator, without fitment limitations with height. Never had heat soak while in Redding CA, where it was 110+ degrees for a week straight.

Yes phenolic spacers work, just winter driving could make icing happen, with todays fuel. A bottle of Heat may help, as i had to use it a few times on my 95 van in Illinois winter weather.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/19/2021 at 8:11pm
Hmmm, that's exactly what AMC used STOCK on 2 and 4bbl carburetors for years. Think of the 390 with the 4300, or the 290 with the Motorcraft 2bbl. (among others - including 1bbl carburetors)
So AMC and other car makers knew of their effect. 

"Heat" won't necessarily prevent carburetor icing, problems with water in the fuel and fuel line freezing, yeah  - icing occurs because the expanding air below the venturi removes heat from the carburetor, and fuel being atomized, it all results in freezing moisture in the air. 
Decrease air pressure and the container it's in cools - such as the carburetor throat. 
When I put headers on my first Javelin I had the throttle stick at about 2,000 RPM one humid fall day - shut it off and dropped the clutch in gear to kill the engine and got out to see the lower half of the carburetor covered in - yeah, ICE droplets and the throttle shaft was frozen solid. This was in the 1970s, pre-ethanol, etc.
Fuel line icing - yeah, heat - but then you should buy fuel from a better place and store your car with a fully full and sealed tank to prevent moisture in the fuel. 
But it will do nothing for real carburetor icing. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jun/19/2021 at 9:27pm
My first experience with a carburetor icing was in a snow storm. 50 MPH winds and blinding snow. I opened the hood and could only see the top of the breather, the rest was packed snow and ice. Plugged the snorkel with a rag and jammed the heat riser open. 10 minutes to thaw and start, 15 more minutes of hellish drive, do it again and again .... It was a long trip and little in the way of places to stop in 1978 Bruce County Ontario.
The 68 Javelin got me there, finally!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/19/2021 at 9:33pm
Originally posted by Trader Trader wrote:

My first experience with a carburetor icing was in a snow storm. 50 MPH winds and blinding snow. I opened the hood and could only see the top of the breather, the rest was packed snow and ice. Plugged the snorkel with a rag and jammed the heat riser open. 10 minutes to thaw and start, 15 more minutes of hellish drive, do it again and again .... It was a long trip and little in the way of places to stop in 1978 Bruce County Ontario.
The 68 Javelin got me there, finally!


Yeah, up there don't you guys have some interesting snows? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jun/19/2021 at 10:11pm
Yup, this was one of the roads I was on, just not the year pictured:
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ccowx Quote  Post ReplyReply Direct Link To This Post Posted: Jun/20/2021 at 3:44am
Thanks, that is useful information. I do have minor heat soak issues, where the car doesn't want to start for about 5 or 6 seconds of cranking if it shuts down hot and sits for 10 minutes or so. I have long suspected that heat soak and the infamous Holley issues with that are happening. I don't have any spacer at all between my Holley and an R4B intake, due to a Ram air hood.

I unfortunately don't have much room for a full spacer, but I wonder how thick the spacer would actually need to be? Perhaps a 1/8" insulating layer of something would do it?

Chris 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jun/20/2021 at 6:27am
You need gaskets both sides of a phenolic spacer to seal and phenolic is brittle. 1/8" would crack quite easily. For your case, a single 1/4" nitrile/rubber gasket would be the better option. Edelbrock sells them pre made, but you can buy sheet and make your own.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Jun/20/2021 at 6:45am
the factory heat isolator/ gasket is closer to 3/8". Just like the one sold by Edelbrock#9266. They don't need to be over an inch to be effective. It has the grommets on all 4 corners so it can't be over torqued. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jun/20/2021 at 7:01am
Because of the topic, I dug into my stash. For someone who can't have enough spacer, how about a 2" spacer? Mwhahahahahahahahaha!

71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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