Or are they just a snake oil? You see the products that state big reductions in carb heat and fuel temps. My truck with a sbc, an edelbrock alum intake and edelbrock 4 barrel runs great all day. On hot days if I shut it off and let it sit for say 30 mins. It bakes the fuel and has hard time starting but once it does it runs like normal. And on really hot days sitting in traffic, it'll stutter like the fuels boiling. Will a isolator help, or are they just a high dollar spacer? Thanks David Posted using the Full Custom H.A.M.B. App!
It didn't work for me on a 56 Chevy I had with the same set up as you. Years ago it probably did, but not today with the ethanol. However, I still read of guys who say it worked for them. Maybe it's only an Edelbrock carb thing.
That's what I've been hearing. The fuel today has such low boiling points. Barely hit the key and it fires right up when cold. Posted using the Full Custom H.A.M.B. App!
To maximize the effect, you have to block the exhaust crossover in the manifold. Even with the valve removed, it gets real hot. May not even need one without the crossover.
Yup, they work. I had issues just like you described with my coupe (dual Edelbrock carbs). Installed carb spacers and problem gone. Edelbrock carbs seem really susceptible to boiling the bowls dry for some reason. .
To clarify ..... a "spacer" can be any material ( aluminum,etc. )and have no heat preventitve value at all .. I believe they were called a " phenolic " ( sp ? ) insulator and they DO work to insulate carb heat ....... ....... jersey Skip
A friend of mine made one out of a block of walnut and sprayed it with an epoxy paint. He said it worked well at keeping the carb temp down.
I used a spacer isolator on my 39 coupe with pontiac engine and AFB carb. It did help on fuel boil over problems. I also used a factory shield for Ford pickups with 351 W engine and holley carb, It was an alumkinum shield that was larger than the whole carb
Yes. Mine is non-metal 1" thick and lowers carb temp significantly. But there must be good airflow over the top of the engine to cool the carb - otherwise hot air trapped under the hood will raise the carb temp near to that of the engine despite the spacer.
55 Chevy with a C4B intake and a Carter AFB...made my own out of 3/4" white Teflon block worked for 21 years without an issue and was on the car when I sold it
They work outstandingly well. I have the thin phenolic gasket underneath my Edelbrock 1405. The carb is warm to the touch when the motor block is so hot you can't touch it. It completely stopped the boiling of fuel in the Carb.
Yes, wood, plastic, phenolic, anything but ANY type of metal works. Should be at least .50" thk. How well depends on a lot of things. Another thing to try is a heat "shield" . Right under the carburetor, make a Stainless or aluminum sheet, about .09" thick. It should be a couple inches larger thAn the carburetor all the way around. Obviously it may need to be cutout and or trimmed for linkages and such. Both GM and Ford used these in the 60's and 70". Maybe even later. This does a coupla things, it acts like a cooling "fin" it also helps keep heat from the manifold from a direct path to the carburetor as it rises off of the hot intake manifold. Mike
I have a 1" wood Edelbrock spacer & it's the best thing I could've done for it...had bad boiling issues last year.
Ok cool. Thanks guys. I'll have to pick one up and throw it on. Posted using the Full Custom H.A.M.B. App!
I made some isolators for a 421 Pontiac tri power that had carb heating issues. I used thick gasket material sandwiched between aluminum sheets. The aluminum was somewhat larger than the carb base and made cooling fins. the gasket material isolated the engine heat from the carbs. The total stack was around 3/4" high. It helped but wasn't a total cure. I ended up putting on a fuel return line to the gas tank and an electric fuel pump similar to what fuel injection systems use.
Why spend $30 for a spacer,when you can get a cutting board at wally world for about $7 to $9 and make one out of that.The board will be big enough to make several.The boards are about 1/2" thick. Good luck.Have fun.Be safe. Leo
phenolic wood is the best. A standard phenolic spacer can work well too. here in vegas i had the same issues, i could also feel it start to boil at low speeds around town. If i shut it down i could hear fuel boil, so much that you'd see it coming out of the boosters with the engine off. I added a spacer and it pretty much solved it (NO metal ones or cheap plastic!) an RPM air-gap intake in addition made it real good, i no longer have any issues with hottie carbs! Get yourself a good phenolic wood spacer, there not real cheap but the diffference they make is well worth it. .
Last year had the same problem of hard starting after the motors been run, over winter installed a phenolic spacer, and it's worked perfect so far. Bob
For low RPM street engines, a four hole one inch black plastic spacer works good. For higher RPM's, a guy can experiment with one big hole, or a spacer with four shaped holes like an upside down funnel. Small motors up to 325 inches or so really wake up with that.
Where I live a heat riser is a liability 90% of the year. And in my experience an insulating carb spacer is a requirement. No questions asked. If you're not a desert dweller, YMMV.
Picked up a spacer over the weekend and can already tell it's helping! Posted using the Full Custom H.A.M.B. App!
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