Searched And Searched Is There Anything To Gain Polishing Tripple Webbers

[Guest iskone]

I belive I read in Vizard's book "How to build horsepower in any engine: Vol. 2, Fuel and induction" that when intake manifolds are polished it helps to reduce IAT.

 

Now with an aluminum heat sheild and my header wrapped would this be a waste of time? I was thinking about polishing the under side of the heat sheild if anything. This is all a result of some to-do's I've got to do when my car gets back from the body shop.

 

Isk

[pparaska]

"...Is There Anything To Gain Polishing Tripple Webbers?"

 

Yes! Chicks!

[Guest iskone]

I got shinny wheels.

 

But I've been thinking and can't see how it would really help to reduce fuel temps or IAT's but you never know so I thought I'd ask.

 

Isk

[phantaz]

hmmm i wonder if they were referring to the inside runners being polished on the intake to help it breathe better???

[brokebolt]

IAT's not familiar with this term...I don't think. What is it.

[Guest iskone]

Inatake Air Tempurture

[ezzzzzzz]

A course surface provides more surface area and should aid in temperature dissipation. Polishing can't do much to help IMHO but it looks pretty. In the old days I painted nearly everything black under the hood and abhorred chrome because it would reflect heat back into the engine...believe it or not. Polishing the runners could help in some measurable way to improve air flow but only in a FI situation. Port matching is always a good idea. With carbs you want to keep the rough interior surface to aid turbulance whichs prevents fuel drop out against the runner walls. Only vapor burns and raw gas will wash the cylinder walls, increase emissions, etc.

[JMortensen]

Back in the day the CP guys would open up their carbs, basically port inside of the carbs out. There was a post either here or on classiczcars a while back where a guy had some. I didn't believe him at first, but he really did have a set. I can't remember how big his were ported out, but I think it was over 50mm. IIRC the outside of a 44 Mikuni is 48mm. So yeah it can help flow which is why it was done in the first place, but I don't think its going to help intake temps. If you're worried about temps add a cold air box.

 

I did know a guy who instead of buying bigger venturis would polish the ones he had with jeweler's rouge. He claimed that this would improve the flow. Then if that wasn't enough then he go get the next larger size venturi. Again, a flow thing not an intake temp thing.

[2126]

I agree with ezzzzzzz! Polishing the intake runners on a carburated engine is not a good idea! In order to minimize the IAT, you have to keep heat away from the intake system. Thats why you want a baffle (heat shield) between the exhaust header and the carbs/intake manifold. Your header wrap is also another step in minimizing radiated heat. Running ducting from the front of the car to the carbs will provide cooler air than drawing hot air from the engine compartment.

[brokebolt]

What venue are you planning to run the car in? Street Strip or other? If you use a oil cooler or automatic tranmission cooler, mount it infront of the other coolers your using, and run the fuel through it before the carbs this can cool the fuel before it is feed to the carbs. The unused cooler fuel can return to the tank, helping to keep the tank cooler.

 

While I've mentioned it, Z's are the worst design for gas tank temps, all the engine heat and exhaust pipe heat hits the fuel tank dead on...through the tranny tunnel. Relocating the fuel tank to a higher point in the car could also eleminate this condition of heating the fuel in the tank. I like a cool can before the carbs to help combat this, but who drives around with a ice chest full of ice slurry and a aluminium coil running though it anyway.

 

A fuel cooler, fuel cold can (when needed at the strip), free flowing return fuel line, heat shield between the carbs and exhaust, thermal wrapped exhaust manifold, and cold air induciton plumbing, all used in conjuction with each other would help keep under hood temps low and intake charge cold.

 

Don't know how safe or legal that would be for the street though.

Mike

[Guest iskone]

I think there is some confusion here. I never said the intake runners. I ment the CARBS. After flipping through the Vizard book (which was on my desk, and I didn't even see it.) I couldn't even find that bit of info, maybe I read it somewhere else. But the basic Idea was to reflect heat with a more uniform surface, or so I thought.

 

It does get blazing hot under my hood. If I leave the car idleing till it reaches operating temp water and I pour water on the hood it will stem off rather quickly.

 

I think the best thing to do would be to install a return line and duct some air to the carbs. Of course leaving my header wrapped and my heat sheild in place. I need a new hood to so I may use a 280 hood, but I hate them.

 

I plan to run the car at the local autox events. We have 2 racing bodies I can race with here the SCCA and the BSCC (Bremerton Sports Car Club) If I ever get my car back, then I still have ALOT I need to do before it's ready. Drop the fuel tank, flush system, install return line, new lines for all three carbs after the filter, find a new filter, install fender/hood/headlight bucket/turn signals/headlight/grill/bumper, install new dizzy, relocate alternator, etc........

 

I'll be lucky to get in one race as my arm has recovered enough to finish my house.

 

Isk

[JMortensen]

I'd seriously doubt that it makes a noticeable difference. As 2126 said you can use heat sheilds, coat the header, wrap the header, cold air box, etc, and all that would do a lot more than polishing the carbs.

[Guest iskone]

Thats the plan. The only reason I even thought about it was because my car sat for sooooo long the carbs have surface rust in spots. Gonna have to tear them down I think. Don't forget about that time that my filter caught on fire, LOL

 

Isk

[TimZ]

A course surface provides more surface area and should aid in temperature dissipation. Polishing can't do much to help IMHO but it looks pretty.

 

Not exactly - the coarse surface helps to aid thermal transfer in either direction. In the case of the intake manifold or carbs, what you are worried about is thermal transfer into the manifold (assuming that there is more heat outside than inside, which is generally the case).

 

So, it sounds like Vizard is advocating polishing the surface to reduce it's surface area and thus its capability of absorbing heat from the engine compartment, which should work. I would think a heat shield or thermal coating would be more effective, but this mod is essentially free, except for labor.

 

For this purpose, you wouldn't have to have a show-quality shine. Just smoothing out the graininess from the casting should get 99% of the way there. Scotch-brite on a roloc disk and a die grinder would made short work of this (just be careful not to take off too much material).

[Guest iskone]

I didn't think of it that way but it makes sense. I'll have so much to do when I get back from Fl. so I don'tknow if I want to do anything that is not essential, although this would not take long.

 

I may just take the spare hood from my 71' cut a hole in it and go, a scoop on top of the carbs maybe?

 

Isk

[bjhines]

This was not an easy to manufacture airbox... but with the airbox and baffle... I have drasticly reduced intake temps...

 

 

 

 

 

 

These are some shots of the aluminum baffle plate between the carbs and header... It is kind of buried in there.. but it has cut outs to fit around exhaust runners near head.... and there is onlt a 1/16" gap between it and the back of the airbox...

 

 

 

...

[Guest iskone]

Funny you shold post that. I've been planing just that in my head for a while now.

 

How did you mount the base plat of the air box to the carbs and retain you ram jets?

 

Isk

[bjhines]

I stacked the parts during assembly...

 

first you mount the box... then you slide in the air horns.... then you slip the clamps and nuts on the studs... it is all held in place together...

 

I'll try to find a pic with the cover off...

[Guest iskone]

My setup is different from what you got I'm sure. I'll take some pics to show yoou what Imean when I get her back tonight.

 

Isk

[bjhines]

Here are the pics of the inside of my airbox...

 

 

 

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