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62 / BT7 carb questions

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IMG_0263.jpgstarting pulling out the carbs and parts today. the PO had them rebuilt.

2 questions)

1) i always thought the SU carbs with the brace on the neck did not use vented caps. the ones on these carbs have a hole in them. am i correct there?

2) what do you all use for vent pipes on the carbs and how do you run them?

Thanks
 
Hi TL,
If I'm reading your question correctly, the vent pipes are for overflow and should be connected to tubes that run down past the manifolds and empty on to the ground. I've never actually seen the correct tubes or routing, but I just ran flexible fuel line down through appropriate places (away from the exhaust manifold). Maybe someone else has more information.
Keith
 
Keith
Thanks. so you just used a clear fuel line?
 
I've used both clear neoprene and black vinyl. They both became distorted and brittle from the heat. I made permanent pipes from 3/16" brake line tubing, joined to the Healey stubs with short lengths of rubber tubing and clipped to the inside of the fender with a Moss dual pipe clip 585-595:

PipeClipDualMoss585-595.jpg
 
thanks. i will look in to that. i have some old brake lines left over. guess some soft copper tubing would do the same thing.

speaking of heat. i read somewhere that having the exhaust manifolds done with a ceramic coating keeps a lot of the heat in the pipe and can reduce heat in the engine bay by 25%. has anyone tried that?
 
Drone Dog said:
... speaking of heat. i read somewhere that having the exhaust manifolds done with a ceramic coating keeps a lot of the heat in the pipe and can reduce heat in the engine bay by 25%. has anyone tried that?
Click to expand...

Yep. Only succeeded in reducing the weight of my wallet by 25%. But, seriously, the heat in the engine bay was probably reduced by coating the manifold and wrapping the downpipes, it just didn't produce any noticeable improvement in performance or vapor lock. You might see something on a dyno, but high-heat paint looks as good and is a lot cheaper.
 
Drone Dog said:
thanks. i will look in to that. i have some old brake lines left over. guess some soft copper tubing would do the same thing.

speaking of heat. i read somewhere that having the exhaust manifolds done with a ceramic coating keeps a lot of the heat in the pipe and can reduce heat in the engine bay by 25%. has anyone tried that?
Click to expand...

I have tube headers ceramic coated inside and out. They are quieter - much like the cast iron manifolds; they aren't as hot that way either. Gets rid of the tinny sound tube headers make.
 
steveg said:
I have tube headers ceramic coated inside and out. They are quieter - much like the cast iron manifolds; they aren't as hot that way either. Gets rid of the tinny sound tube headers make.
Click to expand...
Ditto.

jh_headers.JPG


A dozen years later, they're a bit duller, but no areas are flaking off. They were coated in/out from new, before they were ever run on the engine, and I think that has a lot to do with coating integrity.
 
thanks for the info. using the stock manifolds. i had some POR15 left over and have used that. never had great luck with it staying on for a long time. but i never had a way to blast the manifold before. i blasted these, did not touch them and i used metal prep on them before painting. i got some time before they will go on so i am putting them in front of the heater in the shop to help cure the paint before i mount.

i would look to have them coated if i thought they would really help with the heat situation.
 
I found one of those elbows today in one of the boxes. Going to loo for a couple more now.
guess they did not worry about extending down below the manifold....
 
The flexible vent tubes on my 62 / BT7 mkII don't extend any further than the BN7's. When the needles went bad I switched to Grose Jets [ball bearing] and they never vented gouts of raw fuel again.
 
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