Ratco carb cable linkage

[Tinster]

I had to remove my twin carb heat shield plate in order
to install the new Ratco cable throttle linkage. The Ratco
mounting bracket will NOT fit with a carb heat shield
in place.

You folks with Ratcos-- What did you install to keep
your carb float bowls cool from the exhaust manifold heat?

Thanks as always,

d

 

[Brosky]

Nothing on any of the three on mine.

Dale, I've driven that car on 95 degree days in Boston and Providence bumper to bumper traffic with never an issue and I have headers.

In other words........

 

[Tinster]

Hey Paul,

The BCF experts, who have now driven Amos and experienced
the engine shut downs and stutters, are in agreement the
problem is vapor lock from too hot carb bowls.

I'll purchase some exhaust manifold insulation wrap
and see if that fixes the problem.

d

 

[Dave Russell]

Just for a try, you could wrap some foil backed insulation around the bowls, secure it with a piece of wire & see what happens.
D

 

[swift6]

Vapor Lock while driving is pretty rare in my experience. More likely when the gas sits and literally percolates in the float bowls.

If you get quoted some exorbitant shipping price, let me know. I can order two sets when I order mine and ship it to at a real price.

 

[Brosky]

I bow to the consensus of expert witnesses at the scene of the crime, Your Honor.

It won't hurt to try the wrap. At least nothing has to come apart for that.

 

[Guest]

You sure that having 5 filters in there isn't impeding the flow at all? I had that with two pumps and just one powered. I too was ~sure~ it was a vapor lock problem.

 

[Brosky]

That is a lot of filtering to go through for 2 lbs of pressure.

It may be enough to cut back the volume at the worst time to where a "vapor lock" condition is replicated.

 

[70herald]

Hey Paul,


I'll purchase some exhaust manifold insulation wrap
and see if that fixes the problem.

d

Don't do it, the next thing you will be buying is a new manifold after you overheat and crack it. Guess why all the header co's say that manifold wrap clearly state that use of wrap will void the warranty?

Now are your carbs really getting hot? 2nd question, is there an insulating block between the carb and the intake manifold? My car has the same carb (Stromberg) and it is equally hot (or hotter) here in Israel and I am not having problems with the gas boiling away. I also do not have any sort of heat shield between the carb / intake and the exhaust.

Finally when does this problem occur? while the engine is running, the gasoline being pulled through the carb provides a significant amount of cooling. I think you should start by getting rid of a few filters. I eliminated the filters on the Herald and instantly solved most of the drivability problems I was having.

 

[NutmegCT]

Hey Paul,

The BCF experts, who have now driven Amos and experienced
the engine shut downs and stutters, are in agreement the
problem is vapor lock from too hot carb bowls.

I'll purchase some exhaust manifold insulation wrap
and see if that fixes the problem.

d

hmmm - not to put too fine a point on it ... but what do guys who have driven Amos and agree "the problem is vapor lock from too hot carb bowls" say to do about it?

T.

 

[Tinster]

The experts say to wrap the exhaust pipes and exhaust
manifold with insulation and to extend my airbox intake
pipes thru the front grill so I am sucking outside, cooler
air.

d

 

[NutmegCT]

and the experts are ... ?

(sure they haven't spent a little too much time at El Bacaro?)



T.

 

[swift6]

Hey Paul,


I'll purchase some exhaust manifold insulation wrap
and see if that fixes the problem.

d

Don't do it, the next thing you will be buying is a new manifold after you overheat and crack it. Guess why all the header co's say that manifold wrap clearly state that use of wrap will void the warranty?

Now are your carbs really getting hot? 2nd question, is there an insulating block between the carb and the intake manifold? My car has the same carb (Stromberg) and it is equally hot (or hotter) here in Israel and I am not having problems with the gas boiling away. I also do not have any sort of heat shield between the carb / intake and the exhaust.

Finally when does this problem occur? while the engine is running, the gasoline being pulled through the carb provides a significant amount of cooling. I think you should start by getting rid of a few filters. I eliminated the filters on the Herald and instantly solved most of the drivability problems I was having.

Which is also why I am avoiding the typical header wrap. The 'jackets' that I am looking at fit loosely around the pipes and still allow airspace and also allow the pipes to expand without constriction. The typical header tape doesn't like to expand or shrink as it heat cycles, while the pipes are trying to expand when hot and shrink when cool.

Does the fuel in Israel have ethanol added to it? This, even in the 10% form, lowers the boiling point enough to cause a problem where there wasn't one before. Also, does your Herald have a 'header' or a stock exhaust manifold? The headers can put out significantly more heat.

Good question on the insulating block between carburettor and intake manifold.

Agree with the gas providing cooling effect. I can tell you a story about an MGB with a catalytic converter that is quite telling to that effect.

Dale, another thing to think about, cheap to try and quick to install, is insulating the fuel line from the pump to the carbs as well.

 

[70herald]

Which is also why I am avoiding the typical header wrap. The 'jackets' that I am looking at fit loosely around the pipes and still allow airspace and also allow the pipes to expand without constriction. The typical header tape doesn't like to expand or shrink as it heat cycles, while the pipes are trying to expand when hot and shrink when cool.

As I recall reading somewhere the problem is not so much expansion rather that without any airflow over the pipes they will get so hot that they can start to melt.

Does the fuel in Israel have ethanol added to it? This, even in the 10% form, lowers the boiling point enough to cause a problem where there wasn't one before. Also, does your Herald have a 'header' or a stock exhaust manifold? The headers can put out significantly more heat.

Ethanol???? I can still get leaded gas, available at every gas station. No idea why, there aren't enough cars old enough left on the road to justify it. Even I don't use it with either the Herald or the Beetle.
The Herald has a stock manifold, just like Dale.

Dale, another thing to think about, cheap to try and quick to install, is insulating the fuel line from the pump to the carbs as well.

Do it! and Dale, since you are a master of making stuff out of sheet metal, you could make a heat shield which fits properly.

 

[Tinster]

<span style="color: #CC0000">Well now!
Maybe that clicks with me? As all are aware, Tinster knows diddly
squat about things auto mechanical and such. But a in the dirt,
use whatcha got on hand, field designer I yam!

I'm Gonna design this concept, fabricate it and give it over to Tony
at Ratco so he's got it on hand for referral.

Here ya go Doc- the problem and the puzzle.

</span>

 

[Mickey Richaud]

Well, this "expert" that was there this week and drove Amos is not so sure. Here's my input, from when I felt it happen when I drove:

We're cruising along in fourth gear, about 50-60mph - the car is running famously. The traffic light ahead is red, so I let off the gas and downshift. Just as we get close to the light it changes to green, so I drop into second, and that's when the missing begins. Accelerating, the car sputtered, so I backed off. The missing cleared up, and we were fine again - the car ran flawlessly, but repeated the symptom down the road a bit. Definitely intermittent, and the engine temp was barely 160. Not much heat in the day, so I'm not convinced about vapor lock.

Whatever the case, it never died completely on me, and even when it did on Dale, as I recall, he said he was able to restart soon after it did.

Bottom line: I'd drive the beast anywhere! And if it were here, that's exactly what I'd be doing now!

 

[amcboy]

Hmmm, every race car I've ever worked on wrapped the headers.

I've always wrapped mine and have suffered no problems.

I'd wrap 'em. The under hood heat is only a minor part of the benefit.

Your exhaust valves will love you forever...

Extraction goes up (assuming a quality header).

Down side is the wrap traps moisture (when not running) and cheapo headers will rust away mighty quickly...

 

[swift6]

<span style="color: #CC0000">

I'm Gonna design this concept, fabricate it and give it over to Tony
at Ratco so he's got it on hand for referral.

Here ya go Doc- the problem and the puzzle.

</span>

Looks like all you really need is a slot in the right place. As long as the heat shield is stiff enough.

 

[RonMacPherson]

Hey cuz,

Stop by a lot with older Benzes on it, mid 90's. Look under the intake manifold on the sixes. You will find an aluminum shield stamped with a waffle like pattern, some years actually have two pieces of aluminum together with asbestos sandwiched between them.

If you can't find any Benzes down there go look at the Hondas, kinda hard to see their heat shields without getting the cars up in the air on them.

If the manufacturers are employing them, don't you think the body of evidence would rule in their favor?

 

[LastDeadLast]

Dale,

Ron is right on here. I've done quite a bit of research when I was thinking about making a heat shield for my triple ZS's. I talked to engineers as well as a couple of reputable carb guys (including Jeff Palya). They all said the same thing:

Making a single layer heat shield will mostly NOT do anything, as a matter of fact it's likely to make the problem worse. A single layer shield has the effect of bringing the radiant heat source closer to the very object that you're trying to protect.

The solution is to create a dual layer shield with some sort of insulation sandwiched in-between the two layers. Even a few millimeters of air would be extremely beneficial. As a matter of fact I did a pretty good mock-up for a triple carb setup but never really pursued it. If you already have something to work with it might be pretty easy to fab up a second layer based on the first.

Just my .02.