New vacuum line

[Member 10617]

My old vacuum line has been knocked around a lot in its life, but I don't detect any leaks. It looks original, so I would like to replace it.

Can I just take out the old one and install the new one, or is there a procedure to follow. I don't know how undoing the vacuum line momentarily will affect the system.

I tried to find information in various manuals, but found none on this procedure.

 

[poolboy]

There's no vacuum within the line unless the engine is running.

 

[Member 10617]

Poolboy,

Just as I suspected. I will carefully remove the old line and install the new line. Each is a copper tube, easily bent around the front of the engine, but easily broken, too, I suspect.

Many thanks.

 

[poolboy]

Yeah, Ed, but copper will bend pretty well, it's not brittle, just don't pinch it making the bends.
There's some tricks to making a good bend without pinching the tubing. There's even a "tool" for such, kinda reminds me of a screen door spring. Lets see what tips the guys come up with.

 

[NutmegCT]

Hi Ed - Thanks for the PM. Here's an example of the "spring type" bender:

https://www.ridgid.com/Tools/Spring-Tube-Benders

They usually come in sets of various sizes.

Tom

 

[Member 10617]

Thanks, Tom,

I think I can achieve the same result with a length of cleear plastic hose.

 

[lbcs_r_fun]

I don't know how undoing the vacuum line momentarily will affect the system.

The vacuum line is connected to the advance capsule, a part of the distributor. When vacuum is available (highest at min. throttle), the vacuum causes a diaphragm to engage the advance mechanism. As engine speed increases, vacuum decreases and so does vacuum advance. However, a centrifugal mechanism takes over to provide appropriate amount of centrifugal advance.

 

[TR3driver]

The original advance line on a TR3 was steel, I believe. Sounds like yours has already been replaced once (so has mine). As noted, there is no reason you can't replace it. However, making the connections with plastic tubing may be a problem, as the fittings are threaded and the thread into the carb is not common.

 

[Member 10617]

My new tubing is not plastic, but copper, and the connections are brass.

I may be wrong about the existing tubing. It may be steel, I didn't take a very close look.

 

[NutmegCT]

My new tubing is not plastic, but copper, and the connections are brass.

I may be wrong about the existing tubing. It may be steel, I didn't take a very close look.

Copper isn't a ferrous metal, so it's not strongly affected by a magnet. Steel on the other hand is *very* affected by a magnet.

Just my two cents ...

Tom

 

[PeterK]

When using copper on an engine, It's a good idea to put a couple of loops on one end to insulate vibration from cracking the line over time. All it takes is a small diameter 1-1.5" loop.

 

[Keoke]

When using copper on an engine, It's a good idea to put a couple of loops on one end to insulate vibration from cracking the line over time. All it takes is a small diameter 1-1.5" loop.

No that is not necessary.However if the line is long it should be attached to the engine in at least a couple of places. I would imagine the manufacturer would have done that originally--Keoke

 

[TR3driver]

The loops are appropriate, if the copper bridges between the engine and the rest of the car. Eg the line to the temperature gauge on the dash.

In this particular case, though, both ends are attached to the engine so all it needs is some support to limit vibration. I've been running the same soft copper line since probably 1985, with no loops and supported only in the factory location (clip to the thermostat housing) and it hasn't broken yet.

 

[Member 10617]

I took another closer look at my vacuum line. It is steel, and it is in better shape than I first thought. It is held by a clip under the thermostat housing. I am going to leave it alone and put the new copper line away for some future need.

 

[PeterK]

I guess you're right on the line since it isn't bridging the body to engine. I was thinking of a friends Bugatti Type 37 fuel line that had the loops in the fuel line. Looks pretty though.

 

[DNK]

Yea, Peter it is tough to keep the Buggati Type 37 and a TR3 separated.
Sheesh!

 

[PeterK]

Yea, Peter it is tough to keep the Buggati Type 37 and a TR3 separated.
Sheesh!

It's an unmolested all original one too owned by an older woman in our club.

Here she is doing a hill climb event. We're not active in this club so I grabbed this shot of her off the club page.