MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Inlet manifold heating pipe

Hi All
The 1/2" pipe that passes through my inlet manifold is a bit tatty and as the manifold is off for a conversion to SUs anyway I thought I would try and renew it, has anyone done this job and how did you go about it? any tips very welcome.
[don't want to goose the manifold]
Ron
R. Algie

Ron, I simply bypassed the thing. My info is that it was originally part of the omissions set up. I see no reason to preheat the input fuel mixture (other that extreme cold weather driving). Either cut the protuberances off to clean up the appearance or leave them for the next owner. He/She may want the full stock look. SC
Steve C. (member)

Hey, Ron. What you could do is find some stainless steel tubing where the OD fits into the existing pipe ID, then cut off the tatty ends and fit the tubing in there. It won't get quite as hot, but will still be functional. I by-pass it in summer, but valve it in in winter, btw.

Brent
Brent B

Hi Brent
Thanks for the suggestion, I've since discovered that 1/2" copper plumbing pipe [UK spec] is exactly the same OD as the original pipe so I'm going to cut it off and bore the remains out, I think I will also do as you suggest and use a bypass for the warmer weather as I am bit wary of doing without it altogether in case I get problems with carb icing in cold weather
Ron
R. Algie

Something in my ever fading memory tells me that there may be a problem with copper and aluminium in contact with each other - could someone please set me straight!! - I know that there is a major reaction between zinc and copper, and as Al and Zn can be combined to form a galvanising coating, is there a possibility there is a problem with copper and ally?

(Chemistry majors please!)

Roger H

This could definately be a problem in a wet climate or if the coolant is in contact with both metals.Without these conditions, it could work for quite a while. Maybe istall new pipe with epoxy or some other 'insulating' material. In the presence of moisture, galvanic action WILL occur when these metals are in contact. Peter G
Peter Gooch

Good point, never thought about galvanic reaction looks like it will need to be stainless pipe then.
Ron
R. Algie

Like peter said - galvanic corrosion between aluminum & copper won't be a problem unless the metals are wet. The Al would corrode, not the Cu.

I think Ron's repair using copper would work for many years.

Brent
Brent B

....so what are the long term implications for aluminium thermostat housings, where the coolant it is circulated through a copper radiator??? - are they intended to be sacrificial? (Good job the heads are
steel!)

Roger
Roger H

I believe the metals have to be in contact for one side of the circut, and the liquid (electrolyte) completes the circut. The rubber hoses then electrically insulate one metal from another for the pure galvanic corrosion case. There are other corrosion processes at work which is why coolants contain inhibitors.

I doubt the thermostat housing is intended to be sacrificial - mine looks fine after 30+ years.

BB
Brent B

Hi Brent - yeh mine looks fine also. Ally corrosion problems are probably more to do with salts in the 'coolant' when your average joe tops up the radiator with water at the gas station.

I was told years ago that the water runoff from a zinc roof or gutter must NEVER discharge onto a copper gutter for this very reason - never saw the results of such a move, but it was hammered into me!!......or was that copper onto zinc?....hmmm

R
Roger H

Rather dissimilar materials can be used together if there is some means of galvanic protection. This protection may be in the form of finish application, a faying surface seal, a barrier layer, etc. You may recall on in some earlier postings that I mentioned installing items with wet paint or with wet sealer. It was to form that barrier in situ. If you go the sealant route do not use regular hardware store silicone sealer for something like this. They emit an acid as they cure (that vinegary smell is from the acid). Use a hylomar type sealant instead.

Galvanic impact is definitely increased in the presence of moisture, especially in a "marine environment." A common method of testing parts and component assemblies is to run a salt fog test. So if you live near the ocean coast, this will be more of a problem for you than for the guy living in the high desert.

Yea, but that's only for metals you might say. Well, did you ever hear of "corroded" composites? It can happen. BMI (bismaleimide) matrix composites will lose the matrix when in contact with metals (particularly aluminum) in a marine environment. Once that matrix gives up, we get back to one of those lessons that had to soak in if you were to pass Physics 101 i.e., you can't push with a string.
SteveP

This thread was discussed between 23/01/2004 and 29/01/2004

Triumph TR6 index