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Braided injector pipes


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April Issue 297 of TR Action carries an article about poor starting associated with braided injector pipes.

 

I fitted Exact branded pipes February 2016 and of late starting has being getting worse and worse - in fact exactly as described in the article.

 

Has anyone else found this?

 

John

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Hi John,

 

lots of people over many years have found the braided pipes to be yet another bling 'upgrade' that doesn't actually function as well as the original, in this instance the utilitarian original black pipes.

 

But the bling looks good, tends to be reassuringly expensive, and serves to help keep classic specialists in the style to which they'd like to be accustomed.

 

And, to be fair, as more and more classics are purchased for investment rather than driving, cosmetic appearances may well matter more than functional efficiency.

 

Cheers

 

Alec

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There are many posts on here in the subject of braided injector lines a large number of them bearing my contribution on the subject which is exactly as described in the TRR article. Get back to nylon and the problem goes away.

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I recently had an injector pipe split and close inspection of the others showed a couple more

 

looking the worse for wear,so decided to change the lot.

 

Original intention was to change like for like, however non of the usual suspects are carrying

 

the nylon pipes in stock and are reluctant to supply them,prices quoted were more than for a

 

set of braided ones.

 

Eventually spoke to Revingtons who also no longer stocked them but could supply pipe by the

 

meter to order if a customer insisted. There reason being that they have had instances of

 

customers cars catching fire due to leaking nylon pipes and there is concern about the effect

 

of modern fuel on the nylon pipes.

 

So I decided to invest in a set of their teflon lined braided pipes ,we shall see what happens

 

over time. I`m sure nylon pipes are still available from some suppliers, just thought I`d

 

Share my recent experience.

 

Cheers

 

Brian

Edited by brian -r
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I have the same issue with the exact braided hoses. I have proved that they have caused the car to take much longer to start. I replaced the 4 easy to change pipes back to nylon and, although it didn't fire on all 6 cylinders, it started straight away and soon progressed to firing on all 6. Did this a couple of times over a 2 week period with the car starting straight away. Put the braided hoses back on and back to the terrible starting problems. Nylons back on and problem solved. Now replaced the complete set with nylon and full refund from the supplier.

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Hi,

 

I recently had a new set of nylon ones made up by Neil Ferguson, along with reconditioning all the other PI bits. Lovely guy, highly recommended.

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My lines looked ok-ish, but were of unknown age; one was locally a bit thinner due to rubbing (sorry for the poor wording, you know what I mean).

You can buy the plastic pipe on ebay, but I did not feel comfortable with sticking the tube on the existing fittings myself, so did send my existing fuel lines to Neil Ferguson.

He did an exellent job, electrically plated the fittings, fitted new plastic (nylon?) pipes and suplied them with the correct O-rings, in viton, for a modest charge.

This is what I do recommend.

Regards,

Waldi

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I am already receiving a few email messages confirming that this issue is probably quite widespread ...I even agree with Alex which is not always the case.

 

We are all being offered various flavors of "Fluffy Dice" to decorate out TRs with and exercise our Credit Cards at the same time.

 

It is nothing new ...going back in Roman times Caveat Emptor says it all!!

 

Robert Johnston

Auckland, New Zealand.

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My # 4 pipe was leaking at the injector elbow (common problem if mishandled apparently) and I was lucky enough to purchase a genuine replacement from the NZ TR Register. However, prior to hearing back fom the Register I came a across a pipe replacement kit on eBay from "triumphstuff" for NZ$45 complete with clamping blocks. Enough nylon hose to do all the injectors plus some to spare (see photo below).

 

Needless to say I made up my own replacement from the kit as the OEM zinc parts didn't match my other five. It was so easy I would never contemplate any other option.

 

Unfortunately the item's not currently listed so I can't include a link, but perhaps a question via one of his other listings may prompt him to re-list.

 

post-14246-0-99006100-1492570499_thumb.jpg

 

Gavin

 

 

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If you can get the pipe the fitting kit is easy to make. I think the details are on here somewhere but you just clamp two pieces of wood together and drill the correct sized hole where they meet. Did this and warmed the nylon pipe and it all fitted like a dream..

Cheers

Tim

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Is the slow starting with the braided pipes to do with the non return valves in the metering unit, the braided pipes have a much bigger volume of fuel in them compared to the nylon ones.

So if the braided pipes have a leaky non return valve there is much more weight of fuel on the non return valve, and then it takes much longer for the MU to generate enough fuel to fill the pipe and eventually squirt the injector.

I have taken 4 of the non return valves apart and changed the rubber disc over so it has a better sealing. This did improve the starting. Unfortunately I haven't managed to get the 2 banjo non return valves apart.

John

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I have read this article and to my surprise it does not fully state what actual materials that have been are used for these hose examples? It mentions rubber that to me is a complete no no in this application. The other material I suspect is thin wall PTFE also known as Teflon a Dupont trade name another no no because of wall thickness shown. I do not like S/S braid or the larger S/S Aeroquip type end fittings that are used here because S/S acts as a very good heat soak and radiation of heat than M/S, into the fuel. I believe that this vaporizes the fuel in the injector fuel lines and causes a type of cavitation also expelling the free air, in the fuel which us old TR owners are only too well aware of with the Lucas pumps.

Lucas/CAV used/spec in nylon tube, the grade is nylon 6 or nylon 66, this is readily available from a large number hose distributors also in assorted colours. The only slight downer with these two grades of nylon tube it is not as resistant to modern fuels as it was to the old leaded fuel! The Test Report that I have read, says use nylon 12 instead but this grade does not seem to be readily available in the UK. The end fitting are M/S which absorbs less heat and are of a much smaller mass and the combination of this means very much less heat is transferred.

Therefore, as others have stated not suitable.

 

Bruce.

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This is the stuff I purchased to do the job...Dead listing at the moment but I'm sure he still stocks the item if required

 

http://www.ebay.co.uk/itm/TRIUMPH-PI-LUCAS-FUEL-INJECTION-INJECTOR-PIPE-KIT-TR5-TR6-2000-2-5PI-/142318961644?

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Hi John,

 

lots of people over many years have found the braided pipes to be yet another bling 'upgrade' that doesn't actually function as well as the original, in this instance the utilitarian original black pipes.

 

But the bling looks good, tends to be reassuringly expensive, and serves to help keep classic specialists in the style to which they'd like to be accustomed.

 

And, to be fair, as more and more classics are purchased for investment rather than driving, cosmetic appearances may well matter more than functional efficiency.

 

Cheers

 

Alec

I replaced mine because I genuinely believed they were more fire resistant than the nylon ones, that was 25 years or so ago, so when I was buying shiny things for the rebuild I bought a new set, then Stuart pointed out that if there was an under bonnet fire the PTFE inner would melt any way Doh ……fool and his money and all that :unsure: so have messaged Neil F for a nylon set now …………….

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Pirtek sell a roll of fuel grade nylon pipe for the cost of a single pipe.

Choice of colours. Re-use your own fittings and make a clamp as described above (and in the brown book) a bit of time and practice and off you go.

 

The braided ones are bling. The pressure is limited and nothing to chafe on so performance and safety are not real gains like you might get with a brake hose.

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Andy,

 

The key issue is what spec is the Pirtek nylon tube? There is about 8 types of nylon tube that I know of? When they say fuel grade what type of fuel. This is a mine field area. A well known TR parts supplier sells the H/P hose from steel pipe to M/U but its not suitable for current petrol and that was 2 weeks ago? Unless a supplier can give me a spec. number I treat every thing with suspicion! That includes Pirtek as I have seen what they offer for current petrol H/P hose?

 

Bruce

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I replaced mine because I genuinely believed they were more fire resistant than the nylon ones, that was 25 years or so ago, so when I was buying shiny things for the rebuild I bought a new set, then Stuart pointed out that if there was an under bonnet fire the PTFE inner would melt any way Doh ……fool and his money and all that :unsure: so have messaged Neil F for a nylon set now …………….

 

I bought the SS hoses about 15 years ago because the nylon ones were splitting at the fittings. My thinking was that the SS hoses would stand up to the hot dry conditions I live in although the heat under the bonnet is hotter than what the outside air temp is, even in the middle of summer (although sometimes I am not sure about that). I have not noticed any starting or vaporization issues.

 

Simon

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I had to replace a split original style injector pipe on a TR6 i had some years ago.

 

TRGB supplied the exact one i needed complete.

 

Regards

 

Steve

 

Steve,

 

I don't know about TRGB, but when I was looking a few months back they could only be purchased as a complete set from the main suppliers at quite exorbitant prices. Getting Neil to make them would seem to be the best option for those who don't want to try making them up from a repair kit.

 

Gavin

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My # 4 pipe was leaking at the injector elbow (common problem if mishandled apparently) and I was lucky enough to purchase a genuine replacement from the NZ TR Register. However, prior to hearing back fom the Register I came a across a pipe replacement kit on eBay from "triumphstuff" for NZ$45 complete with clamping blocks. Enough nylon hose to do all the injectors plus some to spare (see photo below).

 

Needless to say I made up my own replacement from the kit as the OEM zinc parts didn't match my other five. It was so easy I would never contemplate any other option.

 

Unfortunately the item's not currently listed so I can't include a link, but perhaps a question via one of his other listings may prompt him to re-list.

 

attachicon.gifInjection Pipe Kit.jpg

 

Gavin

 

 

now re listed http://www.ebay.co.uk/itm/-/142356883964?

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I've been following this thread.

 

I have SS braided hoses on my 6 and yes, it takes a long time to start after it's been standing. The braided hoses look to have been made from Dash-4 hose, which is 4/16" = 1/4" or 6.3mm internal diameter. I checked the old nylon pipes and they are about 4mm ID.

 

So definitely, the original hoses have a lower internal diameter and so less work for the metering unit to refill if all fuel pressure has been lost on standing. By my calculations, 1 metre of original hose contains about 13ccs of fuel. The Dash-4 hose by the same calculation holds about 31ccs of fuel. Around 2.4 times the volume to refill and repressurise, so easily enough difference to explain the slower starting.

 

For those interested, the volume of a cylinder (and the inside of the hose is approximately cylindrical) = πR2 x Length.

 

Dash-3 braided hose, 3/16" ID or 4.8mm ID ought to give better starting than Dash-4 and still flow enough fuel.

 

Hope this makes sense, my maths education finished a long time ago!

 

 

Nigel

Edited by Nigel Triumph
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