19 replies to this topic

[katsuro]

Hello everyone.

I'm looking for information on how to convert the current plastic elbowed vacuum pipes with silicone ones in a 1996 Mayfair Spi. Over the last 12 months I've had 3 separate occasions where my Mini had trouble which was caused by the vacuum pipes leaking/cracking/splitting etc. Being fairly new to fuel injected Minis, it turned out being costly sending it into garages to have the issues fixed. I didn't know at the time it was this simple tubes that were causing havoc with the engine management system. I was so close to coughing out on new sensors and the like.

 

Having done a bit more homework on these vacuum pipes & speaking to other very helpful Mini owners, I understand there may be a solution to solving this vacuum pipe issue once and for all. Apparently you can replace all the plastic pipes with silicone ones. Has anyone done this with their Spi/Mpi Mini? Also any tips & advice on how best to do this conversion would be most appreciated. Fed up of having to keep replacing them every other month. 

[FlyingScot]

I usually replace them all as a standard maintenance item after purchasing any SPi.
Not had any repeat trouble after this?
Using pipe without elbows I would be concerned about making sure the runs are smooth and not pinching the tube.
However Alpenflitzen has had good experience with 3mm silicon pipe, so maybe he can comment.

FS

Edited by FlyingScot, 17 September 2014 - 05:35 AM.

[Guess-Works.com]

You can't use silicon as a vacuum pipe as it'll collapse ( flatten )  as soon as a vacuum is introduced....

A vacuum pipe needs to be rigid, or reinforced

Edited by Guess-Works.com, 17 September 2014 - 07:01 AM.

[rover96]

I have used small fuel hosing with good results, especially for the vapor trap. 

[firstforward]

It is cheap enough, easy enough to replace with correct items from the usual mini suppliers. If replaced in one hit the cost is cheap and will last some years. No need to take it to a garage it is very simple to unplug a few pipes and reconnect up.

[Alpenflitzer]

I am using, based on an advice from a German Mini-Specialist, Samco Motorsport 3 mm silicon pipes without elbow  since 3 years and they work wonderful .

A common silicon pipe  as you use it in electricity to protect things of heat is of course the wrong thing.

 

All of the contacts in the German Mini-Forum which used the Samco material have never had any problems with flattening because these pipes with 2mm wall thickness are firm enough to withstand the Mini-vacuum underpressure.

 

go to:    http://www.samcospor...cuum_tubing.asp

Edited by Alpenflitzer, 17 September 2014 - 11:08 AM.

[katsuro]

Thanks you all for the advice. I have had the standard vacuum tubes replaced on each occasion I had the issues. They dont seem to last long which is frustrating. Hence why I'm exploring this option. A good samaritan who helped me out on the London2Brighton Run earlier this year when the black vac tube melted, was the one who first suggested the silicone conversion to me. He had done the same done to his Spi Mini Sidewalk. Unfortunately I didnt get the chance to speak to him in depth about the what he did because we were in a dangerous spot fixing my Mini to have a chat. Never saw him again when we got to Brighton. A few of my Instagram followers also suggested using silicone vac tubes to solve the issues once and for all. I'll let you know how I get on.

[brivinci]

The Mini Sport dealer here in the US recommended going silicone. I bought some from him and its great. No elbows and its very thick walled so there is no worry of it collapsing. Also, no worries of it being kinked like the hard plastic pipes as well. I'm sure there is plenty of "wrong" type of piping out there. Go with a size/branded that others have already used and tested.

[minisilverbullet]

Thanks you all for the advice. I have had the standard vacuum tubes replaced on each occasion I had the issues. They dont seem to last long which is frustrating. Hence why I'm exploring this option. A good samaritan who helped me out on the London2Brighton Run earlier this year when the black vac tube melted, was the one who first suggested the silicone conversion to me. He had done the same done to his Spi Mini Sidewalk. Unfortunately I didnt get the chance to speak to him in depth about the what he did because we were in a dangerous spot fixing my Mini to have a chat. Never saw him again when we got to Brighton. A few of my Instagram followers also suggested using silicone vac tubes to solve the issues once and for all. I'll let you know how I get on.

I think your problem lies in the routing of the pipes. Since you say it melted suggests it is routed too close to the block.

Using silicon I would be concerned with whether or not the provide a tight seal on the nipples.

The vacuum lines are a definite weakness of the spi mini, that's just how it is. We as spi owners know about it and should be servicing them as needed. Luckily it takes less than 5 minutes to replace all four.

[Alpenflitzer]

The connection of 3mm Samco Motorsport silicon pipes on the nipples is not only 100 % vacuum tight it is even better than with the originals.

 

Reason: If you put the elbow on the nipple to far in, then it is blocked.

[IainStallard]

Thanks you all for the advice. I have had the standard vacuum tubes replaced on each occasion I had the issues. They dont seem to last long which is frustrating. Hence why I'm exploring this option. A good samaritan who helped me out on the London2Brighton Run earlier this year when the black vac tube melted, was the one who first suggested the silicone conversion to me. He had done the same done to his Spi Mini Sidewalk. Unfortunately I didnt get the chance to speak to him in depth about the what he did because we were in a dangerous spot fixing my Mini to have a chat. Never saw him again when we got to Brighton. A few of my Instagram followers also suggested using silicone vac tubes to solve the issues once and for all. I'll let you know how I get on.

I think your problem lies in the routing of the pipes. Since you say it melted suggests it is routed too close to the block.
Using silicon I would be concerned with whether or not the provide a tight seal on the nipples.
The vacuum lines are a definite weakness of the spi mini, that's just how it is. We as spi owners know about it and should be servicing them as needed. Luckily it takes less than 5 minutes to replace all four.

I was the person who helped out on that rather hot day! I've still got my Samco 3mm silicone vacuum hose and had no issues with it. I've routed it all around the pedal box so it's out of the way. Not had any issues with it sealing and seems to be far better than original

[Sprok]

Any photos of them at all ?

[minimat]

I think i used 4mm internal diameter silicone vacume  hose but it still seems a tight fit and so much easier to fit than the original pipes not to mention it was under 3 quid for a metre which is plenty just run plenty of pipe so as to avoid kinks etc. No problems so far and its been on over a year, still hasnt fixed my intermitent idle hunting though but that problems been there for years , some days perfect, other days hunts about.

[katsuro]

Any photos of them at all ?

 

Here is a short video clip of one of the silcone hoses (red) running from the ECU to the back of the injector assembly: https://www.instagra...m/p/u2n3Nih3Dc/

I made the one to the ECU longer than the OEM plastic one so I can route it far away from the hot manifold which melted it. 

The rest of the pipes are blue. I matched their lengths with the OEM ones. Here's a photo showing them under the air box: https://www.instagra...m/p/wMVf_KB3Cq/

 

Installed these 4 years ago and I've not had a vacuum problem ever since. 

Edited by katsuro, 13 November 2018 - 10:15 PM.

[Sprok]

Thanks they look way better