Hi all. Today I am doing post track day repair and maintenance on the Mini MCS. I am continue to be amazed with the things that break and come loose driving on the track. I have to fix something after every single track day this year, and the HPDE yesterday is no exception. I observe the tailpipe drooped down again half way thru the track day, and this morning I thought I would go fix that as it is easy as pie.

Then I observed small oil stains on the driveway under the engine. One thing led to another and I thought the mechanical oil gauge's compression fitting was not adequately tighten. I removed the header heat shield to gain better access and visual sight line. There is a tiny trace of oil on top of the compression fitting. So I tighten it a bit more. Then I notice the green plastic of the stock oil pressure switch connector is charred, evidently from the heat emitted by the header pipes. I know this would not happen with road use.

1) Does anyone who track their Mini do not have charred oil pressure switch connector?

My thought is may be my connector charred because I push the oil pressure switch farther away (about 1.5 inch) from the engine due to the addition of the T-fitting. This further out location is now less in the shadow of the starter heat shield which partially protects it.

the Craven Speed T-fitting I used


I am now struggling my additional of a oil pressure gauge is making my Mini less reliable for the sake of more information.

To my horror, the oil leak that caught my eyes is not the compression fitting. The T-fitting is finger loose . I know I adequately tighten it when I installed the oil pressure gauge. At the time, while it cross my mind as to the suitability of using generic white teflon tape for the pipe thread in application with exposure to engine oil. As the fitting is now figure loose, I suspect the engine oil has dissolved the taflon tape.

2) Does anyone know if white teflon tape is NOT suitable for engine oil applications?

I am glad the Mini is not damaged, and I have been catching all these problems.

Thanks in advance.

 

I googled burned oil pressure switch connector and I found this NAM thread.

It is remarkably similar to my connector though mine is a bit more char broiled


To me it is clear the burn is from the radiant heat of the header pipes. You can see clearly he has a oil pressure sender using a similar (or identical) T-fitting which extends out the oil pressure switch about 1.5 inch. In the photo you can also see the white teflon tape.

 

I think I've gotten to the bottom of it.

here is my charbroiled connector - hurt but not dead



I opine the cause is the addition of the T-adapter fitting which pushed the connector farther out by ~1.5 inch from the radiant heat shadow of the header feeder pipes, and prolonged WOT from driving on tracks. One of my idea is to wrap the connector with a few layers of fiberglass cloth. You can see that MINI already have a heat resistance silicone cable sleeve for the wire.

As to the finger loose T-fitting, I didn't tighten it one more turn for the fear of damaging the boss on the oil filter housing. The oil and vibration of tracking eventually worked it from snag tight to finger loose.

For now I decided to undo the oil pressure gauge until I decide on a satisfactory and bombproof implementation. I am a bit uncomfortable with the nylon line exposing to the extreme radiant heat of the header tubes.

back to the factory configuration


As to the teflon tape, I found no evidence that it is not suitable for used with engine oil. I got like 12 rolls for $5 from Harbor Freight. I prefer it over the $15 a tube of automotive thread sealant.

 

Any thoughts to using some thermal tubing to insulate the wire/connector from the increased heat?

I have the same T-Fitting and was planning on installing it in the near future. Now I of course am not hitting up HPDE as you are, but nonetheless I would still not want a crispy connector.

 

As I wrote above, my idea is to wrap it with a few layer of white fiberglass cloth. Then secure it with a few loops of steel wire. I have plenty of s-glass remnants. They are silver white so very good in reflecting radiant heat of the Mini's infrared broiler. I should bring a piece of steak in the next track day.

 

As yes, right you are, I somehow missed that part of the post.

I am curious to see how the fiberglass works out, I was also kicking around the idea of building a heat shield extension.

Let me know how that steak tastes I am guessing the seasoning will be spot on.

 

A metal shield extension was my first idea. But I scrapped that right away knowing the extreme vibration on the track can do to parts especially poorly constructed and supported heat shield. I have little doubt that fiberglass cloth would be very effective, as well as it breath any hot air. I am going to properly test the heat tolerance of the nylon line of my oil pressure gauge before I will entertain recommission it.

To lose an engine because of an addition of a oil pressure gauge will make me feel really stupid.

 

The negative of Teflon tape is if poorly applied, small bits can break off and work back into the supply line. It's also not a sealant.

It was interesting to read that plumbers tape has actually never been made by the company that owns the rights to "Teflon".

Carry on!

 

I am all too aware of the potential pitfalls of said tape if used by incompetent hands. I read countless fear mongering on the web of it plugs up oil galleries on the engine. So too with specialty automotive thread sealant. I actually like teflon tape as I have always able to retrieve every last fiber of the tape when reservicing a pipe joint.

I don't know why you say it is not a sealant. It is a filler to take up the crevices that between the thread. It performs a exactly what is required for the application - to prevent pressurized fluid from getting pass.

While we are on the subject of teflon tape. I use the same HF tape on natural gas lines while the fear mongers will tell you you must buy the more expensive yellow one designed for gas.

 

This is the reason I can never throw anything away. I found the piece of remnant of the nylon oil pressure line that came with the Autometer mechanical oil pressure gauge that I installed. It is no cheap tubing like most aftermarket automotive gauges that are made in China. It has marking of "airlite s&l nylaflow pressure tubing" with the manufacturing date stamp. Google it and I found the very detailed and complete product specifications.

The tubing is type T which has a melting point of 500F. However the suggest application temp is only 150F. I infer it is this low to take into consideration of plastic creep under the maximum rated pressure.

 

Here’s some unsolicited advice: change to an electrical gauge for your oil pressure, and I think you know why I give this advice. If that oil line were to let go on the track, wouldn’t take much to light the car up on fire. Especially if the factory connector is charring from heat. Probably just a matter of time before the oil line let’s go.

 

Thanks for chiming in. My decision to go with mechanical gauges was not made lightly. Much thoughts and deliberations had gone into it including planning the routing of the lines, and orientation of the fittings.

There are pros and cons with electric versus mechanical gauges. For the price point, the electric one does not come close. I picked up this gauge for $55 shipped. It has 270 degree sweep so you get better granularity over sub $100 electric gauge that has 90 degree of sweep. You can get electric gauge that has full sweep but they run about $240 as they are built with stepper motor instead of cheap electro-magnetic amp meter. I also dislike the oil pressure sender because of the internal diaphragm actuating a potentiometer. The mechanical gauge has no middleman and should be more accurate due to simplicity.

270 full sweep mechanical gauge


$84 electric gauge 90 degree sweep gauge



$240 full sweep stepper motor gauge



This Nylaflow nylon line is very tough. Look at the parameters in the first column above. I think more reliable than old school metal line like the Smith Gauge often used in classic Minis. Their biggest enemy is extreme temperature, and chaffing. They should stand up pretty well to vibration if you strain-relieve them at the right places. I orientated it quite well to avoid exposure to the header radiant heat. When I recommission it, I plan to add a length of heat resistant silicone heat sleeving like that already on the stock pressure switch wire.