gauge fitting help

[VeeDubGTI16v]

yo, im fitting some mechanical gauges and am trying to figure out what i need to install them. can anyone explain what is meant by NPT, BSP and UNF? all threads seem to be labelled this way 

[topher]

It's just the type of thread, NPT = National Pipe Thread (american), BSP = British Standard Pipe thread, UNF = Unified Fine thread (u.s and canada).

That one day plumbing module i did at college finally came in useful for something

Seems odd that they're all labelled different?

[VeeDubGTI16v]

yeah theres loads of sizes available. Are there pitch sizes associated with them?

[yossarian]

Hi,

I thought I'd resurrect this thread as I can't see another relevant one to my question. I hope that's OK.

VeeDubGTI16V, I'm looking to fit some mechanical gauges into my Mk3 2.0 16V GTI for Oil temp, Oil pressure and Water temp. The car will do trackdays only next year and I want to make sure the basics are taken care of before painting on the go-faster stripes!

Where did you connect your gauges to, and what were they please?

I've seen some Mocal gauges for a good price and want to snap them up. But only if they will fit.

Thanks in advance.

Yossarian

[Paul86S2]

Connect your oil pressure gauge sender to the top of the oil filter housing. Get a sender with either a low or high pressure warning switch and it will save you fitting it into a T piece which can mess up your readings.

Connect your oil temp sender to the spare port at the back rh side of the head.

Thread size for the senders is M10x1

Paul

[yossarian]

Hey Paul, thanks for coming back to me on this. I didn't get an email through telling me the thread had a reply, so thought it had been ignored...My bad for not checking back, sorry for the delayed response. I've checked the option to notify me of responses now! 

This could be as stupid question, but you talk of sensors whereas my question relates to mechanical gauges. It's probably just semantics, but I would have thought there would be some form of diaphragm-based setup for the oil pressure gauge rather than electrical senders for mechanical gauges? Ideally I'd like to retain the original buzzers and lights etc.

Oil temp sounds and looks straightforward enough, so I'll give that a go.

Final question is coolant temp. Will i need to cut into a hose, or can I just t-off somewhere.

I've attached a pic of the type of fitment connected to the engine-end of the temp gauges as they come direct from Mocal (oil and water are the same). the brass nut with thread (possibly some form of adapter, although by eye the thread looks the same) can be removed.



Thanks in advance

[Paul86S2]

To fit the temp sender into the spare port in the back of the head you will need an adaptor. The temp probe is too long to fit into the oilway (they all are) so you will need a long adaptor with a male thread size m10 x 1 and a female thread size to suit the thread on your temp gauge, as on this page from demon tweeks

http://www.demon-tweeks.co.uk/Motorsport/Gauges_&_Instrumentation/Gauge_Pipes_&_Adaptors/LMA_Gauge_Sender_Unit_Adaptors/1773/1847

For the water temp you will need to cut a hose and insert a take off adaptor similar to the one on the following link, and specify the take off thread to suit your mechanical temp sensor (you can get these cheaper elsewhere)

http://www.demon-tweeks.co.uk/Motorsport/Gauges_&_Instrumentation/Gauge_Pipes_&_Adaptors/Revotec_Aluminium_Hose_Adaptor/1773/5863

For the pressure gauge you can use a T piece connector in place of one of the pressure sensors in the top of the oil filter housing. Screw in the T piece and then connect your mechanical gauge sensor into one of the ports and the original pressure sensor into the other port. Thread size into the top of the oil filter housing is M10 x 1  and the thread on the sensor is m10 x1. The other port you can specify with the thread on your sensor. Available from Demon tweeks and other places.

Some people say you shouldn't use a T Piece with pressure sensors because it can cause foaming of the oil and give you a false reading, I never had a problem with mine and all the shops seem to sell them.

Hope this helps a bit

Paul
               

[yossarian]

 
Paul it helps a lot, thank you for taking the time to provide such a thorough response. I am now confident I know what I need and what to do. You're a true gent - Cheers!

Yossarian

[VeeDubGTI16v]

im gonna ditch the capillary/mechanical temp gauges, they are too fragile! have already broken one water temp one and the one on there now has started to develop a wobbly needle

the mechanical oil pressure gauge is staying though

but if you want to go that way the best place fir the water temp is with an adaptor on the top rad hose, and for the oil weld a threaded plug into the sump

[yossarian]

Thanks veedub. That's exactly where I was going to put the water temp, so it's good to know it's been tried and tested. Why did you put the oil temp into the sump? Was the back of the head not accurate enough? If I went for the sump, I'd probably get one of those sump plugs with a thread inside for the sensor.

Has anyone got any experience of these please?
Cheers