oil pressure gauge

So after 14 months of meticulous work, my first aircooled build fired up in the van this afternoon. Before I go any further I thought it would be wise to fit an oil pressure gauge to monitor the running-in process. However, the only gauge/sender I can find is a VDO 80psi from Megabug. Will this be OK or should I wait until there is more choice from alternative suppliers? None of the usual suppliers seem to have anything in stock at the moment, which has been the ongoing theme of this build.

 

80 psi is a pretty good max range. .typical cold start might hit 60+, running pressures being say 15 to 45 psi..

I have a gauge based on a cheap sub £20 chinese analog sender that produces 0.5 to 4.5 volts for 0 to 100 psi that actually maxes at 105psi and it was only with a faulty pressure relief valve, -5C temperature and 20W50 oil did it ever hit the max.

I think the problem is that not many analog gauge setups are being manufactured any more, so it may be more a hunt than a wait to find more stock, or you may need to go to motorsport suppliers e.g. Demon Tweeks have a couple.

 

A 5 bar (~72 psi) gauge should be fine for your van. It's what I've got in mine. If you've got good oil pressure, it should hit around 3 bar most of the time, dropping a bit if you're tootling around with hot oil. Max oil pressure (determined by the relief valve) is about 42psi (3 bar) anyway.

If you're hitting 60psi, there's something wrong with your engine.

Worth fitting an oil temp gauge as well.

 

My pressure gauge is not as damped as a lot of mechanical gauges, and the engine is about 35000 miles on from being a new build on a new engine case from the VW Engine company. As it settles to the 36-42PSI region at speed once the oil warms up, and 16 psi at idle, I dont think there is anything wrong there.

 

Thanks. Already have an oil temp gauge. Went for the VDO from Megabug. Bit pricey but what can you do when it's the only option? And I've had so many delays with this project. I had to wait months for some engine parts.

 

The 5 bar one from VDO will be fine, if that's what it is. Be aware that the 1/8" NPT sensor thread isn't quite the same as the 10mm x 1.0(?) hole in the crankcase that VW made, so don't go mad tightening it up.

 

If you want a 5 bar VDO gauge I have a new one I don’t need. But it’s in France.

 

In other words, I'll need an adapter.

 

Not...necessarily. The standard straight-sided oil pressure hole in the case is 10mm, with a taper on the pressure switch to seal (a "keg" taper). 1/8" NPT by coincidence is very close and might seal ok, but the oil hole threads take a right beating and might not like being too stressed.

Adaptors do exist, tho'

 

Just had a quick measure-up. The oil pressure switch is M10 x 1mm (tapered).

 

Great, Megabug just canceled my order. Back to square one again

 

If you don't mind a digital one I can recommend Dakota Digital.
Sit down before you look at the price though.

 

The adaptors commonly sold can be a bit awkward..
The end facing the left is very close to the tinware.



That has the analog sender on the left e.g.https://www.ebay.co.uk/itm/16605628...QOYZ9GYR8i&var=&widget_ver=artemis&media=COPY


0.5 to 4.5 volts for 0 to 100 psi.


I managed to find an electrical pressure gauge with sender on eBay for £5 new. Shockingly cheap..
Probably the sender is junk but the meter might be modifiable to go with the analog sender above.

https://www.ebay.co.uk/itm/13484956...QOYZ9GYR8i&var=&widget_ver=artemis&media=COPY

I think I will hit buy it now to take a look ..

 

Why did they cancel? Most odd.

 

I'm not after anything super accurate. That's going to cost. I just need something to initially monitor the startup and break-in process. I've found a new VDO 5bar in Germany for a similar cost but it will take a couple of weeks to arrive.

 

Items unavailable. So why indicate that they are in stock? Still showing as in stock now.

 

Finding a matching 5 bar/80 psi VDO Senders isn't a problem. There seem to be plenty available with different thread sizes. Also plenty of options for reducers and adapters to make them fit. I'll be fitting a sender with the twin contacts, so if I use a short adapter it shouldn't foul any of the tinware. 100 psi seems too high. The critical area to be read is way down on the scale making it difficult to read. I did see a 70 psi gauge but couldn't find a guaranteed compatible sender.

 

The 5 bar one is the one to go for, otherwise as you said, you'll only be halfway up the scale with normal oil pressure.

Sure you're aware, but the pressure switch in the dual senders operates at a higher pressure than the (very low pressure) stock switch, so you may get a flickering oil light when hot. Could fit a t-piece with just the pressure sender and a stock switch.