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Sat Dec 01, 2018 11:29 am

What thread size and pitch is the oil pressure sensor hole in an AS 41 case?

I tried to use both a 27 tpi (1/8 npt) and a 1.0 thread gauge on an idiot light sensor. The 27 fit better than the 1.0. I'm just a little surprised that the hole is tapped npt instead of metric.

Olli

Sat Dec 01, 2018 11:43 am

They are 1/8" pipe threads. At least some of the senders or universal liquid oil pressure gauges are. Check this out: Oil pressure switch thread size?

Sat Dec 01, 2018 12:00 pm

That Explains why so many cases get like this, I just use JB-Weld on a cracked one. If I have a case that is not cracked I use Teflon tape and take great care not to over tighten the fitting or sender to it.

Sat Dec 01, 2018 12:27 pm

Yep. I found out the hard way.

Sat Dec 01, 2018 12:37 pm

They are NOT 1/8" NPT, they are 10mmx1. The two are nearly identical except 10x1 is 24.5 threads to the inch and NPT is 27 threads to the inch. If you buy the correct sender they are 10x1 and do not interchange with NPT.

Sat Dec 01, 2018 1:09 pm

Everything on a VW engine is metric thread. Nothing on a VW engine is American SAE threads.

The only fastener on an entire VW that was American SAE threads were the bolts that secure the seat belts.

Sat Dec 01, 2018 3:13 pm

I asked the same question a while back. I got the correct answer from these guys. Sorry, didn't check but same folks may be answering u now. Thx, Dennis.

https://www.thesamba.com/vw/forum/viewtopic.php?t=708397&highlight=

Sat Dec 01, 2018 6:05 pm

It was 10x1 metric, metric pipe is the worst. Feel free to tap it to NPT, but once you do it.....no going back, or maybe you can...but...well you know, only a virgin once.

Sat Dec 01, 2018 6:19 pm

M10X1... Close to 1/8 NPT but NOT!

Dale

Sun Dec 02, 2018 5:19 am

OK, 10 x 1.0 seems to be the consensus, makes sense. (metric)

This product page on ACN site really makes you second guess the thread size and type. http://vwparts.aircooled.net/VDO-Sending-Units-s/725.htm

The product descriptions on CB's site also make you believe that it is 1/8" npt.
http://www.cbperformance.com/product-p/2355.htm

http://www.cbperformance.com/product-p/2349.htm

Olli

Sun Dec 02, 2018 7:25 am

I see a wide selection of senders and adapters and plenty of VDO stuff M10x1 on ACN site and CB Performance site.......

Do not understand your confusion...

Dale

Sun Dec 02, 2018 11:19 am

so 10x1 straight thread on the senders and a selfing washer may be better?

Sun Dec 02, 2018 11:44 am

This link claims that the threads are 1/8"-27.

http://vwparts.aircooled.net/VDO-300F-Oil-Temp-Sending-Unit-1-8-X-27-NPT-p/v323057.htm

Do you now see the confusion? The links that I posted from CB's site also claim 1/8". I never said that either vendor does not sell M10 x1.0. The question is what is the correct thread size and pitch.

Olli

Sun Dec 02, 2018 12:16 pm

1/8 - 27 tapered is the same as 1/8" Pipe, or 1/8" NPT. It's 6s or half dozen, your choice how you describe it.

The original threads were 10x1mm TAPERED, but the 10x1mm senders out there are straight, and designed to seal against a true, flat surface with a copper sealing washer.

The tapered threads are self-sealing, but I do recommend a thread sealant. 10x1mm and 1/8 NPT are virtually the same. I've been using 1/8 NPT for over 35 years without issue ever.

Sun Dec 02, 2018 12:25 pm

Olli from NJ wrote: This link claims that the threads are 1/8"-27.

http://vwparts.aircooled.net/VDO-300F-Oil-Temp-Sending-Unit-1-8-X-27-NPT-p/v323057.htm

Do you now see the confusion? The links that I posted from CB's site also claim 1/8". I never said that either vendor does not sell M10 x1.0. The question is what is the correct thread size and pitch.

Olli

There's something weirdly satisfying about a whole thread about a hole thread.

That said: I've had the VDO 360 006 sending unit in the side of my 1835cc engine since 1976. The VDO website itself shows that as 10M x 1 https://www.vdo-gauges.com/sensors/pressure-sensor...-30-2.html

The VDO site confirms TEMPERATURE sender part 323057 (from the aircooled.net link) to be 1/8"-27 https://www.vdo-gauges.com/sensors/temperature-sen...1-9-1.html
But it's the aircooled.net site that states that this fits the oil sender hole, not VDO. So if you want to use a 1/8"-27 sender of any kind, I'd proceed with caution and not overtighten; and adapter might be a better choice https://www.vdo-gauges.com/accessories/adapters-fo...28bsp.html

Sun Dec 02, 2018 1:22 pm

Danwvw wrote: They are 1/8" pipe threads. At least some of the senders or universal liquid oil pressure gauges are. Check this out: Oil pressure switch thread size?
No ther’s not ANY npt, all’s metric!!

Sun Dec 02, 2018 1:36 pm

Why would Germany use NPT, which is an american standard (National Pipe Thread)? Germany uses the SI-system (Système International d'Unités), like like the rest of the world (Minus USA, Myanmar and Liberia...)
Threads on a VW is metric. Period.

Sun Dec 02, 2018 2:48 pm

Had to look up where Myanmar is.

flat4olsen wrote: Threads on a VW is metric. Period.
Seat belt bolt thread pitch is 7/16"-20.

Some claim M11 x 1.25, which you will find impossible to purchase.

Sun Dec 02, 2018 4:24 pm

Something else that can be really confusing, the VDO T-adapter 240-850 is metric M10x1, but aircooled states that it is 1/8-27 (I have measured one with a pitch gauge and can confirm it is actually 1MM pitch):

http://vwparts.aircooled.net/VDO-Sending-Unit-T-Adapter-1-8-27-V240850-p/v240850.htm

https://www.vdo-gauges.com/accessories/adapters-for-sensors/brass-t-adapter-m10-x-1.html

Sun Dec 02, 2018 5:16 pm

Cusser wrote: Had to look up where Myanmar is.

flat4olsen wrote: Threads on a VW is metric. Period.
Seat belt bolt thread pitch is 7/16"-20.

Correct. I think there's a federal standard that requires 7/16"NF on seatbelt retaining bolts on all USA sold vehicles. (FMVSS?)

FYI the HF oil pressure gauge kit ($10?) has an adapter to go from 1/8NPT to 10x1.