Lehman 120 - Temp and Oil Pressure sender thread size

[slowbutsteady]

Hi All,

81' CHB 34 trawler owner here. I'm replacing my old original AC delco temp and oil gauges both at helm and flybridge with modern VDO ones. I'm looking at dual station senders and am wondering if anyone knows the thread size of the temp gauge sender. I'm not able to get to the boat for a bit and want to buy the right one.

If I had to take a guess based on what I see in the lehman owners manual in the exploded diagram I THINK its 1/2 npt. This is for the sender location under the expansion tank on the port side. The oil pressure sender I'm a little less worried about as it appears the thread is pretty commonly a 1/4 npt.

Thanks in advance

 

[slowbutsteady]

Hi Folks, I didnt get any traction here but I figured I would reply with the answer to the question for any other lehman 120 owners out there. I spoke with Brian at American Diesel and not only did he have the right gauges and senders for my replacement, but also confirmed the thread size which I'll share here for you.

The temp gauge sender that is on the port side of the engine under the expansion tank is a 3/8" NPT thread.

As always, I suggest you call brian at American Diesel if you have any engine side work you are doing - he's heard just about everything from us vintage lehman owners and can tell you a lot. Turns out he had dual station gauge package kits for my oil and temp gauge replacements AND he saved me about 100 bucks over the vdo gauges I was looking at with a better product for a cheaper price (Vee Three Gauges)

 

[Comodave]

I just saw this thread. If I had seen it earlier I would have referred you to Brian. He is great.

 

[CharlieO.]

Hi Folks, I didnt get any traction here but I figured I would reply with the answer to the question for any other lehman 120 owners out there. I spoke with Brian at American Diesel and not only did he have the right gauges and senders for my replacement, but also confirmed the thread size which I'll share here for you.

The temp gauge sender that is on the port side of the engine under the expansion tank is a 3/8" NPT thread.

As always, I suggest you call brian at American Diesel if you have any engine side work you are doing - he's heard just about everything from us vintage lehman owners and can tell you a lot. Turns out he had dual station gauge package kits for my oil and temp gauge replacements AND he saved me about 100 bucks over the vdo gauges I was looking at with a better product for a cheaper price (Vee Three Gauges)

Hey Slow, I'm interested in knowing what you bought from Brian, It is a maintenance project of mine to do the same refurbishment.

Thanks.

 

[Cigatoo]

Hi Folks, I didnt get any traction here but I figured I would reply with the answer to the question for any other lehman 120 owners out there. I spoke with Brian at American Diesel and not only did he have the right gauges and senders for my replacement, but also confirmed the thread size which I'll share here for you.

The temp gauge sender that is on the port side of the engine under the expansion tank is a 3/8" NPT thread.

As always, I suggest you call brian at American Diesel if you have any engine side work you are doing - he's heard just about everything from us vintage lehman owners and can tell you a lot. Turns out he had dual station gauge package kits for my oil and temp gauge replacements AND he saved me about 100 bucks over the vdo gauges I was looking at with a better product for a cheaper price (Vee Three Gauges)

Thanks so much for following up with your results! That is what makes this forum so valuable. Thanks again!

 

[slowbutsteady]

Hey Slow, I'm interested in knowing what you bought from Brian, It is a maintenance project of mine to do the same refurbishment.

Thanks.

Hey Charlie, Brian had a kit that includes the two gauges for helm and flybridge and a dual staton sender for $100 bucks each (I bought one kit for the oil pressure gauge, and one kit for the coolant temp so $200 total). He said the brand was Vee Three.

I also bought an expansion tank gasket JUST in case I have to remove the expansion tank to get at the temp sender. Its in a tight spot but Brian seemed to think I could cajole it out with a straight wrench and some light swearing.

Oh, and the oil pressure sender is a 1/8" npt but the outlet on the engine is a 3/8" npt that commonly has a bushing to reduce it to 1/8". that said if you are replacing your oil pressure sender just have a look to make sure it has that bushing. It probably does as I haven't seen any oil pressure senders with a 3/8 npt thread (yet)

He also gave me some great info on heat exchangers and oil/trans coolers but thats for another thread

Some pictures of the gauge kits in question:

825-0800_gauges_and 825-0502_sender.JPG

ADC_Gauges.JPG

825-0820_gauges_and_825-0822_sender.JPG

 

[CharlieO.]

Thanks for the info, looks good. I need to redo the tach and voltmeter also. I haven't really looked into any of this stuff yet but is a project coming soon along with an alarm panel for Bilge switches/counters with High Water and for Exhaust Temperature warnings.