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Help with throttle valve

Posted: Mon Aug 13, 2018 3:46 pm
by gfdmatt
Hey guys,

I am posting this for a friend of mine. He bought a nice little engine that he is attempting to get going again. The only identified issue is the throttle valve which was diagnosed with a significant leak.

I have attached photos of what came out of the locomotive. Would it be best to rebuild what he has, or is there another option to replace that throttle with something similar or better?


Re: Help with throttle valve

Posted: Mon Aug 13, 2018 5:42 pm
by Soot n' Cinders
I don’t see any reason that throttle can’t be reused. Just get some lapping compound and take some time to lap the slide and body to each other.
Another question is how bad is the leak? Every valve is going to leak some amount. A friend of mine who spent his career working on the D&RGW narrow gauge K series says he’s never found a locomotive that doesn’t have leaks

Re: Help with throttle valve

Posted: Mon Aug 13, 2018 6:03 pm
by Marty_Knox
I would rebuild what you have. The Allen throttles work well if you put a little work in them. You will need access to a lapping plate and some Timesaver non-embedding lapping compound. The disc and seat both need to be flat. Once they are flat, you need to lap the disc to the seat. You need to put a stainless steel spring in the arm behind the disc. It also helps to put a spring on the post to hold the arm against the throttle body.

Re: Help with throttle valve

Posted: Thu Aug 23, 2018 6:38 am
by Vance Nickerson
I have a few spare throttle castings for Allen boilers but like Marty said fix yours. The more time you spend on it the better it will work.

Vance Nickerson

Re: Help with throttle valve

Posted: Fri Aug 24, 2018 1:52 am
by gfdmatt
Awesome, thank you guys for the feedback. It's much appreciated.