The new-to-me truck is a '42, but the motor is an 8RT Flathead, made sometime between '48 and '53. Here's a quick five-minute video, halfway through:


It's been sitting for a number of years, at least a decade. It seems at least some of the valves are stuck open.

How best to remedy this? Major surgery? Or is there a less invasive option?

 

Remove the intake and bathe with your snake oil of choice?

 

old timers swore this stuff was the best

 

Agree with pulling the intake, so you can see if it's the valves or the lifters that are stuck.

 

Pulling the intake also means you don't have to drain the water or do any other extra work besides generator and carb.

 

Bingo, was getting irritated at the thought of managing that coolant.

Thanks!

 

Bingo, was getting irritated at the thought of managing that coolant.

Thanks!

 

Aha, good extra reason I hadn't thought of.

Thanks!

 

Everybody keeps sayin' that!

Guess I'm going to have to jump on that wagon 🙂

 

Good solution, thanks.

 

> Remove the intake and bathe with your snake oil of choice
> Agree with pulling the intake, so you can see if it's the valves or the lifters that are stuck
> Pulling the intake also means you don't have to drain the water or do any other extra work besides generator and carb

Thanks to all who chimed in on that. @moejr , I went and bought a gallon of the stuff.

After a measure of debate, we decided to pull the heads after all. We wanted to get a better look at what's been going on inside this motor. The pistons and cylinders look good.

But BOY did I have to whack on some of those valves to free 'em up! I was able to get all but the final ones—#5 & #7 exhaust—with a rubber mallet, but I had to break out the brass drift for those two. #7 was the worst. After a hefty give-it-all-ya-got with the side of my 28oz framing hammer, it finally broke free. Have a look—this punch was brand-new this morning:
--
And that was only two valves 🤨

But in the end, the intake has to come off. At least one of the valves spins freely and I can lift it up and down by hand with at least an inch of play. So we're looking at broken springs or keepers.

It's just as well—since we're going this far, I don't want to cut corners. (The seats feel pretty rough as well—I've been concerned about that.)

Here's the latest video:
Thanks for all the help so far 🙂

 

Welcome to you and your Marmon Herrington.

 

Thanks, I'm hoping to have fun with it.

Shucks, I guess I already am 🙂

 

The here is a small number here that have them.

 

MHs or SnoGos?