willysmjeeps.com

Hi Guys,
Got a problem. Tearing down and starting to rebuid the 134 F-Head engine out of my 1952 M38A1 #10015 and I have orded one set of M38A1 exhuast valves from two different websites and gotten the wrong ones. I have know idea what to tell them when I try to explain that they sent me the wrong exhaust valves.

In the picture, the valve of the left is out of my 134 engine and the one on the right is the one they keep sending me even tho I tell them its the wrong one.

Any help is appriciated.
Thank you,
Mike

I believe the valve on the left is an early exhaust valve (637183) used without the rotator caps. The one on the right is later (800829) and used with rotator caps (800827). The valve on right is the better valve and all you need to do to use them is buy the parts that are used with them. Namely the four rotator caps (800827), four retainers (800828) and the 8 retainer locks 800826) . Or ask them if they show a different number for the L134 exhaust valve (637183) which came without the rotators and order four of them.

The rotator style valves are no longer made. With the unleaded fuel today, you should not be using them anyway. The new type valves require you to use a different type spring retainer and keepers. I manufactured both and have them in stock to make the conversion.
www.midwestmilitary.net
John

John, can you help out with this topic of discussion and post photos of the new parts you supply that must be used together?

Wes,
They are posted on my featured parts pages. Perhaps you can extract them from there and post here.
John

Ah ha, I don't know how I missed those right at the top of the page!

http://www.midwestmil.com/m38a1p12.html

Jeep Exhaust Valve Parts
This is the new style valve to replace the rotator style.
Requires the use of this retainer and keeper set. Rotator style valves are no longer available.
Valve - $17.00
Retainer - $5.00
Keeper Set - $2.50

" Ah ha, I don't know how I missed those right at the top of the page! "


It's an age thing. We're gettin old! But, it happens to everyone.

We're gettin old!

Who's gettin old? I've been there awhile already!

Is this replacement somthing that is recommended on a preventative basis?

If what you have (either rotators or the old system) works then stay with it. The new replacements are a place to go when you can no longer find the older parts. Unless you are doing serious high volume off roading or are putting 20,000 + miles per year on the jeep it will not be an issue.

Thanks!

Unless you know you have hardened seats or you are running an additive int the fuel, it should be considered. The lead in the fuel was the lubricant for the valves. Today's fuels have nothing for lubricant and the valves without hardened seats can chew themselves right into the block. This was evident in an engine I just did for a friend of Wes'. We almost did not have enough block left to put the seats into. So, in this case, I have to disagree with Wes in that even IF the old parts are available, you should not be running them.
John

And of course I must disagree with John to a degree. The harden valve seats and stelite or sodium filled exhaust valves are improvements that handle modern fuels well. The old parts even in early OHV engines do fine under normal use with unleaded gas. Unless the jeep is being driven extremely hard at high RPMs consistently your valves and seats will outlast your piston rings. Also I want to point out that Willys was a very late comer to the practice of building in replaceable valve seats. In early days of L134's the blocks became throw aways if the exhaust seats were damaged or the #2 & #3 cam bores were wiped out.

The engineering behind these issues can be found by googling antique vehicles. E10, E15, and unleaded gas.