Repair/Replace Threads on Briggs FH Head

Hello. I have a head for a Briggs & Stratton Model FH. The threads are all but gone. I would like to know what is the best way to restore this head so that I can get a muffler to screw into the head. THANKS!!

That would be 3/4" female pipe threads I think. I don't know of any "Heli-Coil" type insert repairs for such a thing. They are available for the spark plug or bolt threads. My suggestion might be to turn down a 3/4" pipe coupling and bore out the old threads to accept the coupling. You could silver solder it in place. If you don't have access to that type of machine work, try to repair the threads with some JB Weld. Goop them up and screw your pipe right in and let it dry in place. It should work. You might not ever get it out, but you shouldn't need to. Kevin

Pipe thread Heli-Coil inserts are NOT a problem.


Heli-Coils on MSC

Kevin,

Don't think JB Weld will stand up to heat from the exhaust. Tried restoring threads for a muffler on a Tecumseh lawn mower engine using JB Weld. Didn't last 5 minutes.

Bill

As the threads are PIPE threads and are tapered, howes about just tapping the thread a little deeper. JOE

I have a model Y Briggs that was damaged during shipping (packed upside down). My plan is to braze the damaged area up, dress to shape with a file and rethread. Then I'll have good solid material that will hold up under the heat and vibration. Heat proof paint should hide the repair.

Both FH and Y heads in good shape can still be found. Not being a metal worker I'd probably opt to buy a "new" head.

Steve, In the past I have had the same problems with FI's and other early engines. I have just re-tapped them find a 3/4 npt tap it should work fine ,also new briggs muffler are tappered the farther your screw the muffler in the tighter the fit. Last week I bought a project Fairbanks Morse engine at a swapmeet it came with 2 heads 1 new and 1 used , the used head the exhaust threads looked all but gone (these are 1" npt)so got my tap out of my set and screw it in all the way and back out a couple times , i then took an original fairbanks muffler off another engine , it screw in all the way and didnt wobble Hope this helps ~ Jonathan

Say you FH guys, what kind of timing marks are on crank and cam gear I can't see any?? is it a dot or teeth filed ?? Thanks Guys

Has anyone tried Kevin's idea of brazing, or silver soldering the female coupling threads in the head? The port is shallow so a pipe tap bottoms out before doing much re-cutting of the threads. The cast iron in this area of the head is also very thin. While FH heads are still plentiful, the FI and other rarer model heads are not. A proven fix method would be great.

You dont use marks on a Briggs FH . Go to Antique Small Engine Collecters Club, go to the Technical Data board it tells you how to do it.Dave

Here is a scan from one of our books.

[jeffrey Marhafer]

Originally Posted by junkpluse

Say you FH guys, what kind of timing marks are on crank and cam gear I can't see any?? is it a dot or teeth filed ?? Thanks Guys

I could not find any timing marks on the one I rebuilt,so i made my own,lining them up withe key way

[Sky]

if it were me, since i dont have much BIG machinery, i would end up taking the head to a machine shop to let them oversize the hole and put a bigger exaust pipe in it then reduce it down to the size of the muffler with a cupling or what ever those things are called. i dont have much machinery at all, just a drill press.

[Anthony J. Wiegand]

Here is my 2cents worth. My dad found this fix a thread stuff. I cant remember if it is for hot tempuratures. I believe it was. It looks similar to JB Weld. First you put the glue stuff in the hole, then you put some sort of release agent (included), then put them togethor and let them set. I havent used it yet but I will have to soon.
I hope this helps, Anthony

[Dustin D Ehli]

Anthony i have used the thread repair goop that you are talking about with no success. maybe i did somthing wrong or i am just stupid but i don't plan on trying it in the future.
Just my experience
Dustin Ehli