Replacing exhaust gasket on 1951 A

From what I read and can see, there is two ways to approach the repair. 1- Remove hood, fan shaft, etc, and leave the head on the tractor. Or, 2- remove the head with the manifolds still attached thru the tractor frame.

I believe the valves are ok on this tractor, but a leakdown tester has revealed that I do have considerable piston ring leakage on both cylinders. There is considerably blow-by thru the oil filler cap while the engine is running as well. Is blow-by normal for this tractor? Power seems to be ok.

Back on the farm in the 70's, we had a 1951 A (same as this tractor), and ours had a problem with breaking the compression springs inside the governor housing on the fan shaft.

So here's my questions-
1- Would it be wise to to do the "pull the fan shaft" route and replace these springs while I'm doing the manifold? 2- Or, should I pull the head and then also pull the pistons to survey the situation, and then just wait on those compression springs IF they ever fail?
3- Or, basically do both?

I don't have lots and lots of time for working on this tractor, but I do want to be sensible about this too and not regret that I took the easy route.

Thanks in advance for quality answers!

I don't think I'd worry too much about that governor spring being broken as your other one musta been a rare problem. Over the years I have worked on and parted out many A's and others and I don't think I ever saw that spring break. A more common problem on those A's often overlooked was worn camshaft bearing on the Left Hand side more than the right. Cracked heads and blocks are pretty common too as are loose and worn clutch drivers and flywheels and of course like all other 2 cylinders the governors bevel gears and bearings are areas of concern.If you are really worried it won't take that long to remove the gov. LH cover and pull out the shaft. Just reuse the old shims and put it all back if it looks good it doesn't cost anything if bad then it costs $$ but then your glad you found it.

Blow by through the filler cap is not NORMAL,but also don't mistake blow by for the air being pumped out by the ventilating pump when that filler cap is removed while running. I guess if it smokes more out the crankcase than the exhaust then you got blow by. I worked on a G for a fellow and he knew he had enough blow by when he was starting to get afixuated (sp?) while driving it from all the fumes coming up out.

I like to pull off the head,do the valves (don't overlook the guides) and resurface the manifold gasket area. Then if you do suspect bad or broken rings (cleaned off oily areas on the tops of the pistons is a real good clue)then it doesn't take much more to pop out the pistons and at the very least $$ stick a new set of rings in.

If your like me you work for yourself for free then it doesn't take too much but time and a few gaskets to pull off some covers and check some stuff out looking for problems that are laying in wait. That's where all my tractor parting out was really helpfull learning tool as you soon see what a good part and a bad one is to look like.

Thanks for the prompt and very informative replies!! LOTS of good info! There is always a better way to repair stuff.

Thinking back about those compression springs... I remember that the tractor suddenly stated using LOTS of oil, and even the John Deere dealer was stumped. However, the local Allis Chalmers dealer had previously been a twin cylinder mechanic and he had to think about it, and then he mentioned it just MIGHT be those springs. Sure enough, the springs were busted to pieces. If I recall, there were two springs total in there.

Ok, so for my tractor..... I plan to take another check at that blow by and then decide whether to replace only the exhaust gasket right now OR roll up the sleeves & do the complete job. Most likely, I'll run it this summer and then tear it apart this fall/winter. I have some small jobs for it starting in just a couple of weeks, so it would be better to get it useable for the summer ASAP.

Thanks again!

Bz Joe