Dad's NAA - - restoring it for him have lots of questions

My dad's NAA Jubilee will be at my house next weekend and my son & I am planning on fixing numerous projects on it for him, then repainting it for him. I have some background in the F-series Farmalls, but not much in Fords. After the tractor gets here, I plan to do a analysis on it to find out exactly what work it needs before we get to the paint process, them plan the repairs accordingly.

Questions for today are:

1) What wet/dry compression results should it exhibit? How much variation between each cylinder is OK ?

2) The throttle is operating wierdly. Engine speed is controlled fair in the lower speed range, but zips up to full speed very quickly at about mid-throttle range. Govenor also does not like to respond to a load anymore. Thoughts here?

3) Am getting some white smoke after the engine warms up, and he is losing some coolant. Oil never appears to get milky, thus it appears the coolant is leaking into the combustion chamber from a leaky head gasket or a cracked head. Any tell tales of a leaky head or gasket?

4) The tractor used to have a stubby muffler that resided above the manifold and discharged behind the headlight. Dad put a system on it that discharges behind the rear axle. This system has the tube 50% collapsed near the fan area. I am assuming this situation isn't too good for engine back pressure. Any body have any experience with these systems ?

5) Engine used to start at the slightest touch of the starter with no choke. Engine now won't start unless the throttle is parked wide open. Thoughts here?

6) The 3-point bounces every several seconds while a load hangs on it. I am assuming the piston is leaking, and from what I've heard, it is because the open ended cylinder is flaring outwards. Is this cylinder repairable or should it simply be replaced?

More questions will be coming later as we get into the tractor.

Thanks for your wisdom !

Pete

1 - 100 psi is usually the bottom you want in compression on a 134ci engine. I have seen some work fine on lower as long as they are fairly equal between cylinders. You don't want to see more than 10% or so between cylinders ideally.

2 - Governor is gone and needs to be rebuild/replaced. Luckily, the NAA governors are easy - especially is you have the later two-piece front covers.

3 - Here is the bad news - NAA heads were VERY prone to cracking. Mine was and what probably did it in. Here is a pic of mine:

The later Hundreds series and early Thousands Series 134ci heads were improved and a good bolt-in replacement.

4 - I would not worry about the exhaust - most are bent/crimped at some point and doesn't seem to make a difference. Replacements are still available if you just want to replace it.

5 - Too many variables to answer this one - but the white smoke would be the first place I would start.

6 - Could easily be a leaking piston O-ring or valve. The NAA hydraulic valves are VERY prone to bouncing and "if" you can find a replacement valve, and "if" you can find the exact same size (there are 4), and "if" you want to pay the hundreds of dollars to buy it - you "might" fix that bounce. Most just live with the bobbing. I rebuilt my hydraulics three times and while it will hold a very heavy old mower completely off the ground for over 15 hours overnight - it bobs while mowing.

Check out my NAA photo log below if you want to see what an NAA looks like completely taken apart and put back together.

Good luck,
Dan

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