New valves

"New stronger springs" installed when you rebuild the engine may help...most noteably if the old ones are worn out or broken, but as Zane has pointed out, it is very likely a combination of factors, not just valve springs that causes the engine to need attention.

We've been running a 52 8-N for the last 15 years.
Over that time span it has gone from a good strong tractor, to one that is very hard to start, and lacking in power.
It is used mostly for general grading and landscaping, so the (gradual) power loss has been acceptable.
Last fall, after having to pull it to start when needed, the decision was made to tear it down over the winter.

The first thing we found, was badly burned exhaust valves on # 2-3-and 4 (#1 was ok).

Large chunks of the valves were burned away...amazing it would run at all!

Probably a waste of time, but after installing the new valve assemblies (all of them) we're going to reinstall the head temporarily to check compression levels.

Had 90# on #1 but because of the burnt valves the others were rather low...20#

More to come.

Rob

If you do buy new valves you must re grind the valve seats in the block in order for the new valves to properly seat. If you fail to re grind the seats you just think you now have a poor running engine compared to what you will have then. Poor running engine is likely caused by any of a number of things that are not right with the engine such as ignition, ignition timing, fuel to air ratio wrong, bad plugs or wires or points etc and on and on. About the only thing that can happen to the valves on the N engine that will have any big noticable effect on the way the engine runs is if it has a burned valve or sticking valve/s. The valve stems and guides can be worn so badly that they wobble in the valves wobble in the guides and the engine will still run fairly good if everything else is in good condition that I mentioned earlier. It is almost impossible to have sticking valves in one of these old engines that has lots of time on it because of the clearance that has worn in the stem to guide relationship.

What do you call "poor" running????

Zane

Good luck,
Dan