N Board Forum - Expanded Thread Page

Subject: Stuck Valve Or Worse

[Back] [Return to Top of Forum]

Charles Hudson    Posted 07-23-2020 at 16:56:10 [URL] [DELETE]        [Reply] [Email]  
  • Stuck Valve Or Worse
  • I'm keeping this brief but can provide more background if needed.

    My '48 8N runs but roughly at higher engine speed. Battery, spark gap, wires, points all have been checked, seem to be in spec. I suspect a stuck valve may be part of the problem. I ran a compression test and got 90#, 100#, 30# and 60# front to back.

    Because I have never worked on this part of the engine I thought I would ask here for advice. Should the manifold come off? Should the carburetor come off? Anything else?

    When I have removed the covers what am I looking for? If I find a stuck valve (open, I hope) what is the recommended procedure to try to loosen it?

    When I replace the covers, what should I be careful to do or not do?

    I have the manuals but I don't see much on the subject there. Thanks for your suggestions.

    Charles Hudson    Posted 07-24-2020 at 13:01:19 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stuck Valve Or Worse
  • Just returned from a visit to a local tractor repair shop. Visit was regarding another, unrelated problem with the 8N: The right rear wheel, a 28x11.2, has leaked at the stem. The tire does not hold air for more than 24 hours.

    The tractor has a front-end loader - I think it's a Dearborn - and has always been stored outdoors. To provide ballast for the FEL the rear tires have been "loaded" with a chloride solution. Evidently that has taken its toll.

    The tractor repair shop owner was not encouraging: he advised me not to put any money into tire repair unless I was willing to perform engine repair ($2000 "basic"; $3000+ "deluxe"). The tractor might run, he said, but "couldn't get out of its own way". He also advised me to scrap the FEL entirely; said it was "junk" and "lethal"; said he couldn't give them away.

    I could probably do most of the rebuild work myself, but my problem is that I don't have a workshop or barn in which to do the work. I could scrape together the funds but the time involved might be a problem, and winters here are long and cold.

    I got the tractor to handle logs. You could argue that I got my money's worth out of it and should let it go. I hate to do that but you could also argue that any money spent repairing this 8N would be better spent on a newer and more compact tractor, albeit one with hydraulics.

    Any opinions? Thanks.

    Bruce(OR)    Posted 07-26-2020 at 00:02:16 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stuck Valve Or Worse
  • My 2 cents is try the snake oil cure and see how the engine works out. As for the rim, you can pick up a new one for about $110, with some 12Ga plate steel, a hammer with welder and possibly a torch, you can fix the old one. Simply put, grind off the rusty metal, Spot weld the patch to cover the hole. Heat with torch, beat around the hole in the same shape as the rim. Drill a new hole 180 degrees away from the patch for the new valve stem. You might also need to heat that area and beat the valve stem hole flat. Grind smooth so the inner tube doesn't get pinched, reassemble.
    Oh! Draining the fluid can be done with a 55 Gallon plastic drum, a hose and compressor. With tire standing up up, valve stem on the bottom, remove the core.
    Slide a hose firmly over the valve stem. Put the other end of the hose into the drum. When it stops draining, blow compressed air into the hose. The air goes into the tire, expands it and with the air removed will force more fluid into the barrel.
    Once it stops draining, lay the tire at an angle and repeat getting out more fluid. You will wind up with about 1/2 gallon remaining in the tube.
    Gemplers sells the fill valve for one, there are other suppliers.
    I have personally not filled one yet, just drained.
    FEL handling can be improved with truck tires, 225/75R16. Flat tread is easier to work with with an FEL. Your steering links on top of the steering knuckles can be lengthened about 1.5 to 2 inches. That will make steering easier with an FEL.
    However that will also increase the distance you need to turn around. Not a problem if your individual brakes are working. Simply use the brakes to assist turning.
    Handling logs should be done as low as possible to the ground.
    Comp checks are usually not accurate until the engine has been run to operating temp, pull all plugs and see what you get. Add a teaspoon of oil to each cylinder, then repeat it. A good cyl will show no increase in comp. Weak rings will show a good increase and bad valves might not become apparent dependent upon how much oil gets thrown up on them to assist sealing.
    Have fun!
    Others with far more knowledge will be along shortly.

    Charles Hudson    Posted 07-26-2020 at 07:50:54 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stuck Valve Or Worse
  • Thanks, Bruce, for your advice about wheel repair and the tips about front-end setup. I use the FEL to raise logs off the ground as I section them. I have a couple of chainsaws and a log splitter and the final destination is the fireplace or wood stove. I have a five-acre, mostly-wooded lot, old growth; maple, poplar, oak, beech and ash.

    I priced out new rims, tubes and tires - but not 110# of calcium chloride - and came up with a little less than $1000. A rebuild kit for the engine is about $350 to $500, parts only. Clearly the big expense in all of this is the "expert" labor.

    I can and have rebuilt engines from the crank out before - they even ran afterward! The lack of an enclosure to work in is something of a hindrance but if I can get the tractor on its feet I may be able to move it to a suitable space.

    I'll service the distributor again and re-run the comp test following your procedure.


    Jack - Iowa    Posted 07-25-2020 at 07:05:59 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stuck Valve Or Worse
  • My opinion is, I would find a different consultant! He is certainly a negative person.

    As for the front end loader: Do you use it? Does it do what you want? If so, it is not junk but has value to you.

    You already know if it will "get out of it's own way"! Does it handle the tasks you put it too?

    Yes it has a weak cylinder. But again, Does it do what you want it to do?

    I believe there have been a number of postings regarding adding hydraulics to these old girls.

    As a youth I drove a '39 Ford from SE Iowa to Seattle, most of the time hitting on 7 cylinders. Over the Rockies in high gear which was a huge disappointment.

    Your money, your time, your choice. My 2 cents. Here is Iowa we also know long, cold winters some years.

    Good Luck,

    Jack - Iowa

    Charles Hudson    Posted 07-26-2020 at 08:04:27 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stuck Valve Or Worse
  • Jack, thanks for your reply. Actually, this mechanic was the second source I contacted and was more positive than the first, who told me he wanted no part of my old tractor as it was not worth working on. "It might be worth $1500," he said, "and at my labor rate of $110 per hour I will blow through that in no time." Fun guy.

    The tractor has a use; it performs certain tasks well that are difficult to accomplish otherwise. I bought it because of the FEL, the 3-point hitch and the PTO. I have other attachments for it as well, acquired over the years, and a comparable replacement would likely cost more than the necessary repairs.

    I have to admit to an affinity for anything that runs on gasoline and a love of finding out how old things were designed and built. Bessie and I are almost the same age, and I'm not as strong as I used to be, either. But we're both pretty stubborn, and neither of us is going anywhere yet...

    Thanks for your good wishes.


    Scott    Posted 07-26-2020 at 19:57:18 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stuck Valve Or Worse
  • If your budgeting a rebuild, plan on about $1100 for machine work. That should cover a pretty comprehensive rebuild. This is machine work only-no parts or labor. Good luck with it

    8n13325    Posted 07-23-2020 at 21:49:35 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stuck Valve Or Worse
  • Uncle Vern would pour transmission fluid down the carburetor for a sticky valve.
    Watch him do it to the old Plymouth in the field back in 62-64.
    Mystery oil would work to, seen both used on the farm.
    Stinky ass sheep.
    Damn good lamb chops.

    Tim Daley(MI)    Posted 07-24-2020 at 09:11:40 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stuck Valve Or Worse
  • The old timers had many of their own 'cure-all' myths for engines. My late Uncle Bernie told me to use STP Oil Treatment in their (now mine) early 9N for improved engine life. Even today, many 'snake-oil' products are sold and the consumer who doesn't do his homework will believe and buy anything. There is no 'Mystery' to MMO and many other products. The main ingredient is plain mineral spirits, a very effective thinner and cleaner.

    74% -Mineral Oil

    25% -Stoddard Solvent*

    1% -Lard

    *Stoddard Solvent is defined as Mineral Spirits, for one.

    You'd be better off buying a can of mineral spirits at NAPA or paint thinner or plain charcoal lighter fluid -it's all the same. You can for a list of product MSDS sheets on our SAFETY forum to see for yourself.

    Tim Daley(MI)

    Tim Daley(MI)

    Bruce(OR)    Posted 07-23-2020 at 18:12:48 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stuck Valve Or Worse
  • Comp check was cold or hot? Wet or dry? Open or closed throttle? 6 or 12 volt?
    Stuck valve would not give any pressure, ~zero~

    Charles Hudson    Posted 07-24-2020 at 10:59:52 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stuck Valve Or Worse
  • This is a six-volt system. Before testing compression I removed all plugs, the throttle was open and I pressed down the clutch pedal while cranking. The engine was cold and the test made without adding oil to the cylinders, although I had added oil the day before when starting for the first time this year. The engine had been warmed up several times since then and the extra oil had burned off.

    Before making this test, and in order to get the tractor started the day before, I had removed, cleaned and gapped the plugs and removed the distributor to clean and set the points. Static timing is as good as I can get it; I have ordered the timing jig from Windy Ridge Farm and Machine.

    The tractor starts readily, runs a little rough at 2/3 throttle, runs better after a little warmup, starts breaking up as throttle advances. Could be a bad points condenser / capacitor, could be stuck advance weights in the distributor (went through that last year) or could be a sticking valve. I thought I had eliminated the first two but I can recheck if you think it can't be a valve.

    [Back] [Return to Top of Forum]