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Subject: 8N Newbie, need advice

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Cliff    Posted 09-04-2020 at 15:23:49 [URL] [DELETE]        [Reply] [Email]  
  • 8N Newbie, need advice
  • I've just purchased my first tractor, of any kind. An 8N that runs pretty good but has been neglected. It had a 12 volt conversion and I already had to replace the starter and Bendix drive. Cleaned the oily plugs and ran the machine all day pulling downed trees that I cut up into bite size pieces. Pulled the plugs again and they were covered with oil and carbon. Looks like I'll have to get into the engine. Questions: How difficult is it to pull the cylinder sleeves? Can I do the job with the engine connected to the rest of the tractor? Will the crank be in the way of a sleeve puller? While I'm into the engine I'll do a valve job as well. This will be a working tractor. Any and all help is appreciated.


    Bruce(OR)    Posted 09-07-2020 at 07:48:45 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • I'll throw 2 cents in. 20 PSI hot oil would NOT be getting an overhaul.
    I read most of the post and I didn't see plugs mentioned.
    Autolites work better than a whole bunch of them. Or at least used to. The manufacturing went off shore, south or east and the QC can be a shot in the dark from what I have heard.
    Your running 30 W oil and good enough for lawn mowers, I might step it up to 15/40.
    Shell, Chevron being the two most used. I used to work at a Shell gas station. I won't use their oil in anything. IMO.
    You might also be able to get a hotter range spark plug. Example being Autolites and going from, say a #26 spark plug to a #27. That hotter plug can stop plugs fouling.
    A catalog search might show you available heat range plugs for your engine.
    Another option, is a set of "anti-foulers" that screw onto the ends of your plugs and remove the electrode from the cylinder and protect it. Problem is the electrode was designed to be in the plug hole for a better burn and while it would take longer to foul out a plug, your not doing your engine any favors.
    Yes, I have seen engines running anti-foulers and a hotter range plug. Poor engine.
    12V conversion.
    Are you still running a .025" gap? If that 12V conversion was done the right way, widen the gap to .045" Lets try a hotter spark to warm things up a bit.
    That might be a good starting point.
    Mind you, everyone else here that has chimed in before me are more intelligent than I am, which is why you only got 2 cents worth from me.

    Cliff    Posted 09-07-2020 at 19:21:26 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • Plug gap is .025". Machine has front mounted distributor and conventional breaker point ignition. I've never had problems with AC Delco, Autolite or Champion spark plugs in any of my vehicles and equipment in the past. I want to believe that the AC Delco plugs in the machine now are good quality. After all, the engine starts pretty quickly and runs well. So I believe things are not too far gone, and with some care and attention it can be made better without an overhaul yet. My local NAPA dealer stocks many parts for this tractor so I will patronize them and try the NAPA 15W40 engine oil you suggested.


    Bruce(OR)    Posted 09-11-2020 at 12:56:09 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • And if your running a 12V system it should be running a 40K volt coil. That voltage will jump a .045 gap with no problem. Points just open to discharge the coil. That 40K voltage is not on the primary circuit that the points are. A wider gap, a hotter spark and a cleaner burn.
    Champion plugs generally run on the cold side from the catalog. They run good in the old Chrysler's but I have dealt with too many fouled champs in most every other application. IMO.

    Ultradog MN    Posted 09-05-2020 at 11:13:36 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • Unless the tractor is a family heirloom or some such they are no longer worth doing a major reman on the engine. Sad but true.
    What kind of oil pressure is it producing? If the OP is half decent I would just run it.
    Think about it this way:
    What is the tractor worth to you per hour for the work it does?
    Is it worth $10/hour plus fuel?
    If so that means you could run it for 170 hrs and it would have paid for itself in work done. At that point you would be much better off to find another engine to put in it or, start looking for a newer tractor that will do more work and has more features.

    Cliff    Posted 09-05-2020 at 17:54:15 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8N Newbie, need advice
  • That's a good point Ultradog, the tractor runs good with cold oil pressure at 40 psi. When hot it is 20 psi at idle. I'm running NAPA SAE 30. I like the tractor and I feel eventually it is worth the engine overhaul. Even if it is just for personal satisfaction. The machine has already cut down on my workload maintaining my property...as Henry intended.


    Tim Daley(MI)    Posted 09-05-2020 at 06:53:53 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • There has been good advice given already by the others, so I will just ask if you have the ESSENTIAL MANUALS. They are by far the most important tools in your shop. Read religiously. Do you know how to pull correctly with your tractor? That and other safety tips are in the OEM Owner Manuals. Parts are a vital piece and the FO-4 Manual is the most important manual for rebuild and repair of systems. What does the oil pressure gauge read when engine is started from a dead cold start? At idle when warm, it should be about 27 PSI. After it works for while and gets hot, see what it reads then. If half that or less means engine is worn. If under 10 PSI it's time for an overhaul. As stated, don't assume because you have a 12V battery it was switched over correctly. No OEM manual has a 12V job diagram in it but JMOR has put together his "WIRING PICTOGRAMS" which does. What 8N setup do you have -you don't tell us. Is it a front or side mount? No quick fix Band-Aids. DO THE JOB RIGHT THE FIRST TIME.


    *PICTOGRAMS courtesy of JMOR


    Tim Daley(MI)

    Cliff    Posted 09-05-2020 at 18:06:39 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8N Newbie, need advice
  • I will need to learn how to pull correctly and I'll get the manual you suggested. I've already ordered a Shop Manual and a Parts Manual, Carburetor overhal kit and new gas cap. The ignition system is a front mounted type. As far as the 12 volt conversion, I do not know if it was done right but the tractor was used for several years to cut grass with a finish mower. I have no background in farm work, I'm a street kid from Queens, NY. Now at 59 years old I've purchased a house with property in SC and this is a whole new learning experience for me. I'm eager and enthusiastic to learn though. The idea is to start a hobby farm. Beats sitting on my butt watching TV.


    Ultradog MN    Posted 09-06-2020 at 06:01:14 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice

  • "Beats sitting on my butt watching TV."

    Amen brother!

    John in Mich    Posted 09-04-2020 at 20:07:03 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • If you worked it hard all day it sounds like you can get by for awhile. Fouled plugs have numerous causes.
    Is the tractor exhaust smokey? Internal oil leak would, exhaust would be blue. Rich fuel mixture? Rich fuel, exhaust would be black.
    Have you done a compression check? 12v conversion may indicate that the previous owner used that as a bandaid for a weak (low compression) engine.
    How is oil pressure both at idle and at wide open throttle (WOT)?
    What brand are your spark plugs and what heat range? (what is number on the plugs)
    All of these factors have an affect on engine operation and performance.
    Go through all of these before considering an overhaul. Until you can answer all of these, don't spend big bucks.
    Others will chime in.

    Cliff    Posted 09-05-2020 at 18:23:54 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8N Newbie, need advice
  • Exhaust is not smoky but it does smell fuel rich, but not bad. I tried to lean it out a bit with the main jet adjusting needle. Oil pressure with warm engine is still good, 40+ psi at WOT. 20 psi at idle. The tractor was neglected for some time. The air cleaner was full of sludge, engine oil was black with sludge around the screen when I drained it. Oil filter canister was sludged up as well. Spark plugs are AC Delco. I do not remember the number on the plugs and I'm out of state right now and can't check. My plan is to run the tractor for awhile and treat it right with regular service and maintenance before I do anything drastic. A compression test was next on my list to do. Then after a full season of work and proper treatment I will do another compression test to see if there any differences. I've ordered a carburetor overhaul kit and a parts manual and shop manual as a start. Brakes need work as well as steering adjustment.


    Jack - Iowa    Posted 09-07-2020 at 07:00:08 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • With 20 PSI at idle, I certainly would not consider an overhaul.


    Cliff    Posted 09-07-2020 at 19:09:00 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • No not yet. After a compression test I'll try Marvel Mystery Oil in the cylinders to help un-stick the oil control rings. Hopefully this is the trouble with the plug fouling. Then after working the machine for awhile I'll do another compression test.


    Bruce(VA)    Posted 09-04-2020 at 15:31:52 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8N Newbie, need advice
  • How much money do you care to spend?

    Pull the engine, take it to a shop that has rebuilt N engines ( ask them if they use a sleeve puller) and let them do all the work. $1200-1500 depending on how much machine work is needed.

    Cliff    Posted 09-04-2020 at 15:38:56 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8N Newbie, need advice
  • I'm not sure I want to spend that much but I will consider it since I do not have the barn set up well for a workshop yet. I paid $1700 for the machine.


    Bruce(VA)    Posted 09-04-2020 at 15:54:25 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8N Newbie, need advice
  • Parts alone are close to $500.

    And then you will need to buy a sleeve puller.

    And....got all the mics, etc, to check the crank, etc? If the oil pump is worn, you will need to align bore the block.

    The list gets pretty long.

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