compression tests

[MarlinSlayer]

Ok, I've already made a pretty good shopping list for my Ford NAA that I paid $3500 with a double axle trailer in good shape except for no brakes. It ran like a top...that is until it didn't. I don't want to throw good money after bad and thought about just trading this thing for a Kubota....but I think it has a seductive grasp on me now....like Turkey hunting, and CMP rifles....

I'm not a mechanic, but have done brakes, struts, suspensions, and replaced bolt on accessories, and understand systems since I fly airplanes for a living....I think I'm up to it. I have the IT manual, but it assumes a lot of Tractor Mechanic knowledge that I don't have.....yet.

Before I fill my shopping list to get my tractor running (I still plan on buying a four wheel drive with a loader so why don't I just quit now?) I figured I ought to compression test it. I did a dry test. I didn't do a wet test as I don't know how much oil, and what kind, to put in cylinder......then how do you get it out? or do you need to.

#1 132psi, #2 135 psi, #3 137, #4 140. I was happy to see they were so close. Are those reasonable numbers?

Please someone spoon feed me through a wet test...

 

[Soundguy]

Those are great numbers, in fact.. i doubt I WOULD wet test it after seeing dry numbers like that. In any case, to do a wet test, just pour a tablespoon or so of oil into a cyl and re test.. no need to remove the oil, though you can run it over and blow excessive oil out if you overdid it ont he oil. otherwise it will burn up at first start anyway.

on the dry/wet test. if the numbers come up from dry to wet, that tells you the difference is rings, as the oil seals the rings. if the numbers do not come up on dry to wet, and the numbers are low to begin with.. that tells you the valves leak. you however have good+ dry numbers, so I don't suspect you will see tangible difference wet.

Now. You say it ran good, now nothing?

First thing you do is check spark.

does it have spark turning over?


next, is she still 6v positive ground with a generator and on points? or is it 12v negative ground now, with an alternator? and on points or EI?

if she turns over good but has no spark, simple things like the key or a wire could be bad.. or the points, coil or condensor, or a short in the dizy.

A quick test ( points only ) is to jump bat hot to the coil and then retest. if she starts.. you have a bad contact or wire or switch back in the wireing.

if still no spark after the hotwire, hook a test lamp inline from battery hot to the post on the coil the key switch wire originally hooked to. run starter over. lamp should blink. if it does, points ARE opening and closing. if NOT then: Lamp stays on: points are closed up, or otherwise shorted. possible shorts are at the hinge insulator, a shorted condensor ( rare but happens ), and at the small insulator where the wire goes inside the distribuitor.. the insulator crumbles and lets the wire short to the dizzy, thus making lamp always on.

if lamp never comes on, check breaker contacts.. they may be gapped too wide or burned, no contact. could even have the end burned off.

naa gaps points at .025 with rubbing block on the high side of a lobe. plugs gapped .025



now, if you have spark, or got sprak back and no start, then lets look at fuel. a can of start fluid helps here. if she rolls over good, has spark, and won't pop, she ain't getting fuel.. a spritz of start fluid and she coughs to life for a second confirms this.

Note. we are assuming good compression ( checked ).. air flow ( had to have that to get good comp # ), and at least close timing. ( timing was at least close if she ran before, and the dizzy is not now loose and snatched all the way around to one side. ).


be carefull with the start fluid. don't stand or look directly into the carb mouth just a spritz across the front of the mouth, with your hand not inthe way. rare, but it could cause a pop BACK thru the carb making a momentary flame plume.. so no open solvent, cleaners, you, combustables or flamables in t he way of the carb or around the sparkies, and always do this with clutch blocked down, in neutral, and only attempt starting while setting in the seat.

post back.

 

[MarlinSlayer]

It runs. I had great spark and huge backfire when i tried starting fluid. I took an hour to clean the flywheel through the little viewing window one 1/4 inch at a time before I realized I could shoot it down with PB Blaster while motoring engine, then hold up small wire brush to flywheel through port. Set 8 degrees before top dead center....looked at which set of contacts the distributor rotor was pointing. Used that as #1, and put the wires back 1243.....little starter fluid and it ran like a top....till the starter fluid ran out. figured carb had gotten messed up from sitting so long. was going to pull carb...but when O pulled off gas line, no gas came out. so I blew back up the gasoline till I heard bubbles, then gas began to drain. I guess I displaced whatever stuff was clogging line or filter (I think I learned there is one in the bowl from this site)...then gas ran out... hooked up the carb and it started and ran like a top. Gas tank leaks pretty good...Soundguy recommended new tank. Before I do I have two critical questions to answer....One ...small water jacket leak by drain cock...thinking about using a ceramic sealer (Never done it before...it was covered by some JB weld or something that I chipped off.) also, tapping noise...maybe a valve issue? I had good compression...maybe something just needs adjustment...is that easy?

Should I just trade this for a Kubota now that it starts easy and get a 4wd with loader? I'm going to get one someday anyway? Am I throwing good money after bad? I will upload video in other thread

 

[Soundguy]

lets see that block crack...