2N engine rebuild questions

HFJ · Dec 15, 2015

hi, i'm putting my 2N engine back together - new sleeves, pistons, rings, and connecting rod bearings. did not do the mains.

my ring kit (3 ring pistons) includes the second (middle) compression ring which has a dot on one side, and a beveled inner edge on the other. i'm getting conflicting info, some people say any marks or writing should be up, but some say the bevel should be up. help! :shock:

also, i am having trouble nailing down a clearance spec for the connecting rod bearings. i've seen .001 - .0025 for the mains - does this range apply to the connecting rod bearings as well?

any and all help appreciated

TheOldHokie · Dec 15, 2015

(quoted from post at 18:23:04 12/15/15) hi, i'm putting my 2N engine back together - new sleeves, pistons, rings, and connecting rod bearings. did not do the mains.

my ring kit (3 ring pistons) includes the second (middle) compression ring which has a dot on one side, and a beveled inner edge on the other. i'm getting conflicting info, some people say any marks or writing should be up, but some say the bevel should be up. help! :shock:

also, i am having trouble nailing down a clearance spec for the connecting rod bearings. i've seen .0013 - .0035 for the mains - does this range apply to the connecting rod bearings as well?

any and all help appreciated

Crankpin oil clearance is .001-.0035 with a wear limit of .005 so you should be shooting for the low end of that range.

TOH

Mike Groom · Dec 15, 2015

Normally any marks on the rings should be up,check with the supplier on there recommendation to verify.

ZANE · Dec 15, 2015

If the journals have been re ground there should be stamped numbers on one of the crank balances or else where if no balances.

Marks go up

as to the bevels. Inside up outside down.

Zane

Hobo,NC · Dec 15, 2015

From my experiences...

Dots go UP

No Dot Inside bevel always goes up.

Dot trumps the bevel Dot goes UP I have never seen it do down...

YMMV...

HFJ · Dec 15, 2015

thanks for the feedback, folks

i'm trying to get word on the ring from the manufacturer thru the kit's vendor, but so far, no luck

ASEguy · Dec 16, 2015

Pay attention to the ring box flaps. They usually indicate which ring is top compression, second compression "etc."

HFJ · Dec 16, 2015

yes, they did. i know which ring goes where, my problem is the conflicting stories about whether dots or bevels should face up or down.

i have seen plenty of instances of people saying both should face up. in this case, that's impossible, since they are on opposite sides of the ring.

it's been stated that dots nnalert bevels. i am hoping to hear the manufacturer's feeling on the subject, but the longer it takes, the less optimistic i become about hearing from them.

i find it absolutely astonishing (and disappointing) that the ring kit itself does not specifically say which way that ring goes.

thefishhunter · Dec 16, 2015

(quoted from post at 15:23:04 12/15/15) hi, i'm putting my 2N engine back together - new sleeves, pistons, rings, and connecting rod bearings. did not do the mains.

my ring kit (3 ring pistons) includes the second (middle) compression ring which has a dot on one side, and a beveled inner edge on the other. i'm getting conflicting info, some people say any marks or writing should be up, but some say the bevel should be up. help! :shock:

also, i am having trouble nailing down a clearance spec for the connecting rod bearings. i've seen .001 - .0025 for the mains - does this range apply to the connecting rod bearings as well?

any and all help appreciated

Here ya go...

http://korihandbook.federalmogul.com/en/section_18.htm

https://www.hastingsmfg.com/ServiceTips/compression_ring_installation.htm

Ultradog MN · Dec 16, 2015

Looks like you got plenty of help on the rings.
I just have a question.
You are that far into it. Why wouldn't you do the main bearings?

HFJ · Dec 16, 2015

two reason,s ultradog.

first, the person advising me made it pretty clear he didn't feel it was necessary in my case, from the symptoms i described - mainly, he felt the tractor's oil pressure was an indication that the mains were still fine.

secondly, what i *am* doing, i am able to do without splitting the tractor.

between those 2 things, i made the decision to not redo the mains.

HFJ · Dec 18, 2015

just heard from the vendor, who finally got word from the manufacturer.

he confirms bevel with no dot goes up, but dot trumps bevel.

thanks for the help, everyone. now i feel good about putting it back together

HFJ · Dec 27, 2015

another question - like an idiot, i didn't take "before" pics.

both the old and new pistons have a V shaped notch on top by the edge. is that notch supposed to be toward the front of the engine, or the rear? i've only been able to find a couple of pics online, and they show it forward. is this right?

R Geiger · Dec 27, 2015

If you would read the FO-4 you would find that it says notch towards the front. I do hope you have one.

HFJ · Dec 28, 2015

i don't know what an FO 4 is. so i likely don't have one.

R Geiger · Dec 28, 2015

The FO-4 is the service manual that you should be using to overhaul your engine.

HFJ · Mar 27, 2016

turned it over, had no oil pressure. primed the pump, one problem solved.

tried to start it with a temp rigged fuel supply (hood still off). coughed and wheezed, but wouldn't run. that was yesterday, put my money on flooded, disconnected temp gas tank, let it sit overnight. pulled breather pipe off carb, watched gas pour out onto ground. let it do that for a few, came back, and with no fuel supply connected, it fired right up.

time to put the body back on.

thanks for the help, one and all

HFJ · Apr 5, 2016

finally finished putting everything back together normally (no temp fuel tank) and started it up today. it runs great, for a while - and then dies abruptly. i can easily restart it, then a few seconds to a couple of minutes go by, and then it dies again. did it several times. any thoughts on this?

JCinKY · Apr 5, 2016

(quoted from post at 12:22:48 04/05/16) finally finished putting everything back together normally (no temp fuel tank) and started it up today. it runs great, for a while - and then dies abruptly. i can easily restart it, then a few seconds to a couple of minutes go by, and then it dies again. did it several times. any thoughts on this?

Verify proper fuel flow...open the shut off two full turns and remove the carb bowl drain. Make sure gas runs for a minute or so without slowing down. Good flow not a trickle. Clean all three screens as needed.

Check spark on all four plug, good blue spark with a plug gapped to about 1/4". Clean and gap points.

Jump the key switch temporarily. If this fixes your run time issue. Replace the switch.

HFJ · Apr 5, 2016

thanks JC. the sediment bowl is brand new, just put it in yesterday. i know all too much about how they work now, but don't ask me how many times i ran out with an inch of gas in the tank and the fuel knob wide open, not knowing there was a plugged reserve pickup involved

the issue actually appears to be choke-related. turns out that if i manually baby the choke when it dies, i can keep it running. i don't remember ever having to do this before, but then, i won't swear that i've ever started it up on a day this cold. could that be all it is, gotta baby it till it warms up? (altho i'd swear it was warmed up the last time it did it). i can't see where the rebuild would have affected the choke, manifolds and carb weren't touched. throttle linkage was disconnected, but not choke.

on the positive side, i have ~ 38 pounds of oil pressure, and i fear the military will now cancel their smokelayer contract with me, since the exhaust is now clean - something i had never seen from this tractor until now

HFJ · Apr 5, 2016

to clarify "this cold" - it's about 40.

JCinKY · Apr 6, 2016

(quoted from post at 13:39:09 04/05/16) thanks JC. the sediment bowl is brand new, just put it in yesterday. i know all too much about how they work now, but don't ask me how many times i ran out with an inch of gas in the tank and the fuel knob wide open, not knowing there was a plugged reserve pickup involved

the issue actually appears to be choke-related. turns out that if i manually baby the choke when it dies, i can keep it running. i don't remember ever having to do this before, but then, i won't swear that i've ever started it up on a day this cold. could that be all it is, gotta baby it till it warms up? (altho i'd swear it was warmed up the last time it did it). i can't see where the rebuild would have affected the choke, manifolds and carb weren't touched. throttle linkage was disconnected, but not choke.

on the positive side, i have ~ 38 pounds of oil pressure, and i fear the military will now cancel their smokelayer contract with me, since the exhaust is now clean - something i had never seen from this tractor until now

Fiddling with the choke keeping it running points to a fuel issue. Get it running and as soon as it dies on you pull the drain on the carb. Not now, not when you limp it back to the shop...immediately.

Clean/check the screen in the carb elbow. I'm sure you're aware of the two in the sediment bowl.

Loosen the gas cap, it might be vapor locking if you have a non vented cap.

Last step would be to open the carb up and wire out the passages. JMOR has an excellent diagram of the carb and where each hole leads. Ensure the float is set right and not hanging on the side of the bowl.

HFJ · Apr 6, 2016

Get it running and as soon as it dies on you pull the drain on the carb. Not now, not when you limp it back to the shop...immediately.

the tractor is in the pole barn, where it spends all winter, every winter. it doesn't need to limp anywhere.

the plug on the carb is pretty mangled, and i only managed to break it loose last night around midnight. until i replace it, i won't be performing a flow test, and that won't be today, as i don't drive when there's sleet and freezing rain falling. this CAN wait, and it will.

Clean/check the screen in the carb elbow

if it acts the same way the next time i try to start it and fails the flow test, i will.

I'm sure you're aware of the two in the sediment bowl.

yes, i am aware of them. i suspect u missed where i said the sediment bowl is brand new, and was just installed monday.

Loosen the gas cap, it might be vapor locking if you have a non vented cap.

i'm reasonably sure the cap is vented, but i'll try to confirm that. i have never had this problem before, and i haven't changed gas caps.

Last step would be to open the carb up and wire out the passages. JMOR has an excellent diagram of the carb and where each hole leads. Ensure the float is set right and not hanging on the side of the bowl.

the float hug when i first put gas in it via a temporary tank last week. that has since been freed up, and i am now in the habit of smacking the carb bowl with a chunk of wood every time i go to start it.

i hope it doesn't come down to tearing the carb apart, but i realize it might. ty for the feedback

Ken(Ark) · Apr 6, 2016

i'm reasonably sure the cap is vented, but i'll try to confirm that. i have never had this problem before, and i haven't changed ........

The gas tank has a small dome built into the top . you can not see this dome when the tank is installed . the dome has a small vent hole that can become clogged with dirt / etc and become a problem overnight .

Easy to check fuel flow . remove the drain plug on the bottom of the carb . add a 1/8 npt easy open drain cock if you wish . see if it will full a quart jar jar in about three minutes . don't stop after one cup as that might not be sufficient to test .

Sounds like mmo in the gas cold help with rust / crud / sticking float , maybe not.

I like to drain a little gas before starting for the day and half of the time I get a few bb sized drops of water removed . I pour the cup of gas back into the tank .

HFJ · Apr 6, 2016

i like the sound of replacing the plug with a petcock.

i'll take the gas cap off next time i try to start it. not optimistic, but i like performing tests that are both simple and free

HFJ · Apr 8, 2016

what's break-in time on an in-frame rebuild? i looked thru the FO-4 (yes, i have one now

), but if there was any mention of this, i missed it.

HFJ · Apr 11, 2016

float is sticking. opens the fuel flow just fine, won't shut it off.

carb's gonna get taken off and pulled apart.

does anyone know the breakin time for a rebuild?

HFJ · Apr 11, 2016

this is an experiment. on modern view, i see 2 different threads here. i've been replying to folks in the second thread there (to me, this is the first one). now i have to wonder if they ever see my replies :lol:

so i'll try thanking tom HERE for his tips this time, and hopefully, you'll see it, tom

HFJ · Apr 12, 2016

good deal, tom. i guess the secret is to read your posts in the "second" thread and reply here in the first :lol:

den, all i do with this is mow my lawn. am i ok to mow in short bursts, say 5 minutes, during the first hour? or should i stick to joyriding?

HFJ · Apr 14, 2016

thanks, den, glad to hear it. i assume i want to change the oil at the end of the 4 hours, right?

HFJ · Apr 18, 2016

took the carb apart and cleaned it, only to discover the venturi was cracked. anyone got a part number handy on that? any other things to look at before i reassemble and reinstall the carb?

HFJ · Apr 18, 2016

ok, found the part number. it looks like everyone is selling a plastic replacement. should i be concerned about that and keep looking for what i assume is a brass one? or are the plastic ones ok?

HFJ · Apr 18, 2016

thanks, as long as it works, i'll happily go with the plastic one. i'm guessing it's less likely to crack like the one i'm replacing - at least i hope it is

HFJ · May 6, 2016

replaced the venturi, at which point it ran without choke, but would cough and/or die every so often. turns out the reserve pickup on the new sediment bowl will flow, but not enough to run without interruption, even with no load. apparently the reserve is plugged/restricted already :evil:

poured a couple more gallons in, and it started purring like a kitten. well, ok, a big loud kitten. mowed the lawn, and no smoke coming out of either end now

tomorrow i'll recheck torque on head bolts. will also do a compression test, just cuz. i've got about 38 pounds of oil pressure cold, 30 when warmed up and 20 when mowing. i'm ok with those numbers, right? carb tweaking on the list too, would like to see more power when mowing thick/long grass uphill.

thanks again for the help, folks.

love my new 69 year old tractor

2N engine rebuild questions

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