Jump to content

Garden Tractors and Parts on eBay



Photo
- - - - -

Rework the rod?


  • Please log in to reply
43 replies to this topic

#1 dodge trucker ONLINE  

dodge trucker
  • Senior Member
  • Member No: 19314
  • 2,909 Thanks
  • 3,529 posts
  • Location: kankakee

Posted February 28, 2018 - 07:20 PM

I have a K321 Kohler 14hp here, that I got apart (the rest of the way) this past weekend and took the bare block and crank into the machine shop yesterday, I got the phone call with the "results" of the machine shop evaluation. 

This is/was the original engine from my '72 New Holland S14. the most recent PO dismantled it part way before I got the tractor. 

 

 

debating what to do with it..... go ahead and have it machined out and buy the matching parts to the machining needed, or whether to cast it aside and put one of my others onto it..... I have a good engine on that machine as we speak but it is "only" a 12 hp, I don't like downgrading HP on a machine. 

 

anyways, there's more to the story regarding the block, it's machinable and reusable. no big deal. oversize parts readily available, as needed to bring clearances back into tolerance, easily. both OEM/NOS and aftermarket. 

 

but, this post is about the crank and rod from this engine, and I have a question about it.  

 

This engine has been apart and "rebuilt" previously, and not very well. Definitely it was never measured out and just got thrown together with replacement standard sized parts. done by a past-past owner, before the guy that I got it from, had it. 

The guy I got it from did not have this tractor very long. and it ran when he got it, before he dismantled it. 

 

Well I found out today that the crank is already 0.013" under standard size. Machinist wants to take it down to a -0.020". 

I know that I can't get a -0.020" rod in an OEM Kohler replacement,   and I am still leery of the quality of most of the aftermarket Kohler rebuild parts that are being sold these days.   though -0.020 is readily available in aftermarket. 

 

the machinist said that there is an application for a set of bearing inserts like a car engine would use, where he can get as much as -0.040" inserts, if that were what it would take to clean up a Kohler crank. He would bore out the crank end of my current rod to accept those bearing shells.  My concern is that this is a splash lube engine, not pressure lube like a car engine.  

I have 1 for sure, and I think I may have 2 rods left over from past rebuilds, where I had replaced the rod with a 10-under rod and saved the old rods  for him to "play with"  I know that Brian Miller offers this service to fit an old rod for inserts for (something like) $25+ postage both ways.

 

Has anyone here ever used a rod that had inserts in it, on a Kohler single?  I like doing a given job ONCE, I hate redo's. 

This isn't a competition pulling engine that would come apart several times a season. I would hope to potentially get 1000 + hours out of this rebuild, mowing, blowing towing and plowing. I could see an advantage to inserts on a competition engine.  something that would be replaced  perhaps after every race weekend, or at least once a season. 

 

I am NOT interested in an overpriced Ebay crank, that will in all likelihood also need to be ground to be usable "the right way"... 

I'll put this engine aside and use either my 14hp Magnum or my K341 (16hp) before I pay Ebay prices for a crank. 

 

 

 


  • boyscout862 said thank you

#2 Dayton_King OFFLINE  

Dayton_King
  • Senior Member
  • Member No: 68926
  • 1,553 Thanks
  • 1,176 posts
  • Location: Atlanta Georgia

Posted February 28, 2018 - 07:40 PM

I have bought 2 engine shops, I rebuild engines and my good friend machines and rebuilds engines. Do not machine the block and then buy parts. Have the machine shop tell you what size to buy, buy them, and have the machine shop machine the block to your parts. I don't care what people say and I have had this discussion a few times. If you want it right do it right. All .010 pistons don't measure the same. This is a trust me please comment lol

Edited by Dayton_King, February 28, 2018 - 07:42 PM.

  • olcowhand, Gtractor, CRFarnsworth and 5 others have said thanks

#3 Gtractor ONLINE  

Gtractor

    the homeless tractor hoarder

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 782
  • 9,967 Thanks
  • 5,148 posts
  • Location: Chillicothe, MO

Posted February 28, 2018 - 08:05 PM

Every K series Kohler I've ever had rebuilt has been machined for an insert.  I won't rebuild an engine without doing so. 

It makes an already great engine TOTALLY bulletproof. 


  • boyscout862, dodge trucker and Mark 149 J. have said thanks

#4 Dayton_King OFFLINE  

Dayton_King
  • Senior Member
  • Member No: 68926
  • 1,553 Thanks
  • 1,176 posts
  • Location: Atlanta Georgia

Posted February 28, 2018 - 08:08 PM

I agree with inserts. Great addition to rebuilds.
  • boyscout862 and dodge trucker have said thanks

#5 dodge trucker ONLINE  

dodge trucker
  • Senior Member
  • Member No: 19314
  • 2,909 Thanks
  • 3,529 posts
  • Location: kankakee

Posted February 28, 2018 - 08:14 PM

I have bought 2 engine shops, I rebuild engines and my good friend machines and rebuilds engines. Do not machine the block and then buy parts. Have the machine shop tell you what size to buy, buy them, and have the machine shop machine the block to your parts. I don't care what people say and I have had this discussion a few times. If you want it right do it right. All .010 pistons don't measure the same. This is a trust me please comment lol

yup I have rebuilt more than a few engines this isn't my 1st one.... but might be my 1st time redoing the rod to make it reusable like this rather than tossing it and just putting in a new one....  

 

as far as the buying of the parts before or after the machine shop work is done, I have yet to have any, ask me to supply parts before they finish machine work. I have had a couple of them get pizzed at me suggesting that they don't know their trade as they know what "10-under" or "20-over means....   I have asked if they need parts in hand before finish-machining  and have always been told "no-- we will refinish to what ever over/undersize it takes to restore tolerances, and then we will tell you what size parts to buy"....     

I ask as the machine work is in progress and they always tell me to wait til they finish their job to buy the parts

 

 

I didn't mean to open that can of worms by starting this thread, just wondering about the feasibility of adding bearing inserts to a rod/ engine that was never designed that way..... 


  • boyscout862 and Mark 149 J. have said thanks

#6 Dayton_King OFFLINE  

Dayton_King
  • Senior Member
  • Member No: 68926
  • 1,553 Thanks
  • 1,176 posts
  • Location: Atlanta Georgia

Posted February 28, 2018 - 08:20 PM

Honestly on rods when we do ours we use a new rod. I don't know the history of the old rod. Just my preference.
  • olcowhand, boyscout862 and Mark 149 J. have said thanks

#7 JBRamsey ONLINE  

JBRamsey
  • Senior Member
  • Member No: 61995
  • 1,594 Thanks
  • 886 posts
  • Location: North Carolina

Posted February 28, 2018 - 08:21 PM

Listen to Dayton King. He's spot on. A good machinist wants parts in hand to measure first before cutting blocks and cranks.
  • olcowhand, Gtractor, boyscout862 and 2 others have said thanks

#8 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 43,169 Thanks
  • 32,012 posts
  • Location: South Central Kentucky

Posted February 28, 2018 - 08:29 PM

I have bought 2 engine shops, I rebuild engines and my good friend machines and rebuilds engines. Do not machine the block and then buy parts. Have the machine shop tell you what size to buy, buy them, and have the machine shop machine the block to your parts. I don't care what people say and I have had this discussion a few times. If you want it right do it right. All .010 pistons don't measure the same. This is a trust me please comment lol

Yep, I've always taken a machine shop the new replacement parts with the block and/or cranks.


  • boyscout862 and Mark 149 J. have said thanks

#9 dodge trucker ONLINE  

dodge trucker
  • Senior Member
  • Member No: 19314
  • 2,909 Thanks
  • 3,529 posts
  • Location: kankakee

Posted February 28, 2018 - 09:07 PM

Honestly on rods when we do ours we use a new rod. I don't know the history of the old rod. Just my preference.

well in this case the only suitable rod available is a China made aftermarket, being I need 20-under

I don't like that idea. I'm thinking that to rework the old rod would be at least as good.... that's why I put the question up. 


  • boyscout862 and Mark 149 J. have said thanks

#10 Achto ONLINE  

Achto
  • Senior Member
  • Member No: 83574
  • 349 Thanks
  • 125 posts
  • Location: Redgranite, WI

Posted February 28, 2018 - 09:08 PM

Adding replaceable bearings to the connecting rod is a very common practice with high performance pulling engines. If this practice benefits engines pulling way more horse power & RPMs than they were designed to do from the factory, then I would believe that it should greatly help increase the longevity of a stock engine.


  • Gtractor, boyscout862, dodge trucker and 1 other said thanks

#11 dodge trucker ONLINE  

dodge trucker
  • Senior Member
  • Member No: 19314
  • 2,909 Thanks
  • 3,529 posts
  • Location: kankakee

Posted February 28, 2018 - 09:11 PM

Yep, I've always taken a machine shop the new replacement parts with the block and/or cranks.

 

on that subject I was always afraid to buy parts before the machinist has started his work. Don't want to buy a 10-over and then find out the engine needs 20. Then I gotta buy another and am stuck with one. On the other hand if it will clean up at 10, I don't want to buy 20-over parts.    I want as much meat as possible left in the cylinder wall both for strength and for future rebuild ability  especially as they aren't a dime a dozen any more, many good blocks have been scrapped over the years,and the pullers have driven the price of "good rebuildable"  engines, too high. 


  • boyscout862 said thank you

#12 dodge trucker ONLINE  

dodge trucker
  • Senior Member
  • Member No: 19314
  • 2,909 Thanks
  • 3,529 posts
  • Location: kankakee

Posted February 28, 2018 - 09:13 PM

Adding replaceable bearings to the connecting rod is a very common practice with high performance pulling engines. If this practice benefits engines pulling way more horse power & RPMs than they were designed to do from the factory, then I would believe that it should greatly help increase the longevity of a stock engine.

 

but again a puller is dismantled  (for various reasons)  way more often than I want to dismantle this engine......    and the environment and conditions aren't the same as yours or my GT.    I don't overly rev my tractor.  but I'll mow a heavily overgrown field for hours at a time. 

I looked and I do have 2 rods here, gonna run them down to the machine shop tomorrow. 


Edited by dodge trucker, February 28, 2018 - 09:14 PM.

  • boyscout862 said thank you

#13 EricFromPa OFFLINE  

EricFromPa

    Tractorholic

  • Senior Member
  • Contributor
  • Member No: 2135
  • 4,303 Thanks
  • 3,415 posts
  • Location: Bedford County Pa.

Posted February 28, 2018 - 09:18 PM

I'm fighting with a K321 crank debate myself. My crank journal is oblonged and I snapped the threaded end off of it when I was pulling the flywheel so I definitely need another crank.

I actually JUST (a couple minutes ago) found a K341 long block forsale locally.Going to go look at it in the morning.

 

 

If you have the money to put it together with Bearing inserts and good quality Rings I would definitely do go that route. It will last just as long or longer than a NEW engine. You should be able to easily get between 1,500-2,000 hours out of it (with regular oil changes and maintenance).


  • boyscout862, dodge trucker and Mark 149 J. have said thanks

#14 dodge trucker ONLINE  

dodge trucker
  • Senior Member
  • Member No: 19314
  • 2,909 Thanks
  • 3,529 posts
  • Location: kankakee

Posted February 28, 2018 - 09:29 PM

it is definitely, w/o a doubt, getting bored over and a new piston AND rings will be bought.  It is currently +0.006" over, and not egg or barrel shaped, or tapered much. Machinist said going to +0.010" on the cylinder will be no problem and plenty to clean it up/true it up. 

 

This is the 2nd Kohler I have taken this guy, while he had the 1st one I went out and bought my own bore gauge and it measured out exactly what he said it did when I got it home....   the 1st was a K301,  its crank was polished std and honed to where an OEM/NOS Kohler 0.003 piston with its included std rings was perfect to get it back to factory tolerances. I will be checking his work again when I get this one home. I have 2 maybe 3 more cast iron Kohlers, that I want to rebuild in the not too distant future

I usually get a new rod when I rebuild one of these engines and have yet to use an aftermarket one.  

but given your guys' input I think I am gonna try the insert idea on this one.   

 


  • boyscout862 and Mark 149 J. have said thanks

#15 Dayton_King OFFLINE  

Dayton_King
  • Senior Member
  • Member No: 68926
  • 1,553 Thanks
  • 1,176 posts
  • Location: Atlanta Georgia

Posted February 28, 2018 - 09:49 PM

on that subject I was always afraid to buy parts before the machinist has started his work. Don't want to buy a 10-over and then find out the engine needs 20. Then I gotta buy another and am stuck with one. On the other hand if it will clean up at 10, I don't want to buy 20-over parts.    I want as much meat as possible left in the cylinder wall both for strength and for future rebuild ability  especially as they aren't a dime a dozen any more, many good blocks have been scrapped over the years,and the pullers have driven the price of "good rebuildable"  engines, too high.


If your machinist is good you don't need to order parts twice. You order parts off of his measurements and recommendations.
  • boyscout862, MiCarl and Mark 149 J. have said thanks




Top