Kohler engine ring gap problem - MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information
Register Home FAQ Garage MTF Gallery Search Today's Posts Mark Forums Read Store Chat Room

Backyard Round Table - L & G Tractor Related Topics Lawn and Garden Tractor Related Topics General Discussion Board

Reply
 
Thread Tools Display Modes
Old 01-10-2010, 09:14 PM   post #1 of 34
ACmowerguy
Proud Member of the 1K Club
 
ACmowerguy's Avatar
 
Join Date: Mar 2009
Location: Winfield, Missouri
Posts: 1,281
MTF Member # 22929
Images: 2
Default Kohler engine ring gap problem

Hi.

I have a 16hp k341 Kohler I am rebuilding. It was freshly bored .020 over. I have a new .020 piston and rings, these are PrimeLine aftermarket parts. I have had them for quite a while (couple years) and am not sure I could send anything back. I checked the ring end gap on the top compression rings and found that the very top ring has 25 thousandths gap. The kohler manual states that it should be no more than 20 for a new ring, but that 30 is acceptable for a used ring. The lower compression ring is just fine at about 15 thousandths. Do I need to get a different ring or can I still use this.

Thank You.


-Chris
__________________
SIMPLICITY- 700, 3410, 17GTH-L, 727, 75th anny Sovereign, '98 Landlord, '99 Landlord DLX
Allis-(2) B-10's, B12, (2) B110's, B-207, (2) B210's, B212, HB212, Homesteader 8, 416H, 710, 912H, 914S
Massey-MF12 and MF16
Sears- 1971 HT14 hydro
ACmowerguy is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-10-2010, 09:45 PM   post #2 of 34
Steevo
2000 Posts and climbing!!!
 
Steevo's Avatar
 
Join Date: Jun 2008
Location: Idaho
Posts: 2,430
MTF Member # 13492
Images: 3
Default Re: Kohler engine ring gap problem

It'll work, but . . . .
Was the cylinder bored for the piston you have?
If so, I would worry that the cylinder clearance is too large.
The rings came with the piston, both specified for .020" overbore.
If the piston/ring manufacturer is working to the Kohler specification of .015" for ring end-gap, then the cylinder bore diameter must be larger than desired. It is more common to have to file the ends of a ring to attain minimum gap than to have to worry about being too close to maximum.
__________________
Steevo
_________________________________________
My GT Iron:1256-01(parts); 1476(parts); 1250 (future resto proj)
1886-01-repowered w/ Kohler Command 22HP V-twin
HT-20 (rebuild in progress); Johnson 14 loader (restored!)

Steevo is offline   Reply With Quote Quick reply to this message
Old 01-10-2010, 10:38 PM   post #3 of 34
Tencubed
3K Poster!!!!
 
Join Date: Aug 2009
Location: Washington
Posts: 4,726
MTF Member # 31735
Default Re: Kohler engine ring gap problem

I'm inclined to agree with Steevo. Think I'd take that block somewhere besides where it was bored and have the bore checked. Could be they cut it out oversize. Probably not but I'd sure check it.

Take the piston with you and see if the bore is proper for the piston, remote chance you have a ring that is just a tad loose.

Mike
Tencubed is offline   Reply With Quote Quick reply to this message
Old 01-10-2010, 11:02 PM   post #4 of 34
Pintony
Senior MTF Member
 
Join Date: Oct 2009
Location: illinois
Posts: 193
MTF Member # 33959
Default Re: Kohler engine ring gap problem

0.005???
A piece of paper is 0.007 .....
I do not see what the big deal is???
Pintony is offline   Reply With Quote Quick reply to this message
Old 01-10-2010, 11:07 PM   post #5 of 34
eastonct124
Proud Member of the 1K Club
 
eastonct124's Avatar
 
Join Date: Sep 2009
Location: ct
Posts: 1,990
MTF Member # 32697
Default Re: Kohler engine ring gap problem

With heat and expansion....005" is a big deal.
On the race engines I used to build (BB chevies), we always ran .012" file fit.
Too tight, you'll score the cylinder from expansion, too big, you psh oil, and lose comp.
There's a reason for factory recommended gaps.
__________________
Flyfishing isn't a sport, it's a way of life.
eastonct124 is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 12:59 AM   post #6 of 34
Pintony
Senior MTF Member
 
Join Date: Oct 2009
Location: illinois
Posts: 193
MTF Member # 33959
Default Re: Kohler engine ring gap problem

Quote:
Originally Posted by eastonct124 View Post
With heat and expansion....005" is a big deal.
On the race engines I used to build (BB chevies), we always ran .012" file fit.
Too tight, you'll score the cylinder from expansion, too big, you psh oil, and lose comp.
There's a reason for factory recommended gaps.
Is your race engine air cooled???
C'mon we are talking a tractor engine not a RACE engine.
It is not like it is .005 on the bearings...
THAT would be a BIG deal!!!!!
Pintony is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 07:51 AM   post #7 of 34
eastonct124
Proud Member of the 1K Club
 
eastonct124's Avatar
 
Join Date: Sep 2009
Location: ct
Posts: 1,990
MTF Member # 32697
Default Re: Kohler engine ring gap problem

Quote:
Originally Posted by Pintony View Post
Is your race engine air cooled???
C'mon we are talking a tractor engine not a RACE engine.
It is not like it is .005 on the bearings...
THAT would be a BIG deal!!!!!
Exactly, aircooled means more dramatic changes in heat loss, and heat gain....also inconsistent heat pockets.

Everything in regards, whether it's a race engine, street engine, work engine... car, truck, or tractor....ring gap has a dramatic effect on performance, and endurance.
__________________
Flyfishing isn't a sport, it's a way of life.
eastonct124 is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 09:14 AM   post #8 of 34
Pintony
Senior MTF Member
 
Join Date: Oct 2009
Location: illinois
Posts: 193
MTF Member # 33959
Default Re: Kohler engine ring gap problem

Quote:
Originally Posted by eastonct124 View Post
Exactly, aircooled means more dramatic changes in heat loss, and heat gain....also inconsistent heat pockets.

Everything in regards, whether it's a race engine, street engine, work engine... car, truck, or tractor....ring gap has a dramatic effect on performance, and endurance.
OK U R right.
Never mind...
Pintony is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 11:30 AM   post #9 of 34
ACmowerguy
Proud Member of the 1K Club
 
ACmowerguy's Avatar
 
Join Date: Mar 2009
Location: Winfield, Missouri
Posts: 1,281
MTF Member # 22929
Images: 2
Default Re: Kohler engine ring gap problem

I tend to think it has to be my rings, not the block. Reason being is that the rings were placed at approximately the same location in the cylinder when each was measured, and still there was one that was perfectly fine and the other was .005 out of new spec, but its still in spec for a used ring so I guess it will have to work. I'd buy the OEM piston and rings but they'd cost a minimum of $130, and I paid $60 for the prime line so I'd just be out too much money. The cylinder was bored to Kohler .020 specs, not to the aftermarket piston size nor was it just bored .020 beyond what it was previously. The piston and rings were designed to fit the .020 Kohler spec.
__________________
SIMPLICITY- 700, 3410, 17GTH-L, 727, 75th anny Sovereign, '98 Landlord, '99 Landlord DLX
Allis-(2) B-10's, B12, (2) B110's, B-207, (2) B210's, B212, HB212, Homesteader 8, 416H, 710, 912H, 914S
Massey-MF12 and MF16
Sears- 1971 HT14 hydro
ACmowerguy is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 11:57 AM   post #10 of 34
Glenn M
Proud Member of the 1K Club
 
Glenn M's Avatar
 
Join Date: Jan 2008
Location: Middle of the Mitten
Posts: 1,900
MTF Member # 9020
Images: 14
Default Re: Kohler engine ring gap problem

The newer Kohler engines have .025 ring end gap.
Having the top ring end gap a little wide, is better to than too narrow. With too tight of a gap on the top ring especially, since it receives more heat than the other rings, it will expand, butt up and break, then you'll have real problems.
If you want it dead nuts, buy another .020 over ring set. If it were me, I'd put it together with what you have, being the second ring is at the correct gap, the compression lose would be minuscule.
__________________
Glenn

It's never over untill your pockets are empty.




My GT pic's

07 DGS 6500
74 MTD 990
71 MTD 760
91 Craftsman GT6000
JD "80" cart

Last edited by Glenn M; 01-11-2010 at 12:40 PM.
Glenn M is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 12:53 PM   post #11 of 34
oldsarge
Senior MTF Member
 
oldsarge's Avatar
 
Join Date: Sep 2009
Location: Illinois
Posts: 737
MTF Member # 32130
Default Re: Kohler engine ring gap problem

Do yourself a favor and break it in on Straight 30 wt NON Detergent oil for a couple hours.
oldsarge is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 01:05 PM   post #12 of 34
Glenn M
Proud Member of the 1K Club
 
Glenn M's Avatar
 
Join Date: Jan 2008
Location: Middle of the Mitten
Posts: 1,900
MTF Member # 9020
Images: 14
Default Re: Kohler engine ring gap problem

AC
Are the top and second ring the same thickness and style?

The reason I ask, after reading this, if you swapped the rings they would go along with this quote from Speed- Pro.

" Recent testing has proven that a
larger second gap increases the top ring's ability to seal combustion. This larger "escape" path prevents inter-ring
pressure from building up and lifting the top ring off the piston allowing combustion to get by. Many engine builders
have reported lower blow-by and horsepower gains at the upper RPM ranges with wider second ring gaps. Also,
almost every new car made is using this inter-ring pressure reduction method to lower blow-by and emissions and to
increase engine output".
__________________
Glenn

It's never over untill your pockets are empty.




My GT pic's

07 DGS 6500
74 MTD 990
71 MTD 760
91 Craftsman GT6000
JD "80" cart
Glenn M is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 01:50 PM   post #13 of 34
Glenn M
Proud Member of the 1K Club
 
Glenn M's Avatar
 
Join Date: Jan 2008
Location: Middle of the Mitten
Posts: 1,900
MTF Member # 9020
Images: 14
Default Re: Kohler engine ring gap problem

I see that Tulsa Engine Warehouse sells PrimeLine parts. Maybe you could give them a call and see what they say.
__________________
Glenn

It's never over untill your pockets are empty.




My GT pic's

07 DGS 6500
74 MTD 990
71 MTD 760
91 Craftsman GT6000
JD "80" cart
Glenn M is offline   Reply With Quote Quick reply to this message
Old 01-11-2010, 02:09 PM   post #14 of 34
roosamaster
Senior MTF Member
 
roosamaster's Avatar
 
Join Date: Jul 2008
Location: Western Pennsylvania
Posts: 158
MTF Member # 14583
Default Re: Kohler engine ring gap problem

You have hit the nail on the head yourself. Anytime an overbore is needed, the machine shop should require you to supply the piston that is going into the engine, not just to bore to a "spec.". Since this has already happened, as long as the top two rings are the same (as they may be) use the second ring as your top ring (properly gaped) as this will affect your compression directly, then use to "larger gaped" ring in the second position, which isn't as critical.

Good luck with your rebuild
Roosamaster
roosamaster is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-11-2010, 06:05 PM   post #15 of 34
Walt 2002
Senior MTF Poster
 
Join Date: Jan 2006
Location: IL
Posts: 10,734
MTF Member # 1229
Default Re: Kohler engine ring gap problem

I quit using a custom machine shop years ago because, even after repeated complaints, they were boring the cylinder too large. They do this to CYA, ensure rings don't seize.

Now there has been a bunch of posts here about end gaps, saying .025" end gap is OK. I disagree. B&S engines of similar bore size specify .008" min. end gap. I have used this for years, hand fitting, and absolutely no problems. I don't think there is that much difference between a Kohler and a B&S, actually I have been doing that also on the few Kohlers I have done. Heck, .025" is pretty nearly worn out with .035" being replace. By the time .025" end gap rings are seated, the end gap will be .030" or close to it.

I now oversize cylinder bores myself to suit and use .010" oversize rings when installing new rings in a bore that does not need oversizing, hand fintting to as near .008" end gap min. as I can.

Walt Conner
Walt 2002 is online now   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:11 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
Compact Tractor Reviews Tractor Reviews Snowblowers Lawn Mower Forum
My Tractor Forum Snow Thrower Power Equipment Forum
Combine Forum Snowblower Forum ATV and UTV Reviews