1976 K341 Overhaul - Worth It or Not?

[richmondred01 2,205]

Shoot pb blaster in the Allen holes and keyway. Let sit and clean up the crank shaft for a smooth pull while removing the pulley.

The pulley is made of cast and will break if forced.

if the pulley breaks let me know I have several.

[HappyHillbilly 86]

3 hours ago, richmondred01 said:

Shoot pb blaster in the Allen holes and keyway. Let sit and clean up the crank shaft for a smooth pull while removing the pulley.

The pulley is made of cast and will break if forced.

if the pulley breaks let me know I have several.

 

I was able to get off. Sure wasn't easy, though. As hard as it was to get it off I might have to have it "pressed" back on. Dang! Maybe I can get it all cleaned up good enough for an easier installation.

Thank's fellas!

[richmondred01 2,205]

No need to press it on. Start the engine, let it idle shoot some wd40 on some 240 grit wet and dry paper and run it along the shaft. That cleans it up real nice. 

[HappyHillbilly 86]

That sounds like a winning strategy. Why do I get the idea that you’ve replaced a few of ‘em before? 

[HappyHillbilly 86]

Update, with some questions:

Took my engine to a good engine machinist and he was thorough, informative & helpful.

This 341 has been previously bored .020" over and cylinder walls are within specs & in good shape. There weren't any metal shavings in oil pan & all gears look great.

Crankshaft pin appears to have been ground down to -.010, to a solid 1.490" diameter.

He noticed the exhaust valve is bent & not getting a good seat/seal on the piston side of the valve.

I told him I planned on replacing both valves, springs, guides, etc..., and he suggested replacing piston rings as well since it's been sitting for 12yrs.

 

I'm shopping for a valve replacement kit & engine gasket/seals kit. I've ordered a piston ring compressor w/removal tool and a valve spring tool.

 

Questions:

1 - I've seen there's a special tool for removing the valve guides. Do I need it or is there a DIY trick?

2 - What's the best way to clean what I believe is the valve seats - where the valves sit in the block? In the attached photos you can see my exhaust valve seat(?) isn't too bad, but the intake one is a bit more crusty.

3 - Would I be going too far overboard by getting all new valve components?

 

As always - Thanks for your time, patience & help!

Have a good one!

HH

 

[bc.gold 3,399]

On 3/9/2019 at 7:35 PM, HappyHillbilly said:

That sounds like a winning strategy. Why do I get the idea that you’ve replaced a few of ‘em before? 

 

Edited March 12, 2019 by bcgold

[953 nut 51,655]

On 3/9/2019 at 8:21 PM, HappyHillbilly said:

I can get it all cleaned up good enough for an easier installation.

You can use the W/D sand paper wrapped around a wood dowel with oil inside the pulley too. Follow that up with Never-seize when installing.

2 hours ago, HappyHillbilly said:

Questions:

1 - I've seen there's a special tool for removing the valve guides. Do I need it or is there a DIY trick?

2 - What's the best way to clean what I believe is the valve seats - where the valves sit in the block? In the attached photos you can see my exhaust valve seat(?) isn't too bad, but the intake one is a bit more crusty.

3 - Would I be going too far overboard by getting all new valve components?

Here is a good read for you.

http://gardentractorpullingtips.com/valvecam.htm

There are two ways to measure the amount of wear in valve guides. One way is with a dial indicator. The other way is with an "go/no go gauge" and a micrometer. It's best to have a local machine shop do the measuring because they have the right tools and they're experienced with such things.

How to Remove and Install Pressed-In Cast Iron Valve Guides in a Cast Iron Block Kohler Engine:

1. Acquire a 1/2" diameter x 5" long grade 8 bolt. Machine the threads down to .300" so it will become a pilot to fit inside the valve guide. This will be the driver tool.
2. Remove the valves, springs and retainers. Measure old guides to ensure if they are actually worn or within specs.
3. To remove worn valve guides:
   • On the Kohler engine models K141, K160/K161 and K181/M8 and all flathead twin cylinder Kohler engines, if the lifters (and camshaft) are installed, break off half of the guide inside the valve spring compartment with a cold chisel and medium size hammer, then use the machined bolt as mentioned above È and a big hammer to drive the remaining guide out and into the valve spring compartment. If the lifters and cam isn't installed, just drive the entire guide out into the valve spring compartment without breaking it off.
   • On the Kohler engine models K241-K341, if the lifters (and camshaft) are not installed, drive the entire guide out into the valve spring compartment with the machined bolt and a big hammer. But if the lifters (and camshaft) are installed, and if there's not enough space to remove the entire old guide, then half of the guide will need to be broke off with a cold chisel and hammer, then the rest of the guide can be removed.
4. Install the new guide with the machined bolt with a flat washer under the pilot so the guide will be flush inside the intake and exhaust pockets.
5. The new guides may need to be reamed out with a 5/16" reamer so the valve stems will have correct clearance.

FYI - In most cases, worn valve guides don't necessarily need to be replaced. They can be repaired with a thin-wall bronze sleeve/liner, like the ones installed in automotive cylinder heads. Also, a bronze liner will last longer than a cast iron guide because bronze retains more oil for better lubrication for the valve stem.

 

[bc.gold 3,399]

3 hours ago, 953 nut said:

There are two ways to measure the amount of wear in valve guides. One way is with a dial indicator. The other way is with an "go/no go gauge" and a micrometer.

 

That works for me.

 

 

 

 

 

Edited March 12, 2019 by bcgold

[953 nut 51,655]

1 hour ago, 953 nut said:

Acquire a 1/2" diameter x 5" long grade 8 bolt. Machine the threads down to .300" so it will become a pilot to fit inside the valve guide. This will be the driver tool

Had to go out for a while and didn't get to finish up here.

If your guides measure up as needing attention I would favor the bronze sleeves. If you decide to change the guides out since you will probably only use this tool a few times so it would be a shame to spend the money on machining a grade 5 bolt. I would take a grade 5  1/2" bolt and center-punch the end, drill and tap it for a 5/16 bolt, screw the 5/16 into the end of the 1/2" , cut of the head and then sand off the shank of the 5/16 down to the point where it fits into the guide. I'm cheap thrifty.    

Intake valves seldom need to be replaced, your machinist can cut the valve seats for you. He probably has a valve spring tester to see if your springs are good. I would buy the valve and rings from him too, that is a way of saying thank you for the time he put into measuring the block and crank.

 

[HappyHillbilly 86]

5 hours ago, 953 nut said:

You can use the W/D sand paper wrapped around a wood dowel with oil inside the pulley too. Follow that up with Never-seize when installing.

Here is a good read for you.

http://gardentractorpullingtips.com/valvecam.htm

There are two ways to measure the amount of wear in valve guides. One way is with a dial indicator. The other way is with an "go/no go gauge" and a micrometer. It's best to have a local machine shop do the measuring because they have the right tools and they're experienced with such things.

How to Remove and Install Pressed-In Cast Iron Valve Guides in a Cast Iron Block Kohler Engine:

1. Acquire a 1/2" diameter x 5" long grade 8 bolt. Machine the threads down to .300" so it will become a pilot to fit inside the valve guide. This will be the driver tool.
2. Remove the valves, springs and retainers. Measure old guides to ensure if they are actually worn or within specs.
3. To remove worn valve guides:
   • On the Kohler engine models K141, K160/K161 and K181/M8 and all flathead twin cylinder Kohler engines, if the lifters (and camshaft) are installed, break off half of the guide inside the valve spring compartment with a cold chisel and medium size hammer, then use the machined bolt as mentioned above È and a big hammer to drive the remaining guide out and into the valve spring compartment. If the lifters and cam isn't installed, just drive the entire guide out into the valve spring compartment without breaking it off.
   • On the Kohler engine models K241-K341, if the lifters (and camshaft) are not installed, drive the entire guide out into the valve spring compartment with the machined bolt and a big hammer. But if the lifters (and camshaft) are installed, and if there's not enough space to remove the entire old guide, then half of the guide will need to be broke off with a cold chisel and hammer, then the rest of the guide can be removed.
4. Install the new guide with the machined bolt with a flat washer under the pilot so the guide will be flush inside the intake and exhaust pockets.
5. The new guides may need to be reamed out with a 5/16" reamer so the valve stems will have correct clearance.

FYI - In most cases, worn valve guides don't necessarily need to be replaced. They can be repaired with a thin-wall bronze sleeve/liner, like the ones installed in automotive cylinder heads. Also, a bronze liner will last longer than a cast iron guide because bronze retains more oil for better lubrication for the valve stem.

 

 

That link about valves looks to be a good one with, with a lot of info that will help me. Thank you!

 

2 hours ago, 953 nut said:

Had to go out for a while and didn't get to finish up here.

If your guides measure up as needing attention I would favor the bronze sleeves. If you decide to change the guides out since you will probably only use this tool a few times so it would be a shame to spend the money on machining a grade 5 bolt. I would take a grade 5  1/2" bolt and center-punch the end, drill and tap it for a 5/16 bolt, screw the 5/16 into the end of the 1/2" , cut of the head and then sand off the shank of the 5/16 down to the point where it fits into the guide. I'm cheap thrifty.    

Intake valves seldom need to be replaced, your machinist can cut the valve seats for you. He probably has a valve spring tester to see if your springs are good. I would buy the valve and rings from him too, that is a way of saying thank you for the time he put into measuring the block and crank.

 

 

Thanks a lot, Richard! I'll wait till I get the valves/springs off & have a look at the guides.

 

The rest of this is jibber-jabber, so you might want to skim on by:

Machinist - The problem is that the machinist I went to today is an automotive machine shop in Andrews & he said he was swamped due to it being racing season. He said he can do whatever I want but it might take him awhile. I'm in no hurry and would've loved to have left it there for him to fix the valve(s) but I felt bad already about him stopping what he was doing just to help me, knowing there's a whole lot more money to be made from all the automotive blocks already in his shop than in this piddly 'lil 16hp. He spent about 15-20 mins with me and I gave him $10, which he refused but I made him take it. For a fella in his 30's, maybe 40, he came across as an 80yr old man that had been in the business for 65yrs.

I had the printed Kohler spec sheet with me & I told him it was supposed to be 3.750 w/.003 tolerance. He grabbed a bore gauge & came out to my truck. When he first measured the bore he said it was well over that. Then he scraped some carbon off top of piston looking for a mark & found the .020 stamp. He went back into his shop & got another bore gauge attachment & measured again, several places, both, around & up/down the bore & said it was within specs and he showed me what to look for on the dial as he measured. My confidence in him skyrocketed.

 

Last Friday I took the motor to another shop, that wasn't very busy, in another town in GA. A fella in his 60's broke out his handy-dandy digital vernier calipers (like I've got & already used) and he measured one spot across the top and said it was 3.756". Well, there's a corrosion or carbon ring around the top 1/4" of the cylinder. You can see it & feel it. I estimated it to be about .006" thick. (Since I now know that it's been bored .020", subtract this dingleberry's 3.756" from 3.770" and that means that the corroded ring is actually .0065" thick. - I was close)

I thought to myself - "This guy can't be seriously trying to find out what the actual bore size is."

I said; "Fella, I hate bothering you but I'm willing to pay you for your time. I drove 25 miles to get here - would you mind using a bore gauge & measure on down in the bore for me?" He's an employee, not the owner, so he's already getting paid & they were just standing around chatting when I walked in.

Lo & behold - he turned towards his toolbox and as he did I could barely see him rolling his eyes. The old me almost kicked in but I held back. 20-30yrs ago I'd have verbally assaulted him right then & there.

Well, he used a bore gauge & did measure in various places. When he finished he said; "It's within .001" of the top".

After seeing him in action & his attitude I didn't have a bit of confidence in him. Now I know why they weren't so busy. That's why I took it somewhere else that came highly recommended from a small auto parts store owner.

 

Thanks, everyone!

 

Edited March 12, 2019 by HappyHillbilly

[bc.gold 3,399]

Next time just drop off the engine with instructions and a decent retainer, I'm willing to bet the farm your retainer is going to put your work order into the pecking order.

 

If the engine shop you choose to do the work hot tanks your engine be prepared to replace the camshaft bushings and any parts you left on the engine block made from aluminum.or die-cast.

 

Did you check with the Better Business Bureau to see if there were any complaints against this business.

 

https://www.bbb.org/us/nc/murphy

 

 

 

 

 

 

 

 

Edited March 12, 2019 by bcgold

[bc.gold 3,399]

Any decent engine machine shop is going to tank your engine block before proceeding, a clean block with all dirt and carbon removed will return precise measurements and also keep the crude from spreading around the shop and onto equipment. 

 

Hot tanks that use caustic soda will destroy parts made from die-cast, aluminum and things like camshaft bearings if left installed also these new ultrasonic cleaners can cause cavitation damage to the parts made from softer metals.

 

Re' Bronze valve guides there are two types, the thin wall that I use the old guide is reamed to size the thin wall installed then knurled from the inside to expand the wall, the knurled wall serves two purposes to secure the bronze liner and to retain oil for lubrication.

 

The other type of bronze guides have a heavier wall and are press fit and do not require knurling after installation.The K-Line install set in the video used a ball broach to expand the guide wall.

 

Cavitation Damage from Ultrasonic.

 

 

 

 

 

 

 

Edited March 12, 2019 by bcgold

[953 nut 51,655]

6 hours ago, HappyHillbilly said:

I felt bad already about him stopping what he was doing just to help me, knowing there's a whole lot more money to be made from all the automotive blocks already in his shop than in this piddly 'lil 16hp.

That is the kind of shop you want to find. The fact that he is doing race engines speaks volumes about his work. Racers are a tight knit group and if he wasn't good the word would spread and he wouldn't get their work. This man loves his work and will make sure it is done right.             As for what is behind door #2, that is about average!        

Chances are the valve guides are going to be OK. Overhead valve guides are known to wear because the rocker arm exerts side thrust on the valve stem, these flat head engines with tappets don't.

[bottjernat1 2,189]

14 hours ago, HappyHillbilly said:

Update, with some questions:

Took my engine to a good engine machinist and he was thorough, informative & helpful.

This 341 has been previously bored .020" over and cylinder walls are within specs & in good shape. There weren't any metal shavings in oil pan & all gears look great.

Crankshaft pin appears to have been ground down to -.010, to a solid 1.490" diameter.

He noticed the exhaust valve is bent & not getting a good seat/seal on the piston side of the valve.

I told him I planned on replacing both valves, springs, guides, etc..., and he suggested replacing piston rings as well since it's been sitting for 12yrs.

 

I'm shopping for a valve replacement kit & engine gasket/seals kit. I've ordered a piston ring compressor w/removal tool and a valve spring tool.

 

Questions:

1 - I've seen there's a special tool for removing the valve guides. Do I need it or is there a DIY trick?

2 - What's the best way to clean what I believe is the valve seats - where the valves sit in the block? In the attached photos you can see my exhaust valve seat(?) isn't too bad, but the intake one is a bit more crusty.

3 - Would I be going too far overboard by getting all new valve components?

 

As always - Thanks for your time, patience & help!

Have a good one!

HH

 

Try stens for parts, pistons,gaskets,seals. My late dad was a dealer for them we always had good luck with there stuff.

[HappyHillbilly 86]

10 hours ago, bcgold said:

Next time just drop off the engine with instructions and a decent retainer, I'm willing to bet the farm your retainer is going to put your work order into the pecking order.

 

If the engine shop you choose to do the work hot tanks your engine be prepared to replace the camshaft bushings and any parts you left on the engine block made from aluminum.or die-cast.

 

Did you check with the Better Business Bureau to see if there were any complaints against this business.

 

https://www.bbb.org/us/nc/murphy

 

 

 

 

 

 

 

 

 

Thanks!

They're not even listed with the BBB. Being in the boonies, a lot of places around here aren't & the average person around here wouldn't even think about checking BBB ratings. It's the good, old-fashioned word of mouth that we use around here - and I like that.

 

4 hours ago, 953 nut said:

That is the kind of shop you want to find. The fact that he is doing race engines speaks volumes about his work. Racers are a tight knit group and if he wasn't good the word would spread and he wouldn't get their work. This man loves his work and will make sure it is done right.             As for what is behind door #2, that is about average!        

Chances are the valve guides are going to be OK. Overhead valve guides are known to wear because the rocker arm exerts side thrust on the valve stem, these flat head engines with tappets don't.

 

Totally agree with your "shop & door #2" statements. I've been blessed so far on this engine so I'm leaning a bit more towards the positive side that the guide(s) are good, after reading more. Thanks!

 

4 hours ago, bottjernat1 said:

Try stens for parts, pistons,gaskets,seals. My late dad was a dealer for them we always had good luck with there stuff.

 

Thank you! I've seen their parts for sale by different places and was wondering about the quality. The wiring harness I just put on is a Stens and I was impressed with it's quality & price.

 

 

I've been runnin' around like a chicken with its head cut off workin' on this thing. Making several mistakes & overlooking stuff. Mostly due to not knowing much about small engine repair & an overwhelming feeling of uncertainty. I've got to slow down & get my act together. Some of the questions I've asked & things I've overlooked are right in the manuals, I just missed/overlooked it.

For example: I had already had the bearing plate off & measured the crankshaft pin before I took it to the machinist. There's no "apparently" (as I stated in an earlier post) that the pin had been turned. The manual & the connecting rod part# confirms it. Dang it, man! Tighten up!!! Haha!

 

Ya'll have a great day!

HH

(Mike)

Edited March 12, 2019 by HappyHillbilly

[RJ Hamner 992]

On 3/5/2019 at 6:11 AM, gwest_ca said:

I don't think you can see the piston through the spark plug hole? Are you sure it is not moving?

If it is lacking compression you may have a valve that is not closing.

 

Garry

 

I think Gary is right.  With the plug removed you are looking at the top of the exhaust valve.

Just my two cents

As a side note I just rebuilt a K341 for a C160.  I spent $400 at the machine shop but that included bore .20 over, crank .20 under plus some work on the PTO end, decking the block,truing the head and a valve job.  The rebuild kit was approx $300 including a new carb.  Was it worth it?  OH YEAH

[HappyHillbilly 86]

59 minutes ago, RJ Hamner said:

 

I think Gary is right.  With the plug removed you are looking at the top of the exhaust valve.

Just my two cents

As a side note I just rebuilt a K341 for a C160.  I spent $400 at the machine shop but that included bore .20 over, crank .20 under plus some work on the PTO end, decking the block,truing the head and a valve job.  The rebuild kit was approx $300 including a new carb.  Was it worth it?  OH YEAH

 

Yeah, it is the exhaust valve. Thanks!

You did a great job on that restore. Looks & sounds awesome! 

Hopefully one of these days mine will look similar. Now I know who to pester about some parts I’m gonna need some info on. 

[RJ Hamner 992]

Not a problem.

You will be amazed by the amount of available knowledge and the willingness to help from the folks here on Red Square

[953 nut 51,655]

Mike, it is funny that you should post this page, it opened up the next topic to be discussed. Balance Gears on Kohler have been nick named "Granade Gears" because of the hole they can put in a block. Read through these threads and see what you think.

There are a lot of posts on here about them

 

[HappyHillbilly 86]

3 hours ago, 953 nut said:

Mike, it is funny that you should post this page, it opened up the next topic to be discussed. Balance Gears on Kohler have been nick named "Granade Gears" because of the hole they can put in a block. Read through these threads and see what you think.

 

There are a lot of posts on here about them

Wow! What are the odds of me posting a screenshot of that page & you catching it?

I'll take a look at them, if they're still in there from previous rebuild, in the morning. Boy, am I glad you caught that! Thanks - I owe ya!

 

 

[HappyHillbilly 86]

It's me again, with another question;

Is there a way to remove the crankshaft from the PTO side "without" a press? I've searched but can't find anything.Thought maybe I could use my harmonic balancer tool but the arms aren't spread out far enough to keep the bolts inline.

[oldredrider 2,547]

A rubber mallet will knock it out. No need for a puller.

[HappyHillbilly 86]

8 hours ago, oldredrider said:

A rubber mallet will knock it out. No need for a puller.

 

Thanks, Paul. I put my 16lb sledgehammer back up & grabbed a rubber mallet instead. Got it out easily.

 

Everything is out of the block except the cam & governor. To me, the gears, themselves, all look to be in good shape but I'll let you experienced folks be the judge of that. (pics below)

1 - The balance gears' stubs are in spec. I think my calipers might be off a thousand or two but I got .506" on both. The only thing I see bad about them is that there are metal shavings near the needle bearings, which I believe came from a shim or 2. All 27 pins are in each bearing but I'm concerned about some of the metal shavings getting into the bearings. Thinking about going ahead & replacing the bearings - IF - I do reinstall the balance gears. When people talk about leaving the balance gears out, are they talking about just the weighted halves or the whole gear assembly?

 

2 - Valve area in the block: After some cleaning there is still a visible ring in the valve recesses. I'm thinking this needs to come out - if so, how?

 

3 - There's a pic of my intake valve after removal, for reference on it's performance(?).

 

4 - Valve guides feel really tight, solid. That exhaust valve was bent & it was a booger to get out.

 

Thank you!

Have a great day!

Mike

 

[pacer 3,159]

Another in the 'remove the balance gears' camp here. And, heres a thought on replacing them -- they can be a b*%$^ to get back in time.

 

I've removed 2 sets of them and can literally tell NO difference in the engine -- cept I think they are a bit quieter. They had a .... clatter? instead of knock and its gone. Both were noticeably worn just from the obvious looseness to them.

[HappyHillbilly 86]

So this repair’s gonna turn out like all my other repairs - I’m gonna have parts left over.