M-18 Going in

[pfrederi 17,741]

Asked awhile back about what to do with the Magnum 18 in my 418A.  Decided to go for the gusto, full overhaul. I have done several singles Kohlers Techy only one Twin a Mil Std (Hercules 2a042) This is different so I thought i would share some pics of the process occasionally.  (KT-17 would use a virtually identical process)  After you strip external stuff you get Flywheel and stator off.  First issue. Kohler used self-tapping screws to hold stator on.  It is 3/8' thick and tightly sealed on the back.  different juices had no effect.. broke all 4 screws.  Then the stator was fused to the crankcase.  Couldn't get  clear shot at tapping it off til I got the jugs off.  They came off easily then you take the pistons off the rods.  Rods stay on the crank and you have to keep them from flopping around. Kohler used adhesives instead of gasket to hold end plate on so it was hard to get off (compounded by me over looking one bolt  )  Crank case has to be split there are two spots you are supposed to insert a screw driver and twist.  NO way the adhesive they used between halves was too strong.  Used an old very dull cold chisel.  Crank looks good will have it measured may just need a polish.  You can see in one picture the needle thrust bearing WH specified to deal with manual PTOs.  Only a very few Magnum spec numbers have it.

 

 

[oliver2-44 9,759]

Thanks for starting this thread. I'm following along as I've never seen a twin apart.

[SPINJIM 1,981]

Very timely information.  The Kohler KT17 series II in my 417-8 just dumped all of its oil in my driveway while I was running my snow thrower.  I'm hoping it's just an oil seal, but could be a cracked block.   It still ran while loosing oil, so the rods and pistons seem okay.   I'll have to wait until warmer weather to dig into it, but all of the pictures and updates are appreciated.   Good luck with your rebuild.  

    Jim

[pfrederi 17,741]

1 hour ago, SPINJIM said:

Very timely information.  The Kohler KT17 series II in my 417-8 just dumped all of its oil in my driveway while I was running my snow thrower.  I'm hoping it's just an oil seal, but could be a cracked block.   It still ran while loosing oil, so the rods and pistons seem okay.   I'll have to wait until warmer weather to dig into it, but all of the pictures and updates are appreciated.   Good luck with your rebuild.  

    Jim

I would bet on a seal.  the only cracked  crankcase KT I saw the crack was caused by the rod slamming into the case.

[ebinmaine 67,596]

Cool stuff.  

 

 

 

 

[cod 120]

Thanks for sharing as I've got a spare M-18 that may get the same treatment.

[pfrederi 17,741]

Been getting some things done on the engine between snowflake rearrangement sessions.  These engines involve more effort than the K/Magnum singles.  Got one side of the case cleaned.  There are a myriad of little spaces to clean out.  Parts washer is in the part of the shop I don't heat very often so the fluid is at 27degrees,  used a pint of brake clean after the parts washer and a bunch of Q-tips and brushes.  Outside has has a bunch of dirt traps also but I don't care as much about that.  Wound up shearing off all 4 of the self tapping screws that hold the stator on.  3 left enough sticking out to try to get it out after the stator was off.  Over a couple days applied Kroil, PB Blaster, Liquid Wrench, BG In-force and heat.  Would not budge broke off flush.  Gave me an excuse to get another helicoil set (#10-24)  so some small drills, carbide bit on the dremel and the helicoil have two fixed.

 

Now have to pull off all the little black threads around various spots of the case.  Kohler used some kind of sealant between the case halves not a gasket.  They also caution not to use an scrapers on the mating surfaces.  The little threads of sealant  that squeezed out on the inside are a stark reminder to NEVER USE RTV in a hydro.

 

 

[pfrederi 17,741]

Other projects have taken priority.  The machine shop got back to me need to go .010 over under on the pistons and rods.  Also decided to get new valves and guides, machine shop will install the guides and surface the valves/seats as needed. Took a few days to find the best sources for all the stuff.  Prices vary widely...Also Kohler decided at some point to change valves from 45 degree to 30 degree.  i need 45 and they are harder to run down. 

 

Placed a $496 order for parts this morning.  Doubling the cost for a singles machine shop work and throwing in valve stuff that will probably add another $300+.  Hope i do not need any other parts

[midpack 866]

On 2/7/2021 at 4:32 PM, SPINJIM said:

Very timely information.  The Kohler KT17 series II in my 417-8 just dumped all of its oil in my driveway while I was running my snow thrower.  I'm hoping it's just an oil seal, but could be a cracked block.   It still ran while loosing oil, so the rods and pistons seem okay.   I'll have to wait until warmer weather to dig into it, but all of the pictures and updates are appreciated.   Good luck with your rebuild.  

    Jim

They will run on one cylinder, and with a big hole in the block   

[ebinmaine 67,596]

3 hours ago, pfrederi said:

Placed a $496 order for parts this morning.  Doubling the cost for a singles machine shop work and throwing in valve stuff that will probably add another $300

You drop 800 to $1,000 into an old torque monster engine like that and you get your value out every time. 

[squonk 41,150]

On 2/7/2021 at 4:32 PM, SPINJIM said:

Very timely information.  The Kohler KT17 series II in my 417-8 just dumped all of its oil in my driveway while I was running my snow thrower.  I'm hoping it's just an oil seal, but could be a cracked block.   It still ran while loosing oil, so the rods and pistons seem okay.   I'll have to wait until warmer weather to dig into it, but all of the pictures and updates are appreciated.   Good luck with your rebuild.  

    Jim

I had an Oman do that. Turned out the bolts on the PTO bearing plate all backed out and dumped a quart all over the garage.

[SPINJIM 1,981]

3 hours ago, squonk said:

I had an Oman do that. Turned out the bolts on the PTO bearing plate all backed out and dumped a quart all over the garage.

 

My leak turned out to be the oil pressure sensor.  The plastic top cracked under the wire terminal, and shot high pressure oil everywhere.   

[pfrederi 17,741]

10 hours ago, SPINJIM said:

 

My leak turned out to be the oil pressure sensor.  The plastic top cracked under the wire terminal, and shot high pressure oil everywhere.   

 

This M18 did the same thing with its oil pressure sensor a few years ago...

[pfrederi 17,741]

Like all my projects this one is way over its time line.  Got the stuff back from the machine shop yesterday.   Bored .010 over  crank .010 under and he replaced valve guides and ground  the new valves and seats.  Now if i can remember how it all goes back together (and find all the other parts).

 

Picture is of $496 in parts and $250 for machine shop (Total $746  ouch)

 

 

Edited May 28, 2021 by pfrederi

[kasey54 305]

Looking good. Maybe I can make some room in the basement this fall so I could start a similar project.

Your efforts and narrative are inspiring. I'll be following.

[WheelhorseBob 1,549]

Makes my K341 rebuild look rather simple! Good luck, and I know what you mean about the price of genuine Kohler parts, $$$.

[pfrederi 17,741]

34 minutes ago, WheelhorseBob said:

Makes my K341 rebuild look rather simple! Good luck, and I know what you mean about the price of genuine Kohler parts, $$$.

These were after market parts.  Most items are NLA from Kohler and aftermarket are hard to find anywhere. 

[pfrederi 17,741]

Stage one done, have to wait now until I buy the recommended sealant they used instead of gaskets between case halves.  First step is oil pump related but they recommended you leave it be and I did.  Next step is governor which is just like the singles.  However then we go off the single script,  Next is mounting the connecting rods, putting the bearings on the crank and dropping it in the #1 half of the case.  Tappets next then camshaft.  I have two manuals.  One is a download for M-18 with crappy pictures and a original print version of the M18V manual with beautiful pictures....There are some differences almost forgot to put in the oil screen (right side of last pic) as the vertical doesn't have the same design.

[WheelhorseBob 1,549]

3 hours ago, pfrederi said:

Stage one done, have to wait now until I buy the recommended sealant they used instead of gaskets between case halves.  First step is oil pump related but they recommended you leave it be and I did.  Next step is governor which is just like the singles.  However then we go off the single script,  Next is mounting the connecting rods, putting the bearings on the crank and dropping it in the #1 half of the case.  Tappets next then camshaft.  I have two manuals.  One is a download for M-18 with crappy pictures and a original print version of the M18V manual with beautiful pictures....There are some differences almost forgot to put in the oil screen (right side of last pic) as the vertical doesn't have the same design.

Squeaky clean, I love it! I don’t know what they sealed the cases with but threebond or yamabond work great on chainsaw cylinders and cases. 

[kpinnc 12,087]

Very nice rebuild!

 

Ashamed to say it, but cleaner than anything I have done!

Edited May 30, 2021 by kpinnc

[Tuneup 1,433]

Those gasket-less case halves remind me of my Beetle and 914 days. With the removable cylinders, too!

[pfrederi 17,741]

Been a long time but the grass has never stopped growing this year.  Too much seat time.  Anyway heavy rain yesterday and too soggy to do anything outside today made some progress.  Got the jugs back on.  You have to put the piston into the jug sitting on the bench push it down until the wrist pin hole just clears the bottom (but don't push it so far the oil ring pops off) and put one pin retainer clip in place...(And waste a few minutes trying to find it after flew off into space.  you know I bought a bag of 1/4 ball bearings to use in manual trannies so i don't waste time trying to find them when they fly out...May have to buy a bag of wrist pin clips)..  Then you have the apply the sealant to the block (I used Loctite SI 593 one of the Kohler approved ones) Then you have to push the pin into the piston through the connecting rod and place the second spring clip in hoping it doesn't pop off into the block and also support the jug.  Then push the jug onto the studs in the block.  I don't have a cylinder base wrench in 1/2'"  (I have a big but not 1/2). Kohler wants you to torque the 6 nuts in a specific sequence starting at 100 inch pounds finishing at 200.  There is no way to get a torque wrench on the stupid nuts,.  Used a crow foot on  some (had to find a table for torque spec changes using a crow foot).  The others I tightened by hand to match the torqued ones.  (Plus or minus a grid square as the artillery guys used to say).

 

Then another favorite pass time adjusting non adjustable valves and in this case 4 times not 2. First you have to lap the valves (machine shop ground them and the seats but you still have to lap.). Multiple trips to the grinder trying not to take off to much   (did that on a KT17 has a distinctive click on #1).  If you screw it up too bad you are looking at another valve which in this case is hard to find.   Actually getting the valve springs and keepers in is a bit easier than on K singles and the valve spring compressor can stand by itself while you wrestle with keepers...

 

Thinking ahead I will have to see if this thing will fit on my test stand or just put it back on the 418 with out engine tins and hope there is enough clearance for a torque wrench to re-tighten the head bolts after warm up  (no holes in the tins like the Singles have ).

 

 

[oliver2-44 9,759]

Great information, keep it coming. 

[953 nut 55,307]

18 hours ago, pfrederi said:

There is no way to get a torque wrench on the stupid nuts,.  Used a crow foot on  some (had to find a table for torque spec changes using a crow foot).

Great thread Paul, hope this is being saved to the tutorial/reference section.

           If the crow foot is at the side rather than the end there is no change;   1 : 1

[Gregor 4,846]

My MV 16 is still in parts, on a shelf, in a tub, in coffee cans, patiently waiting. The crank and jugs are still at the machine shop, I am waiting to hear back. It will be 5 weeks Monday. (I think) Sounds as though it could be an expensive rebuild, especially since I really don't have a use for this motor, being it's a vertical shaft, but the experience will be worth it, I hope. Keep posting lots of pics, and do's and dont's. I'm gonna need all the help I can get.