LT155 - Engine rebuild - have some questions

[SteveinNC]

All,
I have a LT155 with the Koehler CV15s and I had the lifter tick and then low power. Measured lift on the end of the push rods and getting measurements of .177 intake /.192 exh as compared to the factory specs of .353/.360 lift.
So I'm pulling the engine to go through it.

#1 Question: How do you get the PTO pulley off the bottom of the crank so you can remove the engine from the frame? My pulley has 2 really small holes in it 180 degrees apart. These holes are 3/16" dia. Didn't want to use the standard gear puller on the outside flanges of the pulley so to not bend them up.

#2 Even though its not aprts yet, its fairly certain the cam and lifters will need to be replaced. Was going to go ahead and do a completed rebuild, and replace all bushings, bearings, seals, and gaskets. Any other suggestions of know issues to replace or upgrade while I have it apart?
Does the replacement cam/lifters still have the same issues that causes this original loss of power due to cam wear?

I'm all ears. Thanks in advance for any help any can offer.

Steve

 

[Born2Mow]

Welcome.
Lift has to be measured in VERY precise locations. I notice your numbers are almost exactly half those specified, which simply makes me wonder. And wonder. Then rocker arms often multiply the lift of the cam. I've replaced lots of camshafts, but never one worn to half. I'm not doubting, just scratching my head a lot.

1) You need a "balance puller". Then you need bolts to fit those 2 holes... which are threaded. LIKE THIS. Works just like your wheel puller, but uses bolts. A very handy item to have.

2) With that much wear you'll need a new oil filter ! Don't forget new o-rings.

Hope this helps.

 

[SteveinNC]

Welcome.
Lift has to be measured in VERY precise locations. I notice your numbers are almost exactly half those specified, which simply makes me wonder. And wonder. Then rocker arms often multiply the lift of the cam. I've replaced lots of camshafts, but never one worn to half. I'm not doubting, just scratching my head a lot.

1) You need a "balance puller". Then you need bolts to fit those 2 holes... which are threaded. LIKE THIS. Works just like your wheel puller, but uses bolts. A very handy item to have.

2) With that much wear you'll need a new oil filter ! Don't forget new o-rings.

Hope this helps.

Born2Mow,
I'm with you. I did not do these measurements on the cam nor with a magnetic base so no these are not precise. They were take at the end of the push rod while seated into the rocker arms. So there is some side to side movement with will not report exact measurements. I was simply looking do I have a proble or not and when I saw numbers that I could repeat with my measurement placement, I said yea, it needs to come out.
Last time it ran, I couldn't even engage the mower deck or it would almost kill the motor. So I know it was lacking power and I heard the lifter ticking previously. So, looking at the big picture... at least cam/lifters.
But I'm with you on your way of thinking.

on to the the PTO pulley... I left it soaking with penetrating fluid for several hours. Went out about 20 min ago and applied some heat used the side of a hammer and started tapping it and it came right off with no damage to the pulley flanges. That sucker wouldn't move .001" earlier with anyhting I tired. I was going to run to the hardware store to get the puller you talked about if this didn't work. I jsut wondered about the size of those small holes and stripping out. But that is water under the bridge now.

with you on the new oil filter also. It's coming 100% apart and will take everything to the car wsh with pressure and saopy hot water to have it sparkling clean before anything go back together. Will keep an eye out for shiny particules.

Thanks for your help. I might have more later on, but I'm off to the races on it for now.

Steve

 

[SteveinNC]

OK fellas I got it apart and have a surprise. No shavings at all. Lifters do have a small divot started. Exhaust is more pronounced than the intake lifter. But no shavings are anything else in the crankcase to say major issues. But I had absolute loss of power after the lifter clatter started and stopped.

Attaching some pictures for some more experienced opinions. I've had plenty of V8 motors apart before but never a lawn mower engine. And we all now each have their won little quirks about them.

Piston: Doesn't show any excessive heat or issues as far as I can see. Looks like standard wear on the skirt, and crank journal surfaces in the connecting rod looked good.

Cam: I see issues but expected a whole lot worse. Thoughts? I think Born2Mow hit the nail on the head with the 1/2 values I got for lift measurements. Probably going to need to get those measurements out at the end of the rocker arm to get true lift values. That is on me. But irrelevant at this point with the motor 100% disassembled.


Lifters: Hopefully the pictures show the slight elongated divot started in both lifters as it appears they both quit spinning and started wearing in one spot. The push rods did have pressure on the rocker arms so it isn't a collapsed lifter. ??? I can compress the lifter real easy with finger pressure. I know with SB Chevy lifters that isn't possible. So don't know if that is an issue or not with this motor.


Any suggestions on rebuild kits? I saw one with a replacement piston, but I don't believe I'll need the piston replaced? Should just need rings, shims, bearings, probably cam/lifters. Any other suggestions?

I'm a do it right the first time guy.

Steve

 

[Gumby83]

But doing it right the second or even third time is so much more fun!

I’d just get the Kohler rebuild kit if you’re wanting all the bushings, bearings and other wear parts replaced and want them to be right. If it’s not a huge difference in cost, a replacement piston certainly won’t hurt.

Tip for washing the case and heads - if it’s not too grimy, a dishwasher on high temp cycle does the job as good as a hot tank at an auto shop.

 

[Hammermechanicman]

. "The push rods did have pressure on the rocker arms so it isn't a collapsed lifter. ??? I can compress the lifter real easy with finger pressure"

You should not be able to compress the lifters with your fingers. They should be pumped up with oil like car lifters. When you take them out of the engine it should take considerable force to compress the oil out of the lifters. I wonder if you have an oil pump problem?