Help needed, I tore into the 800

Roanoker494 · #1 01-13-2011, 05:29 PM

Well.... Managed to get off work at 1pm today so I decided to tear into the K181 on my recently acquired Model 800. Everything went very smoothly, this seems to be a fairly easy engine to work on, and I believe I even found the cause of the low compression. In my opinion it looks like the head gasket was leaking. What do ya'll folks think? You see how it looks like exhaust gas has been blowing by the gasket around the exhaust valve? (Don't go away yet, it gets better)

Now on to the next issue I found.
The intake valve is making no movement what so ever. I pulled the carb and valve cover and confirmed the tappet is also not moving. I did use a screwdriver to raise the valves and they look to be seating well, looks like there is no burnt valve. Guess this leaves me at the camshaft? Do I need to pull the engine to get to the camshaft? Since this engine probably has 1500+ hours, should I consider going through the whole engine? Seems that I can pick up a complete rebuild kit for less than $100. The kits I have found are on Ebay, anyone have any suggestions of a better place to look? I looked through the sponsor links, at the top of the page, but I did not see any complete kits.

Matt G. · #2 01-13-2011, 05:36 PM

A leaky head gasket would cause low compression and a few other things. Yeah, the engine basically has to come apart completely to get the cam out. Go to Kohler's website and download the service manual if you don't have one. You need it if you are going to be inside the engine.

Instead of those rebuild kits, I'd go here and pick up an aftermarket gasket set and the OEM rod. You choose between OEM and aftermarket piston.

Seems like either that cam lobe went flat, or the cam broke between the intake and exhaust lobes.

TEET · #3 01-13-2011, 06:00 PM

I'm with Matt..sounds like a broken cam..Ive never seen one worn down that far that it doesn't move the valve at all, but I suppose its possible.

Sounds like you need a new/used cam and rebuild kit..or piece one together. I'd definitely go Kohler brand on the Rod/Piston/rings...and like Matt said again, aftermarket gaskets. They have worked well for me...Ive used them on umpteen rebuilds with excellent results.

A K181 is a great engine to get your hands dirt on....pretty simple.

Let me check my parts stash and see, but I think I have a good used cam...

Jeff (teet)

Yosemite Sam · #4 01-13-2011, 06:08 PM

If you got stuff that ain't movin then you gotta pull the pan to find out why.

If everything else moves like it should then I would suspect a broken cam or a worn lobe.

Roanoker494 · #5 01-13-2011, 06:17 PM

Quote:

Originally Posted by Matt G.

A leaky head gasket would cause low compression and a few other things. Yeah, the engine basically has to come apart completely to get the cam out. Go to Kohler's website and download the service manual if you don't have one. You need it if you are going to be inside the engine.

Instead of those rebuild kits, I'd go here and pick up an aftermarket gasket set and the OEM rod. You choose between OEM and aftermarket piston.

Seems like either that cam lobe went flat, or the cam broke between the intake and exhaust lobes.

Quote:

Originally Posted by TEET

I'm with Matt..sounds like a broken cam..Ive never seen one worn down that far that it doesn't move the valve at all, but I suppose its possible.

Sounds like you need a new/used cam and rebuild kit..or piece one together. I'd definitely go Kohler brand on the Rod/Piston/rings...and like Matt said again, aftermarket gaskets. They have worked well for me...Ive used them on umpteen rebuilds with excellent results.

A K181 is a great engine to get your hands dirt on....pretty simple.

Let me check my parts stash and see, but I think I have a good used cam...

Jeff (teet)

Thank you fellers for the responses and the information. I will have to agree with the broken cam theory, the owner said the engine quit running quite suddenly. Seems a worn cam would have caused problems for a while before it quit and I have also never seen one so worn that it will not move the valve at all. Now all of my 4 cycle experience has come from the automotive field, but I figure the same basics should still apply. I have always preferred OEM over AF parts when it comes to the "major" engine components, but I have been known to "cheap out" a few times. I am going to go ahead and install the head with anew gasket to see if that fixes the compression problem before I go any further. The cylinder walls look to be in great condition and there is no ridge what so ever, if automotive terms apply here.

Roanoker494 · #6 01-13-2011, 06:21 PM

Quote:

Originally Posted by Yosemite Sam

If you got stuff that ain't movin then you gotta pull the pan to find out why.

If everything else moves like it should then I would suspect a broken cam or a worn lobe.

Oh well, so much for the quick fix I was dreaming about. Well..... I guess the original compression problem is a quick fix, it is the deeper issues that are going to take some time and money. Looks like I am pulling a engine on my next day off.

Matt G. · #7 01-13-2011, 07:10 PM

I wouldn't even bother bolting the head back on until you figure out what's going on inside. A broken cam is a really strange failure; you should find out what happened and what parts you'll need to order before you go much further.

Measuring the piston, bore, ring gap, etc. while the engine is apart will give you a better idea as to its condition than just bolting the head back on and seeing if you have compression.

Roanoker494 · #8 01-13-2011, 07:29 PM

Quote:

Originally Posted by Matt G.

I wouldn't even bother bolting the head back on until you figure out what's going on inside. A broken cam is a really strange failure; you should find out what happened and what parts you'll need to order before you go much further.

Measuring the piston, bore, ring gap, etc. while the engine is apart will give you a better idea as to its condition than just bolting the head back on and seeing if you have compression.

Anything special I need to know to remove this engine? The service manual gives a good idea on taking the engine down, but nothing on removing it.

Edit:
I had already talked myself out of installing the head first. The only possible thing that could cause low compression, that I am not already going to replace, is the block itself. If the block is cracked the engine is junk anyway.

_DX3_ · #9 01-13-2011, 07:38 PM

The two front motor mount bolts are between the frame and front axle. You need to lift up the mower and allow the front axle complete pivot in order to have room to get the bolts out. Also the only way to get them comfortably is to use an offset 9/16 wrench. I took the front tires off so I didn't have to jack the front up too high. Other than that, it is pretty straight forward. You also need to download the service manual for this series. It describes the motor removal and other things you need to know. Manual is here: http://ccmanuals.info/pdf/1x8-9%20&%...e%20Manual.pdf

Roanoker494 · #10 01-13-2011, 08:03 PM

Quote:

Originally Posted by _DX3_

The two front motor mount bolts are between the frame and front axle. You need to lift up the mower and allow the front axle complete pivot in order to have room to get the bolts out. Also the only way to get them comfortably is to use an offset 9/16 wrench. I took the front tires off so I didn't have to jack the front up too high. Other than that, it is pretty straight forward. You also need to download the service manual for this series. It describes the motor removal and other things you need to know. Manual is here: http://ccmanuals.info/pdf/1x8-9%20&%...e%20Manual.pdf

Thank you for the information and the link to the QL service manual, I will put both to good use. I plan to pull the engine on Sunday, as long as the weather is decent, and get it torn down. Man was I ever excited when I seen a leaky head gasket, I just knew I was getting off easy. Glad I decided to bump the engine over and check the valves anyway.