Not a pretty sight!

[dschwandt]

Taking apart my twin stick 1450's engine to locate an oil leak and discovered the cast iron oil pan is cracked on one corner. The engine has always smoked since I had it and the head gasket is also leaking so further dismantle was also warranted. Had planned on installing a snow blade using the hydraulic angle parts I picked up over the weekend.

Removed the head to repair the head gasket and found the engine has a .010 o/s piston. It was covered in oil and the valves were encrusted with carbon. So...it looks like a complete tear down and overhaul is in order.

BY the looks of the piston, being really clean on the one side opposite the valves, I am hoping that the issue is miss- aligned ring gaps maybe all in line???
What are the chances of that

I did my 1650 last year about this time and it turned out really well and is about the best running Cub in my stable at present. I plan on using the same machine shop in Cedar Rapids on this job as well. Pictures or it didn't happen.

 

[kmcconaughey]

That's a lot of oil and carbon.

 

[dschwandt]

Got the piston out and there was only 2.25" between the end gaps on the rings right below the valves.
.010" O/S piston w/no signs of any crosshatch left at all.

 

[mfrade]

I'll have to ask you to clarify the end gap measure. As written I'm reading 2 & 1/4 inch. Did you mean two hundred twenty five thousandths? Also - the rings do not stay stationary, they do rotate slowly on the piston, Looking at the pictures above, I see worn valve guides causing you the oil coking problems.

Just my opinion, that and 2 bucks will get you a coffee... maybe!

 

[dschwandt]

I always read the rings should be placed so the end gaps are spaced 120* apart.
Anyway, it's going to the machine shop next week for an evaluation.
Lots of erosion on the upper land of the piston and there was lots of slop with the piston in the bore before I removed it. Yes, 2-1/4" Mike.
The kits from Isavetractors come w/new valves and the guides are only about $10 each more. I'm sure the shop will note the guides also, they did the last time around w/the 1650 engine.

 

[hdeloach]

Remove one of the piston rings.Place it in the cylinder making sure it is square in the bore ie the same distance from the top of the block---not crooked in the bore and about 1" down in the bore. Now measure the gap in the ring---that is end gap.

 

[dfrisk]

You must idle that engine ALOT. Typically Kohlers turn the exh valve white and burn the carbon off because they run yellow hot under load. Can't begin to explain why so much oil on top of piston. The carbon build-up also hints excessive idling. I've explained several times here how to remove carbon from the combustion chamber using a spray bottle of water. Start engine, remove air filter cover, spray small stream of water into carb, engine rpm should be around half throttle. Doesn't take much to clean things up so they run better. Normally replace the spark plug when I did this.
Lack of cross hatch on block leads me to think somebody did a quick and sloppy rebuild, removed +.010" piston, ran a bottle brush hone thru the bore, new +.010" piston & rings and put it up for sale. I'll be curious what the rod and crankshaft journal look like.

 

[dschwandt]

Used it with a tiller for 2 years before this last season so it ran more or less wide open for that.
Sat in the shed for the last year after the 1650 got the tiller this past spring.
Judging from how clean 75% of the piston top was, I think you are correct with the cobble O/H job,
Odd there was no ridge on the top of the cylinder either.
The head bolts all came out easily with my DeWalt drill motor
Everything but the head gasket was goobered up with red silicone sealant oozing out all over the place over what looked like petrified gasket remains. I'll get the skinny on the spec's next week some time and come back with an update.
They will tell me what I need to order in terms of parts.

Well that's all history now . It will be done right this time around.
It was a $250 pick up with a bunch of other stuff a few years back including another twin stick 1450 that I have not messed with yet. Don't even know if the engine is free or not. I do know both hydraulic sticks are all rusted tight.
I was needing a tiller Cub at the time and this one I was able to get running fairly easily.

 

[dkirk]

David,

Some good commentary by other members. The missing aluminum on the top land is caused by hard carbon, building up on the bore surface that actually shaves off the land. On these L-head engines, the hottest area of the bore is at the block deck in the vicinity of the exhaust port. This heat is fed back into the bore, causing not only hard carbon buildup here but the bore expands inward, thus causing the piston shaving action. It looks like the top ring may be stuck in the groove and this can be contributing to the high oil consumption. A .020 rebore and oversize piston and rings should cure the problem.

Alignment of ring gaps at 120 degrees is always proper for assembly. But in a running engine, these ring gap locations continually change and probably align/mis-align many times during the life of the engine.

Another good tip is to always use a larger ring end gap on the second compression ring as compared to the top ring. Only .003 to .005 increase is all that's necessary to greatly reduce oil consumption. Example - top ring measures .012" end gap: recommended second ring gap should be .015 - .018.

 

[dschwandt]

Appreciate the input David, Thanks!!
I guess now it's time to start cleaning the rest of it up.
Lookes like the steering needs some attn. as well as the axle bushings.

 

[dschwandt]

Here's the scoop on the end gaps.
The top ring had .039
The 2nd ring was at .051!
That explains a lot.
I'd sure like to know who put this thing together last!!
Would it be possible they/someone/whoever used standard size rings on an O/S piston??

 

[mfrade]

David,

Some good commentary by other members. The missing aluminum on the top land is caused by hard carbon, building up on the bore surface that actually shaves off the land. On these L-head engines, the hottest area of the bore is at the block deck in the vicinity of the exhaust port. This heat is fed back into the bore, causing not only hard carbon buildup here but the bore expands inward, thus causing the piston shaving action. It looks like the top ring may be stuck in the groove and this can be contributing to the high oil consumption. A .020 rebore and oversize piston and rings should cure the problem.

Alignment of ring gaps at 120 degrees is always proper for assembly. But in a running engine, these ring gap locations continually change and probably align/mis-align many times during the life of the engine.

Another good tip is to always use a larger ring end gap on the second compression ring as compared to the top ring. Only .003 to .005 increase is all that's necessary to greatly reduce oil consumption. Example - top ring measures .012" end gap: recommended second ring gap should be .015 - .018.

Yeah what he said! I just got home from work so I couldn't reply earlier. Sounds like you've got it well in hand now!

 

[mgonitzke]

Here's the scoop on the end gaps.
The top ring had .039
The 2nd ring was at .051!
That explains a lot.
I'd sure like to know who put this thing together last!!
Would it be possible they/someone/whoever used standard size rings on an O/S piston??

Yeah, I'd say that is possible. I had an 800 years ago that looked great inside but smoked like crazy. Turned out the rings had huge end gaps. A correct set of rings and a light hone and it ran great with no smoke. It is amazing what some people will do sometimes.

 

[mjame]

Is the seat split or am I just seeing things

 

[dschwandt]

Carbon build up.
It was level with the face of the valve almost 1/2 the way around

 

[dkirk]

Looks like the previous owner re-bored it .010 over and used standard bore size rings!

 

[dschwandt]

Kinda what I thought also David.
Going to carry the frame and trans in one piece over to the house with the loader cub where I have water next week when it warms up some and give it a bath w/the power washer.
Will need a new cork gasket as well and I can't stand working on a greasy filthy piece of equipment if I don't have to.
I think I can just stand the ol' girl up on her tail to do the gasket without splitting it seeing as how the engine is out.
Film at eleven!!

 

[kmcconaughey]

I think I can just stand the ol' girl up on her tail to do the gasket without splitting it seeing as how the engine is out.
Film at eleven!!

Like this (Photos from Big Bob, of his 127):

 

[dschwandt]

Well, it looks like I have another boat anchor!
Picked it up yesterday when I dropped off two K341's to get checked out.
Just what I need, NOT!!
Amazing how nice 'n' clean they can get this stuff

 

[mfrade]

Well that stinks. Now what?