Sunday, February 22, 2015

MTD Inch Rear Thine Yard Machine Tiller


It is cold out but I wanted to get a handle on what shape this tiller's engine was in.



The cylinder does not seem to have any major scoring.  Just light lines from the carbon that should hone out.  Need to check these.


We need to see how the cylinder compares to the 2.5625 aka 2 9/16 inch. The standard bore.



Built up 2.6520 inches with blocks and locked the gold digital caliper there.  It does not matter what the caliper reads.

Put the bore gauge in the caliper and set it to zero.
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Measuring the cylinder.  Contrary to the caption in the video the tool was zeroed using the gauge blocks.








A set of chrome rings alone could do the job.  I think I read anything to .005 over can be fixed with just chrome rings.  Briggs 298982



Ordered NOS briggs chrome rings off ebay.
Unfortunately Briggs never made chrome rings so don't follow my example here.

There is a popping noise when you turn the engine over without the head.  Could be a reluctant breather.  Need to check it when warmer.

The intake valve is loose.  Turns even on the power stroke where it should be shut.  This engine still may be useable without a rebuild.

Wednesday, February 25, 2015

Took the engine off and then took it and the tiller to the car wash.

Striped the carb and gas tank off the engine.  This is one of the newest engines I have worked on and it used torx and maybe other strange fasteners.



The valves are out.  Note that spring retainer 40B goes on the exhaust valve.

The intake valve tappet seems odd.  Check that out.

Cleaned the valves and breather in the ultrasonic cleaner.







Next I need to take the air wrench after the nuts on the crankshaft.  There is one holding the drive pulley on.

Friday, February 27, 2015

I started on this yesterday but could not get the nut off the flywheel.  I filled the starter drive cup with PB blaster and let it soak overnight.   This afternoon I tore down and cleaned the 1/2" impact wrench.  With the cleaned wrench it came right off as did the flywheel.

The rod cap bolts are 5/16" hex heads.  I was fearing they might be torx drive like the 18HP.  I don't care for them.

No surprises but the governor has not come loose from the cover.

The oil remaining in the engine seemed to have a lot of aluminum in it.  Well I guess that is where it goes when it leaves the cylinder bore.


The outside face of the gear is flat and of course it will have the timing mark on it.

The pan gasket is in good shape but stuck to the block.  I will see if it comes loose when I soak the block.  It is too cold to clean the parts outside and the kitchen is busy so I may make a pattern for a new gasket.

The crank has a bit of end play need to watch that when I assemble it.  My gasket material is the same thickness as the standard gasket .015" but I ended up reusing the original gasket.  If the engine works I may fix the end play by using a thin layer or RTV.

Monday, March 2, 2015


I spent much of yesterday reassembling the engine.  The assembly was done with vasilene and a couple of tablespoons of motor oil when installing the piston.  Had I done this in the shop instead of my office I would have used much more oil.  It should be ok.

Today I ground down the intake valve stem to get .005" clearance.


The chrome plating has worn off the piston.  Looks to be the rings are too weak to hold it steady in the bore or the bore is just too large.

Anyway I just want to get it back together and see how it runs cleaned up ad adjusted.

The rings I ordered are a total flop.  They do not fit this new style piston and they are not chrome. So much for trusting a single document even if it is B&S!

Maybe just maybe one of the pistons from a mower can use these rings.  No real plans at this point just want to see what it does.


Original 
Raster Export MTC
Cleaned the carb.  It may have been OK as is but as long as I had it off the motor I did not want to take the chance.  Still have to cut a new gasket.  Actually 4 to get past the .05 thickness of the original.  It took way to long to cut a gasket from this image.  I had to trace over it and ended up with just a few nodes which cuts quite fast. Still need to adjust the size of the bolt holes.

The linkages are on the complex side.  Took lots of pictures but I do have a similar tiller in the garage that maybe identical motor wise.  That would be very helpful.

So about all I need now is to clean the gas tank, put the head one,  and put it all back together.  Maybe bring some oil in the house to warm up install the motor before it gets too cold.

This is kind of neat.  I have taken a shine to zip lock bags of all sizes.  Up to the point a motor is all buttoned up keeping it clean is essential.  These may even be a good idea for storing smaller unused engines.  Might cut down on condensation.


The 5.5HP tiller motor is on the left and the 1st 18.5 on the right.

Wednesday, March 4, 2015

Cleaned the head bolts.   Gasket looks reuseable.  The last of the parts are in the tub soaking.

I am dreading getting the linkages right.






Installed and torqued the head.  It has a lot more compression than prior to cleaning.  Will have to run a compression test once I get it running.  Note the optimism!


Sorted out where most of the bolt nuts and screws came from.

I am missing the muffler and its bolts.  The special washer that goes under the flywheel nut and the entire shroud.  Me thinks they are hiding out together.








Thursday, March 5, 2015

Cut the carb gasket today.  Three layers combined it .05 thick uncompressed. Cut a 4th but did not use it.  Had to redo node work as it was lost or misplaced.

Found the muffler and shroud.  I am thinking briggs may have done away with the washer.  Still looking for it but I am getting doubtful.

Need to drag the engine over to the shop and connect the carb to the gas tank then that unit to the engine etc.
This picture was taken during disassembly.  It is fairly conclusive evidence that there was no conical washer on the crank nut.







The engine is now in the shop for reassembly.  As I imagined the linkages are somewhat of a challenge.  Esp the stuff between the carb and governor.



Friday, March 6, 2015

Finished putting the engine back together.
Found a youtube vid to explain the bits of the linkages.

Ran the engine on the picnic table.  Smoked.

Aired up the tires using some bead sealer.  I think the problem is/was dirt on the beads.

Installed the motor on the tiller and did some tilling.  No problem with power but it still smoked.  Ordered some new standard rings.  Think the oil control ring is bad as it has good compression and power.