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Discussion Starter · #1 ·
ok the hh120 that had a bad knowck after piston and rings heres the lates
I tore it down pulled the piston pulled the crank pulled the cam all MIC out to spec. I did notice that it looked as if the mag on the flywheel was hitting the ssi ???? not sure how thats posible but could that be my knockin noise
 

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Magnets can come loose from the flywheel and cause such problems..not very common though,but it can happen..excessive bearing play can let the crank get pulled upwards and let the flywheel contact the SSI armature sometimes too...some have J-B Welded the magnets back in sucessfully,but I wouldn't want to trust that with something spinning at 3600 rpms,if it ever let go,the results would not be pretty,and could be harmful to your health!..
 

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Magnets can come loose from the flywheel and cause such problems..not very common though,but it can happen..excessive bearing play can let the crank get pulled upwards and let the flywheel contact the SSI armature sometimes too...some have J-B Welded the magnets back in sucessfully,but I wouldn't want to trust that with something spinning at 3600 rpms,if it ever let go,the results would not be pretty,and could be harmful to your health!..
I did glue my magnets back on, 6 of them, as they all came off. I have no fear they will come lose, they were only held on from the factory what looked like a super thin layer of either adhesive or double sided tape. I used JB weld and am not worried cause the JB weld is holding them in place, because they are a magnet, they stick themselves to the flywheel anyway.
 

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Cranky Motorsports
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centrigugal force would almost keep them on- they only need to ke stuck lightly to the flywheel to keep them from sliding around.
 

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my bet is to much endplay...or carbon causing the knock..but end play is my bet cause the mag got hit..
 

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Discussion Starter · #6 ·
ok give me some pointers or bearing numbers if possible and do you change the races too or not im not a mechanical idiot but never gone this deep in a small motor engine is a 143.602022 12hp i know i need a bearing spreader and need to heat the new bearings but any other tips would be nice
 

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ok give me some pointers or bearing numbers if possible and do you change the races too or not im not a mechanical idiot but never gone this deep in a small motor engine is a 143.602022 12hp i know i need a bearing spreader and need to heat the new bearings but any other tips would be nice
Did you check the end play? Since it has roller bearings the end play should be zero to preload the bearings properly.

You'll need a bearing separator and puller to remove the bearings from the crank. You'll need a hot plate and a container of oil to heat the bearings for installation. You could always have a local machine shop do it for you...

The races don't necessarily need to be replaced, you can inspect them and if they look good you can reuse them. Otherwise you'll have to press or knock them out of the cover. New ones will need to pressed or hammered back in. I have a bearing and race driver kit that I use with a press or hammer.
 

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Tecumseh actually has a kit with shims i bought once that u use...for the flywheel side..and then to adjust preload take out the shim on the sump cover side..that will make the preload tighter, thats what the white thin gaskets are for...
 

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I have read here someone got a head gasket for a HH100 and though its got the same bolt pattern as the HH120,,its inner diameter is smaller by enough that a HH120 piston can whack into it and make a disturbing knocking noise!..
 

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Discussion Starter · #13 ·
it is either crank end play or the crank is out of round I took the crank out put the piston and connecting rod on it try to turn it and it binds is that normal ????
 

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It should not bind up,if it feels stiff only at one point,its possible the crank journal is egg shaped,and you measured it where it had the largest diameter...also they can wear tapered at an angle side to side too,that will show up as unever wear at the journal on the rod surfaces..since these engines had no oil pump or oil pressure,its critical the rod and crank journal clearances are within spec and not out of round,as they dont have any oil pressure to help cushion the parts and keep them quiet like you would in a pressure lubed engine...some cast iron engines are just noisy anyway,their cam gears and lifters can cause a lot of noise ,yet its considered "normal"--to a degree of course..
I cant hear how bad yours knocked,so I have to take your word for it that it sounds "bad"...
 

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If ur napa store has a decent machine shop have them check it...They can tell you if its round or not...most likely the rod could be worn....its softer then the crank...and if cranks turned, then u replace rod with an undersized rod..
 

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I dont know if they do sell undersized rods,if not,a good machine shop could probably shave some meat off each side of the "standard" rod and cap ,then hone it to the right undersize diameter,like they do when re-sizing a rod for a car engine...
 
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