small engine question, crank shaft sleeve

[jake00]

Long story short, My lil brother blew up my parents areins snowblower.

it has a tec LH318sa Engine. I found one and ordered it,

The only problem, is the original has a 1" crank and the new one has a 3/4" crank. Both are keyed and tapped

Now, theres a triple pulley keyed sleeve setup (for the blower) that fits the 1" crank.

Can I somehow sleeve the 3/4" crank, but retain the keyway?

the pulley/sheave, looks sorts like this http://thumbs4.ebaystatic.com/m/mKEDqZ-wWTK5YVu0GAk5rwQ/140.jpg

 

[Torque1st]

Hardware stores sell sleeves for shafts pulleys, and sprockets. Sometimes a special key is required when the keyway size changes. Hardware stores also have those items.

 

[tkiranch]

I would just bite the bullet and purchase a new pully for the 3/4 shaft you know the size pully you need, just get one for a 3/4 shaft.

 

[eddyyy302]

Some people use the sleeves, but I do not like them. I either swap the crank out or replace the pulley, as stated above. Crank swap takes about an hour.

Dan

 

[jake00]

Heres the prob with just swapping the pulley, its not just a pulley, its 3, connected to a shaft that fits over the crank and is secured to the crank with a bolt and a key (I could find a sleeve, but the key is part of the pulley/sleeve

I could swap the crank if tecumseh dodnt go out of business 3 years ago..

attached are pics of my pulley/sleeve (extends past crank by a couple inches)
and the crank

 

[Torque1st]

The real impediment to an easy fix seems to be the key. Is the key actually part of the pulley assembly or is it just a steel part imbedded into it? The key should be a piece of square stock fit in a keyway. You should be able to remove it with a punch or something. Extended multiple pulley assemblies like that are fairly common in the garden implement industry.

 

[jake00]

the key is part of the assembly.

What if I somehow sleeved the crank, then assembled everything then drilled through the assembly , through the crank then ran a nut and bolt through it?

 

[rwhite692]

Why not return the one you bought, and order one with the correct size crank?

 

[jake00]

because Tecumseh went out of business a few years ago, All of the engines that were available have been bought up...


Back to the original problem, I think I'm going to try post # 20
http://www.diygokarts.com/vb/archive/index.php/t-8363.html

 

[Torque1st]

I wish I had your pulley assy in hand to look at. The picture is way too fuzzy to see anything. The solution in #20 would be OK. I would check it often to make sure it did not come apart.

 

[Skin]

because Tecumseh went out of business a few years ago

no they havent. Their assets were sold off. Parts are still being manufactured. Short blocks and complete engines are still available from existing supply. Have your SPEC number from the dead engine handy? Its just below or next to the model number.

Also have you checked the crank from the existing motor to see how much transfer there was? Could be very little in which case you could just take emery cloth to it to smooth the burrs.

 

[jake00]

Lh318sa-156601h

 

[Elroy]

No doubt in Elroy's mind, that key is cast integral on that custom pulley. Surely you could get an engine with the correct shaft diameter but that would likely be a PIA at least

Probably the easiest solution would be to take that special multi-groove pulley to a machine shop and have them cut the key stock out in a lathe and re-broach a conventional keyway in the pulley. Then build a bushing that was slit the full length with the proper ID / OD. Then use a custom rectangular key that would mate into the pulley and the crank.

Sure it might cost you $100 or so but you'd have it in a day. How much time and trouble is it going to take to exchange that engine ??

 

[Skin]

Lh318sa-156601h

crankshaft is P/N 35372A. Cheapest way to fix it would be to salvage the original crank, if possible, or buy something similar off ebay. LH318SA is better known as HMSK90. An HMSK80/8HP engine would probably also work fine its just a matter of finding the same size pulley [including length and keyway]. But here are some options that i found for you.

http://www.partstree.com/parts/?pn=35571A Crankshaft.

Sears [believe it or not] also has the crank under a substitution number http://www.searspartsdirect.com/par...A/0071/143&pathTaken=partSearch&blt=14&prst=0

And lastly this B&S engine should be a bolt on complete replacement and would be the easiest option and probably what i'd do as opposed to dropping $150 for a crank. No modification necessary. Double check the crank dimensions of the original with the ones he listed first though. "PTO (Extension): 1” dia., Keyway, tapped 3/8-24Dimension: 2-3/4(c)"



http://cgi.ebay.com/BRIGGS-AND-STRA...304?pt=LH_DefaultDomain_0&hash=item5ade01a4c0

 

[jake00]

Thanks for the Help. I did salvage the crank, but will it fit the new engine I have? LH318SA-156574

 

[Skin]

Thanks for the Help. I did salvage the crank, but will it fit the new engine I have? LH318SA-156574

Its giving a different cylinder cover # for the front of the engine but the crankcase bearing in that cover, the oil seals, connecting rod, and the crankcase itself are all the same so i'd say yes. Should be a direct transplant. Just take a tape measurer to the cover and check the depth, if its the same it should be fine. The number difference is probably due to something like differing oil fill holes.

Be careful when you put the cyl cover back on. The gov. gears can snag on the camshaft. Very light taps should be all it takes to get it to go back together. Dont forget the timing mark if the cam comes out.

Torque specs are as follows:

210 in. lbs for the connecting rod bolts.
115 in. lbs for the cylinder cover
700 in. lbs for the flywheel nut
45 in. lbs for the ignition. [should not have to remove though]

 

[jake00]

thats probably the best way to go, Thanks.