# Some Quick Questions



## smokestack (Nov 30, 2006)

1. I've been looking at replacement engine for my snowblower and found a couple time a statement that says " Can be converted for a snowblower ". So what is different between a regular engine and a snowblower engine?

2. I have a Tec H 70 which the connecting rod exploded at the crankshaft and the crank is scored badly. One thought I have is getting the crank machined and using oversized bushings on the connecting rod, but it doesn't look like there is bushing (bearings) on the existing pieses and cannot find any on internet. Can this be done and does Tecs use bushing or bearing on the connecting rod? 

3. I assumed that this happend because I let the oil level get too low and it was low but when I took it apart everthing seems to have a nice coating of oil particularly the wrist pin at piston. The only parts that looked dry was where the con rod at crank. If it was so low on oil should I have not seen damage at the top end?
Thats it and if I could be directed to a good parts website I would appreciate it.


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## justin3 (Apr 10, 2007)

#1 certain snow blowers have 2 shafts on the engine, one driven by the crank and one buy the cam. I believe your engine should have one shaft so for a replacement engine you would have to make sure the Shaft, foot pattern and throttle are the same. Its best to replace your motor with a newer 7hp Tecumseh Snow King, you would then not have to worry about hooking up any wires or throttle cables since its all built into the motor. A Newer 7hp Tecumseh would have the same foot pattern as your H70 but you may need longer mounting bolts since I believe the H70 has a thinner mounting plate. The last thing you need to check is your shaft and keyway size on the motor then match it up to a new engine. 

#2 Tecumseh engines do not have bushings on there connecting rods, it all rides on a bare chunk of aluminum... If you have an older Tecumseh engine you probably cannot get oversize rods or even a replacement rod. Plus any engine that throws a rod probably has more damage or problems within its walls.

#3 Its hard to say really, i've seen Tecumseh engines with full fresh oil throw rods, If the rod broke at the connecting rod most likely it was due to low oil, and loosening connecting rod bolts. Loose bolts are normally caused by an uneven crank or worn down crank, that would be the scoring you see. With a worn down crank you will get vibrations or (rod knock) that will cause things to loosen up. You probably just had enough oil to lubricate the top end.

#4 For parts I love http://www.jackssmallengines.com/

Heres some Tecumseh engines for snowblowers!
http://tewarehouse.com/Catalog/Snow-Blower-Engines
Good luck!


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## smokestack (Nov 30, 2006)

Thank you very much for your thoughtful and imformative reply. The con rod coming loose does make sense, since it was rebuilt 2 years ago and I have had to tighten everything else plus I don't see any bluish tinge on any parts indicating overheating. Strange they wouldn't use bushings, are all small engines that way? The crank is badly scored and replacement costs are going to be more than half the cost of a new engine so new engine will be the way to go.


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## justin3 (Apr 10, 2007)

To answer your question mostly all 4 stroke small engines for lawn equipment and snow blowers do not have bushings. I guess this is because a lawnmower or snow blower wont be running very high rpm's that something like a quod or motorcycle would. 30yeartech would probably know more on the bushing subject. Im glad I was able to help, enjoy the snow if your in the northeast haha!


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## smokestack (Nov 30, 2006)

3 stroke per shovel load!:dude:


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## 30yearTech (Sep 14, 2006)

justin3 said:


> To answer your question mostly all 4 stroke small engines for lawn equipment and snow blowers do not have bushings. I guess this is because a lawnmower or snow blower wont be running very high rpm's that something like a quod or motorcycle would. 30yeartech would probably know more on the bushing subject. Im glad I was able to help, enjoy the snow if your in the northeast haha!


Some of the engines may have a bushing pressed into the engine block or oil pan at the pto, but most do not. Several of the engines have replacement bushings available for the block and pto as well. 

I have seen bearings on the connecting rods of some engines Onan comes to mind, but only on engines with full pressure lubrication. I really think the reason for this is simply a cost issue, it's just less expensive to machine in a bearing surface then to install actual bearings or bushings, and for the most part the design works fine as long as you follow regular maintenance and do not run the engines beyond the designed parameters.

The connecting rod may have not been properly torqued when your engine was rebuilt, too tight is just as bad as not tight enough. It's also possible that damage may have occurred once due to a dirty or low oil level, and once there is damage thats it, even if the engine continues to run after the damage it will eventually fail no matter the condition or level of the lubricant present.


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