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I have an old Briggs and stratton 3hp 175cc motor (early 80s) engine 80202-1647-01. I need new piston rings (all three). I downloaded the part list and it gives several options and I do not know what to order. I am given five options on the part list:
294224 SET, Ring -(.010 Oversize)
294225 SET, Ring -(.020 Oversize)
294226 SET, Ring-(.030 Oversize)
294232 SET, Ring -(Standard)
297201 SET, Ring -(Standard)
This engine has never been serviced *EVER* and I have never taken an engine apart before. So which one(s) do I need? I assume that "SET" means that when I order one of the above I get three rings. what does the oversize mean?
THANK YOU!!!!!!

Oversize means that the cylinder has been bored to a certain thousands over the standard size(basically requires going to a machine shop). the only rings available are the .020 rings and the 294232 standard rings which is what you will need. Oversize rings also require the use of the oversize piston.

Don’t order anything until you have taken the head off the engine and measured the cylinder properly. You may find that it is too worn to spend money on. You need to know the size of the cylinder now and if it needs to be glaze honed or bored before buying parts. Just throwing parts at it will only cost you $$$ and get you no where. Might want to read this manual and visit this website first before proceeding. If you have more questions, please come back and ask, we’ll be glad to help.

If you've never had an engine apart, that means this engine is still assembled? In that case, how do you know the engine needs rings?

My advice is to make sure you know what parts you need before you buy any. In this case, if you've never rebuilt an engine, it will be unlikely that you'll know what to look for in the way of worn or damaged parts that need to be replaced.

I'd recommend just buying a replacement engine.

Wow, thanks for the replies. I actually took the thing apart and used youtube as my guide. I purchased set of replacement seals/gaskets online. I know the rings are broke because when I tried to put them back in one snapped off. I would think that I should be able to just buy the standard rings. I know it has never been re bored so.... let me know your thoughts.....

With an engine that old, the cylinder is probably worn and putting in a set of standard rings is not going to help much. You can do as you want but remember without knowing the size of the cylinder it is a crap shoot that in the end you will have solved your problem.

For some of these old engines Briggs makes (used to make?) a chrome ring set that you can just put in and run. These rings will cut into the cylinder enough to seat and seal. One of those numbers for standard rings might be that type ring. And be sure to run oil designed for these old engines, look for the SJ or SH designation on the oil bottle. That little engine is a very good learning experience too.

Thanks. The learning experience is why I did it myself. I have already learned a ton thanks to you guys. several more questions:
1) I replaced the crank shaft bushings (I think that is that they are called). However, when I try to turn it while the shft is in the hole in the crank case, it does not turn that easily. I applied the permatex red sticky grease but it is still hard. I would think this should move freely. Also, when I took it apart, I was surprised that the crank shaft/sump housing "connection" did not use a bearing of some sort for it to turn easily. a bushing or grease seems like it would be far more prone to failure over time. just curious....
2) in terms of piston rings. If the standard rings are no longer large enough (due to wear on the block) I would think that this condition would happen slowly over time as the piston/rings grind up against the block. Thus, the sudden/immediate crank shaft seizure that I experienced would seem to be an unlikely culprit to my engine's failure. Also, when I tried to reinsert the piston with the original rings it seemed like a SUPER Super tight fit.
I know nothing, so please please correct me where I am wrong.
thanks again guys!!!!

That bottom bearing deal is designed to be plain aluminum, does get oiled from the sump, the top gets oil from the splash from the oil slinger. Usually lasts a long time. You can put one of the rings in the cylinder, use the piston upside down to push the ring in a bit and get it nice and straight, then check the ring end gap with a feeler gauge. Have to squeeze those rings in tight to the piston to get it all back in the cylinder, use a gizmo called a ring compressor. Youtube is a handy guide for all this.

You guys have very helpful, thank you!!! this has been a great experience and I have learned a ton. One last question. I have searched the internet and cannot get a reason for this: On this engine there are tappets below the valve. There is a clearance between the two. why? I would think that the tappet would need to hit the bottom of the valve to make it go up? with my mower they never touch wether the piston is top dead center or not! thanks again guys!

The clearance is so that the valves can seat completely. If the tappets never touch the valves, the valves will remain shut ALL the time, no matter where you turn the crankshaft.

Is this the situation you're describing?

There is a camshaft inside the engine that gets turned by gears from the main crankshaft. Some how those gears aren't lined up right or something is actually broken inside.

The tappet clearance is to account for heat expansion and to prevent the valves from being slightly open when hot. The tappets should push the valves up when the crankshaft is turned which turns the camshaft and the lobes open the valves.

cpurvis said:

The clearance is so that the valves can seat completely. If the tappets never touch the valves, the valves will remain shut ALL the time, no matter where you turn the crankshaft.

Is this the situation you're describing?

Click to expand...

That is exactly what I am describing. when I put my hand in the engine block and push the tappets up as far as they will go they never hit the bottom of the valve. This is the scenario even when the valve has the spring seated properly. I did not shave off any of the tappet or valve either. this is odd.

thanks again for your help!!!

When is the last time this engine ran?