OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines B&S 3HP - M#80202

Actually the Briggs Hone and the Lisle hone are setup the same way. Two stones and two wipers. The stones does the honing and the wipers both stabilize the carrier and cleans the bore wall. Now this cleaning is not completely done so once the oversize piston drops in you want to clean the bore and check it size by either using a micrometer or inserting a ring and measuring the end gap for minimum clearance. Also cleaning the cylinder will you know if you have good clean hone job as the grit will fill in the imperfections. I have hone cylinder to oversize to only find that there was a hidden air pocket in the cylinder wall left when the cylinder was cast.

Lisle 15000 Ridge Hone

It does require a low speed 1/2" VSR drill (0-500 rpm) or drill press. You definitely want to keep the max speed down as it will gall the bore if ran to fast. You will also need to secure the engine to it from rotating as quite a bit of torque is involved. Both hones has a micrometer adjustment to set the stone pressure and to increase as bore enlarges and the stones wear. Using drill will make your back hurt as it takes a long time to hone these cylinder to the oversized and I would highly recommend using a drill press.

The ridge hone picture is the Lisle 16000 which is for smaller bores 1.75"-2.75" depending which stone/wiper set you use and there is the Lisle 15000 which uses different racks as you do bores from 2.75" up to around 10" diameter bores when appropriate racks and stone/wiper set.

I don't know where to go with this now. I've been given an information overload (it's amazing).

the piston has minor scratches, but there is one scratch that I can slide my finger nail over and it catches. I've been told by a mechanic and my old boy that given it's usage that it won't be a problem and to just put it back together and away you go. At the same time, a huge part of me still wants to get the O/S piston and so fourth.

I guess given this is my first time doing this, I could put it back together and give it a new paint job and focus on the restoration of the mower. Worst case buy a new B&S if it fails and then rebuild it with O/S when time and costs permit.

I'm not too sure.....

I made a few calls to motorbike and go-kart mechanics and all say that you cannot hone an alloy block as the stones play havoc on the alloy, and insist it requires a re-bore, but given it's not a sleeved cylinder that it's tricky to do properly. Don't get me wrong, I do believe them to a degree, but given their background, I can't help but take their advice with a grain of salt as their boring and build jobs are for high performance engines of which require such precision. I admire their passion and so fourth, but I want "real" advice based on the application this motor and the low rev's it's to be used. In any case, the information you blokes have given me is unbelievable and all those I've spoken to about these forums, I've held this place in high regard due to this wealth of information and experience.

In the end,

Someone be real with me.... What should I do? Should I be concerned with what I've got and just put it back together along with new seals and gaskets and focus on the external aspects of the motor? Or do these scratches warrant further work?

Chris, just put it back together and hopefully you haven't taken the rings off the piston and if you have you know which way up they were

Chris86, Apparently they were using the wrong stones as it does take different stone materials and grits for aluminum, cast iron and Nikasil. Using the wrong stones will definitely mess things up and as well as previous mention running hone too higher of a rpm will also gall the aluminum cylinders.

Even if the cylinder is bored it still got to be honed to produce the appropriate 45 degree cross hatching.

These guys are probably the same guys that say you can't hone 2 cycle cylinders because they don't know they got use ball type flex hones because regular flex hones catches on the ports. Yes some cylinders can't be honed or bored due to ultra thin chrome or Nikasil coatings and the honing ears right through that coatings. The problem is that equipment like chainsaws and trimmers is even if you hone to remove the scoring oversize pistons and rings are not available so there is no point in doing it. Now larger 2 cycle engines which I have not worked on may have OS pistons and rings available.

AVB, thanks for the rundown on the hone type, and pic. As you'd gather, commercial workshops here don't find it worthwhile to resize Briggs bores! And 'backyarder' repairers generally don't shell out for the special tools required.

Chris86, the benchmark on cost is, that a 550 series 3.5hp sloper Briggs can be had for under $300 new, with 2 year warranty. And that gets you an OHV engine with cast iron sleeve bore. 'Chondas' are even cheaper, but it may be difficult to find one with the right shaft size for the SB clutch.

So it's just not worth putting a lot of coin into parts for the old Briggs, as I see it.
As a guide, the gasket set will cost $30-60 [quality aftermarket vs genuine]. That, plus seals, carby pump diaphragm and a ring set, will get you to around $100 or so - personally I wouldn't be inclined to go any further. Put it back together with those, set the points, do the valve clearances, and it will run for years. Oh, replace the spark plug too.

I'd agree with you that motorcycle, and even go-kart, mechanics are used to dealing with much higher-tech engines than this low-compression alloy bore side-valve! So there are things they just don't get, about what can and can't be done successfully on these.

Thanks guys, I really appreciate the input.

Chris86 as Gadge noted it is probably as a cost effective to replace the engine with a new one than to rebuild it if it is an one off rebuild as tools are expensive for such projects. Not only you need the hone, you probably would the valve guide replacement tools and hopefully you don't need the valve seat cutters. So far I have manage to avoid buying the valve seat cutters.

We here in shops don't do much on rebuilds either as noted rebuilds vs new are simply too close to justify the costs. Most times we can buy and install a promo engine for less. The only time around here it cheaper to rebuild is went it come to horizontal engines as they are usually more costly on larger engines. It is still cheaper to rebuild a $2000 Kawasaki v-twin engine than the replacement cost just depends how quick the customer need the equipment back up and running.

The reason I have my hones is from a couple antique horizontal engine projects that the customer wanted me to rebuild which I did then the customer stuck with repair costs. Next time I will insist on at least 50% of the rebuild up front on an approved rebuild. It cost me more than I was charging for the rebuilds as I had buy the two hones and the stone sets. I was hoping to more rebuilds so I could offset the tools cost. I still rebuild engines for myself as you don't count the labor when doing it for yourself and also to keep in practice.

Repair costs is why I don't repair and sell used equipment anymore, I just do repairs now. Customers simply won't pay a fair amount for the equipment when it repaired. I got several pieces here that I did repair and I can't even sale them for what it cost me in parts to repair.

AVB,
My motorcycle mechanic has sworn off doing even engine restorations for customers, for the exact same reason, after getting stuck with one or two. No way to make a worthwhile hourly rate, particularly if any chasing up of rare parts is needed!

Even though he has no shop overheads to speak of [has a big concrete floored shed on his rural block], apart from electricity, just isn't worth doing. And he has a home workshop that's better equipped than any of the local MC shops - up to date Dynojet chassis dyno, lathe/mill, top end tyre changer etc.