# New member here, I teach a small engines section, general question



## shopteacher (Dec 9, 2004)

Hi guys, glad to find this website. Im sure it will help. I teach a general tech course and do a little with small engines. I know enough to do minor repairs, have done carb rebuilds, etc. I am hoping I can ask questions that come up from time to time, and all you experts out there can help. COOL!!

First question of many to come: Are engines worth rebuilding? I was under the impression when you bore out, say, a briggs 18hp, the cylinder walls are too thin and they don't make all the parts you need (gaskets sets etc) But.....an older kohler is ok.

Your thoughts?


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## bugman (Aug 12, 2004)

no briggs makes theyre replacement parts etc. a briggs can be bored 30 thousandths over before you have to get a new short block. i/c's are the best briggs. they also make the rings for 10 through 30 thousanths over. your cast iron bore's can sometimes just take a simple hone then new rings. engines are very worth rebuilding. 8 hp murray 8. made in 1982. simple bore/ hone, then rings and she runs like new. just check out the briggs's website www.briggsandstratton.com great pdf's of parts breakdowns /order numbers and owners manuals. also gives you the parts numbers for over sized rings etc.


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## hankster (Jan 1, 1998)

As an additional note: A complete 18hp Briggs is about $1500 so even if you need to replace the whole short block it is well worth doing.


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## Scott15 (Nov 11, 2004)

That's a lot of money for a replacement engine.


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## scrench (Dec 8, 2004)

i have freshend up alot of engines , about every thing from old old boat motors to 3 cyl diesel engines , to 6 cyl tractor engines and i have never had one resized i always do on cars if i go through one for someone , but on the small engines i never use cast rings i use chrome , they are made a little bigger i could tell ya how much but i would have to dig out the old book ,,, also with chrome you dont have to hone cyl wall ,,, so my thoughts on rebore on small stuff thumbs down -- but i almost always use a new piston ,, just depends on the $$ ,, and if the engine has ever been hot or ran out of oil you can pretty much tell also how far gone she is by feeling the cyl wall at the top of the cyl -- :thumbsup: just my 2 cents


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## bugman (Aug 12, 2004)

yeah them 18 hp blocks where expensive. i did get lucky one time and got the twin cylinder cast iron bore model in great shape. only a couple years old. hardly used for 500 bucks. mower and all but the only kind of engine that is easy to fix and replace a block is a 3.0 hp one to maybe a six. any bigger and its money. yep those chrome ones finish out the bore when put in. no honing but i like to hone em out. sometimes you can use fine sand paper on them and new rings.


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## bugman (Aug 12, 2004)

one thing a ball honer requires no skill to use and turn great results for beginning people.


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## bbnissan (Nov 7, 2004)

I definately think that engines are worth rebuilding...especially Briggs & Stratton engines. I have aquired two generators in the past few months because both of them had engine problems. One (this one) had never had the oil changed in it before and the crankshaft seized in the journal bearing of the crankcase cover. I tore the engine down and did some work to it. The piston and cylinder were ok, but a little worn, so I went ahead and bored the cylinder and put 0.010" over rings in it. The only other problem the generator had was the cranshaft being seized in the journal. This was easily solved by cleaning the aluminum off (I have a trade secret for doing this) the crankshaft and having a machinist friend of mine bore out the crankcase cover and install a bronze bearing. After I did this work, I put the generator back together and it cranked up and ran perfectly.

The second generator (this one) I aquired was pretty much wrecked when I got it. The guy that owned it did construction and decided that when the air filter clogged up, it would be a good idea to poke holes in it instead of going and buying a $5 air filter. Because of this, the engine ingested tons of sheet rock dust which honed away a good portion of the cylinder. When I got the generator it would crank, but it was hard to start and burned a significant amount of oil. I tore the engine apart and honed the cylinder to 0.020 over and installed new oversized rings. I also ground the valves and seats and lapped them. The rest of the engine was ok so I threw it all back together and cranked it up....ran like a dream. It was easy to start and didn't burn any oil.

Since I decided to rebuild the engines on these generators, I ended up spending about $60 in parts but I ended up with about $2500 worth of generators.


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## bugman (Aug 12, 2004)

man that was stupid. poking holes in the filter. i wonder where he went to school stupid high. hope he doesn't do it to his car. but yeah rings and all are pretty cheap. that 18 hp one i got cleaned up and sold for $900. the mower was crap. it was on a dynamark mower. it always pays to rebuild. briggs engines ain't cheap, they last a long time and are cheap to fix. tecumsehs have very tight clearances so if you rebuild one of those you have to rebuild it within the tolerances do it will not run right.


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## bugman (Aug 12, 2004)

one thing i own a briggs 6horse ohv generator craftsman. runs like new and its a year or so old. ran it during the last hurricane 8 days straight. still starts right off the bat. briggs is the better way to go in any rebuild or new engine. darn thing powered a freezer, tv, two fans, and a coffe maker. and those coffee makers draw alot of power. lovely engine. might even later buy a bigger generator and use this one on a go-cart it runs so good. don't use oil but of course its a briggs. hondas don't last very long tecs do but can be a pain in the rear. and kohlers are good but can be expensive.. others can be good but when it comes to over 100 years of quality briggs is it. know this dude that owns one from over 90 years ago. still runs good. he's got hundreds along with those old john deeres from then.


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