11hp Briggs & Stratton Rebuild

[Big Al]

So how big of a job is it to rebuild an older (mid-80s) B&S engine?

My $130 Snapper likes to leak oil, so a rebuild is in order. I might just try and only replace seals instead of a full rebuild to get it through the season.

Any thoughts or experience?

 

[DieselPower]

It's not that hard. Buy a engine service manual for starters. If you have never done one before give it a good read over. You will probably also need a flywheel puller. Other than that it's a fairly easy job, at least it is for me.

 

[slowrev]

Al, is it a cast iron sleeve engine ? If aluminum bore, just get another one.

Ben

 

[Fordlords]

Most of the '80's vintage Briggs engines were just Nikasil bore throwaways. If the crankshaft seals are leaking, it's probably not even worth the bother of taking it apart to replace them. The Snapper is an easy rider to retrofit just about any vertical shaft engine on to that has the same crankshaft diameter and width, I'd go that route at the end of the season, and just keep filling the old engine with oil until then. A little bit of Bar's engine oil stop leak will lessen or stop the leaks too.

-Fordlords-

 

[Big Al]

Thanks for the advice. I will try the Bar's engine oil stopleak.

A new engine is only $350 from SEW, although the replacement would be a Tecumseh, which I'm not overly thrilled about. I think that would make a nice winter project.

Now to do something about the oil stains on the driveway...

 

[slowrev]

If it is cast iron bore it should say I/C on the cover.

 

[Kyle_in_Tex]

I'm interested in doing the same thing only mine is 10HP. I think it is aluminum bore but not sure. I can't tell you how hard of a life this engine has endured. We used to NOT have tractors. It still runs but knocks and is a bit low on power.

The manual says to hone the bore out .010" to get the oversize piston to fit. If it is nikasil lined, the hone won't be able to touch it (hardness). You can't bore nikasil either, you just put a fresh piston in if the bore is not scarred or cracked. I'll look to see if I/C is on it. It is pretty old and the stickers are long gone. I thought that I/C meant internal combustion??

I've seen online rebuild OEM kits for about $70 less the rod which is about another $25-30

I was thinking about it more for the experience than keeping it for the long haul. I'll probably sell it as I have a new mower.

 

[Big Al]

I'm interested in doing the same thing only mine is 10HP. I think it is aluminum bore but not sure. I can't tell you how hard of a life this engine has endured. We used to NOT have tractors. It still runs but knocks and is a bit low on power.

I've seen online rebuild OEM kits for about $70 less the rod which is about another $25-30

I was thinking about it more for the experience than keeping it for the long haul. I'll probably sell it as I have a new mower.

You got me to thinking -- why isn't a nikasil engine worth rebuilding? Assuming the cylinder & piston are in good shape, I'm really just looking at seals & (maybe) bearings. I don't need this to last forever -- ideally a few years and then I would swap in a fresh engine.

Where were you finding the rebuild kits online? I might check those out.

Ah well, this is all moot right now, as I can't tear down the engine right now since it's the mowing season and all..

 

[dqdave1]

I/C = industrial/ commercial

 

[Kyle_in_Tex]

Where were you finding the rebuild kits online? I might check those out.

briggs and stratton small engine parts, briggs & stratton lawnmower motor,

 

[Fordlords]

With a nikasil bore, the nikasil (which is a coating on the aluminum) typically wears down off the bore at a rate equal to that of the wear on the rings. You obviously can't overbore the block, and attempting to hone it will just wear off even more of the nikasil. Unless there is a cast iron liner in the block that will take well to a hone, such as on the I/C engines, I wouldn't bother doing anything to try to help a nikasil block. By pulling off the cylinder head, you can usually tell immidiately if the block has an iron cylinder liner.

It is not even typical to overbore an aluminum small engine block with iron liners, for tolerance reasons it is a safer and more economical bet to just replace the short block with a new one.

-Fordlords-

 

[Big Al]

Right. However, since my engine isn't showing signs of knock or oil consumption (just oil leaking), I'm going to give new gaskets & seals a try. I'm not looking for another 10 years out of this engine, just 1 or 2.

After that, I'll swap in another engine.

FYI - I just read an article online about honing that goes into detail on diamond honing. Apparantly it is possible to hone nikasil cylinders using new, high-pressure diamond hones.

Probably a bit of overkill for an 11hp lawnmower engine, tho. ;D

 

[Fordlords]

It is a lot of fun and its easy just to tear the engine down and put the seals and gaskets in, and you'll likely get another year or two out of it. I just wouldn't invest in a major overhaul on it

They are mainly developing the honing techniques for nikasil blocks because they were used on some exotic sports car engines, Porsche was especially successful with getting nikasil to work well. On those engines you are talking thousands of bucks to replace the block, thus it's worth it to try to refurbish it.

We had a neighbor back in the late 70's who was all proud of himself snubbing his nose in our faces because he bought a new John Deere rider mower about the same time my dad bought a Craftsman. Well, three years later we noticed someone else was cutting his grass for him, this being as he smoked the little nikasil Briggs in his JD, while the iron sleeved Tecumseh in our Craftsman lasted 10 years.

Just about all small engines above 10-12 HP today have iron sleeves and full pressure lubrication.

-Fordlords-

 

[Kyle_in_Tex]

The manual says my 10HP is aluminum. I guess I can pull the head and look. If the cylinder looks good, I'm guessing my knock is the rod. There is a spec to check the crank for excess wear. If too worn, then the cost to repair will be too much.

Yamaha used nikasil in the cylinders for the old TT600's. Saved 3 lbs weight. They were extremely durable. They rings for TT' s were made from soft ductile cast iron.

 

[Big Al]

We had a neighbor back in the late 70's who was all proud of himself snubbing his nose in our faces because he bought a new John Deere rider mower about the same time my dad bought a Craftsman. Well, three years later we noticed someone else was cutting his grass for him, this being as he smoked the little nikasil Briggs in his JD, while the iron sleeved Tecumseh in our Craftsman lasted 10 years.

Funny you mention Tecumseh -- I was taught to not trust Tecumseh engines. "They run too fast." is what I was always told. From what I can tell, when it comes time to replace my engine (B&S L-head which it seems they made for ages), my choices are either Tecumseh OHV engines or a B&S Intek. Unless I happen to find an L-head, but Briggs finally quit making them a few years ago and supplies are getting short on new engines...

Anyways, any thoughts on the merits of either brand?

 

[Big Al]

briggs and stratton small engine parts, briggs & stratton lawnmower motor,

Thanks for the link, Kyle. I ordered a rebuild kit, service manual and a Gator blade from them. I hope to have it all by next week. In the meantime, I'm going to add oil & Bar's leak and mow the lawn.

 

[jonwheelhorseb112]

do you know what the max bore size is in the 11hp B&s because im restoring mine and its got some pretty good scaring on the inside sleeve and the piston to i think the guy who had it befor me over heated it . and my friend
rod thinks that it had dirt in the motor all i know is its pretty much screwed right know

 

[The Toolman]

Al, if its just leaking oil, I'd just buy the seals an gaskets an replace them an forget about any rebuild.


Ronnie-The Toolman