Scored cylinder?

[Nick R]

So I pulled the head off our 08 MY Briggs 675. I had pulled the spark plug and noticed it looked kind of gunky. A little oily looking maybe. So I pulled the head, and this is what I see. This is AFTER I cleaned it somewhat with a screwdriver and wire brush. Doesn't look very good, the cylinder is mostly smooth, but if I run my fingernails over it I can feel it isn't, there are a few scratches in it. I wonder if this is why it's been burning oil. The amount of carbon and build up certainly seems to support that.

 

[Donald]

Are you going to remove the piston and have a look at the rings? Does not look like there is much of a ridge. Go over it with a cylinder hone, slap on some new rings and call it a day.

 

[Nick R]

Originally Posted By: Donald
Are you going to remove the piston and have a look at the rings? Does not look like there is much of a ridge. Go over it with a cylinder hone, slap on some new rings and call it a day.


I wasn't planning on pulling the piston. I mean, I shouldn't have to. This engine has ~75-80 hours on it, and I've changed it every season with a high quality syn oil (currently rotella T6 5W-40)

 

[spasm3]

looks like an aluminum cylinder

 

[Nick R]

Originally Posted By: spasm3
looks like an aluminum cylinder


Nikasil bore, so yes aluminum.

 

[Slick17601]

In all honesty, that will run at least another 10 years.

 

[The_Eric]

I'm having a hard time believing that B&S would use Nikasil in one of their engines. The finish looks a bit dull for nik as well.


At any rate, it's a B&S, clean it off and run it.

 

[Nick R]

Originally Posted By: The_Eric
I'm having a hard time believing that B&S would use Nikasil in one of their engines. The finish looks a bit dull for nik as well.


At any rate, it's a B&S, clean it off and run it.


Sorry not nikasil, they use a kool-bore, which is a mix of aluminum and nickel I believe.

 

[01rangerxl]

That amount of scoring can cause some oil burning, but I've seen worse on engines that were still running okay. Not much you can do except keep running it. It probably still has a lot of life left.

 

[Propflux01]

Looks like most B&S's I've seen over the years

 

[tomcat27]

while you dont need to, I'd run a bottle brush hone through the cylinder to restore the cross-hatching for improved lubrication and oil control. although I'm not sure what that would do to the kool bore coating, if there is one.

 

[Shannow]

Too shiney (mirror like) for my liking...glazed ???

Really light ball hone...or back in the day, we'd use 800-1000 grit wet and dry sandpaper, and sort of 'swirl' it down the cylinder on glaze.

dino, sae30 for a few 4-5 hour ocis, with some decent load

 

[TFB1]

Originally Posted By: 01rangerxl
That amount of scoring can cause some oil burning, but I've seen worse on engines that were still running okay. Not much you can do except keep running it. It probably still has a lot of life left.


Agreed...

You go screwing around with the bore finish without a ring job and it will use oil... Put the head back on and forget about it...

 

[TurboLuver]

Since you have gone that far I agree with Donald, hit it with a cylinder hone, replace the ring and button it back up.

 

[01rangerxl]

Honing the cylinder and re-ringing it would probably end up being a lot more work than just popping the cylinder head off. With an aluminum bore engine he's going to need special stones to hone it, and I don't think Briggs advises honing aluminum bore engines. Plus then you have to take the engine off the mower, take apart the bottom end, replace the crank seal, etc. That's more time and money in the engine for possibly no gain in longevity. I think just putting the head back on and calling it a day is the way to go with this one.

 

[sdowney717]

not worth any more effort. I might use next higher weight oil if it is blowing any blue oil smoke.

 

[sdowney717]

What type of air filter is on engine?
IMO, the foam filters are much worse than the paper ones.
If the air filter gets damaged, dirt and grit is going to get in there and make a mess of the cylinder and wear down the rings. Took apart an old Briggs edger that had low compression. Aluminum bore and piston were ok. The rings had completely wore away so had lost much tension.