Slight cylinder/piston scoring - Hone or replate?

[TheBreeze]

Well I slightly scored the mag side on my 2010 M8T. I believe the mag side was just a BIT too lean for a short period of time. PTO looks good. There is oil burned on the back side of the piston crown on the mag side and none on the PTO. ZERO pitting on head and pistons. Rough looking crowns are from the race gas.

This must have happened at some point last week in Cooke City. The sled ran very well, but egt's would climb if I stayed in it for more than 4-5 seconds WOT and I would back out of it. I recently switched to premixing, and did not bump up the fuel numbers to account for the oil in the fuel. I think this may have contributed to the damage.

The marks are on all sides of the piston and cylinder, and seem relatively uniform.

Here are some pics of the markings. They can be barely felt with my fingernail.

Should I just deglaze the cylinder, and throw in new pistons?

Am I correct in my thinking that this is damage from a slightly lean condition?

 

[RACINSTATION]

The front or the exhaust side of the cylinder would be the one I need to see. From what I can tell it looks like you can just hone this one out and put in a fresh top end.

Lean condition.

 

[TheBreeze]

Ill get a pic of the exhaust side and put it up. Thanks for the input. What do you use to "hone" them racinstation?

 

[TheBreeze]

Here are some more pics showing the exhaust side of the cylinder, and some of both pistons side by side.

 

[J almont]

I know the answer you are looking for is to hone and new pistons, but
if you can feel the scoring with your fingernail I would definately replace
cyls, and pistons. Afterall it is a high performance machine.

 

[diggerdown]

Matt, wipe it with some acid then hone it with a ball hone. After you are done you may still see some marks but if you can't feel anything you should be good to go. Pics never give a real good perspective. Looks like you could bump your fuel up a little, still looks a lot better than MM's engine, that really sucks!

 

[TheBreeze]

I am not looking for any specific answer, but reusing this one would be nice if its not bad practice. Just trying to do it the right way, without wasting money.

Diggerdown- Im not to torn up about the damage. I definately learned some things this time around, and clearly I need to add a bit of fuel. Hopefully, this will be my top end job for the rest of the season! Really no big deal though, since I was taught buy the best. I just wish cylinders were free......lol

 

[Rixster]

The jugs dont look bad, runa hone through them and see how they look after that. As stated above, if there is any anuminum on the cylinder walls from the piston (and it doesnt look like there is) get some muratic acid and clean it off. That acid will eat the aluminum but not touch the nikasil. Then hone. Get a fresh set of pistons and your good to go.

 

[TheBreeze]

I cleaned them up with acid last night, and the cylinder appearance remained the same.

 

[Hardass]

As stated if you can feel any of it replate if not run it.

 

[TheBreeze]

I am going to giver' one more time with acid tonight, as it seems that most of what I am feeling is above the nicasil level, and I can almost see the cross hatch underneath it. I have a hone on the way to give it a run just to see what happens. If I can still feel anything on the bore, ill just be replating.

Got ham, these turbos are sure pull the rope and go.....lol

Thank God for backup sleds.

What is acceptable to use for lube when honing? I don't really want to sit around and wait for "Flex-hone" oil to show up, but I will if it is the only option.

I am not to worried about damaging the cylinder, as I am likely going to be replating anyways.

 

[RACINSTATION]

Wd-40 or PB blaster works fine to hone with.

If you can feel a bump or disturbance it need replated, if not you are good to go.

 

[SnowDevil]

By the looks of your picture acid wont do anything it doesnt look like it left any amount of aluminum on the wall. only when it leaves the aluminum material does acid do any good (a desent amount), a good test is take some 120 grit sand paper below the exhaust port and scrub the bad spots. once you see it clean up move up the wall, I have wore my thumb out doing this and never hurt the nick. On my 1200 i did this 2-3 times and never had any problems

 

[TheBreeze]

Thanks for the input everyone. If there are slight aluminum deposits, how quickly does the acid take them off? Is it just a matter of wiping it down with a rag and acid? Fortunately, I have never had to remove aluminum from cylinder walls before.

 

[diggerdown]

It should start to bubble and smell within a few seconds. I usually let it sit for a few minutes then wipe it with a rag, try a little hone, then repeat. If it isn't working it means there is no aluminum and it may be gouges instead of buildup. Like was stated above you can take a little emery cloth and work a heavy build up area while letting acid eat away the thin stuff. If you are on the fence about the condition of it you could just run over to Millennium and see what they think, can't be too far from you.

 

[TheBreeze]

They are an hour or so away. That is who will be recoating, but I go through my dealer which saves a chunk of $$$.

I have pretty much decided on plating, but I want to see what a hoan job does to these scratches out of curiosity before I send them off.

 

[TheBreeze]

Ran a flex hone through it this morning. No change in surface texture. Off to Millennium they go.

Thanks for the help everyone.

 

[TheBreeze]

Just an update. Sent the cylinders to Millennium, and they re-diamond honed them, and sent them back looking good as new. $90 .... not bad, and fast turnaround.

 

[M1000Mod162]

Where to get acid

where can i get this muratic acid at?

 

[diggerdown]

where can i get this muratic acid at?

Hardwear store or building supply stores. It is used to clean mortor but it really eats aluminum. Keep it off parts you don't want ate up and after you do a cylinder give it a good wash out with lots of detergent and hot water.