Question about Mastermind cylinder cleanup method

[huskihl]

If a guy ran that in a drill, he could wrap the sandpaper the other way and run it in reverse

 

[Al Smith]

They make 3 m flap wheels but because I don't do that many rebuilds I don't own any .Don't get yourself in an uproar about this,again it's not a race.get it right the first time ,

 

[David Young]

If a guy ran that in a drill, he could wrap the sandpaper the other way and run it in reverse

This helps.

If you spin toward the port it doesn't eat the edge as much reverse it for the other side. Notice in the op pics. Only got too rank on one side. I bet he was going clockwise.

Clockwise on the right side of the port counterclockwise on the left side of a port.

Hope this makes sense

 

[riverrat2]

If a guy ran that in a drill, he could wrap the sandpaper the other way and run it in reverse

yeah!!! it works well

 

[Jon1212]

If a guy ran that in a drill, he could wrap the sandpaper the other way and run it in reverse

Egg Sack Lee.....

This is the way.....

 

[RIDE-RED 350r]

Thanks for the input guys. Ill even out the exhaust port and see if the piston skirt covers as Treemonkey suggested. It it does I'll be ok, might benefit from a little more exhaust area anywho.

If it doesn't work out, lesson learned and I still have the cylinder on the saw to work with. It has a bad piston and I'm sure transfer on the cylinder as well, but this time I'll be more careful.. thinking about trying the acid method next time just to see what method I like better (no disrespect Randy). Just don't want to mess up another 394 cylinder as I would like it to stay a true 394

 

[Stump Shot]

They make 3 m flap wheels but because I don't do that many rebuilds I don't own any .Don't get yourself in an uproar about this,again it's not a race.get it right the first time ,

I'll confess here and now that I have been using a small flap wheel on the cable drive to do this work as of late and it has been working out pretty good. This has been more for convenience for me and not to say superior to other methods that work just as well. I find myself hard pressed to try and tell someone else how to go about something like this as it just seems to me once you get the idea, then your off on your own to try for yourself. It is my hope that this does not make anyone thinking of trying this gun shy, as it really is a good method, and I for one am very glad I learned of it here on OPE, and thankful to Mastermind for taking the time to show this process. Have been saving cylinders I would have otherwise thrown out ever since. SS

 

[RIDE-RED 350r]

Don't get me wrong Stump, I'm thankful that Randy and a whole slew of other guys here are so willing to share info like this. I have used this method on two other cylinders previously with success, this one just got away from me.


In other news: that new TSB I got from Fordf150 looks great on my 357!

 

[MustangMike]

I've cleaned up 4 cylinders with sandpaper and the cordless dewalt. My mandrill is a lot smaller than yours, made it from a piece of that wire they use to put the political campaign signs on your lawn!

I spin it in both directions, and am very careful working around the ports, I never let the paper get in a port.

If I'm in at the same depth as a port, I keep it between the ports, and if there is transfer around the port I'll work the top half, then the bottom half, etc, always not letting the paper go in the port.

I think you worked it at the same level as the port, and let it get into to port. Either that, or the Husky plating is softer than the Stihls.

Good luck with the other cylinder.

 

[jmssaws]

Well, I'm going to be starting on my 394 overhaul after the holidays. I have not yet torn the saw down but I happen to have a spare 394 cylinder on the shelf that had some transfer and thought I would clean it up.

I made an arbor from a 1/4" bolt with a slot cut in it and the head hacksawed off and chucked it into a pneumatic die grinder. I wound some 120gr strip sand paper up in the arbor and largely it worked very well. BUT, as I was working around the exhaust port where all of the transfer was, I noticed that the sandpaper was enlarging the exhaust port on one side, the side the paper would drag out of. It actually looks like some nice, albeit excessive port window tapering. My concern is that I'm going to have to match up the other side with a burr and I have seen it said that one must use caution when thinking about widening the exhaust on the 394. I was also wondering what I'm doing wrong to cause that alteration of the port window?? I was able to remove all but a tiny tiny bit of transfer just above the port on that same side. It is almost gone but still visible, but cannot be detected by the fingernail test. This is the second time I have cleaned a cylinder using this method and had this result of altering the port window on one side as a side effect of the operation. Is this a problem or am I overthinking it??? I'm sure I can match it up and even things out with a burr, but how does one prevent this if widening the port is not intended to be done??? I wonder if I need a reversible grinder to avoid this... Maybe muriatic acid is the better method for me??


Thanks

Pics show both sides of exhaust port for comparison.. I'm afraid I just ruined my cylinder..
View attachment 44538 View attachment 44539

394 hasn't got a lot of room for widening the exhaust but you might be able to get it.

I'd do everything I could to save it,there not laying around everywhere.

 

[RIDE-RED 350r]

Roger that Jason, that's the plan

 

[riverrat2]

You didn't fork it up I don't think .However just as an opinion you'd be better off to do like Randy with 3M
scotch bright than sand paper .And use some kerosene or something,don't ever do it dry

I got in a hurry once and used too course of a flap wheel,never again.It's not a race .

When it comes to salvage work, I use marvel mystery oil, a combo of sanding rolls, alum/oxide cloth, scotch brite, an aluminum arbor and a light touch with my foredom hand pieces,,, plenty of lube, no more speed than you need is always best

Have to agree w/@jmssaws do what you can too save it

 

[mdavlee]

I use sanding rolls in the foredom hand pieces. I will use a mandrel with pieces of sand paper if it's above or below a port to not hit the edge.

 

[Mark71gtx]

On cylinders that have insane amounts of transfer, I like to start with acid. I let it eat the majority of the build up and then fine tune it with the Mastermind method. On cylinders with light transfer, I forgo the acid.

 

[PogoInTheWoods]

The key is to stay away from the port edges.

My approach with the 1 1/2" wide paper addresses a fairly large area of the cylinder and pretty much forces a parallel rotational position to the cylinder wall itself for its effectiveness. Can't get overly aggressive (intentionally or not) in any given area that way. And with the size of the paper and mandrel setup I use, (yeah, kinda klunky, I know), the method actually spans the ports and never gets into them unintentionally. I certainly didn't have the foresight to realize this ahead of time..., just a side effect of going to a larger and less precision method than my high-speed / concentrated area experience. It also addresses the entire cylinder (at least I do) for a bit more uniformity in the end result. Never thought of reversing the drill on purpose. Just go clockwise myself. Also go the Scotch Brite route for finishing up..., the purple stuff on a "Wiggs Hone" made out of an eye bolt, a chunk of inner tube, rag, (or whatever) as a stuffer, wrap a chunk of Scotch Brite around it and go to town. Works great, but starts to shred pretty fast in open port cylinders. The pic actually has an old piece of Scotch Brite as the suffer which works too for larger cylinders.

​

 

[Al Smith]

Easy off oven cleaner will work too .My Lawdy that stuff stinks .I don't go that route either unless there is a lot of transfer .

 

[Jon1212]

Easy off oven cleaner will work too .My Lawdy that stuff stinks .I don't go that route either unless there is a lot of transfer .

Gots to be very fast, and very thorough in the rinsing, as the alkali of the oven cleaner will consume aluminum

 

[Chainsaw Jim]

You can see there is still some room left for the skirt by the rub marks left behind by the piston. After you're done it'll look like it was meant to be that way. Technically what you did left a good chamfer for port work.

 

[exSW]

These are nice. Harbor Freight kit. 50 mmish

 

[exSW]

3M and wood dowel,just cut the slot with a thin metabo disk.