Another vertex ring issue

[FMP]

That's decent, might as well box it all up now.
I'd a gone Wisecos

http://www.klemmvintage.com/breakin.htm

http://www.klemmvintage.com/oils.htm

[Capt.Insane-o]

Bull**** on most of that, Those of us that have done the Wiseco/ Steel sleeve high rpm outboards know better. I've been using WSM almost exclusively due to them offering a 1.5 mm ring piston with no issues to 8000 rpm. I have a steel sleeved s3000 block with Vertex in it that has run extended miles in the 8500 rpm range and I am very impressed with them. One piston in that set had excessive end gaps and it took a few set of rings to find a pair in the happy range. The pair of 2 liter motors that I put wisecos is that turn in the upper 9's with 200 psi took some special preparations, cryo, and coatings to be able to run them at "tighter" clearances. High extended RPM 2.5's steel bores are miserable to set up with Wisecos.

[FMP]

How many years ago did you try them? They did change them since those earlier years.
Maybe those bores of the 2.5 just aren't stable enough or consistent to the tighter piston? Lots of different opinions on them.
.

Interesting that they give 0.001"+ to the finished size of the standard and next couple of up sizes.


http://www.wiseco.com/ProductDetail....04&AppID=10547

[Chaz]

The title of my thread is as it is because I've recently seen a couple other threads with people having the same problem with the same rings. I wondered if anyone found a solution to the problem & just didn't bother posting the solution. The block had been bored & honed to Mercury's published specs by a highly regarded local performance shop, one of only 2 places in Southwest Michigan that has the capability. 1 through 5 measure exactly 3.516, Mercury's published spec. #6 is 3.518. not sure why it ended up that size but I told the machinist I'm good with a little extra on #6 so no harm. So the bores are not sloppy, 5 of the 6 are exactly to Mercury spec. Just trying to clarify what I'm working with.

If a machinist want's to cheat a bit. He can look at the Wiseco ring's part number to come up with bore size, but other than that, looking at ring gap now is closing the barn after the horse is long gone.
Put the brakes on and start from the beginning.

If your going to use specs from a book written by Mercury Marine in 1994 about a 1994 model engine using 1994 era pistons. Then you probably should find a set of .015's from WHO ________ and WHEN _______ ?

Lots of things have changed in the piston, ring and cylinder wall finish world in the last year let alone five or twenty five years. But lets go with what you have:

Instructions say .0019 - .0031 per inch of bore round it off .002 - .003 middle of the road .0025

3.5 x .0025 = .00875 Is your piston 3.506 - 3.507 + .008 = 3.515

When I hone outboard blocks I'll take out a few little numbers .. up to a half a thou

3.5151 - 3.5155

out of the bottom two holes, but never whole numbers unless it's a rehone. Then a round hole is really more important than size . ( why forkin says hang it together .. and i said fix # 6 and stab it together )

Forgings will be ground smaller , and high silicon castings will be larger and run way tighter and quieter. Know what you have before you start will save you from paying the "dumb tax" ( I've paid it plenty ) in the long run. Speakin of long run, as long as this thread has run , you could have sweated a new $99.00 dollar sleeve in # 6 and set it at 3.5160-9? and been good to go with what ya got ...

[Tagg]

The piston clearance is where I want it. If I would have had it bored for ring gaps, I wouldn't have any piston clearance. Pro v piston will be here Tuesday. We'll see how that fits & go from there.

[Chaz]

The piston clearance is where I want it. If I would have had it bored for ring gaps, I wouldn't have any piston clearance. Pro v piston will be here Tuesday. We'll see how that fits & go from there.

In the two post's I've made I never mentioned ring gaps. Bore and piston size, yes of course. Get that right, the other falls in line.
You have yet to mention piston size .. ( I asked ) But seem to be hung up on ring gap only ... open one or a thousand boxes. You're still going to have 5 on the big side and 1 .. Ahh, nevermind, Good luck to ya ...

This is from the Vertex web site :

Two-stroke Piston Kits

As the OE supplier of two-stroke pistons to KTM, Vertex pistons has an outstanding reputation for quality and performance. Each gravity cast piston is created with only premium aluminum alloys utilizing an 12-21% silicon content.The silicon content in Vertex pistons is crucial to the quality of the piston. Silicon is critical in decreasing thermal expansion which, when an engine reaches normal operating temperatures, can change the geometry of the piston. Controlling this expansion means that a Vertex piston can be run at tighter tolerances for more power, less noise and a longer lifespan of the piston. Plus, the silicon content decreases wear on the piston skirt which also aids in the life of the piston.In addition to the silicon, each Vertex piston utilizes a unique Molybdenum Disulphide (MOS2) coating which aids in the break-in process and reduces overall wear.

[Tagg]

3.5086. wall clearance .0074. it's all good. I'll get it right.

[FMP]

If you get the chance compare the measurements of the two brands of pistons, weight as well if you can.

[Treeguy]

Sorry for your piston ring end gap issues , JFYI Ive have GREAT luck with mid grade PRO MARINE pistons if I have a customer that’s gonna “lean” on a motor I send pistons to 300 below in Dicatur Il to be cryogenic treated then to Marles to be top pinned always had good end gap numbers works for me and mine ..
Jayb

reading this i am curious as if there is reason to do one process first rather than the other ?

i am sure i will never put together as many motors as you have jay , but my thought would be to have the top pinning done first then the complete piston is cryoed after being top pin welded ?

thank you jay for all your input and contributions here on the forum

[powerabout]

reading this i am curious as if there is reason to do one process first rather than the other ?

i am sure i will never put together as many motors as you have jay , but my thought would be to have the top pinning done first then the complete piston is cryoed after being top pin welded ?

thank you jay for all your input and contributions here on the forum

Jay fixed his post, yes its the otherway around

[Tagg]

For those interested, I got the 15 over pro v piston in today. Piston measures 3.509 exactly. Ring gap in 3.516 cylinders is .021. in the 3.518 cylinder it's .026. piston quality looks good. Probably going to go with a set of these & return the vertex.

[FMP]

Close enough eh

[Tagg]

Close enough eh

I'm thinking yes. The plus to all this grief is if I stick one, it probably won't be #6. Gotta look at the bright side.

[powerabout]

will vertex do a custom ring package so its like a Wiseco?

[Tagg]

I didn't have any luck getting info from vertex. The generic info on their website is all I could get other than "call promarine". I'm pretty much over the vertex thing. Rest of the pro V's will be here tomorrow & the vertex are going back in the same box. I can't say enough good about promarine. I think the guy I talked to was elwin. Great guy. Bent over backwards to make it right. Rare nowadays I.