Narrowed down my possibilities on my broken wiseco.

long story short, i cracked the rear piston up both sides of the skirt, right behind the wrist pin on the intake side. gouged the cylinder pretty good (going to have to bore over again)

I'm going with 10.5:1 this time around (a bit better suited to the W8, and will support a W9 if for some reason I decide the bike needs a 5th cam lol)


Im not afraid to spend $$$ on quality....honestly I prefer it (its always been my luck that its "pay me now or pay me later"...either way it's gonna happen.


and preference to brands? the biggest thing I notice about the wiseco's is how long the skirt is (and it was a SOLID impact...about a 1/8-3/16" dent)

These are all .010" over...i'm already bored .005" over...and my indy seems to think I can get away with the .010" over (ill know for sure tomorrow once he gets em in torque plates and measures them). good thing theres no big price difference.

CP - forged 10.5:1, M5009

JE - forged, PN 134094

KB - forged, with offset wrist pins (not really sure on the upside to these...but their forged pistons all come with offset pins)

KB - hypercast (same as OEM unless i'm mistaken), no offset wrist pin



dunno about a lot of other offerings. I'm really hesitant to even give wiseco another chance. I'm waiting on a call back from them, see if they have any insight as to why these hit.


i guess the upside is I know the clacking I was hearing that I always attributed to those "noisy woods cams" simply isnt the case.


destroyed wiseco's -- for reference

 

Hmmm, my guess is those Wisecos are a stroker kit piston.

Don't use the Keith Blacks, they are hyperteurectic or something fancy and not like OEM...go with forged. I recommend using stock pistons and planing the head to get higher compression as its easier to reverse by using different gaskets.

 

Perhaps that piston was simply fitted the wrong way round? Looks as if the damaged skirt is longer than the other one. Too long since I last had a Harley apart to recall. If it was a stroker piston it would have to be shorter, so it could go further down the bore.

 

Mahle makes one of the best pistons made. Check out the cars running at the front of any NASCAR race and you will see the MAHLE sticker on the fender. I would also like to reccomend Cast iron Total Seal file-to-fit rings. Using the above combination, properly fitted it will be hard to beat. Oh and get some Total Seal "quick seat" to use on the cylinders( there I go giving away tricks again). It will assure that your cylinders are clean and help the rings seat properly. Hope this helps.
John

 

I see a full tear down coming, rod/bearing, crank pin issue?

I guess you pulled up and down on the rod already, any slack?

Unless there was an obvious app, defect or install issue,
the piston's just a casualty.

That jug has to have some major taper at the bottom now, don't see .005 (.0025 actually) cleaning that up.

Need to get all the metal out the engine crevices, oil hoses, and tank anyway.

Hate this happened.

 

John, got a part number for mahle's? I looked for them, didn't see a harley application in their catalog.


I'm fairly sure the piston is the defect. Bottom end is still tight, and no metal shavings were found (the skirt is cracked And dented... No pieces missing). The skirt on the Wiseco is a lot longer than stock pistons, and they were absolutely installed in the right orientation (that got checked 3 or 4 times before the jugs went on. My only guess now is that wiseco put the wrong pistons in the box, or 2 fronts vs 1f and 1r. The skirts are identical heights from the wrist pin on both pistons.

The scoring really wasn't bad, enough to feel, but no major gouges. Hopefully I hear back today as to how much they need to be bored so I can order pistons ASAP. Really wanna limit downtime at this point

 

If it hit hard enough to crack the piston, it didnt do the bottom end any favors. I would pull it apart and measure and check runout, bearings and all. Or do it again after the new top end is done. Your call.

 

Are those dome pistons with big and little valve reliefs?
Kinda hard to install those wrong.

 

Do both pistons have those two notches in one side of the skirt?

 

No, those 2 notches are where the skirt hit either the flywheel or front connecting rod.

The 3 guys I talked to already, (who are all builders) said the bottom end should be fine as long as the rod bearings are good. Either way I don't have the cash to redo the bottom end too. Odds are this hit the first time it was turned over and that's why it's been clacking since day one. I won't know more until I get home from work and can dig in a little deeper


Don't forget, it's been running for 2500 miles or so like this. I only tore down because I recently bought a leak down tester and realized the rear cylinder was low.