Whats everyones choice on aftermarket piston preferences.
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Originally posted by poorbiker View PostOkay, so nobody has a preference or everyone couldn't care less bout question.
....Cotten
PS: Alternatives will be more money for nothing, and cost you a re-balance as well; Now please ask about ring choices!Last edited by T. Cotten; 05-21-2019, 09:58 AM.AMCA #776
Dumpster Diver's Motto: Seek,... and Ye Shall Find!
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JCC, I have never used them, aren't they made in Taiwan or somewhere overseas? What's the good about them, the casting and material or price?
Ring choices, lol, have only ever used Hastings, probably made in China but unless that was sarcasm I'll bite, what's your ring choice?
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Hey Poorbiker. I offer my apologies that this response isn’t more timely.
Since you posted your piston query in the Knucklehead section I’m not sure if my Pan and Shovel experiences will interest you but I took such exception to your statement, “Okay, so nobody has a preference or everyone couldn’t care less bout question.“ that I had to respond.
For it is quite the contrary.
My piston experiences have went like this:
When I bought my 69 Rigid Shovel in June 1992, the previous owner told me it had 9000 miles on it’s last rebuild.
Happily thinking I had years of trouble free riding ahead of me with this so-called “fresh engine” you can imagine my surprise when I found it had burned a quart of oil on the short 150 mile ride home.
For the next few months, it seemed like I was pouring as much oil in it as gas until I couldn’t take it anymore and tore it down to find cheap import pistons that had distorted, trapping the oil rings in their grooves on the front and back sides of each.
I located some NOS H-D FLH pistons that were the same +.030 overbore but measured .002 bigger than the ones that came out. After having the cylinders Sunnen honed for the proper fit, I ran it 47,000 miles and had some of the best times of my life on it until it started knocking from the connecting rod beams coming in contact with one of the flywheel rims due to side pressure wearing out one of the big end thrust washers.
Turns out those cylinders I had honed out weren’t bored straight to begin with, the rods were tweaked and the crankcases needed decking too.
But the pistons held up quite well despite their asymmetrical wear patterns that reflected how out of whack everything was.
This was the summer of 1998 and it broke my spirit to have it down during the warm months, but I had
go through the whole engine. It took another .020 to straighten up the cylinder bores, so I went with some +.050 NOS FLH Harley pistons and now decades later, they’re still in there.
To this day, I continue to have some of the best times of my life on this bike, but I won’t bother listing the high mileage figure the pistons have accumulated over the years, because no one would believe me.
My Wife’s Panhead:
First, let me describe this engine. It had a 69 Shovel left case, 1950 right case, one 1954 cylinder, one 1959 cylinder and two 1955 heads. Both cylinders and heads had broken fins for a total of 8 if I recall correctly.
OK, now I’ll go on.
The year 2000 found us taking a 1000 mile ride with her on this recently acquired 74 inch Panhead. The morning after getting home, I figured I’d take the Pan for a spin to see how it had fared the trip. So I started it up expecting to hear that wonderful 315/405 degree cadence of the exhaust but instead all I could hear was a loud 360 degree hollow knock.
I tore it down to find cheap import +.060 pistons that had been slamming into one another at the bottom of the stroke.
As you near the outer limits of overboring, it’s sometimes necessary to file reliefs on the piston skirts so this doesn’t happen, but these pistons already had that and it wasn’t making any unusual sounds the day before, so what happened?
Turns out these pistons, even though they were cast with the customary steel reinforcement strut in place, had swelled and swelled from the heat of the hard road run and kept wearing down the skirts until one now had .012 piston to bore clearance and the other .014. Then in the cool of the morning the extreme clearance allowed them to rock in the bores so far they could now kiss like long separated lovers.
So the same as I did with the last cheap import pistons that I had the displeasure of coming in contact with, I threw them across the compound into my firewood splitting area so I could flatten them with my 20 pound double jack like the beer cans they were probably recycled from.
Soon after, I got my hands on a 1965 FL engine I liked a lot better and built it as a 3 ½ x 4 ½ 86 inch stroker using S&S cast pistons that were available at the time.
When the engine had 30,000 miles on it, I had to tear the bike down for frame repairs and decided to pull the cylinders off the engine to change the color of them from black to silver.
The old school saying for stroker Harleys was “The bigger you go, the faster they blow”. Well, the 4 ½ inch stroke must not be too big because I found the pistons absolutely beautiful. I put the micrometer to them and could detect no discernable wear against the notes I’d kept on the original build. Only perfectly symmetrical witness marks created by running in a straight and true engine.
This bike doesn’t get the miles that my Shovels do and the engine has only built up an additional 9,000 miles since I repainted the cylinders, but I’m sure the S&S pistons in there are still happy and will stay that way for many, many more miles.
My 73 FLH
In August 2010 I had recently taken a new job 130 miles away from home then found a place to stay 15 miles from work and decided that at least 6 months out of every year the weather would allow me use a bike for both the daily commute to work and the weekly commute back home. But I needed a bike I wasn’t in love with. One I wouldn’t mind riding through sand storms and other adverse conditions that would subject it to treatment that bordered on abuse and neglect.
I found an Electra Glide owned by a widow who claimed the odometer was correct at 15,000 original miles.
While I think she honestly believed that, the bike was telling me a different story and I could also see that the top end had been off. At least the cases hadn’t been split.
Regardless, it was still in full dress, ran well, rode well and sounded good.
So I offered a fair price and she was glad to accept.
Since then, I’ve put 79,000 additional miles on it, went through umpteen tires, a few drive chains and minor miscellaneous, but guess what? I finally got a bike and didn’t have to tear down the engine. Yeaaaahhh, All Right, Whoo Hoo!
I wouldn’t even know what kind of pistons are in it if it weren’t for freak occurrence.
One winter day I decided to check the spark plugs and the sun somehow focused through the wavy glass in the side garage door and illuminated the entire rear combustion chamber.
The first thing that surprised me was the lack of carbon build up on the piston.
Then I noted the fully machined piston dome and Wow! I can actually read the engraved part number and .020 over notation.
Later, I did an internet search to see if that part number matched up with any popular brands of pistons and bingo, found out they’re forged Wiseco 9 to 1’s.
It still runs smooth without a re-balance and reliably performs it’s commuting duties day after day, year after year.
Summary: Cheap import pistons have not proven to be reliable to me under extended use. I feel they are a insult to the fine powerplant every Harley engine has the potential to be.
Note: In 1974, 1/32 shorter Big Twin connecting rods were introduced. These are often retrofitted to older engines. Know which ones you’ve got before you order pistons and what will happen if you use “short rod pistons” on long rods, or vice versa.
Post Script: Back in the summer of 98 when I needed help with my ailing 69 Shovel, I went to a man named Tom Agee. (May he rest in peace)
He bored my cylinders with his Kwik-Way boring bar, trued up my crankcases on his Bridgeport mill, then balanced, assembled and trued my flywheels using the greatest of care.
So, to Mr. Tom Agee; Thanks old man, you did a good job.
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