I always thought the full floater was more of a 2 stroke thing, works better with less oil(especially with a needle bearing in the rod). On a high output 4 stroke car engine, you've likely installed piston squirters, so I don't see the point other than making it easier to tear down and assemble.
If you have a full floating piston in theory there is less points of friction and also if the pin binds on the rod or the the piston you will still have proper action on the rod... In the real world? You could hone the small end of the rod and add teflon buttons. But how do you address the oiling of the small end? I guess splash will get some oil in there... But in a street engine, why bother with the extra work. Spend the time somewhere else making power....
Zomby Woof wrote:44Dwarf wrote:In over 30 years as a mechanic, I've never once seen this happen.turboswede wrote: Another issue with full floating rods is that sometimes the clips fail and can cause massive damage.True i've seen this tons in motorcycle motors, Most drag car engines i've used teflon buttons instead of clips to prevent that failure.
Your lucky ZW! one of my 1st used bike purcases as a kid was a xr75 with a rebuilt top end....even got a copy of the service slip...it lasted a week then lost all compresion clip came out pin moved over and eat the cyl wall. What a mess. oil was full of fines and whole motor was tossed a side for parts as every bit needed cleaning.
oldeskewltoy wrote: semi floating wrist pin - would be the rod is heated, and interference fit wrist pin is fitted so that when the rod cools, the pin is fixed in place. The piston "floats" on the pin, while being fixed to the rod full floating wrist pin - would be the wrist pin is held in place with small clips on the ends of the wrist pin cavity in the piston. The wrist pin "floats" in both the rod, and the piston. full floating is superior.... but it really depends on the application as to how much of an advantage.. (incremental... to significant) my 8000 rpm 4AGE is using semi floating pistons... for what thats worth to you....
Is yours built or like a 20v black top or something? Those are 8000rpm limited and I thought they just had forged internals no "floating pistons" never even heard of that lol.
Is this something that a very high revving engine like a 2zzge would have?
tuna55 wrote:Swank Force One wrote: What i'm being told is that full floating = less frictional losses.Think about this while holding up a rod/piston assembly. How much does it take to flop over the not-even-oiled piston?
Now do it eight times, times a hundred or so cycles per second, and don't forget to measure how much heat you're putting in the oil while you do it.
Super Stock engines are at or over ten grand with pressed in pins.
Super Stock engines are a great exercise in rules bending. Don't they have a lift rule but no duration rule for camshafts, so you get "square" cams with crazy long duration but stock lift?
The ones that have come apart are more likely assembly related, rather than clip failure. Once the clip is in there, there's not much that can go wrong. I have seen several small block chev motors with slots in their bores from the wrist pins coming out of the (press fit) rod's small end.
Let's not forget the millions and millions of Subarus out there that not only have floating wristpins, but have a nice HOLE IN THE CYLINDER at bottom-dead so that you can insert them.
Man, could you imagine the carnage that would ensue if a wristpin walked out and got stuck in there?
That reminds me... how in the world do you assemble a Subaru six?
kanaric wrote:oldeskewltoy wrote: semi floating wrist pin - would be the rod is heated, and interference fit wrist pin is fitted so that when the rod cools, the pin is fixed in place. The piston "floats" on the pin, while being fixed to the rod full floating wrist pin - would be the wrist pin is held in place with small clips on the ends of the wrist pin cavity in the piston. The wrist pin "floats" in both the rod, and the piston. full floating is superior.... but it really depends on the application as to how much of an advantage.. (incremental... to significant) my 8000 rpm 4AGE is using semi floating pistons... for what thats worth to you....Is yours built or like a 20v black top or something? Those are 8000rpm limited and I thought they just had forged internals no "floating pistons" never even heard of that lol. Is this something that a very high revving engine like a 2zzge would have?
the 20V uses full floating pistons... as do all the 20mm wrist pin 4AGE engines... or so says toyodiy.
If you look up MR2(stay consistant look up USA MR2 4AGE)... on toyodiy... begin in 1986.. then 87, then 88. look up the piston section under parts views, they show a clip (part group number 13101A), but when you look for the clip in the descriptions, it only appears available in the 1988 view, both 87 and 86 says not applicable)
The rod number changes as does the piston, for in 1988 is when the 20mm wrist pinned 4AGE appeared
2ZZGE does have these....
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