got the head off #1 piston stuck in the bore help!

4TheKZ1000 wrote: They could be right....so I would go easy on the Cockiness....how many blows are we talking about?

Let me describe the hammering sessions:

- about 50 blows of a very large but still hand-held sledgehammer on a 2x2" piece of lumber wood -- I bought an 8 foot long 2x2 from Home Depot and cut 10-inch-long lengths from the 8foot long 2x2, and hammered on each piece until it split, using between 5 to 10 blows, then cut a new 10" long piece and started over -- did that about 9 times and the piston barely moved, now this is sitting overnight in penetrating oil for several nights too by the way.

- got tired of the 2x2 wood splitting and found a hardened-steel shaft as thick as a broom handle and 3 feet long. This heavy shaft was nearly solid, only a tiny hole through the center, I don't remember how I came by this heavy steel shaft, been laying round the shop some time now


Due to the exasperation of the dang wood splitting and tired of the overall scene of failure, I decided to get that #1 piston unstuck and I hit that heavy steel shaft for a solid 2 minutes, found that the piston had moved a good amount, then another 2 minutes of pounding and she was free.

NOW -- I *did* have the cylinder lifted off the cases and held there by wood shims. I figure the wood shims between the cases and the cylinder absorbed some of the pounding.


Imagine a kitchen broom handle about 3 feet long made of nearly solid hardened steel. Now imagine how heavy it would feel in your hand. Then imagine putting that steel shaft directly on the top center of the piston, no spacer at all, just the shaft's end *directly* on the piston crown, and hitting the other end of the steel rod with the biggest sledgehammer you can have and still be the hand-held type.

I did that a total of 2-4 minutes, roughly.

Another uneducated theory could be that each whack exerted less force onto the piston than the force exerted onto the piston by each combustion stroke in a normal running engine.

If the rod's top end looks okay, and the wrist pin fits comparably as snug as the wrist pin fit in the other rods, and the big end feels intact the same as the other big ends without undue slop, noise or wobble when manipulated by hand -- would indicate that the components probably remain serviceable.

Good Fortune!

Patton wrote: Another uneducated theory could be that each whack exerted less force onto the piston than the force exerted onto the piston by each combustion stroke in a normal running engine.

If the rod's top end looks okay, and the wrist pin fits comparably as snug as the wrist pin fit in the other rods, and the big end feels intact the same as the other big ends without undue slop, noise or wobble when manipulated by hand -- would indicate that the components probably remain serviceable.

Good Fortune!

Darn good point -- I don't know how to compare one hammer blow to a combustion-chamber fuel/air explosion, but -- since each cylinder puts out around 25hp at the crank -- I'm asking myself the following question, and as mentioned it sounds uneducated but it does make sense, can I with my 200lb somewhat in-shape physical condition, hit a downward stroke on a metal shaft with the same force as a 25horsepower motor? No freaking way. Not in a million years.

If I could hook up a 25 horsepower engine to one end of the steel rod I used to knock the piston loose -- pretty sure we'd all agree that a 25 horsepower motor would probable drive my metal 'knock-free' rod clean through the kz1000 motor.

So Patton yours is a really good observation. If I was able to knock on that shaft with even FIVE (5) horsepower of force, I'd be real surprised.

Okay to cap this off, I found a source on the web that says the max horsepower a human can exert is ONLY 2 HORSEPOWER. Here's the link:

www.physics.ucla.edu/demoweb/demomanual/...t_of_horsepower.html

It says this:

"A person in good shape can develop one to two horsepower."


So let's say I hit my metal rod with 2 horsepower, right on the top of that piston #1. Well, if the normal cylinder #1 puts out 25 horsepower at the crankshaft -- that means each hammer blow I hit it with was:

- equivalent to less that 10% of the normal power caused by the normal fuel/air explosion.

(2 horsepower hammer strike)

---

= 8%
(25 horsepower air/fuel explosion)


So each of my hammer strikes was ONLY 8% of the normal combustion in the #1 cylinder!


Good call, Patton, as always.

Here's an excerpt from performancetrends.com/Definitions/Cylinder-Pressure.htm

Combustion / Expansion Stroke

This stroke is where the spark plug ignites the air/fuel mixture, creating very high cylinder pressure which rise very quickly. Peak cylinder pressures near TDC (where spark occurs) will be in the range of 300 psi for engine's at light loads, to 1000 psi for production engines at full power to 1500 psi or greater for race engines. This is where the engine's power comes from, as it forces the piston down. As the piston goes down, the cylinder volume increases which reduces the cylinder pressure. When the piston gets to the bottom on the cylinder (BDC) there may only be 100 to 500 psi in the cylinder.




Good Fortune!

Patton wrote: Here's an excerpt from performancetrends.com/Definitions/Cylinder-Pressure.htm

Combustion / Expansion Stroke

This stroke is where the spark plug ignites the air/fuel mixture, creating very high cylinder pressure which rise very quickly. Peak cylinder pressures near TDC (where spark occurs) will be in the range of 300 psi for engine's at light loads, to 1000 psi for production engines at full power to 1500 psi or greater for race engines. This is where the engine's power comes from, as it forces the piston down. As the piston goes down, the cylinder volume increases which reduces the cylinder pressure. When the piston gets to the bottom on the cylinder (BDC) there may only be 100 to 500 psi in the cylinder.

Good Fortune!

You raise a very good point here -- the distinction between a 'distributed' force and a 'point impact' force. The 25 horsepower developed in cylinder #1 of a kz1000 is distributed, probably uniformly distributed, across the entire piston top, so that no one point on the piston crown is subjected to a higher pressure (in p.s.i.) than any other point.

But a 'point impact' -- where all the force is concentrated in a smaller area of the piston -- is different, since the motor was not designed for that.

So I went and looked on the web to see how much in p.s.i. a human can create -- I was hoping to find that, per your finding:

"Peak cylinder pressures near TDC (where spark occurs) will be in the range of 300 psi for engine's at light loads, to 1000 psi for production engines at full power"



I was hoping to find that the p.s.i. I created on the top of the piston was lower than 300psi.

Here's what I found on the web:

1) "How hard does the average human punch in psi?"
In: Health › Fitness, www.chacha.com/question/how-hard-does-th...e-human-punch-in-psi
The average for a typical human is 80 to 90 psi.

2) however, the psi created by a large, moving sledgehammer can (apparently) easily exceed 1000psi. I found one source that calculated 60,000psi is created by a 50 pound weight dropped 5 feet on a 1.25" area.

So I could easily have exceeded 1000psi on the top of the piston. Now I'm worried again.

The physics calculation to determine the psi is complicated. But ballparking it, dagnabbit I may have 'exceeded design limits.'


You can get a feel for it by this -- if you drop a big sledgehammer from your workbench onto your big toe, it's gonna hurt but probably not break a bone. The psi on your big toe was not too high.


But if you take a sledgehammer and smash someone's big toe, the p.s.i. is much greater on the toe.
It's gonna crush the toe.

as long as the crank wasn't at tdc or bdc while you were beating,i wouldn't worry or do any more math. :whistle:

i would,
now that the jugs and pistons are off.roll the crank through while holding the rod that had the stuck piston.if it feels nice and smooth while rolling the crank around while you feel for any notchyness.
i would assume it was fine and rebuild my top end.
when you start it up your are going to know if anything is wrong,and it is just a matter of some gaskets and labor if it is knocking.

i could what if you to death about everything that could happen.

but these old motors are tuff and will take alot.

so if the rod rolls through smooth has decent big end side clearance,i'd roll it until i had a reason not to.

that is my .02 fwiw.

ymmv,

leon

I forgot to congraduate you on a fubar project.....that sucker was frozen..... :huh:

4TheKZ1000 wrote: I forgot to congraduate you on a fubar project.....that sucker was frozen.....

(from 531blackbanshee)
now that the jugs and pistons are off.roll the crank through while holding the rod that had the stuck piston.if it feels nice and smooth while rolling the crank around while you feel for any notchyness.
i would assume it was fine and rebuild my top end.
when you start it up your are going to know if anything is wrong,and it is just a matter of some gaskets and labor if it is knocking.

i could what if you to death about everything that could happen.

but these old motors are tuff and will take alot.

so if the rod rolls through smooth has decent big end side clearance,i'd roll it until i had a reason not to.

Thanks for the advice, banshee, I could second guess my reason to even buy this guy but your advice sounds reasonable -- I'm going to follow it and if the #1 rod and crank feel okay, I'll do a top end job and see how it goes.


4TheKZ1000, thanks, I had almost caved to the idea of having to take some cutting action on it and only reasons I bought it to begin with was, it was cheap, and I love challenges, you have to admit that reliability gets boring if you like to build and work on stuff. You keep your newer bike for a reliable ride, you buy someone's 'lost interest back yard project bike from 20 years ago' in the hope the bike is going to entertain you and you learn something.

My brother retired, he sold his business, is only 53, I warned him "don't retire but if you do, have a serious time-consuming hobby" and he has not listened to me yet and is bored out of his skull, only 6 months after retiring.

You HAVE to develop a hobby for those times and this is a gratifying hobby, getting a vintage bike back on the road after given up for dead! The steel rod won the battle!


And it's a relatively inexpensive hobby too, because you can recover a lot of your materials and parts cost when you sell, maybe even break even sometimes!

Interesting read. As far as your examples of pressures and related theory's, I see you left out that when running the forces are cushioned by oil pressure. Different for a Roller than a Babbitt bearing though.
All in all I would doubt that the crank would be damaged from the way you had supported the cylinder bock. With the piston stuck, but the crank not at TDC, or BDC, the forces should only serve to rotate a free spinning crank. Hopefully not imprinting the small needles from a Roller Bearing on the crank pin, or on the main bearing balls to race.

Motor Head wrote: Interesting read. As far as your examples of pressures and related theory's, I see you left out that when running the forces are cushioned by oil pressure. Different for a Roller than a Babbitt bearing though.
All in all I would doubt that the crank would be damaged from the way you had supported the cylinder bock. With the piston stuck, but the crank not at TDC, or BDC, the forces should only serve to rotate a free spinning crank. Hopefully not imprinting the small needles from a Roller Bearing on the crank pin, or on the main bearing balls to race.

Good point -- I put 2x2" wood shims, cut down just a tad to fit, under the lifted cylinder, on the front side and on the rear, to keep it off the cases -- your characterization of my downward impact force being transferred to the rod/crank and wanting to spin them -- seems correct.

Before I started pounding to loosen the piston, I made 100% sure that the #1 connecting rod was NOT at TDC, but was forward into its downstroke of the piston, a bit away from TDC -- reason being, if the piston DID come free fast, I needed downward movement available of the connecting rod to accommodate the downward-moving piston if it came unstuck during the pounding.

I'm looking on ebay for a brand new piston -- even if I were to measure the existing formerly-stuck piston #1 and find it to be exactly dimensions as a stock piston, with the ring grooves not compressed at all -- I still would *not* re-use the #1 piston I hammered on. Not at all worth the risk and new pistons aren't too expensive.

your best bet is a floor jack small enough to fit under the jugs and over the crankcase, while being able to fit wood blocks to keep it from being dented. :lol:

I had used the caravan for removing a hanging tree branch, the branch was stubborn and it took a long time, but it is down, and the water pump on the caravan is now toast, so 400.00 in scrap is fair.
What I am getting at is leverage can be your best friend or your worst enemy. also nose wheelies are not so simple.