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Author Topic: KIT ENGINE, First impressions--  (Read 35995 times)

binnie

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Re: KIT ENGINE, First impressions--
« Reply #45 on: August 26, 2006, 04:58:32 AM »
Bob,
I wpnder why and to what criterion, they drill out the little holes in the  flywheels in India...what method are they using to balance what? Are they doing that to rough out the bounce on an initial trial run? I doubt it. There must be a more direct reason for these little holes,(removal of mass, weight) on the fly wheels. Is it to make them equal in weight....or is it at a specific place on the surface of the wheel to minimize the "bounce" ? binnie
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mobile_bob

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Re: KIT ENGINE, First impressions--
« Reply #46 on: August 26, 2006, 05:04:50 AM »
who knows, binnie?

why do the indians do half the stuff they do?

for all we know it is to make it look like they took some sort of care to balance them, perception you know.

if they were balancing the flywheels themselves as individual units, i would expect that if you removed them and placed them on a bubble balancer they would be bubble perfect, but they cannot be!

most of these engines do not have counterweighted cranks, so they have to be externally balanced.

so if the holes are there for balance then the engine shouldnt jump all over the place,,, my bet is it is a marketing tool
nothing else in most cases. or....

it is an attempt to by reason of empirical results that they have found that most engines need wheels that are X amount of heavy on one side, and apply it as a one size fits all fix,, which never works.

bob g

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xyzer

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Re: KIT ENGINE, First impressions--
« Reply #47 on: August 26, 2006, 07:04:51 AM »
  Mine was a jumper...big time!...the warning is on the CD!  I balanced it this way...see all the lead on the flyheel! It had it on both flywheels. Waaaaay Off.......Quality control I believe is a big problem and not building to a spec of sorts. If it is cutomary to bolt it to a ton of concrete who will know....I don't buy the cement is part of the block theory....aint much stress below the crankshaft unless it is out of balance then it is all over the place...just another opinion..... I have a kit motor coming and I am going to do the 1 wheel at a time and see what happens.
   This was my first attempt following the standard method for a 1 cylinder.  It bounced when I was done! fuck!!!!!!!! well then I went to the chalk method and found to get it to smooth out I had to basicaly move weight from one side over to the other. One wheel had more issues than the other. That is how I figured out the 1/2 the bobweight one wheel at a time method. It will address each wheels issues.
                                                            
                                                             Static


                                   
                                                        Chalk method


I made some u shaped weights i could haing on the flywheel to test where and how much.  The chalk method is a lot of work unless you get lucky. Oh..and the heavy spot is not at the chalk mark! The chalk hits after the heavy spot goes by... about 90ish degrees ahead of it. Lots of starting and stopping and moving weights then starting. But it does work. I have seen some 6/1's sit on cement and just run so smooth....so it can be done...I'll know more in acouple of months.
« Last Edit: August 26, 2006, 07:09:24 AM by xyzer »
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Geno

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centrifugal force?????????
« Reply #48 on: August 26, 2006, 12:03:26 PM »
In order for the bobweight method to work wouldn’t the added flywheel weights have to be the same distance from the centerline of the crank as the crank journal?  It looks like a weight 11.5” (29.2cm) from the centerline spinning at 650 rpm will weigh 137 times its actual weight due to centrifugal force. That same weight 6” from the centerline is only 72 times as heavy.

http://www.eppendorfna.com/support/online-calculator.asp

Thanks, Geno

cujet

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Re: KIT ENGINE, First impressions--
« Reply #49 on: August 26, 2006, 12:48:32 PM »
No, the bob-weights just need to have a certain mass at a certain arm. What so many people forget when balancing is that they are dealing with mass, not weight. The terms are Mass, Arm and Moment.

Arm is the distance

Moment is the combination of Mass and Arm.

The typical single cylinder Listeroid flywheel has a certain moment opposite the crank throw. It is simple add/subtract/multiply/divide math to calculate the moment for each flywheel. Now, remember that in theory, the counterweight will ALWAYS be 180 degrees from the crank throw. Looking at his picture, XYZER seems to have had a flywheel that had the mass not centered opposite the crank throw. The running result is an engine that must be dynamically balanced. Or the flywheels must be fixed. Otherwise there is a terrible out of balance situation.

XYZER, did you locate the heavy point on each flywheel before starting? If you did, did it correspond with the correct position?

Chris
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cujet

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Re: KIT ENGINE, First impressions--
« Reply #50 on: August 26, 2006, 12:53:08 PM »
XZYER, what balance factor did you use? From what I see in your picture, I am guessing you added too much weight. Most single cylinder engines run with a 53% balance factor. Maybe 55%. Did you use 100% by mistake? If so, I'll bet that engine was outta control when run!

Also, I agree with you, There is no way the concrete is necessary for crankcase strength.

Chris
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xyzer

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Re: KIT ENGINE, First impressions--
« Reply #51 on: August 26, 2006, 04:04:50 PM »
XZYER, what balance factor did you use? From what I see in your picture, I am guessing you added too much weight. Most single cylinder engines run with a 53% balance factor. Maybe 55%. Did you use 100% by mistake? If so, I'll bet that engine was outta control when run!

Also, I agree with you, There is no way the concrete is necessary for crankcase strength.

Chris
Chris,
I used 50%.......100% Of the big end of the rod + 50% of the piston+wristpin+small end of rod. Like I said I didn't add to much weight, I added not enough to one wheel and to much to the other. Dynamic balancing both flywheels at the same time they become one......but arn't! After I shuffled some weight from one side to the other it improved a bunch...It still has the same total # of "pounds" between the two wheels.
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slowspeed1953

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Re: centrifugal force?????????
« Reply #52 on: August 26, 2006, 05:51:18 PM »
In order for the bobweight method to work wouldn’t the added flywheel weights have to be the same distance from the centerline of the crank as the crank journal?  It looks like a weight 11.5” (29.2cm) from the centerline spinning at 650 rpm will weigh 137 times its actual weight due to centrifugal force. That same weight 6” from the centerline is only 72 times as heavy.

http://www.eppendorfna.com/support/online-calculator.asp

Thanks, Geno


Absolutly!

The rod journal on a 6/1 is 2.75 inches off center and that is where the calculated weight would be placed on the flywheel in order to "balance" the assembly.

If the corrective weight was 10 pounds at 2.75 inches off center you would only need 5 pounds of weight to cure the same imbalance condition at a 5.5 inch weight placement radius.

At a 11 inch radius the necessary weight would only be 2.5 pounds to cure the same imbalance.

So yes, as the radius of the counter balance weight increases the needed counter balance weight decreases.

Simply stated for every 100% increase in bob weight radius there is a 50% reduction in the mass needed to "balance" the assembly

Peace&Love :D, Darren
« Last Edit: August 26, 2006, 07:39:22 PM by slowspeed1953 »

aqmxv

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Re: KIT ENGINE, First impressions--
« Reply #53 on: August 26, 2006, 06:48:47 PM »
for all we know it is to make it look like they took some sort of care to balance them, perception you know.

if they were balancing the flywheels themselves as individual units, i would expect that if you removed them and placed them on a bubble balancer they would be bubble perfect, but they cannot be!

most of these engines do not have counterweighted cranks, so they have to be externally balanced.

I suspect they balanced the flywheels individually to some (large) standard tolerance and a particular center point.  This approach doesn't take the variations in flywheel mass between units or the variation between different cranks, rods, and pistons into account.  Having said that, properly done it should get you pretty close.  As usual with listeroids, the problem is in the execution, not the theory. 

There are notches in the rims of the flywheels on my 6/1 which are obviously supposed to  be light spots which should be at the same place as the crank arm.  I haven't looked to see if they're where they should be on my particular engine yet.

To statically balance a listeroid flywheel individually, the right amount of compensating mass would have to be hung on the rim at the same clock position as the crank throw.  Then you do whatever must be done to the wheel to bring it into balance with  the compensating mass attached.  Remove the compensating mass and it'll (ideally) be out of balance by 1/2 of the desired moment arm desired.  Repeat with the other flywheel paying the same attention to where the compensating mass is attached.  Lastly, you have to make sure that the flywheels are mounted the same distance from the rod journal centerline on the crank when reattached to the engine.

cujet, xyzer and darren have all contributed all that wonderful angular momentum stuff I was trying to avoid including the math for.  Basically, you need to think of any unbalanced rotating mass as a lever.  You can solve it with algebra with lever equations, you can use vector math on it like mech and aero engineers do.  It all works out the same.

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hotater

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Re: KIT ENGINE, First impressions--
« Reply #54 on: August 26, 2006, 07:55:22 PM »
Back to the KIT!---

I just received the cylinder head all it's furniture.   :D

The makers of this engine is SO close to being sho nuff 'RIGHT'.  The head casting is so much superior to the Prakash made head it’s just amazing.  The new PS head is FLAT and the cooling galleys are AT LEAST twice as big as my FuKing.  No signs of parting flash or clogged passages that have to be chiseled out.  There's very little to be done to make this head dead solid perfect.

The valves are NICE.  The fit and finish is again at least twice as good as my FuKing.  The valve keepers are well made and seem to be the same....something different.  ;)   The valve springs are even well finished!

The rocker assembly leaves something to be desired...especially the  "valve rocker striking pin".  The radius is not smooth and the surface of the pin is not square with the lash caps.  (I'm making a fixture to grind these correctly, be patient.)  The rocker bracket is pretty crude *looking* but the holes are square with the ends and each other so the parts are held in the proper alignment.  The rocker shaft is well finished and round and is fed by a small brass grease cup that attaches to one end.
<side note>  I installed a grease cup in my rocker shaft and I grease TOO much, too often, and tend to forget to lube the valve stems occasionally.

Push rods and the pushrod adjuster screws are hardened well and much smoother than my previous engine but there's still enough improvements to be made to make a DIYer smile.

The valve cover is sheet metal instead of the aluminum casting  of #1 and it's probably about perfect for what it's made for...keeping dust out the valve train, but I sure wish the Indians would buy some sheet metal at least as thick as a garbage can.  Theirs seems to be closer to coke can gauge.
  I like the solid and long-lasting look, feel, and sound, of cast iron for covers....or at least something as stout as an American engine valve cover.

The water inlet and outlet in this kit engine is American 1" pipe threaded.  It's more than adequate and sure handy for using (bronze) street elbows on Tees for the cooling system.  I've already plumbed the building for 1 1/4" NPT so will re-tap the engine fittings.

More pictures soon.

I poured grout on the engine stand this morning and I'm welding fuel and cooling tanks this afternoon.  Monday will be 'pull apart and get right' day.
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Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

slowspeed1953

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Re: KIT ENGINE, First impressions--
« Reply #55 on: August 26, 2006, 08:17:17 PM »
The "kit" engines are cool but I dont think I would be interested in one unless they are available in the GM-90 style of engines as they have the bolt on crankshaft bob weights virtually eliminating all of the unwanted crankshaft flex that I believe contributes to the idler gear failure problems.

With the GM-90 engines everything hanging on the weakest part of the crankshaft is neutrally balanced greatly increasing the integrety of the shaft. They also come with all of the "advances" available, oil pump ect.

The GM-90 style engines should be really easy to balance, simply insure the flywheels are nuetral balanced (at your local tire shop) then adjust the bob weight as necessary, worst case being the addition of mallory metal to the bobs.

Peace&Love :D, Darren

Halfnuts

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Re: KIT ENGINE, First impressions--
« Reply #56 on: August 27, 2006, 02:30:54 AM »
Tell me, Darren,

Did you get invited to many birthday parties when you were a kid? 

No?

I thought not.

Halfnuts

slowspeed1953

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Re: KIT ENGINE, First impressions--
« Reply #57 on: August 27, 2006, 03:13:47 AM »
Tell me, Darren,

Did you get invited to many birthday parties when you were a kid? 

No?

I thought not.

Halfnuts

Actually no I only remember going to one or two why do you ask?

Peace&Love :D, Darren

Doug

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Re: KIT ENGINE, First impressions--
« Reply #58 on: August 27, 2006, 04:59:30 AM »
I think there are lessons to be learned from both types, and now with the advent of "Kit engines" one has to ask can I mix and match?

Doug


slowspeed1953

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Re: KIT ENGINE, First impressions--
« Reply #59 on: August 27, 2006, 11:33:44 PM »
I think there are lessons to be learned from both types, and now with the advent of "Kit engines" one has to ask can I mix and match?

Doug



Doug so true!

As the direct injection head that comes with the GM-90 leaves a bit to be desired in its ability to easily cold start with viscious fuels. GM-90 bottom end and brand X in-direct injected cylinder head would be one sweet engine!

Peace&Love :D, Darren
« Last Edit: August 27, 2006, 11:37:30 PM by slowspeed1953 »