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    Re: Need Help With Cooling Options
    #11
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    Was thinking whole engine in car. With a fan in front pushing air across. I'll check the thread.
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    Re: Need Help With Cooling Options
    #12
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    This is what the motor in the cart looks like, except there is about a 4 gallon gas tank above it behind the black speaker box. The fan is on the right side of the motor
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    Re: Need Help With Cooling Options
    #13
    Millenium Member nutz4sand's Avatar
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    Being your a Yooper I would bet a liquid cooled sled engine would be pretty easy to find and likely cheaper than rebuilding that one. Of course you would need to add a radiator and redo the mounts. No big but still.

    I typically never tear an engine apart before I do the pressure test just so I can see if I find a leak to know if it caused or contributed to the meldown. Being you already took it apart that not a big deal as long as you do it when you reassemble. I always do it before and most definatly after a rebuild. No pass no gas! If its not dead sealed I will not reinstall it. This below I typed up a while ago and is cut and pasted.

    From Bill the Troll! :]



    Here yah go. This is part of a teardown and rebuild on any two stroke. It SHOULD be done before you take the worn motor apart and after you got he new motor together to check the work. Anyone who tells you its not needed is gambling.

    NEVER ASSUME new seals have sealed and new gaskets are perfect. Often far from it. Especially with stuff being done cheaper and China crap being substituted in!
    Any two stroke has seals in the crankcase. If these go bad you usually lean out the motor and fry a piston and can ruin a good cylinder along with that.
    To pressure test a two stroke should be done BEFORE you tear it apart for a rebuild.

    (If it fails then a top end rebuild alone will fail due to the bottom end is leaking. If the motor fails a crank pressure test and the pistons is bad the bottom end is usually what caused it.)

    AFTER you rebuild it to check the seals (and gaskets) you just worked with. And at regular intervals (along with piston compression checks) to monitor your engines internal life.
    To do a pressure check you need to remove the pipe and carb and go to a hardware store and get some stuff from the plumbing department to seal both holes. Rubber caps and a hose clamp usually work good on most exhaust pipe snouts and PVC pipe caps can normally be found easy that will fit in the carb boot. You then either need to make or get a fitting that allows you to put an air hose to either one of the caps or into the spark plug hole.

    Basically you need to have a way to feed air into or out of the motor.

    If you cannot find a way to use the sparkplug hole with a fitting then drill a hole in the PVC pipe cap thats in the carb manifold (Take it out of the manifold first if its already in there! I hope I didn't need to tell you that but just in case! I have seen people drill things where crap from the drill falls into the works. Not good). (My Honda Pilot had a fuel pump hose fitting on the side of the cylinder (some motors have these on the crankcase) for the pulse to make the fuel pump pump fuel. If you have that fitting you can use it (on a single cylinder. In a twin it can only be used for the cylinder its under just so you know)

    Once you KNOW the pipe and carb holes are sealed tight (The spark plug too if you have you air fitting there. If the plugs in it should be fine.) make sure the piston is down in the bottom of the cylinder (You don't want it blocking the ports. The very bottom is good. Just clearing the cylinder ports will be fine.) Then you need a vacuum gauge/hand pump ($20 to $30 bucks at any auto store for the hand pump version.) Put about 6 inches of vacuum to the crankcase. If it drops to 4 inches of vacuum in under three minutes the bottom end seals are bad or at least weak. Some say less than an inch of vacuum a minute is fine but as you regularly test your motor if you see it loosing its negative pressure faster then you will know the seals are getting weaker and its a lot cheaper to fix it before it toasts everything. (This requires you to make sure the carb and pipe plugs you made are good so you are only checking motor gaskets/seals.)

    Thats a negative pressure test. You can go up a little higher in vacuum pressure. The motor should be able to hold some for over five minutes or the seals are toast. One inch of vacuum a minute lost is starting to get bad.

    Many also do a positive pressure test. Same deal as above. I like them better as its easier to see soap bubbles and ID the leak. Seal the motor and get a hose connected with the piston at the bottom of the cylinder like before. In the NEG test above the pump stays in the line and holds the vacuum. For the POS test you will want a little on/off valve in the line. Then once you put pressure to it you can close this valve to hold the pressure in. As long as you have a setup that holds the pressure in at the hose your fine.
    HERES THE CATCH. If you put to much POSITIVE pressure to the crack case you can literally Blow the seals out! NEVER JUST PUT A AIRCOMPRESSOR HOSE TO THE SETUP YOU MADE TO PRESSURE TEST IT AND "THINK" YOU CAN HIT IT WITH A LITTLE AIR AND TEST IT THAT WAY. You make one little mistake and its gonna need to be taken apart and repaired. So do this instead. Get one of those small portable air tanks. Put about ten PSI in it with the compressor. Then bleed it down to 6 PSI or maybe 5. This way you cannot put more than that to the crankcase. Better safe than sorry. Put the 5 or 6 PSI to the crankcase and seal the valve. It should not leak more than a pound a minute. Less is better. More is questionable. I will not settle for more than 1 pound every two minutes one my stuff.

    You can get a gauge at the auto parts store that reads both POS and NEG on the same gauge. (They are NOT high pressure they are more for car manifold tests) This gauge can do both tests for you. I have in the past used these (I still have mine and use it) AND used a HUGE syringe to provide both the vacuum and the positive pressure. It sometimes takes a few pumps to get the pressures I wished but it can be done.

    If that did not make sense GOOGLE pressure testing a crankcase and you will get some more insight. I also test the entire motor and all the seals on my test equipment each time. I have had leaks that formed on the tube joints of my test equipment. The soapy water bubbles led me right to it. I check every seal and gasket line and even around bolt holes.
    I HAVE actually discovered air leaking out a cylinder hold down nut like this due to a porous casting flaw from the intake port near the stud the to the engine. I had to go back in and seal it to stop the leak.

    Doing this test while you can still see both sides of the main crank seals is best. Easiest to get to to fix too if need be. Cover the entire outside of the motor with soapy water. I have had slow leaks that make the tiniest bubbles that I could not see/locate till nearly 3 minutes into the test. But then noticed.
    I won't install a motor that does not pass this test
    Now that NOBAMA has PROVEN he is the absolute WORST president in the history of history Jimmy Carter can thank him for stealing the dunce crown.

    Lets hope the next guy repeals NObama care along with the rest of the stupid crap this blight on our windshield has done.
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    Re: Need Help With Cooling Options
    #14
    Millenium Member nutz4sand's Avatar
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    A couple other things I should add to the above (and will) When testing a cylinder/crankcase for pressure integrity you should make sure the piston is at least down past the ports. it will help get faster more accurate results. In a twin you then obviously need to rotate it 180 degrees when you do the other cylinder.

    The air cooled engines I used to mess with were nearly all Cunya's. These had a mean fan but blew the air from the first cylinder right across the second making the second hotter by design.

    Your engine feeds air into the front and across both kinda sorta equal. I cannot help but wonder if it has any air ducting inside that shroud to guide air more equal. Otherwise in a setup like that it may blow more air across to the farther away cylinder? Without pics or seeing it I am just thinking/wondering/guessing.
    Now that NOBAMA has PROVEN he is the absolute WORST president in the history of history Jimmy Carter can thank him for stealing the dunce crown.

    Lets hope the next guy repeals NObama care along with the rest of the stupid crap this blight on our windshield has done.
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    Re: Need Help With Cooling Options
    #15
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    Just curious, would a fan cooled or liquid cooled sled engine run better in summer...? Because to me, if a motor needs to be liquid cooled for winter, I can't see it fairing very well in summer. But that's just my thought process, I could be completely backwards. If we do decide to rebuild this engine, I'll definitely pressure test it. Thanks for the info
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    Re: Need Help With Cooling Options
    #16
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    While it is easier to cool the liquid cooled two stroke one thing you need to get right is the RPM's. A two stroke gets a butt-load of its cooling from the air it takes into itself far far more than a four stroke as the air goes thru the crankcase on the bottom of the piston and up the cylinder ports into the chamber.

    Dogging a two stroke can make even a properly jetted one run hot. Especially an aircooled. By spinning it faster and moving a lot more air it helps cool it better even though its making more fire in the top end. So you gotta get the RPMs where the engine ws built to run.

    Even in the summer a two stroke aircooled sled engine properly jetted in the proper RPM range the engine was built for that's not pulling some stupid oversized heavy load can run cool enough to keep itself together.

    Will it make as much power in the winter when its cold? Of course not.

    Liquid cooling is a better way to transfer heat of course. But either air or liquid sled engines will be fine as long as you obey the three majors. Jetting, Proper RPM's, and not oversized load.

    Most liquid cooled engines make more power than thier air cooled counterparts since they can remove the unwanted heat better. There are some balsy aircooled ones out there but the liquid cooled genrally make more power for thier size.

    Liquid cooling can also take a stick thur the radiator if its not protected well. Air cooling is a little more forgiving in that respect in the boonies.

    In a light weight buggy like you have that motor you have now running right will be faster than the buggy should probably go. Which is just about right!!!
    Now that NOBAMA has PROVEN he is the absolute WORST president in the history of history Jimmy Carter can thank him for stealing the dunce crown.

    Lets hope the next guy repeals NObama care along with the rest of the stupid crap this blight on our windshield has done.
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    Re: Need Help With Cooling Options
    #17
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    It sure is fast haha I've wanted to gear it down a little or declutch it so it has better lower end grunt, and because it already goes way faster than anything else we have on the peninsula I dont mind sacrificing a bit of top speed of necessary lol

    A buddy of mine is selling a mid 90s 440 fanner out of a Polaris sport I think it is. Do you think this would be a good option?
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    Re: Need Help With Cooling Options
    #18
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    If the price is right and it runs good and can be fit to your setup with a reasonable amount of work your cool with I see no reason it should not be OK.
    Now that NOBAMA has PROVEN he is the absolute WORST president in the history of history Jimmy Carter can thank him for stealing the dunce crown.

    Lets hope the next guy repeals NObama care along with the rest of the stupid crap this blight on our windshield has done.
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    Re: Need Help With Cooling Options
    #19
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    He said $200 (which is the same cost as a rebuild of the necessary parts, not counting ones that don't need to but could be replaced too) and he'll help us put it in and make sure it runs. It sounds like a decent option to me, the easiest and cheapest I've found so far anyway
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