so, is there a ring groove without a ring?
another thing that might cause all four valves to hit, is if they put a standard piston in with a stroker crank? no?
should finish disassembly and check everything. I wouldn't trust anything that was said to be done to that engine or most others that I couldn't be 100% sure it was assembled by one of the sponsers here or even a couple members. You got it tore down this far, i would want to be sure without a doubt it has the Z400 bearing in it and crank is balanced correctly.
Motor Breakdown
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Canniboomer
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The intake cams are hitting harder, and maybe then cocking the piston a bit so the exhaust valves are also making contact. And maybe the cam gears were re-installed by following a non-corrected Service Manual for pin locations.
You can visually check if the markings on the cam gears are aligned with the points of the cam lobes.
The piston has the correct rings -- the rather shallow groove is just part of the casting, and likely done to remove some weight where it's not needed.
You can visually check if the markings on the cam gears are aligned with the points of the cam lobes.
The piston has the correct rings -- the rather shallow groove is just part of the casting, and likely done to remove some weight where it's not needed.
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who_gives_a6
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I'm no guru but what makes the valves bad? Just the fact that they were rubbed on or what exactly keeps them from being usuable? Not complaining about advice, just curious. Same thing with the piston. That little bit of wear makes it unusable or still good to go? Should I be worried about the cylinder wall markings or is that just normal with these?
May just be better off sending some parts to someone who knows what they're doing and have them look over/install new parts if necessary. All depends on what that would cost though.
May just be better off sending some parts to someone who knows what they're doing and have them look over/install new parts if necessary. All depends on what that would cost though.
Your last sentence makes the most sense to me.
Personally I would not trust a piston or valves on a head when they could be bad or bent without someone looking at them. Have someone look at it, that stuff would cost you under $20 round trip to someone to inspect. That alone is worth the piece of mind. What if you put it back together as is and the thing grenades bad due to one of those small things that could have been prevented? Spend a little now to save a lot down the road. It is worth it tohave that priceless smile when it is running like a top and you know everything is sound. Just my $.02
Personally I would not trust a piston or valves on a head when they could be bad or bent without someone looking at them. Have someone look at it, that stuff would cost you under $20 round trip to someone to inspect. That alone is worth the piece of mind. What if you put it back together as is and the thing grenades bad due to one of those small things that could have been prevented? Spend a little now to save a lot down the road. It is worth it tohave that priceless smile when it is running like a top and you know everything is sound. Just my $.02
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cannondale27
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who_gives_a6
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Canniboomer
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Since it has not even fired yet, I think you might be alright (except for some cosmetics) after the cam alignment and timing is corrected -- That CP Kit is way too pricey $$$ to give up on yet, and you should send it off (to Timbo?) with the sleeve to be sure. But you might also worry about the starter one-way bearing, if that has been torqued over so hard for all those attempts in the past 2 years! -- hopefully that unit is still OK. The fact that the motor did not bind up at TDC at the low speed of turnover would indicate that the strain on the piston and valves was not so much, and you might be lucky. But if the motor actually ever idled?, and you could assume a typical 3000rpm cold, then there is plenty more risk with the other components.
Your problem points out how important it is to turn a motor over by hand several times, before assuming you can power-crank on a rebuild. Or even the motor builder would have noticed that hard spot on the bench. If something is not right, you can certainly feel it through the wrench handle....and after it's in the frame, even slow hand-turning speed at the flywheel nut will actually pre-oil the motor without pulsing fuel yet -- 20 times is good, and it's probably something we should all do more often..
Your problem points out how important it is to turn a motor over by hand several times, before assuming you can power-crank on a rebuild. Or even the motor builder would have noticed that hard spot on the bench. If something is not right, you can certainly feel it through the wrench handle....and after it's in the frame, even slow hand-turning speed at the flywheel nut will actually pre-oil the motor without pulsing fuel yet -- 20 times is good, and it's probably something we should all do more often..
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MX Quad Dad
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QUOTE (Canniboomer @ Dec 16 2010, 06:46 PM) <{POST_SNAPBACK}>
Since it has not even fired yet, I think you might be alright (except for some cosmetics) after the cam alignment and timing is corrected -- That CP Kit is way too pricey $$$ to give up on yet, and you should send it off (to Timbo?) with the sleeve to be sure. But you might also worry about the starter one-way bearing, if that has been torqued over so hard for all those attempts in the past 2 years! -- hopefully that unit is still OK. The fact that the motor did not bind up at TDC at the low speed of turnover would indicate that the strain on the piston and valves was not so much, and you might be lucky. But if the motor actually ever idled?, and you could assume a typical 3000rpm cold, then there is plenty more risk with the other components.
Your problem points out how important it is to turn a motor over by hand several times, before assuming you can power-crank on a rebuild. Or even the motor builder would have noticed that hard spot on the bench. If something is not right, you can certainly feel it through the wrench handle....and after it's in the frame, even slow hand-turning speed at the flywheel nut will actually pre-oil the motor without pulsing fuel yet -- 20 times is good, and it's probably something we should all do more often..
Your problem points out how important it is to turn a motor over by hand several times, before assuming you can power-crank on a rebuild. Or even the motor builder would have noticed that hard spot on the bench. If something is not right, you can certainly feel it through the wrench handle....and after it's in the frame, even slow hand-turning speed at the flywheel nut will actually pre-oil the motor without pulsing fuel yet -- 20 times is good, and it's probably something we should all do more often..
10th post, last paragraph. he said the preveious owner admitted to putting a 1/2 ratchet on it to turn it over. now this doesn't mean the guy had to stand on it, but it should be inspected very closely. He should be able to pour some fluid in the head to see if valves still seal.