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hotwire

noise maker inside the 16

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hotwire
Hey Fellas, Once again i find the need to seek advise...... unfortunately. I was mowing this weekend with a one owner 1975 7013 (JC Penney version with a swapped out 16 horse Briggs) and in the middle of the lawn, she started making a noise (it was about 90 degrees and i had been hard at it for an hour). I was hoping a bolt or something had worked it's way loose so i took it to the garage and took off the hood and deck and restarted, the noise remains, and listening to it, it's inside the motor (i looked at all other bolted pieces on the motor and everything seems tight). I took off the head to see if a valve was obviously bent or something, but i cant tell. It's a tick, more like a CLACK really and it hits about 5-6 times a second. You know those noise makers you could buy that had a handle and you spin around? Thats what it sounds like. Any advise as to what i need to look for or what it might be? It doesnt sound like a rod, but then again, i've only ever heard a Pontiac 400 and a 2.0 4 cylinder with a rod knock, so, maybe on a small engine it sounds like that... i dont know. I realize this question is kinda crazy, "I have a noise, whats wrong", but i just need some kind of help. Theres a lot left to the mowin season here in NC and I dont have much cash i can put into it. So what are your thoughts fellas? i know some of us here have twisted some metal iside these before....... does this sound like what you did or what you heard? Need some help guys.... Thanks.

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DMedal
ditto what Dan said. Check the bolts that hold the driveshaft to the flywheel too. If those get loose it can cause this right before terrible things happen. If not too much work, drain your oil and run it through a fine screen. Did the noise seem to start suddenly or build slowly from inaudible to alarming?

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MPH
Kinda late now to do it, but was the noise high in the engine or down low. Reason I ask is I bought a gilson/wards with a 16hp briggs in it for cheap because the guy knew a rod was going, when I finally got him to start it for a moment before I'd buy I decided the noise was too high in the motor to be a rod. Turned out to be carbon build up and a can of rislon poured through it made one sweet running motor. You say you have a bent valve????? Have never seen one so I ask, how can you tell it's bent? Seems that would make the noise as it could be hitting the head on the high side of the bent.

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hotwire
Thanks for the replies guys! I didnt check the fly wheel bolts, I should have when i had the deck off, but it sure sounds like it's high in the motor. The tractor is so loud, it's hard to tell when the noise started, but as far as i can tell, it was instantly. MPH, thanks for the reply, no, the valve isnt bent (that i can tell) i took off the head to see if i could tell if it was or not (like if it was obviously bent or something) but everything "looked" okay with them. They seemed to seat nicely and there wasnt any buildup on them, but it sure sounds like it coming from up there. I was gonna spin it over a few times with the head off to see if i could hear more clearly..... Thanks guys... keep the idea coming. I'll look at it tonight again while its cool and see what i can see.

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PeppyDan
Remove the drive shaft and try it again. This would isolate it to the engine. If it has the generator /starter carefully remove the belt by loosening the G/S once it's running, this would elimainate the G/S. Dan

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hotwire
I again took the deck off last night and checked the bolts to the shaft and everything else down there I could see and restarted. It was still there. It really sounds like the engine. Dan, I will take the shaft off tonight and also try to loosen the belt of the S/G without losing a finger. ;-) If I do that and still have the clack, then i'm going to pull the motor out and start disasembly. I hate to go into it blind, but i need it fixed. I'm hoping that maybe somethinig under the cover is hitting, but when i listen, it sure sounds like it's inside.... i guess we'll see. So........ if I were to get a rebuild kit, what source would you guys suggest? Also, any material / manual that you would suggest to follow for the rebuild? I've never done a small engine, but i have done a few V-8's........ Hoping that will help.

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comet66
quote:
Originally posted by hotwire
Dan, I will take the shaft off tonight and also try to loosen the belt of the S/G without losing a finger. ;-)
Make sure bolts are loosened up a bit before you start the engine. Start, then carefully loosen it up. The belt may pop off by itself, if not a screwdriver can flip it off. All without putting your fingers in danger.

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powerking_one
Brad, I would venture to say that the clacking noise could be due to cracked/broken piston skirt or broken ring land. I have seen these 12-16 cast iron motors encounter this failure before. One really can't tell without tearing it down and doing an official autopsy. Tom(PK)

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hotwire
Thanks for the replies so far guys, it's really helping. I took the motor out this weekend and when i took off the sump base, first thing i notice is that the Oiler (i guess it's the oil slinger) was loose on the rod cap and the rod bolts were free to spin by the touch of a finger. The rod bolts have the lockers on them (the metal tab with the edge turned up to prevent the bolt from spinning) but still were very loose. There was play between the cap and rod. I dont assume it should be this way, but i dont have the torque specs for the rod bolts. Can someone tell me what the spec is and if that amount of play is supposed to be there? I'm thinkin not. Thanks!

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hotwire
grass is growing and the motor aint purring..... ;-) pulled the piston and rod out last night. Piston skirt is fine, wrist pin feels tight, crank "looks" good. Went to put the piston back in, and half of one of the rings fell off the piston. I have to assume it was broke in the motor before i pulled it out, cause i just pulled it out, looked at it and went to put it back in and the piece fell off........ so....... could this be what i was hearing? would you be able to hear a broke ring?

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Cvans
Yes although it should have come at a higher frequency than you described in your first post. It would be more of a clicking sound and occur with each revolution of the crank and can be hard to hear. If left the noise will get louder as the ring groove continues to wear and the ring land will eventually fail. The cylinder will also take a beating.

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briggs9498
I would say that most of the noise you heard was from the rod cap being loose. Now I know you said the crank journal looks good but how does the connecting rod journal look as that would be the first thing to get harmed.

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hotwire
thanks for the replies fellas. I didnt mic the rod or crank, but looked at them and they are smooth and shiney..... like it should look, nothing pitted or chewed or scratched. I guess I'm gonna check the land around the rings, get a new set and put it back together and see what happens on the bench. If anyone else has anything to add, i'd love to hear it.

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msiebern
Before you put the new rings on, clean out any carbon deposits on the piston behind the rings. They make a ring groove cleaning tool, but that might be a little pricey for just one piston. You can use one of the broken rings to clean out the carbon if you are fairly careful.

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