Rebuilt engine knock...

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Scrivet
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Re: Rebuilt engine knock...

Postby Scrivet » Tue Sep 08, 2015 9:36 pm

Could the overflow just be that it was a little overfull? By your account in the initial post
CraigKennedy wrote:..... cranked up and let run or 5 minutes, everything was going fine, I idled it up to high idle for a few minutes, It started knocking so I quickly cut it off. I noticed that as soon as it started knocking the overfill hose on the radiator shot out a half pint of antifreeze....
five minutes of idle and a few minutes of high idle should warm it up a little. Maybe it was just coincidence that it knocked and burped at the same time.

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Re: Rebuilt engine knock...

Postby CraigKennedy » Tue Sep 08, 2015 10:11 pm

Scrivet, I only added coolant til I saw it at the bottom of the neck of the radiator, I still don't know myself if those two actions were related or consequence

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Re: Rebuilt engine knock...

Postby Matt Kirsch » Wed Sep 09, 2015 2:54 pm

If you saw it at the bottom of the neck of the radiator, you overfilled the radiator. There should only be enough coolant in the upper radiator tank to cover the tubes, which you can see by shining a light in at a steep angle to one side or the other.

With the bearings looking like that, I doubt you're going to get away with just rolling in a new set. The crank is going to have to come out.

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Re: Rebuilt engine knock...

Postby artc » Wed Sep 09, 2015 3:19 pm

if the crankshaft / cam /idler gears are worn badly you can get an odd knock in the motor, and given that you used assembly lube and probably smeared some on the gears, when it wore off the knock started. if all your bearings are in spec to the crank, or if you had the crank polished or turned, and you have oil pressure, then the problem is not there. What did your front gear train look like?

the motor i had was just rebuilt by a PO, and then gotten rid of when they could not figure out the knock.
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Re: Rebuilt engine knock...

Postby CraigKennedy » Wed Sep 09, 2015 5:14 pm

artc, gears were all good, had something come up today, really hoping to take head off tomorrow and have a look

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Re: Rebuilt engine knock...

Postby CraigKennedy » Tue Sep 22, 2015 6:24 pm

Guys, sorry I haven't keep you posted sooner, been busy lately. I took the engine to another machine shop and they said that everything checked out ok, and told me to reassemble it, and crank it up, If I heard anything else to call them and they would make a house call to hear it.
I'm going to be putting a few pieces back together tonight, hopefully I can get it back in and cranked up by the weekend.
Will keep you posted

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Re: Rebuilt engine knock...

Postby CraigKennedy » Wed Sep 30, 2015 11:06 pm

Guys, heres a update on my little red tractor, I've been putting it together little by little, got everything done a little while ago, cranked it up and ran fine for 30 minutes then it started making the same sound as last time, matter of fact it sounded like it was about to lock up, had good oil pressure, had enough oil, and antifreeze. I cut it off as soon as I heard it. Ive leaving on vacation friday, going to talk to the guy at the machine shop and see if he can make a house call sometime next week. Will keep updating

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Re: Rebuilt engine knock...

Postby ricky racer » Thu Oct 01, 2015 4:36 am

Thanks for keeping us posted. This will be a learning experience for all of us. Enjoy your vacation.
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CraigKennedy
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Re: Rebuilt engine knock...

Postby CraigKennedy » Thu Oct 08, 2015 2:36 pm

Guys, finally got back from my vacation and I was out here trying to see what is going on with my lo-boy, I've had it start knocking twice. 1st time was after 20 mintes at high idle and let set for 15 minutes, cranked back up and let run for 10 minutes, started knocking again. I noticed that my oil gauge dropped from 35 to 29 psi, thats when the knocking starts, any idea what it could be? Oil relief valve maybe? Machine shop guy couldn't make it today and I was trying to pin point the problem myself, thanks guys, Craig

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Re: Rebuilt engine knock...

Postby Eugene » Thu Oct 08, 2015 5:32 pm

Not an oil pressure relief valve malfunction. Engines will run fine with much lower oil pressure.

Engine running and knocking. Disconnect one spark plug wire at a time. If knock disappears, that is the problem cylinder/area.

Gut feeling, one rod bearing is over sized or you have a bad bearing insert. Perhaps out of round journal.

Something else to check. Ignition cross firing. Mechanical advance,
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Re: Rebuilt engine knock...

Postby CraigKennedy » Thu Oct 08, 2015 7:39 pm

Eugene, All the rod and main journals are .10 over, crank was checked at another machine shop and was called good, could the timing be off just a hair and cause knocking? the crankshaft, cam, and idler gears were lined up when reassembling, do you think the the battery ignition could be off causing it?
Will check out some tomorrow and keep updating
Thanks, Craig

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Re: Rebuilt engine knock...

Postby Eugene » Thu Oct 08, 2015 8:24 pm

Ignition timing could cause a ping/knock. Timing could cause a knock if one cylinder were firing before TDC compression stroke.

Ignition timing is easy to check.

Try pulling one spark plug wire at a time when engine is knocking. If isolated to one cylinder, change the spark plug.

Could be a hot, red hot, protrusion igniting the fuel air mixture before TDC.

I previously read and understand that you had the engine mechanically checked by two different firms. If the problem is not ignition related, most likely it's a mechanical problem.
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Re: Rebuilt engine knock...

Postby CraigKennedy » Sat Oct 10, 2015 12:44 pm

Eugene, i went out to the tractor earlier, after 45 minutes it started knocking. Pulled each sparkplug wire off, didn't clear up, but it is running on all cylinders, any other suggestions? I suppose eventually Ill find the problem,
Thanks Craig

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Re: Rebuilt engine knock...

Postby SouthernOutlaw » Sat Oct 10, 2015 1:20 pm

Have you checked the piston clearance. Piston skirt slap will sound like a problem wirh the crank shaft. Normally will start after a motor is warm to operating temp. I notice you dont hear it until after the motor has been running for 15 minutes or more.

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Re: Rebuilt engine knock...

Postby CraigKennedy » Sat Oct 10, 2015 11:06 pm

Southern Outlaw, please explain,
Thanks craig


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