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noisy motor
Topic Started: Sep 30 2013, 08:41 PM (1,347 Views)
garyc1955
Member
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Installed rebuilt motor today ,has a loud knock,sounds somewhat like a loud diesel.Stethoscope suggest a upper end knock .Oil pressure as indicated by light seems ok.Will replace my broke gauge tomorrow and check it. Noise was from the start so am disinclined to think oil pressure problems.Block was decked but did not note any piston protrusion.Motor runs beautifully otherwise.Would incorrect placement of rods cause a knock?Noise does not change tone with rpm nor with cancelling cylinders one at a time.Any guesses ?Gary
1964 cj3b ,extremely rust free seems mostly unmolested and starting a restore in southern New Mexico
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Ratchet
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Check the valve tappet clearance.
Georgetown, IN
A little less rust and a 53 CJ3B
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Motiv8
Member
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If the knock is there while idling, pull one spark plug wire at a time and see if you can isolate it to that cylinder. Usually a loud knock is rod brg clearance, but could be other things. It won't necessarily reflect in oil pressure readings unless you have a known baseline. I've seen bent conrods cause a noise like that. I've seen new pistons w/ wrist pin not square to skirt. Push down the clutch pedal, see if sound changes. Possibly a wrong size brg insert was installed and not ck'd for clearance. There are so many things it could be, but this should give you a starting point. David
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div4gold
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Was it professionally rebuilt? If so I'd get ahold of them before running it any more.
Old retired fart living in Ione, WA. I have a 1964 CJ3B. Recently overhauled original motor, transmission and overdrive. 11" Bronco drum brakes on all 4. Needs a new coat of paint but that will have to wait till next summer, it's next summer and I'm working on that now :) UPS & FEDEX will continue to profit :)
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oldtime
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All previous replies are correct and potentially valid.
You need to help us narrow down the many possabilities.
Please indicate known engine rebuild history and all recent repairs.
Currently building my final F-134 powered 3B .
Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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garyc1955
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Can anyone tell me if correct oil pressure can be measured at the port where the feed tube is for the cylinder head . I now know that the correct place to measure pressure is at the hole below the cylinder head feed.I showed 15 # of pressure prior to teardown and then found out I was possibly using the wrong port.After the teardown of course. I see nothing else wrong with this noisy motor .Everything checks out fine, oil clearances ,assembly procedures and all galley plugs are in .Oil pump is not new but was checked carefully Any thoughts on how to spin oil pump on the engine stand and check oil pressure and watch where oil might be escaping?Still to my satisfaction I found no reason for the noise.This motor came out of a 62 m38 I was told It had been rebuilt once upon a time,and had o/s pistons and undersize crank bearings. I replaced rings and bearings ,decked the block ,did a valve job ,honed the cylinders ,had new cam bearings and hot tanked the block.I have rebuilt probably a hundred motors and never had such problems especially one I could not find Regards Gary
1964 cj3b ,extremely rust free seems mostly unmolested and starting a restore in southern New Mexico
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Motiv8
Member
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Is flywheel tight onto crank? Possibly a piston is installed backward. The pin offset will cause a "piston slap". See if you can force crankshaft fore and aft ck'ing excess end play. Is the noise a steady beat or uneven erratic ? Does it change w/ a bit of load or acceleration? Try putting in gear and just off idle put a little load on the engine and note any difference. Is the noise more or less when hot or during first few minutes? David
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Motiv8
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Adding to prior post. During early '50s I installed the whole set of pistons w/ thrust side opposite. I've always been confused w/ left and right, driver's and passenger side, major and minor thrust side. Have to think more than twice. Gets worse with age.That eng DID have that diesel sound that you earlier mentioned. We actually would do that in some racing classes where stock pistons were required. Since then, I design my own w/ varying pin offset. David
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Bruce W
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Something dropped in a spark plug hole? We sure hope not, but it wouldn't be the first time! BW
Bruce Walker
Northeast Colorado
'53 CJ3B "Nellybelle", '48 CJ2A "Uncle Lyndon", '47 CJ2A "Teddy", '47 CJ2A "Rusty", '47 CJ2A "Zak", '43 GPW "Sarge", '88 XJ "Pluto"
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Motiv8
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Bruce W is right on w/ his post. Often it's a little screw from the throttle plate or choke plate. Or something was in the intake porting. Common in intake manifolds when an eng has blown and pieces scatter. David
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oldtime
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Gary,
I merged your oil pressure question into this topic because it is essentially the same topic.
Yes all ports (1/8" NPT plugs) along the main oil gallery can be used to tap into the oil supply and those ports will all read oil pump output pressure.
I suggest that you prime the oil gallery before starting engine.
Plumb an oil pressure gauge directly into the oil gallery.
It must read adequate oil PSI within 3 or 4 seconds after starting the engine or else shut it down.
Currently building my final F-134 powered 3B .
Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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garyc1955
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Short story is cam thrust plate broke I guess cam was jumping around? Spun oil pump sans gear and had no pressure at the head oiling port and lots at the ops port.The first port is almost at the ass end of the lube system .Pressure must be measured immediately after the oil pump.So now have a quiet motor and 40 pounds at a warm idle.Thanks for all the thoughts and replies Gary
1964 cj3b ,extremely rust free seems mostly unmolested and starting a restore in southern New Mexico
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oldtime
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Breaking the bronze thrust plate is virtually unheard of.
Thanks for the update !
Currently building my final F-134 powered 3B .
Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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garyc1955
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For what it's worth the plate was steel
1964 cj3b ,extremely rust free seems mostly unmolested and starting a restore in southern New Mexico
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dos equis
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congrats on finding the problem pain in the butt pulling it apart again but now you are double sure it is right.xx
1953 willys cj3b,1998 4.3 chev vortec v6 fuel injected,1965 sm 420 trans,11.5 gm clutch, 538 diffs,11x2 brakes,950x33x15 super swampers on 15x8 rims with 2 inch backspace,saginaw power steering,
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