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engine knocking

Posted: Sat Oct 02, 2010 4:25 pm
by crowesnest3
Second question about 1980 1100, engine knocking .... mostly around 3800 - 4200 rpm ... its like, do I have a bad rod? ... but engine runs strong .... do have some faltering, but I really need to sync carbs .... valves have been adjusted and only have slight valve tapping ... engine kinda sounds like a bucket of bolts, although does go away at higher rpm .... could it be related to timing belt? .... which was replaced about 15000 miles ago. Ok, your turn ....

Re: engine knocking

Posted: Wed Oct 06, 2010 7:38 am
by virgilmobile
Uneven compression (eg.110-135-95-120)in my 83 caused acceleration rattle bad.Factory service limit is 8psi difference and 145psi/cyl.I could adjust the carbs to help reduce the noise but it had problems idling.Ended up rebuilding a spare block and changing the motor.You may have a similar problem,just worn out.Even with 150k miles it would still jump up and roar.

Re: engine knocking

Posted: Sun Oct 10, 2010 2:58 pm
by crowesnest3
only got 25450 on 1980 .... 20000 are mine

Re: engine knocking

Posted: Mon Oct 11, 2010 7:15 am
by virgilmobile
Does it knock under load(vacuum advance) or at free run?Can we hear it?

Re: engine knocking

Posted: Mon Oct 11, 2010 10:42 am
by crowesnest3
more under load, wouldn't know how to share sound with all although I know it can be done. Dealing with computer literacy. Also, thinking I may have narrowed the search done to water pump bearings. My search for the cause led me to realize that someone ( and I do recall taking her in for a coolant leak around water pump years ago, before I was doing most of my own wrenching ) installed a 10mm bolt were the weep hole is supposed to be! That sure would stop a " coolant leak"! And, of course when I went to pull the plug the head snapped off! So know I'm looking for someone to give me the approximate size of the weep hole so that maybe when I go to drill out plug I can get lucky and only reinstall weep hole. Been advised from guys over at Nakedwings.com that if weep hole is plugged any coolant that is supposed to weep out builds up in case and can ultimately blow out the water pump bearings. With that in mind, I gotta say that listening to the "knock" it definitely sounds to be coming from front of engine and is reminiscent of worn bearings or even the impeller wobbling inside case because of bad bearing. Gonna drain down and pull off lower radiator neck to see if there is movement in water pump impeller, if so, bearings shot n time to install new water pump and hopefully thats the only problem. I'll revise post once I know more.....and we wonder were the distrust of "qualified" mechanics comes from!

Re: engine knocking

Posted: Mon Oct 11, 2010 12:07 pm
by virgilmobile
:? If it is the pump bearings you'll have to pull the front cover to remove the pump.At that time it may be better to drill a hole next to the plug into the pump cavity.It is just a drain about 3/16".

Re: engine knocking

Posted: Mon Oct 11, 2010 12:10 pm
by virgilmobile
I don' have a pump but I do have the castings if your's are torn up