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Engine Knock or something else?

Posted: Wed Jun 26, 2013 12:13 pm
by Hengy
Hi all...

I was perusing YouTube over lunch and came across this video. Is this an example of a really bad engine knock or is it maybe something else vibrating that I am not able to determine?

It is really loud and can be easily heard throughout the video and sounds like it is about to bust through the block...



Mike

P.S. - This is not my cub...

EDIT to fix Youtube link that I messed up.

Re: Engine Knock or something else?

Posted: Wed Jun 26, 2013 12:58 pm
by RaymondDurban

Re: Engine Knock or something else?

Posted: Wed Jun 26, 2013 1:01 pm
by RaymondDurban
Definitely an engine knock.

Re: Engine Knock or something else?

Posted: Wed Jun 26, 2013 1:05 pm
by John *.?-!.* cub owner
Could be rod slap, or could be carbon on top of piston hitting head, or could be valve with carbon on top, but whatever it is, it definitely needs fixed. i was gritting my teeth the whole time I was hearing it.

Re: Engine Knock or something else?

Posted: Wed Jun 26, 2013 1:09 pm
by Hengy
Thanks for fixing my link, Raymond!

John, I was afraid that we were going to see something explode out of the engine in that video!

Mike

Re: Engine Knock or something else?

Posted: Wed Jun 26, 2013 9:12 pm
by Clark Thompson
that is a wiped rod bearing. when it knocks real loud thats the pston hitting the head on exhaust stroke. It will throw the rod eventually.. im sure the oil oresure is almost zero too..

Re: Engine Knock or something else?

Posted: Thu Jun 27, 2013 4:36 am
by pickerandsinger
Time to get rid of the compression on that cylinder and run it on 3.....lol.....Dave