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Knock Knock
Posted: Sat Jul 13, 2019 6:11 pm
by D.Yoder
for three years I have tried to trace down a knock that has bugged me since I built it.
Think I found it.
Re: Knock Knock
Posted: Sat Jul 13, 2019 6:21 pm
by KeithG
Dean, It's great that you finally found it, but are you going to share what you found with the rest of us?
Thanks,
Keith
Re: Knock Knock
Posted: Sat Jul 13, 2019 6:29 pm
by Burger in Spokane
I am guessing it was the use of plywood behind the electrical panel (?).
Re: Knock Knock
Posted: Sat Jul 13, 2019 6:42 pm
by Les Schubert
Having no information, I’m guessing cam shaft end play!! It can really drive you crazy!!
Re: Knock Knock
Posted: Sat Jul 13, 2019 7:24 pm
by D.Yoder
After I drive it and am positive what it was I will share .no one has hit it yet
Re: Knock Knock
Posted: Sat Jul 13, 2019 7:33 pm
by Tony_H
Re: Knock Knock
Posted: Sat Jul 13, 2019 8:11 pm
by Kerry
Now I'm sure everything would have been sweet when Dean rebuilt the engine so I'm putting my money on a sneaky little knock on the scat hitting the pan horse shoe or one of the bolts holding it.
Re: Knock Knock
Posted: Sat Jul 13, 2019 10:39 pm
by D.Yoder
Not the scat crank hitting .checked that couple years ago.
Re: Knock Knock
Posted: Sun Jul 14, 2019 9:37 am
by Adam
Rod bolt barely tapping the cam? Loose flywheel bolt?
Re: Knock Knock
Posted: Sun Jul 14, 2019 12:05 pm
by D.Yoder
Not the rods. I have checked them three times
Re: Knock Knock
Posted: Sun Jul 14, 2019 12:12 pm
by D.Yoder
Flywheel bolts so tight I thought I was going to have a cheater bar to get them off.
Re: Knock Knock
Posted: Sun Jul 14, 2019 5:31 pm
by Joe Bell
Had one that drove me nuts, .060 over Egge's with the sharp edge on side was hitting head gasket, Another one was piston hitting top of cylinder on high rpm's with High Compression head.
Re: Knock Knock
Posted: Tue Jul 16, 2019 10:27 am
by aDave
Ohhhh - the suspense....
Anxiously awaiting the answer...
- suspense.jpg (10.01 KiB) Viewed 9035 times
Re: Knock Knock
Posted: Tue Jul 16, 2019 10:53 am
by ShirkWood
Bent rod or piston slap?
Re: Knock Knock
Posted: Tue Jul 16, 2019 8:58 pm
by HaroldRJr
Crankshaft pulley/pin assembly?
Re: Knock Knock
Posted: Tue Jul 16, 2019 10:34 pm
by D.Yoder
Removal of one shim cured my knock.
Re: Knock Knock
Posted: Wed Jul 17, 2019 12:26 am
by Kerry
Sounds like you were lucky that your engine didn't eat the magneto
Re: Knock Knock
Posted: Wed Jul 17, 2019 9:45 am
by aDave
Interesting.
So, for further education, why was the shim installed? For some reason it was put there....the result was not to your liking - (nor to the engine's)...is there a lesson to be learned here that you can share with us?
Incidentally - many thanks for the expertise you have shared in the past!
Dave
Re: Knock Knock
Posted: Wed Jul 17, 2019 1:33 pm
by D.Yoder
Dave the biggest lesson is 25- 40 clearance loose
25.
The shim I used is a factory shim.
I made it too tight.
Scat cranks have a large radius fillet if I am setting another scat. On the tight end I will check my radius fit with plastigague.
Re: Knock Knock
Posted: Wed Jul 17, 2019 2:57 pm
by aDave
Thank you.
Another lesson I hope to file away between my ears. (But I will write it down to count for the inevitable "forgetfulness"
