Small block open clone

Bigred28

Member
What could be a make a ticking / rattling noise in the lower block … crank has been shimed and everything only other guess could be the camshaft .. thanks for y’all’s input
 
Some aftermarket cams have lobes that with that will rub against the crank counterweight. Some dont, some do. It's not much and a grinder to the edge of the lobe or counterweight fixes it. Sometimes excessive crank thrust will let this happen. I would first check the crank endplay then go from there. A lot of cam companies notch the cam themselves but not all. Usually you need to yank the sidecover and rotate the crank to see whats going on.
 
As already mentioned the cam lobes hitting the crank . Or could be the rod touching the block as the piston is on its way back down from TDC . Ive seen some blocks that wasnt clearanced there
 
Also check to see if plug is hitting piston it will sound like it's coming from the bottom end too don't ask how I know that one lol
 
Does it only do it while running , or can you hear it when cranking on it with the starter ? Did you check all of your clearances ?
 
Do not know . Its the casting flash . Not the journal itself .
How much have you ran it .
If several races you might be lucky . An its nothing .
Or you may need a broom and dust pan soon .
 
This from a engine noise discussion .
So a little update. I ended up shimming the cam from .029 end play to approx .005, and it did totally silence the noise for about 15 minutes of break in time. then I changed oil and went to go for a rip, first time I revved it up the noise came back. I said screw it and took a couple easy laps up and down the street. The noise goes away as it rev's it up so thats weird. Or its actually getting totally drowned out by other noises Im not 100% certain, but it sure seems to get quieter with higher rpm.

Once I get some more free time and motivation I will tear the engine back out again and open it up. Its a pain in the butt to pull the engine on this golf cart all the time. Im not sure if the case could have worn in a little bit, or the shims might have got ripped out somehow, no clue.
 
Maybe higher rpms make the crank shift ride to one side? I have just taken a grinder to the counterweights and removed material. Didnt want to and I was fearing a balance vibration but it was fine. I have also just ran it that way and it seemed to be self clearancing lol. It got quiet. I also have had a couple of cam swaps that made a lobe nick the bottom of the cylinder in case you havent checked there. Dremel fixed that.
 
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