300ex noisy top end

[arsenal35]

just got done rebuilding a basket case 300ex I bought. fired it up and the top end is noisy as all get out. I started trouble shooting and seen it has a web 236 cam in it thought it might be too much for the springs so i swapped it out for a stock cam still the same thing I checked valve tolerances a hundred times set them .004 any suggestions as to what else it could be i'm open to suggestions

[smr]

most likely timing chain. When you put the tensinor back in are you sure it engaged?

[arsenal35]

yeah it engaged becouse when I swapped the cam I had to take the tensioner out to get the cam sprocket loose from the cam plus I could look down in the head and see the tensioner putting tension on the chain

[Grimzella]

rocker arms maybe? exhaust header nice and tight? piston (wrist) pin tight? valve stems and guides ok? does the cam bearings fit nice and tight? does the cam rock or move from wear in the cam rests?

[smr]

unbolt the tensioner from the jug. see ho far it pops out. you should get at least 1/4 inch. If it don't then replace your timing chain.