Thread: knock noise

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so I guess that you did go back and read all of post #8?

Yes but apparently not close enough. I vote post 8 gets moved to post 2!

Apparently the balancer that the previous owner used is for a 305, found some junkyard writing on it and verified it on the autozone website according to size. After pulling the balancer I found damage to the crankshaft that extends back about a 1/2 inch and maybe 1/8 deep but not affecting the keyway. Looks like somebody installed it with a hammer yikes. I would suspect that theres more damage but think I will shell out the 50 buck for a new one and see what it sounds like.

hopefully the crank isn't cracked at main web

Yep, My hope is the visable damage is the only damage. I have only had the truck for a couple of weeks but it seems to have a lot of power and it always starts up really quick, along with a good compression test I am hoping I get lucky!

Well, after pulling out the crank key the crank slot just about disintegrated, so assuming (Big Assumption) that everything else is in ok shape ( I know wish full thinking) Whaelset do I have to replace when I replace the crank Or should I just save the heads (good Comp Test) and scrap the rest?

Probably time to consider a short block, but definitely need to tear it down.

if its just the crank key area----------the later LT engines don't even use a keyway in the dampners/snout but do fit on very tight---You need an install tool kit to put those Chev dampners on properly and that doesn't just mean a big hammer and block of wood-


You can start and run the engine without the front cover or dampner /pulleys to verify that the knock/noise is gone-----------if it is then why not try a replacement dampner installed correctly?

Jerry, if the knock noise is gone but the keyway area has significant damage, is it a good idea to put a dampner on it. At the risk of sounding stupid ( to late) is there any sort of repair kit for this situation?

You need an install tool kit to put those Chev dampners on properly and that doesn't just mean a big hammer and block of wood-

At the V-8 engine plant in Flint Michigan where I worked for 34 years the harmonic balancer was pressed on with a hydraulic or pneumatic hand held press. This operation was the process on the assembly line, but off line, if the balancer was removed for some sort of repair it was routinely put back on with a few whacks of a large plastic mallet. If I had a dollar for every one I personally put back on this way I'd be a millionaire instead of a hundredaire!

Bulletproof damper install:
Break up dry ice into chips, place loosely in plastic storage bag. Wrap around crank snout. Let cool for 1/2 hour.
Put the damper in a pot of water on the stove, bring to a boil. Remove damper with oven mitts.
Remove dry ice from snout. Insert crank key. Slide damper onto snout. If damper is proper clearance (0.001"-0.0015" interference fit), damper will slide all the way on and "thunk" against the crank drive gear.

Note: interference fit dimension is critical.

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