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I purchased a 496 to replace my 454. Unfortunately, the seller didn't have the specs on it. It came with the old external harmonic balancer but I thought 496s were internally balanced.
Long story short, I added an externally balanced flywheel, broke in the cam for 20 minutes and everything seemed fine. I timed it to 36 total then drove it 40 miles to continue break in.
When I got back home I noticed a moderate noise from the front of the engine and I found the balancer is making a loud tapping noise and shaking.
Is this a symptom of an external flywheel on an internally balanced crankshaft?
Here are some photos of the crankshaft. Can you tell from these whether the crankshaft is internally balanced?
Could be either way. See if you can find a part number on the crank and go from there. Eagle crank is etched into the front counterweight-- Was there a really big weight on the flywheel flange of the crank? Mine is internal balance and I had to cut the hole in the block plate way out to clear it. I don't have a good picture of the rear of the crank, but here's what the numbers look like. https://drive.google.com/file/d/0B7D...ew?usp=sharing
Apparently, I may have had a false alarm. I retorqued the balancer bolt, it seemed tight already. Neither the balancer nor the crank pulley were loose when I tried to shake them. I started the car and observed no vibration on the crank pulley. The engine idled smoothly and when I revved it there was a slight noise.
I shut it down and grabbed the water pump pulley and there was a slight fore to aft give. I tightened the bolts but it still has a little movement. I'm guessing the water pump shaft is worn and the pump needs replacing.
Kris- your crank is externally balanced- ddawson's crank has the extra weight on the flange for internal balance.
Thanks for the confirmation. I figured as much after seeing ddawson's flange. I feel a lot better now! I'm ordering a new water pump as I think mine is on it's last leg.
Engine help needed
