Questions and Answers

Chevy Caprice Crankshaft Bolt Q. Dear Mr. Ciulla: I'm fairly knowledgeable about auto work and I use to be able to get advice from my father, who had about fifty years of experience. But he died a couple of years back. I wonder if you could help me with a somewhat mysterious thing. I am attempting to install a timing chain on a 1991 Chevy Caprice Classic 305 VIN "E".

I am attempting to turn the engine with the crankshaft bolt to align the timing marks. Now the bolt came out fine when I removed the harmonic balancer, yet when I attempt to put it back it won't go. It's as though the bolt got bigger! I check to make sure the was no obstacle and there isn't. The bolt and the crankshaft aren't damaged. The bolt should go on but it won't.

I've put on one timing chain before (on another car) and never ran into this. Am I missing something? In my Chilton's it mentioned a crankshaft key and I'm not sure what that is and if it has anything to do with this. I've asked many mechanics and they didn't know. Anything you can tell me would be greatly appreciated.

David

A. Well to get that balancer off you had to use a puller. It was pressed on, right? So maybe the puller bolt messed up the threads in the crankshaft? The "crankshaft key" is a little piece of key stock that goes into a square cut grove in the front of crank. This key keeps the balancer hub from spinning on the nose of the crankshaft. It can only be put on one way so the timing mark is in the proper spot.

I would suggest getting a thread tap for the crank bolt and make sure it threads into the hole. I'm guessing the threads are buggered up and need to be chased. You can turn the crankshaft from under the car at the flywheel.