289 rebuild ?
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Senior User
Joined: Dec 2004
Posts: 132
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From: Warrenton, Mo
289 rebuild ?
Hello all, I just finished the short block on my 289 rebuild and had a question. ( BTW This is my first engine rebuild that wasnt a motorcycle). The rotating assembly is extremely hard to turn with the pistons installed. I figured it would be a little tight but it is all I can do to turn it with a regular length wrench( I know I really need a longer breaker bar)I have checked all rings for proper gap and lubed all bearings with the proper assebly lube, but the sucker is tight. Is this normal? Shoud I just get a breaker bar and keep going, or might there be something wrong? I spun it after every piston was installed just to make sure and it got progressively worse after each hole was filled. Any advice from experienced engine builders would be greatly appreciated.
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
There is quite a bit of friction from the pistons and rings, but it shouldn't be quite as bad as you describe. some things that occur to me:
What kind of rings did you use? Are they made to fit right out of the box, or are they file-fit? You said you checked the end gaps, they should be in the neighborhood of .016" on the top ring, .010-.012" on the second ring with most rings for a stock or mild performance rebuild.
Was the engine bored out and are these new pistons? Did the machine shop properly hone the cylinders to fit the pistons? Did they tell you the piston-to-cylinder wall clearance, and did you check it yourself? Cast or forged pistons?
Did you Plasti-gauge the rod bearing clearance on the crank journals? Is it a reground crank, and did you double check the size stamped on the bearings to make sure it's right for the crank?
All these clearances must be right or you start running into problems, anywhere from tightness like you describe to total locking up of the motor.
What kind of rings did you use? Are they made to fit right out of the box, or are they file-fit? You said you checked the end gaps, they should be in the neighborhood of .016" on the top ring, .010-.012" on the second ring with most rings for a stock or mild performance rebuild.
Was the engine bored out and are these new pistons? Did the machine shop properly hone the cylinders to fit the pistons? Did they tell you the piston-to-cylinder wall clearance, and did you check it yourself? Cast or forged pistons?
Did you Plasti-gauge the rod bearing clearance on the crank journals? Is it a reground crank, and did you double check the size stamped on the bearings to make sure it's right for the crank?
All these clearances must be right or you start running into problems, anywhere from tightness like you describe to total locking up of the motor.
