I have a 1 pc rms 383 that was internally balanced. I purchased a hays flywheel #10-530 to go with it. My question is does the flywheel need to be balanced to the new bob/counterweight? The flywheel is for 86-up 350's, so I assume the weight attached to the flywheel is setup for the 350? With a internally balanced 383 does that counterweight on the flywheel need to be setup with the new rotating assembly?

The new engine has a wicked vibration from idle on up, can't get above 2000 rpm without the whole car feeling like its going to shake apart. The balancer I believe is right, there are no weights attached to it, and I checked the part number, so all seems right there. No misfiring, I have checked spark on all cylinders so that seems fine. I'm leaning toward something with the flywheel or clutch?

thanks.

 

Sounds like a question for your machine shop. Only they can tell you what they did, and what they were expecting you to bolt up behind it.

They SHOULD HAVE left it such that a stock flywheel would balance with it correctly. But no one can possibly know how they left it, besides them.

 

What you are describing sure sounds like something is not properly balanced. Don't drive it or you'll probably screw something up bad...

All one piece rms flywheels and flex plates have some imbalance in them (check a stock flex plate, they have additional weight welded on them).

Check with your machine shop about whether you specically need a neutral balanced flywheel vs a stock one. You may find out really quickly that the machine shop may need to neutrally balance the flywheel to have it work right.

 

Yea, something is definitely out of balance. I have not driven the car at all. Barely has any run time, I tried to get the idle adjusted, but the vibration put that on hold. I got timing adjusted, but that was it.

I've been trying to get in touch with my machine shop this afternoon, I guess he's out.

Is it unheard of to have a totally internally balanced one piece rms crank and use a neutral flywheel? I'm thinking that I might need a to have my flywheel neutral-balanced.

 

When it comes to balancing, NOTHING is "unheard of". I've seen some of the wackiest things imaginable, crap that even a 2nd grader would look at and know was bogus, done in the name of "balancing".

We'd all love to be able to look inside your motor for you and tell you what they did; but unfortunately I think it's a little too far from your monitor right now. My view of your crank counterweights is too fuzzy to be sure of what I'm seeing.

Hopefully it'll be something simple, like, the doof that did it, didn't know that a 1-pc crank has the back half of the internal balance weight for the 7-8 journal mounted on the flywheel instead of the crank flange; and he just hacked on something else in there until it was "neutral", without the rest of the externally-mounted internal balance weight. Like I said, that would be FAR FROM the strangest thing I'd ever seen done that somebody tried to call "balancing". But at least if it's that, you can hack similarly on the flywheel and fix it, without having to tear down the motor and get it re-done, RIGHT this time.

 

If the guy who did the balance work added the 7-8 bob weight to the crank, they can machine the weight off the flywheel, thus balancing it to the motor. BUT, to do it proper would mean to tear the motor back down and balance the crank to the flywheel. One-piece seal motors should have the weight on the flywheel since it's not machined into the crank flange.

 

You might have gotten the wrong flywheel also. They actually sell a neutral balanced 1 piece RMS flywheel (NO counter-balance made into it). We put the wrong one behind a stock LT1 (thanks to an idiot at summit racing) in a friends' car and it did the exact same thing you are describing. It shook harder than a dog sheeting tacks (totally undriveable). The correct flywheel solved the problem.

 

Lo-tec - you got it man.

In this case I had the wrong flywheel 2 times. The first one was neutral balance, but for a 2piece rms, the second one external balance for a 1piece rms. Now I'm going to get one that is neutral balance for the 1 piece. Hahahaha, I think I got all the combinations...

However, along the lines of balancing my machine shop was able to completely internal balance my 383 stroker. The crank (cola) had plenty of material on the counterweights to keep it within balance. I also have 6" I-beam rods and forged AL pistons, so a fairly light set-up.

Anyway, I hope it works out. Thanks again

 

IMO, you should always balance the rotating assembly with the flywheel at the same time. Even if it's an internal balanced rotating assembly and neutral flywheel. Every company can make mistakes.

 

check with your machine shop but if the motor is internally balanced then the Flywheel and the balancer should be neutrally (zero) ballanced. That is how I did my road racing motor.

This allows you to upgrade/replace the flywheel or balancer separaley if need be. Flywheels can only be surfaced so many times.

Findanza makes a very nice alumimum model with replaceable steel fricton surface insert.

Ot just take you current flywheel and have it zero balanced. Take the clutch cover and it can be ballanced too. It won't cost that much, My
machine shop included it the engine balance cost.
When done the flywheel reamains zero balanced and so is the cluth cover. The shop just puts some witness marks on it so you know where it lines up. Mine is within 1 gram.

 

that's a good plan, that way if you ever swap flywheels or go to a auto trans you'll need to rebalance everything, no need to worry about making the external parts interchangable.