Don Terrill’s Speed-Talk

...putting all my spare time into may latest project car lately...

Here's a pic of when I first discovered I could use parallel bars to help static balance an internal balance V8 crankshaft (no other pics of doing this anywhere else on the Internet as far as I know)

When I checked the stock mid sixties Rambler V8 crank on the parallel bars, it only took one .5 ounce weight to find 'perfect' static balance -that weight is shown laying on the digital scale. -not much weight? but what the heck why not finish the job? -Forces me to conclude the high speed factory environment cannot afford to do the slower detail work necessary to obtain 'precision balance'.

So when I checked my welded stroker crank on the parallel bars, it would move 'heavy side down' like this:

When I took the crank to have it tested by a machine shop on their dynamic balancing machine, they marked the crank where it needed weight added... which was the opposite side of where my crank would move 'heavy side down'. So proceeded to remove weight from the heavy side, desiring a lighter crank instead.

This could use a longer explanation but I decided to add 'minor weight' evenly onto the center of the crank like this... taping small bits of lead onto the counterweights until the crank would not move 'heavy side down' anymore. -Then remove one, add weld metal, shape it, & check it again on the parallel bars:

Before and after:

Argh! ...sorry again for the pics loading in reverse order.

Next batch of pics will show some of the tools I use to do the work and how I added weight to the 'big ends' of the crank, just prior to having the final dynamic balancing work done to complete the crankshaft project.

This was the last phase of modifying the counterweights prior to having the welded up stroker crank 'finish balanced' on a dynamic balancing machine.

After all the lightening work done and static balancing on the parallel bars, when I paid to spin it on a dynamic balancing machine it still called for adding about 240 grams on the 'big ends', so to save the machine shop costs of adding mallory metal I was able to weld sheet metal plates on the ends like this.

I made the plates to weigh about 250 grams so there'd be enough 'overweight' to guarantee a one time final trip to the machine shop who did the final dynamic balancing work.

Before:

-Built up the beveled areas on the 'big end weights' first with filler metal like this:

After building up the beveled areas on the 'big end weights', I ground them smooth again prior to welding on the plates like this:

Pics of doing some shaping work after welding:

It's not necessary to preheat the crank in order to weld on the counterweights. But it is very helpful to have a few simple tools to grind the welds back down to get the desired shapes.

I was able to make a variable speed piggy tail rig for my angle grinder using a Dayton 7 amp on/off foot switch and a typical hardware store 7 amp ceiling fan rheostat.

Slowing the speed down while using the angle grinder makes the tool so much safer to handle... especially in order to use an adapted circular saw type steel cutting blade -in order to more easily reach down into and grind in between the tight spaces of the counterweights.

The variable speed rheostat only seems to extend the life of the angle grinder, whereas the angle grinder runs 'nice and pleasant' when it's slowed down... makes it easier to concentrate on the work instead of feeling distracted by the loud/buzzy high speed of the single speed grinder.

The added foot pedal to turn the grinder on and off greatly increases safety and precision by not having to fiddle around with an awkward 'safety' switch on the opposite side of the grinder then move one's hands around again on the buzzing unit to make the grind (how to say that right)

I just use a worn out 1/16" thick disc for a spacer to adapt the larger diameter 7" circular saw grinding blade to the angle grinder then true it up like this so it runs smoothly... (and safely at a much slower speed using the rheostat)

Showing pics of the final weights added to the 'big end counterweights' of the crank -adding the steel plates instead of adding mallory metal...

Out of sequence but one more pic of the 'big end weight' after welding to build up the beveled area, then ground back down again prior to adding a plate:

Thanks SpeedTalk forum. Pics of finished crank next.

Keep them coming, looking forward to the finish.

-Unexpected reply = thank you for the polite comment.

For lack of time, due to changes with my 'significant others'/ie 'lifestyle changes' I just decided to end this thread with a link to the Google+ picture albums I made for this project:

4.082" Rambler V8 Welded Stroker Crank:
https://plus.google.com/106358430530058 ... KEqTS6XcgS

Thank you SpeedTalk forum for letting my show my Rambler V8 stuff here.