woodruff key for 4.25 crank size

[wrench87]

does any one know what size woodruff key i would need for the harmonic balancer on a steel 4.25 crankshaft and using the profesional products sfi balancer. i had forte's send one out but i received two 1/4 wide by 3/4 long
pioneeer calls for a 3/16 wide by 1 3/4 long ?.

[philminotti]

Wrench-

If I remember correctly, my Scat crank used a 1/4x1/4x3/4 key for the balancer. I had to massage it a little to get it to fit. Just to pick a nit or two, the Woodruff key is the semicircular key used for the crank sprocket.

phil

[wrench87]

so you are saying you use 1/4-1/4 barstock for the balancer?, is a woodruff key acceptable?.

[philminotti]

I don't think you have a choice. I seem to remember that the snout was machined for a barstock key in the balancer area. However, the crank area of the snout was machined for the woodruff key. Also, your crank spacer should have a 1/4x1/4 slot as well.

Just as an aside, your balancer should not just slip on. It should be about a .001 interference fit. I got my balancer from Gessford and provided my crank snout measurements so that they could hone the ID of the balancer for an appropriate interference fit.

phil

[wrench87]

i have the timing chain on and i have a key for the spacer, i bought the crank spacer from shelby and it had to be honed for it to fit.this engine design is from the 60's but still having problems. i guess it is normal to get poor quality in every thing you buy today?.

[blykins]

This is why engine builders are paid to build engines. This is pretty standard issue stuff with all new parts. You can't assume that everything will just fit together perfectly...because it rarely does.

It's not because it's an FE...you run into this with Windsors, Chevys, the whole deal.

Be thankful you're not building a 383 SBC, where you have to grind the poop off of several connecting rods because they hit the cam....

[philminotti]

Unfortunately, when building up a motor from an assortment of aftermarket parts, one can't expect things to fit together like Legos. That being said, I too ran into some quality issues that surprised and frustrated me. It can be a very trying experience, especially when you take the time to actually do a good job, rather than just bolting the stuff together. Just as an example, the oil slinger at the rear of my SCAT crank was actually to big and it bound in its corresponding relief slot in my block. I had to have it turned down on a lathe. The main bearing bores of my block were quite out of round when I first got it. And that was after it was supposedly align bored. And the list goes on. That's the way it is. The only people who haven't had these sorts of problems are the ones who don't check.

As far as the barstock key, I did have to file it to fit into the crank. I also had to have my spacer honed AND I had to massage the slot in the spacer to get the whole mess to fit together.

phil

[Barry_R]

The 1/4 inch stock does not seem to be real consistant in dimension - I see more variance in the $2 piece of stock than I do in the cranks. I also end up tweaking it to get a decent fit - if you "force" it you'll get a raised burr that'll make things a lot worse.

The damper spacers in steel seem to fit really nice. The ones in aluminum from the same supplier are always tight. They say they're made to the same dimensional spec - which means the problem is either from the alloy expanding during machining or the teflon hard coat anodizing they use - or both.

The stroker cranks use a SBC woodruff key for the timing sprocket which always needs a little massage to get a proper fit.

I have not run into the slinger isue myself - but remember that teh slingerr slot (and seal groove) in a line honed block are going to be smaller in the vertical direction - a potential problem that nobody seems to look for.