I did mine as per instructions from Graham Russell. I put a jack screw and block under each crankpin in turn, so each web finished up the same. I then linished the edges off to smooth it. Final balancing on the machine needed very little off.

If you look at my 1st pic above, you will see that at the crankpin end, the depth is to that machined shoulder. The other end of the cut runs out level with the far side of the main bearing journal. If you cut any further you are reducing the counterweight.

ps. it's not recommended to wedge EN40B  nitrided cranks. [edit] typo

here's a pic of the finished crank installed in my 1412 stroker-

Is there a set (roughf)amount of meterial that needs removeingto make the counter weights correct for the piston and rod combo?

yes steve, Any way to get the metal off will work. But the 4 or 5 cranks i've done on the mill have turned out to be really close on balancing afterwards. Makes sense since you are removing metal from both sides of the crank. I use a mill indexed off of the journals. but like you say after it is balanced it doesn't know how the metal was removed it is still balanced. Just so people know the wedging will only remove a bit less than a pound off the crank.

With no dog in this one I'll be brief. I have wedged a crank myself in my shop. I used a wizz wheel on a big angle grinder. It took hours and put lots of grit in the air. It was a Cooper S EN40B crank and they seem hard though and though. The guy who did the balance work was not a happy camper. You will notice the holes drilled in the counter weights on crank shown.  Wedging does not balance a crank. The nitrocarbuizing is not nitriding which can only be done to special materials. My crank lasted three years of Vintage racing and saw 8700 RPM often. It did break and take everything with it. I can send you a picture of the remains.  My current build is a 1360 Cooper S I did nothing to the crank other than balance and polish. I did install a windage tray and center pickup. I have no thoughts of track day with this unit. If I want to track day or autocross I'll build another car for the purpose.  

Steve

Crankshafts, while looking into a billet crank i read up as much as i could on the subject. Even went as far as drawing up a billet crank. Its one of those subjects that the more you know the less you know. Here is a known fact the a series crank, It is under balanced. how much? The cad program i did i went as far as counter weighting it at 100% the counter weight was huge so my guess is the stock counterweight is about 25% of the bobweight. (100 % of the big end and 50% of the little end and the piston weight) On a four cylinder engine the factory uses the opposite throw as a counterweight what this does is it essentially uses the strength of the steel between 1-2 and 3-4 to transfer the stress. A way around this is to add counterweight between them ending up with the russell 8 counterweight type crank even though it seems this would cancel out each other it just helps keep the imbalance isolated to the individual throw. This helps the crank from flexing at high revs. The real problem comes from the fact that we only have three main bearings and a flywheel mounted 5" out from the rear bearing. Wedging is a way of reducing the weight opposite the counterweight. But hold on a minute which is worse twisting of the crank or under counter weighted? If you look at the metal you are removing in the process of wedging it is around the area of the crankpin Right where you need it for rigidity. So IMO it is a comprimise. If you want that last bit of weight off the crank yes wedge it, if you want maximum life, Don't. It is way more effective to go to a lighter flywheel. Aaron

I have a standard stroke 1360 (Cooper S nitrided EN40B crank) and a 1412 stroker (with the wedged EN16 12G1505 crank I showed previously).
Both were balanced on Graham Russell's dynamic balancer, and at 7000rpm one is as smooth as the other.
If it's mainly for road use it's not really necessary, however for $80 (you sure about that price?) it's a bargain and I would do it.
It took me about 6 hours to wedge my crank on the mill at home, using a 50mm dia 3 insert carbide cutter. And the damned metal chips went everywhere!

Kelley,

I can't speak to the detailed process they used since I'm away out west was was never in the shop.  However, the builder of that GT-5 Mini oversaw the process.  Most importantly, the wedging was only done as part of the balancing process.  The mission was not to build a super light race crank but one that will serve well in a turbo build.

Rick

Did they adjust the amount they wedged based on the results of a balancing machine?

Kelley

Kelley,

The shop that did my crank repairs cranks for very, very high hp drag racers (including welding/regrinding etc.) and does all of the cranks for one of the fastest GT-5 Minis since the 1980s.  When they used wedging as part of the balancing, I accept that was the purpose.

Rick

If it's only $80 difference it's worth nitriding and wedging. If you spin a bearing on a nitrided crank it stands a better chance of surviving. Wedging doesn't balance a crank, helps improve the counterbalancing. The reason you don't see it very often on V8s or a many other engines is that they have 5 main bearings per 4 cylinders. The A-series engine has 3 main bearings. Wedging can help reduce some of the nastier resonances in a 3 main crank.

Kelley

Thank you. I have built a few motors before, but big V8's don't usually have this issue with off balance cranks that SHOULD be wedged. All I had known before this was that wedging was specifically for high-rev motors or motors with extremely tight tolerances in the case as a way to cut down on parasitic harmonics that can be caused by these things.

So my question still stands. Is this something that you would consider necessary or proper for a street 1380 that might see a little bit of weekend tracking?

My crank was prepared by a specialist shop in Michigan.  And...no, I would not do this at home.

So is wedging something I can easily and reliably do at home?

Here's an A+ crank that has been prepared for a turbo build, wedging specifically to address balancing.

Draw a line tangent to the circular shiney faces on the webs at the journals to determine how much to mill off. Personally I wouldn't undercut the shiney faces as shown in the picture. The crank will need balancing after.

How do you konow how much to remove and is balancing an issue

All 1275 cranks have insufficient counterweighting. Wedging addresses this by removing metal from the crankpin side. The benefit (apart from lightness) is the main bearings journals are less inclined to wear more on the crankpin side (as they do when stock).
Here's one I prepared earlier (pic taken before finishing) which is stroked 3.0mm. For the wife's 1412cc van...

Looking to get a new crank. I need help deciding between a standard 1275 crank or a nitrocarburized and wedged crank.

I know what the nitrocarburizing does and I can assume what the wedging does.. but is there any real benefit for a street car with a fast road cam 1380 that will see more street than track?

Am I going to see the benefit for the extra $80?