0HP RESEARCH

Cast, Forged, Billet, OE, aftermarket, stock stroke, stroker, de-stroked....when you think about it, the options for LS crankshafts are many and can sometimes be very confusing when building your next engine.

When we sit down with our customers we always want a good idea of what exactly they are trying to accomplish with the engine and what areas need to have more attention spent on detail work to make the end result more reliable.

As most of you know, the standard Chevy small block has not had a fully counter weighted crankshaft ever, even right up to the new Gen V engines the middle of the crank lacks these. For the OEM and most performance builds this can be over looked and not a mandatory item when building your engine. Even the 650 HP LT4 makes due with a std crankshaft build (although it is a forged piece). However, adding these back into the crankshaft will give you a better crank that will be more rigid, stable, and perform better in almost every way throughout the entire RPM range. This means longer bearing life, smoother engine performance, and less chance of vibration damage in most cases.

Here you can see the difference in this Dart CCW crank on the left vs a modern GM LSA crankshaft on the right.




Now, say you have decided that a CCW crank is right for you, and your build but you want to install this in your LS engine block....


There is a big warning! WILL NOT FIT OEM BLOCKS! While this is listed in almost every case you see, and for the home builder this is very true. The OEM blocks were never designed to accept one of these cranks and the added material of the center counter weights. That being said this is something we have done for a number of years without issue but it does require machine work to the engine block to do so.


OEM Thrust bearing main location

OEM Thrust bearing main location



As you can see there is a lot more material in the center part of the block as the extra machine work was not required given the OEM crankshaft has little in the way of material to hit any part of these areas. Not only the Dart but using a few billet CCW cranks we have measured the clearances needed and can easily machine iron and aluminum OEM blocks for the required clearance while retaining as much material for block rigidity as possible.



HPR machine work to clear CCW crankshafts

HPR machine work to clear CCW crankshafts



Once everything is machined and cleaned, your new CCW crankshaft will drop right in without issue.






So for those wanting to use a CCW crankshaft but always thought they needed an aftermarket block, no need to fear, HPR has you covered!

C5 Pete

At what HP level do you believe these become a "highly suggested" upgrade?

For example;

stock stroke/bore 6.0 iron block. Single turbo 76 or 80.

Or, 388" 4.125 bore filled LS7 block. Also single Turbo. Looking for 1500hp.

My initial thought is to use an LSA crank. But would like your opinion.

Thanks.

0HP RESEARCH

I would say it is more than just a HP level, it is RPM related as well but most can relate more to the HP level when doing engines like this.

Now in both cases you listed above, the Dart crank would be out of the question currently as they only offer a 4" stroke so using a CCW crank in either one of those would mean going billet and doubling the costs of the crank.

You will probably see some NA builds from us here in the near future using CCW cranks in applications under 1000 hp but RPM range will be in excess of 8500 RPM so in that case the CCW crank is going to provide a more stable rotating assembly, longer bearing life, and less possible vibrations at those RPM's that can cause other issues.

For boosted applications, generally we suggest them over 1000 whp, and if you are looking at 1500 whp+ then they should almost be mandatory equipment if you are wanting to build something with as much reliability in it as possible.

The one thing about doing them (CCW cranks), there is no downside at all to adding back those two counterweights other than the time it takes to machine the block for them to fit.

0HP RESEARCH

For those of you using the Dart LSNext blocks, this is what they look like straight from Dart pre-clearanced for the CCW crank.


Bare Dart LSNext block

Polished 4.000" stroke Dart CCW crank

Installed

C5 Pete

Thanks for the reply.

So, essentially, no one makes a shorter stroke CCW crank (at a reasonable price)

Probably Bryant or Winberg but $$$$

0HP RESEARCH

Currently no...there is talk but that is all it is at the current time.

The Dart cranks range from $1400 - 1800 ish...the polished ones like shown above are at the higher end of that range. But again all are 4.000" stroke currently.

Windberg and Bryant cranks are going to start around $2700 ish and go up from there depending on design and what you want for main sizes, rod journals, counter weight design.......

xBoostx

Op thanks for taking your time, have a question how about weight of the ccw crank compared to a non ccw 4 inch stroke for same application thanks again.

0HP RESEARCH

The crank is going to be heavier, you are adding back in two big counter weights.

Now that being said it greatly increases bearing life and makes the crank more stable at speed. As for adding weight, other than adding overall weight the impact is very very little since the moment of inertia is so low. If you were adding that much weight to the pistons, then you would have a greater impact on reducing performance. If that is what you were getting at by the change in weight.

RACER7088

They are a little heavier but it's still weight in a very small diameter or radius so it has little effect on inertia. with the less flexy nature it probably does make a little more power as well as not shaking the cam and valvetrain as well as being easier on the block and main caps too.

Tusc

Resurrecting an older thread.

For those seeking to potentially use the same Dart CCW crank, is it just the center mains which need clearancing? What is a reasonable expectation of expense for a shop to do this on an aluminum LS2 block?

0HP RESEARCH

Yes it is just the center that has to be done, as all of the other counter weights are in the same location and size as the OE crank. Pricing is probably going to vary by shop.

SilverBulletC6Z

Do the Callies compstar 8 counterweight crankshafts also require machine work to the block? Would the stock windage tray end up causing any issues as well?

sccaGT1racer

Yes it requires block clearance on a stock block and I had to shim the windage tray but that was due to the callies rods. A little careful work with a die grinder will get the clearance for the crank.

0HP RESEARCH

Depends.

There is no yes/no answer for that one. If it is the stock stroke 8cw Callies Compstar it should drop in, but if the block has any kind of core shift (and we have seen that before), you will need to cut it. If it is a 4.000" stroke one (or larger) you will have to clearance for the rods but typically not the crank....again unless core shift.

If you spec one of their billet cranks using a full width counter weight like the Dart then yes you will always have to clearance it as shown.

Windage trays are typically hit by the rods...not the crank so that doesn't matter until you start going larger on strokes, which requires shimming of the tray.