Thread: VE Crank

Ok so I have a VE motor that I spun a bearing in, I want to rebuilt the motor.
I do not have a good crank to put in it or a crank pully, would I be able to put a DE crank and pully on it? Any downside to this?

yes you can use a DE crank.... its heavier though. search the forums for 8cw (de) vs 4cw (ve)

^Thanks. Big difference? Cant find threads.

8cw is more equally balanced in my eyes.

I would suggest an 8cw crank, it is overall a much better design and will result in a smoother engine and less overall bearing ware.

That said, both are proven to do a fine job for hundreds of thousands of miles.

FYI:

Mechanically the 8cw is a far superior design. I don't know what Nissan was on when they made that 4cw crank.

Performance wise if the 4cw is truly lighter, the lower inertia will technically allow for faster acceleration.

If you really want to go hard, have the 8cw properly weighted. Compromising weight on a crank generally is not a great idea anyway.

I want to add that the weight of the crank is designed around the weight of the rod, piston and wrist pin. Therefore the difference in weights between the DE and VE components means the DE crank will be improperly weighted. Without doing any mathematics I would give you my opinion that the (most likely overweight) DE crank is still going to provide a smoother engine, however I could be incorrect without knowing the weights of all of the components.

Let me know if you want anymore explanation.

Walker

u answered your own question sir.

and further to that ...cvts and autos were the main receivers of 4cw...

I used a 8CW in my VE for the same reason, spun bearing. I had the 8CW laying around so i decided to use it. This is one of those topics where you will hear good arguments on both sides. People have made good power on both.

If you look at the weights, the 8CW is not that much heavier. If you have the rotating assembly balanced you should not have issues with either crank. Have the 8CW looked over and polish the journals at the least.

Personally, I would run a balanced, polished and knife-edged (full) 8 CW crank from a B14/P12 20V. This is what I plan to do in the near future. Whatever you decide (4 CWC vs 8 CWC), make sure you get a GOOD VE crank pulley. If you have the funds, spend the $150-200 (depending) and purchase a new pulley. If funds are tight, get a low-mileage pulley from a reputable member. Too many people running around with used or worn out balancers on high-priced builds, IMO.

The harmonic balancer/crank pulley is such an important piece for a high revving engine. They do wear out and they (some aftermarket versions) do need to be rebuilt from time to time. I get anxious when I see 9k+ rpm with a lightweight flywheel/pulley/crankshaft (4 CWC) combination. Sure, it will work and has been proven to be successful but for how long will the motor/bearings last? I guess it all comes down to what you want and what your goals are. Are you building an all out beast for some summer fun or are you building an engine you hope to daily drive for 4-5 years?

I have never personally tested a half-weighted crank vs a full-weighted crank but from all of my research and from talking to a few engine builders, I have come up with the following thoughts. On future builds, I will go with a full CW crank with material removed from the leading and trailing edges of the counterweight (as close to the edge as possible/farthest from the axis as possible - to lower the moment of inertia). I would also plan to have the crank micro-polished and balanced. We all know that things in balance are more efficient at generating/transfering power than things that are out of balance.

OP/anybody - Here are some threads for general reading pleasure:

http://www.sr20-forum.com/vvl/54621-anyone-know-how-much-ve-crank-weighs.html

http://www.sr20-forum.com/vvl/29686-ve-4cw-crankshaft-max-load.html

VE cranks and rev limits - SR20 Forum

http://www.sr20-forum.com/vvl/19854-4cw-vs-8cw-vibes.html

I will also post up some interesting infrormation a little bit later. I am off to repair a family member's clothes dryer and get a free dinner!! /

Just want to re-iterate, that the 4cw crank might be lighter, but there is never any (good) reason what so ever to make a 4cw 4cyl crank.

A correctly sized 8cw crank will have half the mass on each counterweight but weigh the same if both are correctly designed. With the SAME mass distributed over each side of each bearing.

The 4cw causes a serious moment to be generated at the opposite side of the bearing which will lead to exaggerated deflection and bearing wear.

The weight of the crank should never change, as I said earlier, it should be a derivation of rod, wrist-pin, and piston weight.

There is no better way to really make a reliable crankshaft.

The harmonic balancer will help to damp higher order oscillation, but in the end has no effect on longevity of the bearings. The orders that that balancer will reduce are way lower in magnitude then the force orders that your counterweights cancel out.

Walker

Thank you.