Crank mods
10-21-2013, 04:21 PM
#1
Crank mods
Butchering/Knife edging troubles. Contacted Darren at FFWD Connections about having him butcher my ecotec crank FFWD - Butcher Crank
He looked into it, here is his reply:
I messed around with the ECO cranks years ago…but I wasn’t liking the trigger wheel/counterweight on there. It would be an absolute balancing nightmare I believe. Actually, I liked the those crank designs. I’ll have to look at one I have here in the shop again and double check a few things.
Which incidentally, I did check into it again, and all those memories came back. I’m afraid I’ll have to turn it down. It would be a balancing nightmare (because of that trigger plate). I recall I really wanted to (as we wanted to start building the ECO motors for folks). The 4B11 Mitsu crank is the exact same thing…which we also had to turn down.
The only alternative is to actually cut one we have here and see what happens (as an experiment)…but it might take some time as I’m really slammed right now. Depends on how quick you’re wanted this done. If for the next race season, then it shouldn’t be an issue if I can pull it off. If by T-Giving, then it’ll be a problem.
So no dice there, at least not anytime soon.
I then looked into paeco, who knife edges cranks CRANKSHAFTS KNIFE-EDGED and they pretty much stated the same:
Mark -You are right – we’ve never seen one like this. We can certainly knife-edge the crank, but your guy is right – balancing afterwards could be a real problem. Normally, we take metal off the counterweights in pairs so that metal removed from one is balanced by metal removal from another 180 degrees apart from it. From your pic, it appears that you have eight counterweights with the reluctor being bolted to the last one. We could knife-edge the first four counterweights and probably be OK since they are 180 apart, but we obviously can’t touch the one with the reluctor, which means we can’t touch the 7th one either, and we can’t touch #5 & #6 because they depend on #7 and #8 to counterbalance them.
If you could install a reluctor on the nose of the crank instead of on the counterweight, the balancing problem would disappear, since we could knife-edge all eight counterweights. - Carl
Thought I would share, see if anyone has gone the distance with their crank and what they had to do to get it done right.
He looked into it, here is his reply:
I messed around with the ECO cranks years ago…but I wasn’t liking the trigger wheel/counterweight on there. It would be an absolute balancing nightmare I believe. Actually, I liked the those crank designs. I’ll have to look at one I have here in the shop again and double check a few things.
Which incidentally, I did check into it again, and all those memories came back. I’m afraid I’ll have to turn it down. It would be a balancing nightmare (because of that trigger plate). I recall I really wanted to (as we wanted to start building the ECO motors for folks). The 4B11 Mitsu crank is the exact same thing…which we also had to turn down.
The only alternative is to actually cut one we have here and see what happens (as an experiment)…but it might take some time as I’m really slammed right now. Depends on how quick you’re wanted this done. If for the next race season, then it shouldn’t be an issue if I can pull it off. If by T-Giving, then it’ll be a problem.
So no dice there, at least not anytime soon.
I then looked into paeco, who knife edges cranks CRANKSHAFTS KNIFE-EDGED and they pretty much stated the same:
Mark -You are right – we’ve never seen one like this. We can certainly knife-edge the crank, but your guy is right – balancing afterwards could be a real problem. Normally, we take metal off the counterweights in pairs so that metal removed from one is balanced by metal removal from another 180 degrees apart from it. From your pic, it appears that you have eight counterweights with the reluctor being bolted to the last one. We could knife-edge the first four counterweights and probably be OK since they are 180 apart, but we obviously can’t touch the one with the reluctor, which means we can’t touch the 7th one either, and we can’t touch #5 & #6 because they depend on #7 and #8 to counterbalance them.
If you could install a reluctor on the nose of the crank instead of on the counterweight, the balancing problem would disappear, since we could knife-edge all eight counterweights. - Carl
Thought I would share, see if anyone has gone the distance with their crank and what they had to do to get it done right.
10-21-2013, 05:19 PM
#9
10-21-2013, 05:30 PM
#12
I've only done 4 Ecotec cranks including my own which has the most work done to it. We will soon see how long the le5 crank holds 12.5:1 compression with a Tvs blower lol
Moderator
10-21-2013, 07:56 PM
#19
What he's saying is most people knife edge for less mass AND easier travel of the crank through the oil. So it "cuts" through it with a sharp edge instead of "slapping" it with a blunt edge. But our cranks don't come in contact with the oil. So this would only be good for reduced weight.
10-21-2013, 08:01 PM
#20
For those of u that r manual transmission i would recommend a light flywheel over knifing the crank. There's Proly more gains from that. Since the stock flywheel weight like 20lbs not sure, its heavy lol. Taking 2-4 lbs off the crank Proly won't gain Wat a light flywheel would.
On the other side knifing a crank lowers oil restriction and windage. How much? I have no idea. My Gess is Proly wat john says about it.
Our crank is so far away from the oil pan that oil restriction is Proly not a problem with a stock crank.
But i Gess wen Ur trying to get every bit of power u can get anything helps.
On the other side knifing a crank lowers oil restriction and windage. How much? I have no idea. My Gess is Proly wat john says about it.
Our crank is so far away from the oil pan that oil restriction is Proly not a problem with a stock crank.
But i Gess wen Ur trying to get every bit of power u can get anything helps.
10-21-2013, 08:14 PM
#22
10-21-2013, 10:18 PM
#23
What about the eagle crankshaft for the 2.2, at only a bit over $400 shipped would it be lighter and stronger or just stronger?
http://www.ebay.com/itm/Eagle-Specialties-Crankshaft-for-GM-2-2L-ECOtec-engines-2237245765-/300992424083?pt=Motors_Car_Truck_Parts_Accessories&hash=item46148be893&vxp=mtr
http://www.ebay.com/itm/Eagle-Specialties-Crankshaft-for-GM-2-2L-ECOtec-engines-2237245765-/300992424083?pt=Motors_Car_Truck_Parts_Accessories&hash=item46148be893&vxp=mtr
10-22-2013, 06:01 PM
#25
In midget racing (smaller sprint cars) many engine builders claim to get more races out of not lightening the cranks. Theory being balance and harmonic issues related to inline 4s. I've always had great results with my v8s of course.
BTW Tjolley, beautiful work on that crank!
BTW Tjolley, beautiful work on that crank!