Knife Edge Crank.
- Thread starter Swiper
- Start date
I don't know the CG too well at the moment, but I would doubt the counterweights touch the oil level...
Never been into knife edging personally, there's money to be better spent on machining other internals, and ensuring you get a good balance for entire bottom end + flywheel+clutch (hard to come by actually).
Crankshaft I normally like to leave as much material on it as possible as it was from factory, no material removed more than just polished journals.
Just my 2p.
What are you going to be revving your motor to mate?
Never been into knife edging personally, there's money to be better spent on machining other internals, and ensuring you get a good balance for entire bottom end + flywheel+clutch (hard to come by actually).
Crankshaft I normally like to leave as much material on it as possible as it was from factory, no material removed more than just polished journals.
Just my 2p.
What are you going to be revving your motor to mate?
Cool.
I don't know enough about the CG Series Motor to give you a definative answer to knife edging that particular crank...
but to aid response, obviously a lighter forged piston, same with con-rod, and a very good balance, rather than taking material away from something that will also make it weaker (removing nitrided/tuftrided surfaces, potentially introducing new localised stress points).
I don't know enough about the CG Series Motor to give you a definative answer to knife edging that particular crank...
but to aid response, obviously a lighter forged piston, same with con-rod, and a very good balance, rather than taking material away from something that will also make it weaker (removing nitrided/tuftrided surfaces, potentially introducing new localised stress points).
Know your stuff.
What spec are you going for? Unless you're going for high duration cams and going to be revving high, there is nothing to warrant that kind of work to the engine. CG13's are good for 7500rpm in standard form, so unless you plan to be making power above that then I would spend your money elsewhere. Simply balancing the engine will not have the effect you are after.
I think I can see what you're after doing Swiper, less mass on the crank means less inertia so the engine revs would pick up faster ? if so then in theory it's a great idea, but as Lawrence says it could alter the way in which the crank handles stress and it could cause it to fail through fatigue even if it was balanced afterwards, I think a better way would be lighter rods and pistons as said along with a lightened flywheel to start with.
OP
OP
i didn't say that balancing the crank was going to have an effect that i'm after. i'm planning a full re-build for a turbo application if all goes to plan. so i'll be stripping down the engine and fitting all new bearings etc, there's no harm in having the crank balanced and straightened as it'll be out anyway. i'd be miffed if it was re-built and the crank wasn't true. for the money i'll be spending, i can justify an extra £40-£60 for the crank(£140ish for knife edge and balance).knife edging isn't about weight reduction as much as reduced resistance, less resistance = more useable power. the same as the lighter fly and crank pully that's on there now. i'll be purchacing forged pistons and possibly rods for the re-build.
I was referring to your post below saying you wanted a more responsive engine, which knife edging wont really help with. As Laurence said you'll get a far better effect from a lighter flywheel, and a 1.0 pulley.....but since you already have one
If you want to do it though, go for it
OP
OP
it was in an advert in one of my many magazines. lol. i'll have to dig it out and find out the ad.
Swiper, definately ask around to see who can balance your full bottom end
(Crankshaft, Flywheel, Clutch at least), because often it's hard to find a good machine shop that can accomodate the full bottom end rotating weight.
I would suggest a piston from someone like Wiseco or JE if they have listed, and Con-rod look at Carillo (I am using Wiseco Forged Piston and Carillo Super-A Conrod in my GTR). ARP Full Fastener package also will be money worth spending.
You'll get greater response from a lighter rod/piston setup, than llightening/streamlining/knife edging the crankshaft.
Sounds like a cool project mate! Good luck
(Crankshaft, Flywheel, Clutch at least), because often it's hard to find a good machine shop that can accomodate the full bottom end rotating weight.
I would suggest a piston from someone like Wiseco or JE if they have listed, and Con-rod look at Carillo (I am using Wiseco Forged Piston and Carillo Super-A Conrod in my GTR). ARP Full Fastener package also will be money worth spending.
You'll get greater response from a lighter rod/piston setup, than llightening/streamlining/knife edging the crankshaft.
Sounds like a cool project mate! Good luck
OP
OP
Swiper, definately ask around to see who can balance your full bottom end
(Crankshaft, Flywheel, Clutch at least), because often it's hard to find a good machine shop that can accomodate the full bottom end rotating weight.
I would suggest a piston from someone like Wiseco or JE if they have listed, and Con-rod look at Carillo (I am using Wiseco Forged Piston and Carillo Super-A Conrod in my GTR). ARP Full Fastener package also will be money worth spending.
You'll get greater response from a lighter rod/piston setup, than llightening/streamlining/knife edging the crankshaft.
Sounds like a cool project mate! Good luck
parts for the micra are normally limited to custom jobbies. i've been looking at the forged pistons and rods from ed (fuion motorsport), i'm not sue that arp list bolts etc for the cg13.
it will be a cool project, but a time scale of about 1.5-2 years, which is a bummer. that's the downfall of being married with two kids, morgage and two cars to run and maintain, although i wouldn't change it.....cos i can wait!!! lol
Swiper, definately ask around to see who can balance your full bottom end
(Crankshaft, Flywheel, Clutch at least), because often it's hard to find a good machine shop that can accomodate the full bottom end rotating weight.
I would suggest a piston from someone like Wiseco or JE if they have listed, and Con-rod look at Carillo (I am using Wiseco Forged Piston and Carillo Super-A Conrod in my GTR). ARP Full Fastener package also will be money worth spending.
You'll get greater response from a lighter rod/piston setup, than llightening/streamlining/knife edging the crankshaft.
Sounds like a cool project mate! Good luck
How much is the Carillo crank may I ask?
OP
OP
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i think you've miss read LAURENCE's post, there's no mention of a Carillo crank, just con-rods.
Swiper, definately ask around to see who can balance your full bottom end
(Crankshaft, Flywheel, Clutch at least), because often it's hard to find a good machine shop that can accomodate the full bottom end rotating weight.
I would suggest a piston from someone like Wiseco or JE if they have listed, and Con-rod look at Carillo (I am using Wiseco Forged Piston and Carillo Super-A Conrod in my GTR). ARP Full Fastener package also will be money worth spending.
You'll get greater response from a lighter rod/piston setup, than llightening/streamlining/knife edging the crankshaft.
Sounds like a cool project mate! Good luck
How much is the Carillo crank may I ask?
i think you've miss read LAURENCE's post, there's no mention of a Carillo crank, just con-rods.
