iam wanting to get a lightweight crankshaft for my n/a while iam doing the rebuild, but i havent been able to find any does anyone know of anyone who makes them?
crank
- Thread starter Nalleywhacker
- Start date
How high do you plan to rev it?
the 6M crank is lighter (early 7Ms) while the 7M crank is smoother (I would lighten this, and use it for an 8k+ rpm N/A)
the 6M crank is lighter (early 7Ms) while the 7M crank is smoother (I would lighten this, and use it for an 8k+ rpm N/A)
From what I've read the 6M is lighter and gives the motor an extra 250RPM range. I'm using a .010/.010 6M crank in my daily driver motor because the block originally came with a 6M.
If you lighten the 6M crank I would take the block, crank, and piston assemblies to a machine shop and get it all re-balanced. Also you might want to look into a lighten flywheel. But if you are going to be spinning that crank faster than stock red line I would definitely look into getting stronger springs for the valves. We don't want the valves to meet the pistons or have a bad case of floating valves or bouncing valves.
(Valves Float: is an adverse condition which occurs when the valves on an internal combustion engine valve train do not remain in contact with the camshaft lobe during the valve closure phase of the cam lobe profile. ;WIKI.)
(Valve bounce: is a related condition where the valve does not stay seated, due to the combined effects of the valve's inertia and resonance effects of metallic valve springs that effectively reduce the closing force, and allow the valve to re-open partially. ;WIKI)
I'm not sure if it's small block Chevy inner spring or big block inner springs you can use to replace the stock springs. I've heard of both types being used. I still need to do some more research and "acceptable risk" assessment before I decide if that is the way I want to go on my next build.
Geez now I'm giving vocabulary terms.. Sorry about that.
If you lighten the 6M crank I would take the block, crank, and piston assemblies to a machine shop and get it all re-balanced. Also you might want to look into a lighten flywheel. But if you are going to be spinning that crank faster than stock red line I would definitely look into getting stronger springs for the valves. We don't want the valves to meet the pistons or have a bad case of floating valves or bouncing valves.
(Valves Float: is an adverse condition which occurs when the valves on an internal combustion engine valve train do not remain in contact with the camshaft lobe during the valve closure phase of the cam lobe profile. ;WIKI.)
(Valve bounce: is a related condition where the valve does not stay seated, due to the combined effects of the valve's inertia and resonance effects of metallic valve springs that effectively reduce the closing force, and allow the valve to re-open partially. ;WIKI)
I'm not sure if it's small block Chevy inner spring or big block inner springs you can use to replace the stock springs. I've heard of both types being used. I still need to do some more research and "acceptable risk" assessment before I decide if that is the way I want to go on my next build.
Geez now I'm giving vocabulary terms.. Sorry about that.
yeah no more vocab! lol my problem is iam rebuilding my motor and i need my crank to be reground because i spun a berring. so would it be cheaper to buy a new crank then you get crank pistons and rods and everything balanced?
It might be cheaper to buy a new crank. The previous owner of my Supra spun bearing number 5 on the main and ate the crank up. Strangely enough that was the same problem my second motor.
Autozone has a reman crank kit from around 350.
Advanced Auto has a reman kit from around 300.
Both should come with matching bearings.
Yes I would take it all in and get it all balanced. And talk to the machinist about possibly lightening it all. Tell him what your plans are and see what he suggests.
Autozone has a reman crank kit from around 350.
Advanced Auto has a reman kit from around 300.
Both should come with matching bearings.
Yes I would take it all in and get it all balanced. And talk to the machinist about possibly lightening it all. Tell him what your plans are and see what he suggests.
Hmmm..... There's a member or vendor here that does spin balancing, and, for the life of me, I can't remember who. He has a Nascar spec. spin balance machine. Has real good prices, to.
FWIW, I've used two different crank kits from Autozone, and one from CarQuest - the clearances are ALL OVER THE PLACE!
Take your block and crank to a machinist. Have him align hone the mains to match the crank (after the crank has been micropolished, or cut, whichever he or she says is best)
Take your block and crank to a machinist. Have him align hone the mains to match the crank (after the crank has been micropolished, or cut, whichever he or she says is best)
gnarkill87;888650 said:
You may not need a new crank, you have to have it checked to see if it can be reground. Then the machinist will mic it and tell you what size bearings you will need. It's best if you let them mic it and set the crank and pistons so they can size the bearings. Another thing is you will have to see if and how much the block has to be bored and get the pistons and rings to match. Block should be line bored, crank, pistons, along with flywheel should all be balanced together. I've used the stock flywheel and just had it turned.
labrat469;888687 said:
#5 rod berring is what i spun, yeah not so keen on getting a cheap autozone crank.
AJ'S 88NA;888999 said:
yeah my situation is my block is already bored .030 over and it has ross racing pistons there not the best but i def cant afford to buy anything even close to the same quality, so is there anyway to just get the crank reground and get oversized berrings and be good to go?
IJ.;888703 said:
figures, IJ's done it before. who woulda thought?
balancing is a must if you're doing any changes to a crankshaft. any machine shop should know this and consider it part of your lightening. if they don't think it's necessary....they may not be the greatest shop for you.
consider these if you intend to rev it high.
http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_114346_-1
Tire Shredder, is that one spring for that price? or is that a set of 8 or 12 or anything like that?