crank and pistons
Thread Starter
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
crank and pistons
I am not going to install this soon so there's a lot of time to figure out what I want and what I need....
I have the L48 block with the 2 bolt main and low compression. I want to upgrade my crank and pistons. Jegs has forged pistons that would give me 10.2 CR with the 64cc heads which I already have. These are reasonable priced, does anybody have experience with these or what would you recommend ?
The crank: Is a forged crank necessary or can I re-install my old crank with new bearings, rods and pistons ?
The cylinder bores looked fine last time I had a look at them... I guess honing the bores is not necessary or should I have that done anyway ??
I have the L48 block with the 2 bolt main and low compression. I want to upgrade my crank and pistons. Jegs has forged pistons that would give me 10.2 CR with the 64cc heads which I already have. These are reasonable priced, does anybody have experience with these or what would you recommend ?
The crank: Is a forged crank necessary or can I re-install my old crank with new bearings, rods and pistons ?
The cylinder bores looked fine last time I had a look at them... I guess honing the bores is not necessary or should I have that done anyway ??
Tech Contributor
Joined: Aug 1999
Posts: 15,176
Likes: 3,990
From: Connecticut, USA
I'm starting the same job now. 72 base motor which is like yours. The cylinders look good so I'm going to measure them and have them honed with a torque plate. The piston and rods also look to be fine,the motor only has 55k miles on it.
Depends what you want out of it. In my case I'm going to use store the stock heads and use (67cc 202/160) SR Torquers that I port and polished, HE260 cam, performer intake, headers 2.5" pipes, stock ignition, and either a 670 Holley avenger or 750 Q-Jet carb. I'm guessing the CR will be about 9:1 using these heads and the stock pistons. I'm running a B&M prepped TH400 with a prepped 3:08 rear gear. This motor might be 300 hp and 350? ft/lbs just about right for the combo I have.
Gary
Depends what you want out of it. In my case I'm going to use store the stock heads and use (67cc 202/160) SR Torquers that I port and polished, HE260 cam, performer intake, headers 2.5" pipes, stock ignition, and either a 670 Holley avenger or 750 Q-Jet carb. I'm guessing the CR will be about 9:1 using these heads and the stock pistons. I'm running a B&M prepped TH400 with a prepped 3:08 rear gear. This motor might be 300 hp and 350? ft/lbs just about right for the combo I have.
Gary
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
I asked a similar question for my 427 BB and the answer was that if you reuse old some old parts, the complete assy must be fine balanced.
So at the end its a price question to either buy a complete rotating balanced kit or single parts and getting them balanced.
Good luck. Gunther
I asked a similar question for my 427 BB and the answer was that if you reuse old some old parts, the complete assy must be fine balanced.
So at the end its a price question to either buy a complete rotating balanced kit or single parts and getting them balanced.
Good luck. Gunther
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Originally Posted by RedBad1979
I am not going to install this soon so there's a lot of time to figure out what I want and what I need....
I have the L48 block with the 2 bolt main and low compression. I want to upgrade my crank and pistons. Jegs has forged pistons that would give me 10.2 CR with the 64cc heads which I already have. These are reasonable priced, does anybody have experience with these or what would you recommend ?
The crank: Is a forged crank necessary or can I re-install my old crank with new bearings, rods and pistons ?
The cylinder bores looked fine last time I had a look at them... I guess honing the bores is not necessary or should I have that done anyway ??
I have the L48 block with the 2 bolt main and low compression. I want to upgrade my crank and pistons. Jegs has forged pistons that would give me 10.2 CR with the 64cc heads which I already have. These are reasonable priced, does anybody have experience with these or what would you recommend ?
The crank: Is a forged crank necessary or can I re-install my old crank with new bearings, rods and pistons ?
The cylinder bores looked fine last time I had a look at them... I guess honing the bores is not necessary or should I have that done anyway ??
2) A forged crank is not necessary if you're planning on staying below a 5,500RPM redline and you're not considering running NOS. For a NOS application, your 10.2CR will be too high anyway.
3) You can save some $ by reinstalling your old crank. In doing so, unless you've got the capabilities, you'll have to get a machine shop to a) check the block to see if needs align bored, b) check for warped crank and possibly turn and c) check crank for wear and possibly turn. Even with a new crank, a) & b) will need to be done.
4) Your cylinder walls need to be checked for perfect roundness and will at least have to be honed to within whatever thousandth of an inch piston-to-wall clearance is recommended by the piston manufacture. Again, this is a job that needs to be done by a good machinist.
Hope this help.
Thread Starter
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
For a while I thought that I could change the crank and pistons with the engine installed - if (and this is a big IF) the bores are in very good shape...
I am convinced that it's smarter to remove the engine and have the block machined.... now this is definately the time to look into the 383 stroker kits...
The rotating assembly is around $1000 - Golan for example offers the complete assembled 383 block, balanced and installed rotating assembly and all the new bearings for $1999 - I wonder if that's the better deal... instead of rebuilding my block...
I am convinced that it's smarter to remove the engine and have the block machined.... now this is definately the time to look into the 383 stroker kits...
The rotating assembly is around $1000 - Golan for example offers the complete assembled 383 block, balanced and installed rotating assembly and all the new bearings for $1999 - I wonder if that's the better deal... instead of rebuilding my block...
