Build a short stroke rpm motor.
10-17-2014, 12:27 AM
#1
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Build a short stroke rpm motor. How strong are the 4.8 cranks. Can the journals be cut to Honda journal sizes, 1.885? I have two sets of Callies 6.2 inch long Honda bearing good rods from a Nascar team. Extra sets never used after they changed combinations.
I want to build a short stroke 4.8 crank 6.0 or 6.2 block which would be around 330 cubes or 345 cubes. With the flow capabilities of the LS type heads it could be a great motor. I have a G8 GT. Using the aluminum block and changing out the DoD, and maybe a small turbo?? Anyhow.
Can the 4.8 crank with Honda journals stand up to a lot of rpm and power? Does anyone make a forged 3 inch or 4.8 crank??
Does anyone have a link to all of the specs on the LS motors. Mains sizes, rod journal sizes, crank materials etc?
Thanks for your help people.
Mark
I want to build a short stroke 4.8 crank 6.0 or 6.2 block which would be around 330 cubes or 345 cubes. With the flow capabilities of the LS type heads it could be a great motor. I have a G8 GT. Using the aluminum block and changing out the DoD, and maybe a small turbo?? Anyhow.
Can the 4.8 crank with Honda journals stand up to a lot of rpm and power? Does anyone make a forged 3 inch or 4.8 crank??
Does anyone have a link to all of the specs on the LS motors. Mains sizes, rod journal sizes, crank materials etc?
Thanks for your help people.
Mark
10-18-2014, 12:59 AM
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Thank you, thank you, thank you. Just what the LS Doctor ordered. I have to find his build thread now.
Mark
Mark
10-18-2014, 09:44 AM
#4
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You'll run into problems with the valve train before you can spin a short stroke motor fast enough to be worth the trouble, with a stock stroke or 4" stroke and good rods you can spin it to 7500rpm, after that keeping the valve train under control is a bigger problem than the rotating assembly. Also a G8 is a heavy car the lose in torque would slow it down off the line.
10-18-2014, 10:56 AM
#5
Valvetrain is #1 for an rpm motor. You can shorten the stroke all you want but if the valves are floating nothing good is going to happen.
For example a factory Honda K24 engine has a 99mm stroke (roughly 4") and I've see people at the drapstrip turning them 10-11k rpm but they have really good valvetrain.
That being said why would you limit yourself power wise with a smaller motor when its easier to make power with a larger motor? The valvetrain in either motor would need to be the same if they were turning the same rpm.
For example a factory Honda K24 engine has a 99mm stroke (roughly 4") and I've see people at the drapstrip turning them 10-11k rpm but they have really good valvetrain.
That being said why would you limit yourself power wise with a smaller motor when its easier to make power with a larger motor? The valvetrain in either motor would need to be the same if they were turning the same rpm.
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07-28-2015, 12:14 PM
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I know this is an older thread but I'm still playing with the idea, only some pertinent parts have changed. I no longer want to do this in my G8GT. I'm almost to a point in my '63 Pontiac Catalina Gasser build that I want to play with this short stroke LS on the side. I'm storing my daughter in laws '82 Camaro at my house while my son completes his shop. BUT--my daughter in law is a big horse person and they own one horse and are bringing a second home. My son made the comment that they may not want to build the Camaro because she is fully into the horses now. So I may end up with it. (Sorry, long post but necessary to explain my position) It has a full updated suspension for handling, was a V6 4 speed car but it's really in great shape and ready for the LS swap.
I want to build the higher rpm motor, run a T-56 with the double OD, and run a very tall rear gear. 4:10 or even up to a 4:56. I'm sure I'll put on less than 1000 miles a year on it so it is just a very fun play car.
I just picked up a 4.8 crank. I find that the Honda sized Carrillo rods I've been setting on for many, many years are too narrow on the big end (.890 vs .940 on the LS) so I can never use them on this crank. So I'm looking at available rod and piston combinations to make it all go together. I feel the crank can take all I can give it. I'll got to after market rods in the 6.2 to 6.3 inch length and buy custom to fit pistons for it. That leaves cams and heads etc. But in the long run, if I can score a complete engine trans take out for what it will cost to build just the motor, then I may just take the easy way out and do that. I have lots to do and think about coming up.
Thanks for all your support and information guys. It is always appreciated.
I want to build the higher rpm motor, run a T-56 with the double OD, and run a very tall rear gear. 4:10 or even up to a 4:56. I'm sure I'll put on less than 1000 miles a year on it so it is just a very fun play car.
I just picked up a 4.8 crank. I find that the Honda sized Carrillo rods I've been setting on for many, many years are too narrow on the big end (.890 vs .940 on the LS) so I can never use them on this crank. So I'm looking at available rod and piston combinations to make it all go together. I feel the crank can take all I can give it. I'll got to after market rods in the 6.2 to 6.3 inch length and buy custom to fit pistons for it. That leaves cams and heads etc. But in the long run, if I can score a complete engine trans take out for what it will cost to build just the motor, then I may just take the easy way out and do that. I have lots to do and think about coming up.
Thanks for all your support and information guys. It is always appreciated.