Rebuild suggestions

[Scrymerr]

I just got a 6bolt motor with shot rings. The cylinder walls look fine. THe motor has about 60k miles on it. I am going to remove the balance shafts, as well as put crower rods and ross pistons .020 over in. I have a few questions though:

1.) what are the pros and cons of lightening the crank? I want the motor safe to rev to 9k, but also last a long time.

2.) What machinework must be done other than the boring/honing of the cylinders, and decking of the blocks face? Is there anything that needs to be done to put new main bearings in?

3.) What would the ideal setup be to preferably be capable of 700whp, yet last a long time. Realistically my setup will only yield ~500whp.

I am just trying to figure out the best way to go to have a solid motor built, that will hold a lot of power, yet last a long time as well. Thanks in advance.

 

[joeracer321]

First you must set a budget, then factor in another 10%. Then you can decide what is affordable, and go from there. If money is no object then of course, go with a lightweight forged crank, forged rods, and lightweight pistons, then add new light valves, springs, retainers, and a good set of locks, throw in cams, blah blah blah and you have a monster.... If you need to hold 500 hp realistically then what you need is a descent crank, good rods, good pistons, and an excellent machinist. Headwork will also help you get the numbers you want, but don't just go hogging out the heads, that will make the situation worse. Find someone who knows how to do it or leave it to the pro's. Good luck with your project

 

[Scrymerr]

Thanks for the response, that makes sense. However, that still leaves one question unanswered: are there any longevity issues associated with a lightened crank?

I plan to run crower rods on ross pistons and pay a machinist whatever it will cost to install those.

 

[joeracer321]

Not really, if it is done correctly, the common practice in modifying the crankshaft is to knife edge the crank, this does significantly lighten the crank but then the entire assembly must be rebalanced. For what you are doing, I don't really think that this process is necessary. But I do recommend when you get your rotating assembly squared away that you bring it all to the machine shop so that it can be balanced. You usually need to bring your dampener, flywheel, crank, rods and pistons. Doing this will increase the longevity and give you a smoother RPM band.