How much is it to machine/balance etc a block to a 306? + other shortblock questions.

[BlueOvalStangGT]

Trying to find ideas for what im gonna do with my engine. Im on a budget so I need to make up a parts list and stuff.

First,
How much does it usually cost to machine/balance etc a block to a 306?

Second,
I found a 331 with a spun rod bearing for cheap on corral, how much is it to fix that or is it not worth it?

3rd, What parts would I need for a 306(stock rods right? what brand pistons, bolts, etc)


Thanks guys/

 

[Joes95GT]

1) Machine costs vary by area. I don't know anyone who has gotten machine work done at a shop. I do all my own, and my friends machining. I use my school's machine shop (University of Delaware) because it's free. Can't help with that one..

2) A spun rod bearing, if that is really what it is, is an easy, but complicated fix.

First you have to check the big end of the rod to see if it needs to be machined (essentially bored) 0.010" or 0.020" out.

Then you've got to mic the crank on that journal to make sure the rod or bearing hasn't scored the crank or taken it out of round. If so, you'd have to get the crank turned 0.010" or 0.020" - whatever it'll take to fix it.

And, if the motor is new(er), I would recheck ALL clearances. On most new motors where you see rod bearing failure, there is a good chance that failure is setting in on other journals as well. You would at a minimum have to check all the clearances again and make sure they check out OK.

3) For the 306, I would reuse the stock rods (first check them to make sure they are all round and still in spec). I would upgrade the rod bolts to ARP, too. Put a good lightweight piston in the motor, and take it to the machine shop to be rebalanced. It should be very close to being "balanced", so it shouldn't cost too much.

Joe

 

[Chythar]

I'm also thinking about going to a 306, like BlueOvalStangGT. What kind of piston would you recommend? Presumedly forged, or stick with hypereutectic?

 

[BlueOvalStangGT]

What pistons would you recomend Joe? What else would I need other then bearings, bolts and freeze plugs for a rebuild. Does summit /murrays carry all this stuff?

 

[Grn92LX]

Joe, thats cool that you know/do that machine work sh it. What do you go to school for?

Blueoval, once you add up the cost of a 306, you'll quickly see its not much more for a 347. If moneys an object you can have your assembly balanced to 50oz even though its not ideal. I have probe srs pistons in my 347. I like them because they have reliefs for inline and TW valves.

 

[Joes95GT]

Kevin - I like Probe. For no other reason than I've never seen any problems with them. There are some people out here that really dis on Probe for some random reason, especially the Ross, and J&E nuthuggers. Those who say Probe's pistons are junk are retards and should be avoided at all costs.

Freeze plugs are freeze plugs as far as I'm concerned. Buy what fits...

Make sure to get a good piston ring. Speed Pro's are the chit, and, should be available through Scummit.

Mike - Machine work isn't a real rocket science....probably why I can do it. It's more of understanding the machine than the actual work. I've never done line hones or bored motors. I've turned/cut cranks and rods, angle milled, and flat milled....pretty basic.

My major is mechanical engineering notnice. I have a double minor - business/economics nonono and partying nice: ).

Joe