383 question

[Hipster]

Balance it. The machine shop should should ask for the balancer and flexplate. If not, your in the wrong shop. I don't mess with Eagle stuff nor any white box special of the week crankshafts. I also don't mess with pre-balanced kits.

 

[Erik the Awful]

When I built my Suburban's second motor (that turned out to have a cracked block) I balanced my rods in my garage with a Harbor Freight scale. Some people will claim you need another decimal place in the measurement to truly balance them, but I got significant gains from the Harbor Freight scale. The guy who bought my Suburban said it was the smoothest running small block he'd seen, and it was a shame the block was cracked. The most difficult part was making a fixture that held each rod straight to get a good measurement - I balanced each end of the rod separately. A machinist should go a step further and balance the rods with the crank.

 

[Hipster]

Pistons get weight matched, rods get weight matched, big and little ends then total weight because the big end is considered rotating while the other end the other end is considered reciprocating. Pins and locks get weighed. Balancer and flexplate go on the the bob weighted crank and it gets balanced. A street balance job is not the same as a race balance job and calculated off difference balance factors to compensate for the rpm ranges the engine is going to be running in etc.

Aftermarket rods commonly need resized/honed on the pin ends which adds a little cost into the grand scheme of things.

 

[Erik the Awful]

I honed my rod ends with some emery cloth, PB Blaster, duct tape, and a drill. Use a fine grit and take it slow and only hone them enough to get the pins in. Keep that drill perpendicular!

 

[98k2500]

Replacing rods and pistons adds about $325 to your build. Cheap enough that I did it on my 'budget build', but if I didn't need an overbore I'd probably have stuck with stockers. If you're going 383, at least pistons are necessary, and the $225 you save by reusing the rods are eaten up by the $90 for rod bolts and $70 for having the machinist install your pistons. At that point you're only $60 from new floating-pin rods.

Pressed pin rods = paying your machinist to install the pistons - the stock rods are pressed-pin.
Floating pin rods = easy DIY, but pay attention to whether they take spiralocs or wire locks - they SHOULD come with the correct locks.

I read this in one of David Vizard's books..."If you are staying with a stock-style piston, which has no means of pin retention, then the press fit pin has to be retained. However, most aftermarket pistons have circlip pin retention built into them so they can be used with full floating pins or press fit pins. It used to be the case that to convert to a fully floating pin end on the rod they had to be bored out to take a thin-wall bronze bushing. That is not the case any more as modern oils have made the bronze bushing a redundant element in this application. If you choose to go to the full float-style pin, have the rods honed to give a clearance of 0.0007 to 0.001 inch."

If I am understanding this correctly you can use the stick rods with floating pin pistons?

Thanks to all who take the time to reply and educate me. I appreciate it.

 

[98k2500]

Also any one know the wrench size for the through bolt on the stock obs 4x4 engine mounts? I need to stop and pick one or two up on the way home and forgot to check.

 

[Manimal]

The bolt was 5/8 on one end and 11/16 on the other. At least mine was.
As for the pin bushing, I have never heard of a wrist pin riding(floating) on steel. It would definitely seize it the rod. That is MY understanding anyway.

 

[98k2500]

The bolt was 5/8 on one end and 11/16 on the other. At least mine was.
As for the pin bushing, I have never heard of a wrist pin riding(floating) on steel. It would definitely seize it the rod. That is MY understanding anyway.

Thanks for the info on the bolt.

I was just reading more about pistons and rods on the web. I'm probably asking questions that have been asked hundreds of times to try and save a buck, lol.

I am realizing it's probably best just to buy a kit. Although, I think it's kind of fun to try and figure out and do things sort of diy if I can. I'm not really in a hurry.

 

[Erik the Awful]

You can probably have the stock rods machined and bushed for floating pins, but the stock rods are weak enough on the small end that I wouldn't do it. Also, what does the machinist charge for that? Floating pin rods are $225.

 

[L31MaxExpress]

The bolt was 5/8 on one end and 11/16 on the other. At least mine was.
As for the pin bushing, I have never heard of a wrist pin riding(floating) on steel. It would definitely seize it the rod. That is MY understanding anyway.

The old solid lifter LT1s and DZ 302s were both built that way. Steel pin to rod and they had floating pins. GM gave those engines a factory warranty too. I would have to check but I am fairly certain the LQ9 was built the same way. I have rods and pistons for one sitting at my shop in a bucket.