Engine Balancing?

[Ed]

I've got a F54 that is ready to put back together. I had the opportunity to weigh the piston/rods the other day and decided, why not. I weighed the piston, rod, cap, bearings & bolts as an assembly. The heaviest was 2 lbs 14.15 oz. and the lightest was 2lbs 13.95 oz. is this difference big enough to have the engine balanced. I was just going to put it all together and not give balancing a second thought but after seeing this??????

What do you guys think? I'm not planning anything drastic with this engine 6k rev limit N/A. Street use. Should I get it balanced?

[2ManyZs]

I wouldn't if it's just going to be a street engine. Unless you just want to play around with a die grinder....:cross-eye

Truthfully, that probably is pretty good for a mass produced engine and parts. That little weight difference over 6 is pretty darn close if you asked me.

[Phred]

2ManyZs,

I Agree. Part of my job as a vintage racing engine builder, is balancing. I just figured this up in my noggin, but I think Im close.

His difference is only .2 oz. One oz. is 28 grams. So .2 oz. is about 5.5 grams. Race engines require a tolerance of plus or minus .5 grams for each component. So for a streeter, thats only

plus or minus 2.75 grams. Actually thats darn good. FWIW.

Phred

[2ManyZs]

Being a "shadetree" mechanic at best, I didn't break it down into grams like Phred did. But thinking about it, I'd say this is quite amazing to see an engine with 70's or 80's technology coming out this closely.

Today's engine are built on an assembly line as well, but because of the compression ratios used, and the temps today's engine operate at for emissions controls etc. the tolerances they are built to would be hard to beat. With today's CNC machines and such making the basic assemblies, they are probably even closer than this. But that's what makes this one stand out. They didn't use CNC machinery like they do now to make their basic assemblies like pistons, pins, rods, etc. They were probably still using just an investment cast part.

Good job Nissan....

[Mudge]

Heh, and name a single American car company using CNC internals?

Is that the ocean I hear?

Cast internals are still abound.