408 Stroker With Stock Rods

[Boosted92LX]

Well, I cant speak for chinese crankshafts, @madmike1157, but I can speak for used oem parts. Think about this.. If you take apart a stock 5.0 and weigh the rods and pistons they can be as far apart as 10-20 grams. These engines will run for literally hundred of thousands of miles. I've put together several 302s and 351s that did just fine up to 6k rpm, but used stock parts. Mind you, they were all from different engines originally. I've heard 393s can be tough to balance, but I'm not sure to what spec that is referring to. If that means anything better than what the factory does, I personally wouldn't sweat it for a street car. Just my .02.

 

[CarMichael Angelo]

Well, I cant speak for chinese crankshafts, @madmike1157, but I can speak for used oem parts. Think about this.. If you take apart a stock 5.0 and weigh the rods and pistons they can be as far apart as 10-20 grams. These engines will run for literally hundred of thousands of miles. I've put together several 302s and 351s that did just fine up to 6k rpm, but used stock parts. Mind you, they were all from different engines originally. I've heard 393s can be tough to balance, but I'm not sure to what spec that is referring to. If that means anything better than what the factory does, I personally wouldn't sweat it for a street car. Just my .02.

I'll see your .2 and raise you a nickle.


I'm playin the " how do you know that if you didn't check it ?" Card.

How did you know that there was such a giant weight imbalance if you didn't check it? And if you found a 20 gram imbalance ( which is just 8 grams short of an ounce) how much heavier/ lighter do you spose that piston would be when you start slinging it around at 5000 RPM?

I'd venture to think that one ounce swinging up and down violently at 5000 RPM would create a massive amount of disharmony between the 7 other Pistons doing the same on that crank.

Think about that for a second.... You can actually feel an out of balance tire that is corrected w/ a simple one ounce wheel weight. And that tire doesn't have a whole bunch of other tires riding on the same axle, on the same corner, going different directions, at a bazillion feet per second.

Now on a street engine using swapped stock stuff for more of the same stock stuff id imagine that things would be pretty close. But I've never checked that, and I don't use stock stuff.

But on a 393 stroker where there is already a crank from Ding Pau foundries in the equation, and 8 little piggies from Speed pro held on w/ a stock 5.96 length Windsor rod......would I neglect to balance that Assy?

( I get to say my patented inconsiderate, jerk like, noob offending single one liner here)

( For the second time in a week)

Sure....


When Hell freezes over.

 

[Boosted92LX]

I'll see your .2 and raise you a nickle.


I'm playin the " how do you know that if you didn't check it ?" Card.

How did you know that there was such a giant weight imbalance if you didn't check it?

When did i say I didn't check it? I haven't always paid for professional balance jobs.. Some I've thrown together, some I *GASP* weighed myself!
Ever heard of a scale, Mike?

It's an amazing invention.. I can't believe you've never heard of one...

 

[CarMichael Angelo]

When did i say I didn't check it? I haven't always paid for professional balance jobs.. Some I've thrown together, some I *GASP* weighed myself!
Ever heard of a scale, Mike?

It's an amazing invention.. I can't believe you've never heard of one...

So ........you checked it w/ a scale, and you had no problem resembling a mis matched recip Assy w/ a one ounce imbalance then?

Or are you saying that Ford actually had a running motor with that kind of imbalance?

 

[Boosted92LX]

So ........you checked it w/ a scale, and you had no problem resembling a mis matched recip Assy w/ a one ounce imbalance then?

Or are you saying that Ford actually had a running motor with that kind of imbalance?

I'm sorry. Did I say they varied in weight 10-20 grams, or did I say an ounce?

 

[CarMichael Angelo]

Hold on, no wadded up panties please.

I said that 20 grams was just 8 grams short of an ounce.

And while you were eating your wheaties that I must've pee'd in, I checked.....

You're right. Ford actually assembled engines with up to an ounce of imbalance that ran for eternity until they were tore down.

So, there.

I said it.

You're right.

You still dress funny.

 

[Boosted92LX]

Hold on, no wadded up panties please.

I said that 20 grams was just 8 grams short of an ounce.

And while you were eating your wheaties that I must've pee'd in, I checked.....

You're right. Ford actually assembled engines with up to an ounce of imbalance that ran for eternity until they were tore down.

So, there.

I said it.

You're right.

You still dress funny.

Why do you question me? When have I lied to you? *sigh*

Edit: and fyi- I found the lightest piston/rod and matched the rest to within .001 gram.

 

[CarMichael Angelo]

Why do you question me? When have I lied to you? *sigh*

Edit: and fyi- I found the lightest piston/rod and matched the rest to within .001 gram.

I was doing something other than questioning you...
Relax.
The one leg that I was pulling on isn't any longer than your other one.

You cannot call in sick tomorrow with a limp.

 

[Boosted92LX]

I was doing something other than questioning you...
Relax.
The one leg that I was pulling on isn't any longer than your other one.

You cannot call in sick tomorrow with a limp.

Good save.

 

[CarMichael Angelo]

Good save.

Thanks,...I'm practicing for an actual instance where I may need my to challenge somebody else.
This is the softer version w/ no after taste, @Boosted92LX

 

[Bradley Duerksen]

So i pose you this...if all parts were ground down to as close to each other as possible, and the crank was zero balanced on its own, could you not consider this to be a zero balanced rotating assy? I mean, the rods and pistons weights are equally dispersed throughout the 360°of rotation, right?

 

[Boosted92LX]

So i pose you this...if all parts were ground down to as close to each other as possible, and the crank was zero balanced on its own, could you not consider this to be a zero balanced rotating assy? I mean, the rods and pistons weights are equally dispersed throughout the 360°of rotation, right?

Only time i ever tried a zero balance setup i took it to a machine shop and had it balanced there. That particular motor I wanted to be dead on because I was going to rev it to the moon....so- to be honest, I couldn't answer that question..

Maybe @madmike1157 can?

 

[CarMichael Angelo]

I can't say either,.I'm certainly no machinist.

Every engine I've had that has been balanced (to include the current one, that uses a SBF balancer) is neutral balanced.
I think that regardless of how it's balanced though, the recip assy has to be balanced taking the bob weight of the rod/piston/ring/bearing assy into consideration. The purpose of the crank counterweight is to offset the rod/piston weight.
Just making sure that the rods/pistons/rings were all the same weight doesn't change the fact that depending on piston weight, the crank counter balance weight may need more or less weight added/subtracted to offset that.

I think most of the time IIRC, all of my strokers (347, 393,363,438) all had mallory in the counterweights

 

[Boosted92LX]

I can't say either,.I'm certainly no machinist.

Every engine I've had that has been balanced (to include the current one, that uses a SBF balancer) is neutral balanced.
I think that regardless of how it's balanced though, the recip assy has to be balanced taking the bob weight of the rod/piston/ring/bearing assy into consideration. The purpose of the crank counterweight is to offset the rod/piston weight.
Just making sure that the rods/pistons/rings were all the same weight doesn't change the fact that depending on piston weight, the crank counter balance weight may need more or less weight added/subtracted to offset that.

I think most of the time IIRC, all of my strokers (347, 393,363,438) all had mallory in the counterweights

I agree with the counter weight vs piston bob weight for performance reasons.. But I think as far out of whack as ford puts them together, and they don't vibrate themselves to pieces as pointed out before, I don't see how matching the weight of the pistons hurts.. especially since they aren't balanced with the crankshaft. Rather, simply manufactured to a factory tolerence.

Now, that being said.. I'm not trying to convince people that paying for a balance job is a bad thing!!

I am saying that it's not always necessary for the application- especially when on a tight budget and not building a monster. In fact, I think in that case If you actually consider what people do with stock bottom ends, it could be an outright waste of funds.

But, for a race engine, there's no reason not to.

 

[Bradley Duerksen]

Yeah ok. I'm trying to do as much of my own work as possible, avoiding paying someone else's labor bill, but not at the expense of safety, quality, or longevity.

 

[CarMichael Angelo]

I agree with the counter weight vs piston bob weight for performance reasons.. But I think as far out of whack as ford puts them together, and they don't vibrate themselves to pieces as pointed out before, I don't see how matching the weight of the pistons hurts.. especially since they aren't balanced with the crankshaft. Rather, simply manufactured to a factory tolerence.

Now, that being said.. I'm not trying to convince people that paying for a balance job is a bad thing!!

I am saying that it's not always necessary for the application- especially when on a tight budget and not building a monster. In fact, I think in that case If you actually consider what people do with stock bottom ends, it could be an outright waste of funds.

Do I get to even out your other leg today?

 

[Boosted92LX]

Do I get to even out your other leg today?

Nothing will stop my battle against ignorance!!!!

 

[CarMichael Angelo]

Yeah ok. I'm trying to do as much of my own work as possible, avoiding paying someone else's labor bill, but not at the expense of safety, quality, or longevity.

All I can say is that if you were building any stock stroke Ford engine, I'd be all on Allen's side of this. It's only the stroked crank that has me erring on the side of caution in your case. After reading that stuff I read last night from engine builder magazine about the factory imbalance being off as far as an ounce w/o detriment, I was surprised to learn that. That same article also stated that most machine shops will balance to w/i a 1-2 gram discrepancy.
I'd defer my judgement to the following two scenarios:
1-2 gram difference.......

What can possibly go wrong with that?

20 oz or more difference....(remember,...you cant spin the crank with a bobweight clamped to the rod throw)

What could possibly go wrong w/ that?

 

[CarMichael Angelo]

Nothing will stop my battle against ignorance!!!!

I'll call you the Grey Matter Crusader.

Dahn da na na NAAH!!!!

I will send you your cape right after I get done with my coffee.