[drewhelm1974]

Aside from the fact that a BBC rod requires a 2.20 rod journal, let's say a BBC rod is 6.635 in length....so it's .010" longer than a stock Pontiac rod, would it work with a piston already swinging on a stock Pontiac rod?

Next question....if the rod is bushed to Pontiac wrist pin size and set up for a floating piston, what needs to be done to convert it to work with press fit wrist pin? Can the rod be adapted or are new pistons REQUIRED?

Thanks!

Drew

[screamingchief]

It's easiest to just modify pistons like those pressed pin TRW/speed-pro style pistons for use with something like those 6.635" bbc eagle rods with their .990" bbc floating pins,as that just requires boring the pin holes bigger and adding the lock grooves to the pistons,not a major deal if your just trying to make some parts you already have "fit together",but if your starting from scratch,it's easier to just use the right pieces from the start.

Rebushing a rod wont work for a press fit piston,so that's a no-go situation there,the piston would still need to be honed and have the lock grooves cut for a .980" floating pin regardless,so you see why it's just easier to go ahead and use the .990" pins and eliminate the need to rebush the rods for .980" floating pins.

What's the deal?
I mean what are you trying to accomplish with this scenario?

If your just trying to get those TRW/SP style forgings up a bit further in the bores,then it's a lotta effort compared to just decking the block.

But if your looking for a way to salvage a injured crank and some decent pistons,then it makes a bit more sense.

More info will surely help us in giving better advice.

Bret.

[crazypont]

I sell H beams that are for the 2.2 journal/6.605 Length/.980 bushed pin if this will help.

I had these made to take a 4.250 stroke crank with the 2.2 BBC rod size to work with any off the shelf Pontiac floater 455 piston and still end up with the "factory" spec deck height. 8740 7/16 ARP rod bolts, 4340 steel, $400 per set of 8. Approx 810 grams. And these use a 1.800" Long rod bolt. The Eagle uses a 1.750" long bolt for comparison, and some use only a 1.600" UHL bolt. Not saying that the 1.6 isn't strong enough, just stating what is available.

[drewhelm1974]

Realistically, I am trying to save an injured crank and decent TRW pistons. I am trying to compare my options to get the most bang for the buck and the least buck, yet swap to a forged rod.

I currently have a 455 crank that's been turned .020 on the Mains and .030 on the rods. The rods need to be turned so I was thinking of having them cut to use a set of BBC forged rods, but I wanted to be able to keep the pistons I already have, too. If the machining is more expensive than it's worth to keep the existing pistons, then I might as well go with new. Just trying to figure out what is feasible before taking anything to the machine shop.

Thanks!

[Skip Fix]

Honing the pin holes to .990 on the TRWs shouldn't big deal for the machine shop. Just get press fit BBC rods.

I think I have a 0.030/0.030 fresh 455 crank if that would help.

[screamingchief]

Skip,I think the only 6.635" BBC rods are all strictly floating pin,no pressed pin applications in that length that I've come across.

IIRC eagle are the only folks selling a 6.635" BBC rod,and it's a bushed rod.

Still like was said,no biggie,just look into the cost to hone the pin bores to use a floating .990" BBC pin and get the lock grooves cut,if it's not too much,then the answer is pretty clear.

There was a set of the 6.635" eagles in the for sale section,they had been re-bushed to use a .980" floating pin,that would work,still would need to do some minimal work on the pistons though.

And Dave's rods are in the same boat,the TRW/SP pistons would still need a slight hone for clearance and the lock grooves cut for the .980" floating pin.

Sure would be real nice if somebody would step up and offer a .980" pressed pin 6.635"/2.20" rod for exactly this reason,would make saving those wore out stock stroke cranks for just a little longer a whole lot easier...

Dave's rod would work for those that choose to offset grind a stock crank for the "extra bit more" of stroke,but often folks dont wanna bother with that if they dont have to,or if they cant find a good place to do that kinda work,but again,would be nice to have a pressed pin option to choose from as well,as there are tons of builds that use those TRW/SP pressed pin pistons out there that would require a pressed pin rod,or mods to the pistons to work with a floating pin set-up.


Bret.

[drewhelm1974]

Thanks for all the info!

Drew

[drewhelm1974]

Skip, what did you want for the 30/30 crank?

Thanks!

Drew

[Skip Fix]

Give me a call.

[drewhelm1974]

Skip, I'll give you a call tomorrow around lunch.

Thanks!