80’s 318 compression ratio figuring out where I’m at.
Will 273 piston pins work without mods to the kB pistons and stock 318 rods? Are those floating piston pins? Looking to do this cheap. I’m not building a daily driver. I know rebalancing is the right way to do things, but with 273 pins could I bolt it together and go? Wonder how much My 0.030 over pistons that are in there now weight compared to KB’s. I think they may be sealed power brand, I’ll check and see if I can tell if not I’ll post a pic and maybe others can help identify.
You can take the KB pins or 273 pins and press fit the new pistons into the existing rods. The 273 pin is .25" shorter so one would have to look at, or ask KB about, the KB piston pin bosses and make sure the pin would bear a minimum of around 0.6" in each pin boss.
FWIW, the pins with the KB's and the stock pins are the same diameter. The difference is in the small end of the rod.... your 318 rods will have a slightly smaller hole in the small end than the pin diameter, for the interference fit of the pin. If you want to float them, then you have to hone the small ends out a bit and float the pins directly in the steel rod ends, or have the small ends bushed. The 273 pins are a bit shorter
Finding 273 pins will take some patience. They can be in good condition because they were in floating pin small rods, but can also be in poor condition. The critical thing is the fine polished finish; that is critical for pin operation. You might have to get 2 sets to get one good set of 8 out of them... won't be easy.
Easier is just to get a few new parts measurements done on your new KB's, and the rings, which you can do with a digital scale. Then get some help with the bobweight number and take the crank only to the shop and say "Balance the crank to this bobweight". Ask them how much it will cost. (Some won't like to do just that, but a reasonable shop will.) I have had it done for $100 and I think Pishta had paid something $75 there in SoCal. Dunno about your area....
BTW, what is the intended use for this car/engine?
