["Puddles the Pontiac"]

will i be able to use a 4.25" stroke crank with standard length h-beam rods? i understand i may need custom pistons but what issues would come up? i would hate to have to get new rods. thanks for any input.

["Puddles the Pontiac"]

oh, how common is it to convert pressed pin rods into full floaters?

[potentpontiac]

Custom pistons with higher pin height no problem. Converting rods to full floating.Make sure it is done by a competent machine shop,otherwise no problem.

[RAIV55]

Originally Posted by Puddles the Pontiac

will i be able to use a 4.25" stroke crank with standard length h-beam rods? i understand i may need custom pistons but what issues would come up? i would hate to have to get new rods. thanks for any input.

If you are having to buy new pistons just order the compression height you need.

If you already have pistons the difference in deck height will be .020. Depending on your deck height you might be able to get away with going to a thicker gasket. If they are flat-tops it is also a simple matter to deck the piston. The shop i work at charges about $50 for such an opperation

[RAIV55]

Originally Posted by Puddles the Pontiac

oh, how common is it to convert pressed pin rods into full floaters?

If you are going to convert your rods to bushings, it is possible to off-set bore the rod to make up deck heights if required. (Tied in with previous question)

["Puddles the Pontiac"]

should i be worried about strength being compromised in the rod with the offset bore or issues with the wrist pin on the custom piston coming too close to the oil control ring land? i plan to make this a twin turbo engine. i am just entertaining the stroker crank idea, an extra .04" stroke may not be worth it. i just can never make up my mind sometimes. this may be a good case of the K.I.S.S. theory here on my part. i appreciate the input though.

[RAIV55]

Originally Posted by Puddles the Pontiac

should i be worried about strength being compromised in the rod with the offset bore or issues with the wrist pin on the custom piston coming too close to the oil control ring land? i plan to make this a twin turbo engine. i am just entertaining the stroker crank idea, an extra .04" stroke may not be worth it. i just can never make up my mind sometimes. this may be a good case of the K.I.S.S. theory here on my part. i appreciate the input though.

I have no experience with twin turbo applications so maybe not the best source of advice. If ordering custom pistons, tell the manufacturer what you intensions are so you get enough thickness and the top ring far enough down. I'd tend to think that you can get the whole ring package set up properly without having the pin in the oil ring land.

Concerning rod strength doing offsets and bushings, most of the rods I'm familiar with will handle up to .025 offset without compromising strength. Follow the advice of the machinist doing the work, some of this could be a judgement call.

[WARPed]

When it is all said and done the cost to “covert/adapt” to use your existing rods may be very close to just getting new rods and a common piston. So do you have a 2.225” journal 4.25” crank? If not you will not be able to use a stock (dimensional) rod and will need to go to a 2.20” rod. I would just build another assembly as rarely do things work out like this in saving money.

[Robert Williams]

I would go with a 6.800" rod with the appropriate pistons.