Can I swap Pinto pistons onto different rods?

[dollie007]

As title says, in my 2ltr Pinto I have some fairly new oversize Hepolite pistons on standard rods, I want to swap the rods for injection ones with ARP bolts to strengthen the bottom end, I know they're interference fit but what is the best way to go about this, if it is at all possible?!

thanks,

Oliver

[Graham]

you severely risk damaging the pistons trying to remove them, the only method i know which will work for sure is to drill a row of 3mm holes in a line right next to each other all the way along the small end, you need to drill right down to the pin, dont worry the pin is hard enough you wont mark it if you only just touch it, the enlarge the holes to 4 or 5 mm, this will weaken the rod to such an extent the pins are easily pushed out

but to be honest injection rods are only a little stronger so i wouldnt bother, you can fit arps to std rods, as its the rod bolt that are the real weakness

[dollie007]

so standard rods with arp's would be ok for a road engine with and RL31 cam? I was worried that 7250'ish rpm would be right on the limit of the rods. And would the big-end on the rods still need re-sizing with the arp's in?

thanks a lot

[Graham]

7250 is pretty much the limit for the rods if thats your everyday rev limit, they will stand a bit more, it all depends how often the motor goes there, they will actually stand just over 8k but not for long or more than a few times

[dollie007]

I'm going to run it on throttle bodies and management so I should be able to control the rev limit fairly easily, I just don't want to constantly think it might cr*p its pants if I push it too hard, destroying an expensive cylinder head and the original block etc. It's not going to spend all day at those rev's because the car is in full road trim, but I do want it to be sufficiently quick to keep me entertained, hence the choice of an RL31.
thanks

[dollie007]

so do the standard rods need re-sizing in the same way as the injection ones when fitted with ARP bolts? i need to weigh up the cost of pistons, re-sizing etc.

[Graham]

i've fitted arps to several sets pinto rods and not had to resize them

[Dyno]

Like Graham says, don't worry about the RPM. Your engine won't be many times at 7250 with the RL31. Normally they don't make much power anymore once over 7000. You will change gear at approx 6500 and still be in the power range of this camshaft.