Quote:
Originally Posted by bluemax_1
Piston slap on a cold engine with forged pistons all depends on the pistons themselves and how well the machine shop knows their stuff.
I've been driving a fully forged bottom end for the past 4-5 years (since I was forced to rebuild due to a stupid local shop spinning a bearing on my car from joyriding in it WITHOUT my permission when I took the car in for some suspension part replacements  ).
I have ZERO piston slap with the off-the-shelf Ross 6g72 pistons when cold and I daily drive this car even through the winter. When I took the block to get it machined, the shop called me back and asked me if I intended to run nitrous on the car. I said no and asked why. They said they bore for looser tolerances for nitrous due to the higher temps (and resultant piston expansion). Since I wasn't going to run nitrous, they called Ross and checked what the allowable tolerances were and bored to that (OTS Ross pistons require an overbore anyway due to being 93mm IIRC).
Max |
I'm glad it worked out for you, but it doesn't always work out that way. The factory didn't just use cast pistons because they were cheaper. Long term wear on stockish power is going to favor the stock pistons because they have less expansion and therefore a more stable bore to cylinder clearence.
The bottom line is really I don't see a point in running forged pistons with stock rods or even if you are under 500AWHP or so. Sure, there are ancillary benefits such as cooler running pistons, maybe slightly less prone to detonation, etc, but as far as straight durability and reliability I don't see the benefits.
Most of the rebuilds I see blown up on here are the people who went stage 3 everything as soon as their stock motor wore out. Too many people feel the need to upgrade when they really just needed new or rebuilt factory items.