is this a rumor about forged internals?

[jaredgsx]

I head that you have to get new ones every year or so, or atleast change the rings. This sounds a little bogus to me, just wondering if anyone else has heard the same or if its true.

 

[GVR4592]

It's not true. If the engine is built properly and properly tuned it should last a long time.

 

[eldiabloz13]

nope there forged internal for a reason. There made to handle what the stock cant. This also being the time spand. Unless you beat on them and put boost like 129291 psi they should last a while. Hell if you had to do that no one would buy them. They would all stick with stock.

 

[jaredgsx]

boost like 129291 psi

haha i wish.

From what this one guy was telling me, the forged pistons are made with 1/1000 tolerance, while the stock ones are 1/1000000. He said that they slap around in the cyclinder wall just a little bit and that is what causes the rings and if not the pistons to be messed up after about a year of hard driving. And that is why they all sound like crap at idle.

Does anyone who have ran forged internals for a while, have you guys have any problems

 

[droppinbottom]

I have been told by a local dsm shop that if you do run forged internals it will wear the cylinder walls quicker than if you run stock internals. Example I was given is forged internals should last about 30k miles and on stock internals you should be able to get over 100k before a rebuild.

 

[jaredgsx]

Well i would like to hear from someone with forged internals about the longjevity of them

 

[Spoolin4Ever]

Cast Aluminum-
- Molten aluminum is poured into a mold, the aluminum cools, and hardens. The casting is then machined. Cast aluminum pistons have a crystalline structure which is not as strong as that of a forged piston. Steel bands are inserted in the mold when the piston is cast, to control expansion of the skirt area to be parallel to the wrist pin, which allows piston to cylinder wall clearance to be set closer, and, therefore, a quieter engine with less piston slap.
Forged Aluminum-
- A solid slug of aluminum is pressed, very quickly, and with a great deal of force into a die. The resulting forging is then machined to shape. Forged pistons have a grain structure rather than a crystalline structure, this makes them much stronger, and able to take more punishment. For many years forged pistons were used in racing and extreme high performance street engines, but recently have fallen out of favour, because of their relatively heavy weight. Forged pistons also cause the engine to be more noisy because wider piston to wall clearances, required by their lack of steel bands, cause more piston slap. Forged pistons should be considered for racing purposes only, if at all.

 

[Spoolin4Ever]

http://www.google.com/search?hl=en&q=forged+internals+piston+slap

 

[wret]

haha i wish.

From what this one guy was telling me, the forged pistons are made with 1/1000 tolerance, while the stock ones are 1/1000000.

So what your friend is saying is that stock tolerance is one thousand times tighter than forged? Someone has their fractions confused. And, are we talking tolerance or clearance? Big difference.

 

[jaredgsx]

So far no one has answered my question. I was wondering if anyone with forged internals could tell me about the longjevity of them

 

[jking29]

Forged pistons require more clearance cold because they have a greater expansion rate than cast. That is why you get piston slap when cold, which doesn't do any damage, just a little annoying. As far as having to change the rings every year it's nonsense. The 5.0 Mustangs had forged pistons stock from 94 on, and I have seen stock short blocks running 10's with 150,000 miles on them. You do have to make the ring end-gaps a little larger to compensate for the expansion of forged pistons though.