FRP Sleeves and Forged Pistons

[bluecb7]

I know traditionally you cannot put forged pistons in an engine with FRP sleeves (such as the h22), but I do not know why, and am in need of a little clarification. Also if it could be done and my horsepower plans are to make about 250whp, and leave the bore alone, would it be better to get the forged pistons that will work with FRP sleeves, or just get it sleeved? Thanks in advanced.

[foamypirate]

First of all, it's FRM.

You could also push 250whp with a completely stock block, as long as your tuner knows what he is doing. If you are interested in spending 1500+ on the block, sleeve it and do rods/pistons.

It's all up to your budget and what your tuner can do.

[judonoh]

first off the issue with the FRM sleeves is that they are dissimilar metals that DO NOT work together at all. The metals will grab each other and grind.

As for the 250hp goal I believe that this is possible without sleeving. I would run the mahle or je coated pistons. Make sure that you get it tuned right, that helps alot.

[mozzandherb]

As stated FRM sleeves would break, crack, basically be no good with forged pistons because of the differences in metals that are used. And yes 250 is achievable on a stock block, and yes the Mahle's would be good to use with FRM sleeves, that's what they are made for, and I would be tempted to try them out

[blazen_accord]

here the techy detail about FRM and while it would not work with forged piston. Basically from what I have learned, the FRM is special soft expanable metal while forge piston is to rigid(tough) for this type of special metal. A special coating on a piston like the Mahle H22A gold are said to be compatable with FRM sleeve.


Making FRM sleeves goes something like this: First a fiber-based material in the shape of the cylinder sleeve is inserted into the die of the cylinder block. Liquid aluminum is then poured into the die and fuses with the fiber sleeves. Once the block is ready for it, the cylinder walls are machined to the desired bore dimension, leaving only 0.5mm of thickness to the fiber sleeves that cover the cylinder walls.

With the reinforcement the sleeves generate lower friction than traditional iron liners, which translates to improved revolutions, power and reduced wear. In addition the thinner fiber sleeves fortify the block, allowing the distance between adjacent bores to be reduced while maintaining strength and rigidity.

There are drawbacks, however. It can be argued that because they are so thin the sleeves were not designed for too much boost pressure, which limits the potential of the stock engine and poses a challenge for us.

Overboring for more displacement is also out of the question since the sleeves are so lean. Even if you machine-off enough material to avoid breaking through to a water jacket, you still have to deal with the softer untreated metal under the fiber layer. For these reasons it is recommended that H22 sleeves never be bored or honed, always replaced.

[bluecb7]

I was planning on going with the Mahle pistons. I was also planning on getting new connecting rods, and all that, I was just wondering if I could get away without sleeving if I used the Mahle pistons.

[mozzandherb]

I was planning on going with the Mahle pistons. I was also planning on getting new connecting rods, and all that, I was just wondering if I could get away without sleeving if I used the Mahle pistons.

yeah that's what they are made for, so you dont have to sleeve

[wed3k]

would anyone know if the mahle's and je's run larger clearances for piston to wall so even a stock block can be honed another thousandths just so you can get the cylinder bores true and straight.

[blazen_accord]

here is some malhe piston info

87.00 90.00mm 143mm 22mm 31mm -7cc 328g 9.0, 10, 11.5
87.25 90.00mm 143mm 22mm 31mm -7cc 331g 9.0, 10, 11.5

[d112crzy]

would anyone know if the mahle's and je's run larger clearances for piston to wall so even a stock block can be honed another thousandths just so you can get the cylinder bores true and straight.

gotta ask the manufacturer. They all have different silicone amounts, so they expand differently.