c32b

Hi, was thinking of a rebuild with the following mods to my f22c:

1. F20 AP1 pistons
Will these pistons have enough clearance? What are the potential downsides of this piston vs a mahle high comp piston?

2. Spoon gasket
which thickness should I opt for and together with the AP1 piston, will it clear safely? What will my final compression be like?

3. BC2 cams
What sort of hp can I expect with these mods together tuned on flashpro?

Thanks much for the guidance if any of you have experience with this setup.

s2000Junky

What is the reason for F20 pistons? As far as simply design goes, the F22 has arguably better pistons.

c32b

Basically i'm looking to up my compression with a set of pistons with/without a thinner gasket and with a set of cams to get more power.

Wanted to review a couple of my options

s2000Junky

Are the F20 pistons taller from wrist pin to deck?

c32b

I think so

wadzii

both motors have 1.181 compression height

ap1 pistons have about a 6cc dome, ap2 is around 3.

if you are on a stock bore engine i'd just mill about 0.020 off the head to get more compression. stock ap1 pistons are expensive as are the mahles.

The chambers are recessed in the head about 0.065-0.075" (you'll need to measure yours, they arent exactly consistent) The piston comes out of the deck 0.040 and the stock head gasket is 0.030.

The piston sticks up above the gasket 0.010, so you need to keep the chambers recessed about 0.040 to maintain 0.030 piston to head clearance.

0.020 off the head will get you about 1.2:1 more compression than stock. the bc2's will work well with a high compression 2.2, especially compared to ap2 cams.

c32b

Thanks wadzii. Don't have the engineering expertise locally to do the milling you mentioned. What sort of total whp will a mahle piston + bc2 give my f22 after tuning on flashpro (assuming no headwork and stock gasket thickness?) in your opinion?

wadzii

I'd say you'd be in the 230-240 range. Pm me on the pistons.

efi2nr

Not a fan of milling the head as it changes the cam centerlines and pushes the valve deeper into the valve pocket. There are better ways to bump the cr

wadzii

These things have tons of room in the valve pockets and milling the head 0.020 retards the cams about 1 degree. Doesn't really change much. The large diameter of the main timing gear keeps the timing pretty normal when you mill the head. Its not like a b or k series where you'll see 3 or 4 deg change milling the head.

Mahle has some 9cc pistons which will get you over 13:1 on a 2.2liter.