I've been researching buying a new set of pistons. I read where on the 5.4 the piston is over .100" in the hole? Is this right??

Not sure the exact thickness of our head gaskets but assuming .050" that would give us a quench of .150"!

Now I'm just a novice engine builder but I've always heard that a quench around .040" is optimal. This would mean the pistons need to be over .110" longer to reach that.

Has anyone used a custom piston that is longer, with a deeper dish to equal out the comprssion ratio?? If so from what company?

 

Up till recently the only off the shelf pistons available were actually 4.6L specific, so yes they are pretty deep in the hole. Supposedly there are 5.4L specific pistons now available(off the shelf) to address this problem, but good luck getting any info about them from anyone but the manufactor, whoever that is. I would start by checking w/CP and JE

 

As I remember stock deck height is 0.135" plus gasket thickness, in other works NO effective quench. My motor has the old style JE's.

CP makes them and believe JE does also. One local set of the new CP pistons required some additional valve relief in the quench area to provide clearance for Patriot/Comp Stage II cam.

Actually the best solution would be longer rods with 4.6 style pistons and deeper dome, but both would be custom.

 

Thanks for the info!

Searched and didn't find any specific part numbers that mentioned a change in deck height. Guess I'm going to have to call. After seeing what Bad as L paid for custom pistons I'd really like to buy off-the-shelf if I can .

 

VTengines has been very helpful...
They carry a zero deck 5.4 piston with a 35cc dish to give 8.5:1 compression on a 2-valve head. They can do a custom dish for $100 more to give 4-valves heads a better compression ratio. Believe CP or Diamond are available.

 

The zero deck pistons are listed as 5.4 specific pistons on one site rather than 4.6/5.4. They will have different part number than the 4.6 2V piston.