Piston protrusion issue

powerstrokeboss · Aug 12, 2018

Hey,
I'm rebuilding my 04 6.0 and come to a little speed bump.
I had the head and block machined and I've got the pistons in now but they have a .040 protrusion above the block. Now I also have a stage 2 cam with more lift which could add to the problem. The thing I'm wondering about is If my fly cut pistons will clearance this or if I need to have them machined, the kit is a stage 2 dynamic diesel rebuild.

Any help is appreciated

Extended Power · Aug 12, 2018

If it were me, I'd get 0.010" or even 0.015" cut from each piston top, and have them de-lipped.
Makes less compression, but since you are planning compounds, it's a good idea.

powerstrokeboss · Aug 12, 2018

They are delipped but I I guess to be safe it would be a good idea to take some off.
Unless anyone has other experience with piston protrusion

Jcpsuperduty17 · Aug 12, 2018

Shave the pistons down.

powerstrokeboss · Aug 12, 2018

Sounds like that's the general consensus, that sucks.

powerstrokeboss · Aug 13, 2018

I took some more measurements and the fly cuts are .010 below the block and the rest of the piston is .040 above. If the valve reliefs are below the block, will this still be a problem?

powerstrokeboss · Aug 13, 2018

Ok, I contacted dynamic diesel and they got back to me right away, assuring me that with the valve pockets it would be fine even with the stage 2 cam. The gasket is about 0.052 this so the .040 piston protrusion is fine!
Big relief.

TRUBBS · Aug 13, 2018

I would be careful, if it was me I would machine the tops while it’s out.
I just finished putting a 6.4 back together that had a dynamic rebuild installed and had .040 Protrusion. Ended up kissing every valve. Granted it was a Stage 1 cam, Non flycut pistons.

Spec calls for .024-.034 of protrusion, weather they say it’s “fine” or not, you’re still out of spec.

powerstrokeboss · Aug 14, 2018

Ya but if you got a .053 head gasket and a .050 fly cut, there is no way you'll nick a valve. Idk just my thoughts. I'll check it when I got the heads on with an old gasket.