Machining pistons??? valve reliefs and delip

[KCTurbos]

I am in the process of building my DD. I am doing a full motor rebuild. .40 over, colt stage 2 cam, oring heads, upgraded valve springs, arp625, all new internals...

I am not building a 1000hp monster and don't plan on doing any racing or spending much time above 4000rpms. Probably going to stay under 600-700hp. I am mostly looking for an awesome, clean running, quick spooling DD.

I am stuck on the pistons. Valve reliefs are not "required". But I have been thinking about delipping and adding valve reliefs.


Questions:

Are their any performance gains/losses from valve reliefs if they are not required?

How deep would you go on the valve reliefs?

Delipping? are there any "proven" performance gains from doing this? Are they mostly for the top end high HP trucks and/or for those who use nitrous?

Does delipping cause any loss in bottom end? That is what I am most worried about.



Basically is machining the pistons needed/recommended for "stockish" trucks that don't plan on racing.

 

[Towerguy]

I don't think delipping is a performance mod although it will lower compression a little. I think the primary reason for delipping pistons is to radius the edge of the bowl and make it less likely for a crack to start.

 

[sideactiondiesel]

I would not do that for the combo u are doing . we make 750+ on a stock cam and heads.

We could supply u with de-llipped and coated pistons.

 

[KCTurbos]

I would not do that for the combo u are doing . we make 750+ on a stock cam and heads.

We could supply u with de-llipped and coated pistons.

Thanks for the offer. Can you PM me pricing. I already have stock mahle .40 over pistons sitting here ready to go... but I could always resell them if it makes sense.

I am getting the block decked so I might have to shave the pistons a little bit, not sure if you guys can do that too.

 

[KCTurbos]

Anybody else have and data on the subject? Pluses and minuses to machining the pistions. I know most guys delip and add valve reliefs when they are REALLY pushing the envelope and making HIGH hp... mostly on the top end. But how does it affect a DD?

 

[sootie]

on my six four i had delipped pistons and valve reliefs. in cold temps it would haze badly when up to heat and smoke blue when cold. rev it up slightly and it cleared right up. i put that down to the fuel not atomizing properly at low rail pressure/rpm due to the combustion characteristics changing with the extent of machining i had done.

i did it because i had a cam as well as prior valve/piston contact. the other thing is that cracked pistons are very common on six fours so delipping almost removes that possibility.

i know its comparing apples to oranges but for a mild built dd, i wouldnt see the need.

 

[co04cobra]

I DD my 6.4 with valve reliefs and delipped pistons. I really had no hazing even cold until I added 100% nozzles.

Like was said before the delipping is to help prevent cracks, which the 6.0 doesn't have as much trouble with as the 6.4.

What are the specs on the stage 2 cam?

 

[hawgdoctor]

I DD my 6.4 with valve reliefs and delipped pistons. I really had no hazing even cold until I added 100% nozzles.

Like was said before the delipping is to help prevent cracks, which the 6.0 doesn't have as much trouble with as the 6.4.

What are the specs on the stage 2 cam?

The stg 2 has just a touch more lift, and duration.

Sent from my SM-G900V using Tapatalk

 

[hawgdoctor]

I am in the process of building my DD. I am doing a full motor rebuild. .40 over, colt stage 2 cam, oring heads, upgraded valve springs, arp625, all new internals...

I am not building a 1000hp monster and don't plan on doing any racing or spending much time above 4000rpms. Probably going to stay under 600-700hp. I am mostly looking for an awesome, clean running, quick spooling DD.

I am stuck on the pistons. Valve reliefs are not "required". But I have been thinking about delipping and adding valve reliefs.


Questions:

Are their any performance gains/losses from valve reliefs if they are not required?

How deep would you go on the valve reliefs?

Delipping? are there any "proven" performance gains from doing this? Are they mostly for the top end high HP trucks and/or for those who use nitrous?

Does delipping cause any loss in bottom end? That is what I am most worried about.



Basically is machining the pistons needed/recommended for "stockish" trucks that don't plan on racing.

If you're gonna dd it, and not push it you would be fine. We just got the shop truck broke in with almost the same setup, but we don't play nice with it. She gets beat pretty hard, and dailied.

Sent from my SM-G900V using Tapatalk

 

[Strokethis34]

Talk to Morgan Midwest diesel he will get you setup, he done my Pistons.

 

[sootie]

I DD my 6.4 with valve reliefs and delipped pistons. I really had no hazing even cold until I added 100% nozzles.

Like was said before the delipping is to help prevent cracks, which the 6.0 doesn't have as much trouble with as the 6.4.

What are the specs on the stage 2 cam?

When I talk cold lol - I talk Canada cold...