Cam,pistons..

Tyler@Street Diesel Performance · Sep 10, 2013

i would say go for it, for what is cost to have a set done its well worth it for piece of mind, i will be running the new billet cam from jared and also have RCD fly cuts

Breaking Habits · Sep 10, 2013

If its any reassurance.. I've been running a stage 1 colt cam for 3 years, longer than anyone else on here, and have not bent a valve yet.

For what it's worth; we've seen many, many trucks with stock cams have piston to valve contact, and many with stage 1s have piston to valve contact

Wanna make it simple, fly cut your pistons no matter what you do

I tell every customer that, because your first free rev @ 5000, chances are, if tolerances are even slightly off (head machining without recession of valve) or slight decking, you will probably have contact.

It's cheap reassurance, and my biggest selling/living point, PREVENTATIVE MAINTENANCE. Why not do it if your there, because chances are you'll need it down the road.

If you can afford to so it right the first time; always, because half ass ends up costing both pockets worth!

Stage 2 cam, pistons with a little bowl work and fly cuts, just like Tyler is doing.

It's a recipe for perfection.

Jared

NathannialD · Sep 11, 2013

We have a set of standard bore pistons with flycut for a smoking price.

Our stage 1 or stage 1x don't require valve reliefs as long as you use stage 1 springs.

In our experience you don't want valve reliefs if you don't need them due to the loss of compression. Lost compression leads to more smoke at low speeds and lack of power at low boost FWIW

TooMuch03 · Sep 11, 2013

delong_1 said:
We have a set of standard bore pistons with flycut for a smoking price.

Our stage 1 or stage 1x don't require valve reliefs as long as you use stage 1 springs.

In our experience you don't want valve reliefs if you don't need them due to the loss of compression. Lost compression leads to more smoke at low speeds and lack of power at low boost FWIW

How much compression is usually lost with the valve reliefs? I realize it will vary some depending on the depth.

I have Elite's Stage 1 and no valve reliefs. Haven't had any issues, been in the truck since 2008.

windrunner408 · Sep 11, 2013

delong_1 said:
...In our experience you don't want valve reliefs if you don't need them due to the loss of compression...

TooMuch03 said:
How much compression is usually lost with the valve reliefs? I realize it will vary some depending on the depth...

Depending on how much compression you're talking about losing, would it be better just to go with lower compression pistons from the start?? I guess, does lower compression pistons necessarily mean more valve to piston clearance??

NathannialD · Sep 11, 2013

windrunner408 said:
Depending on how much compression you're talking about losing, would it be better just to go with lower compression pistons from the start?? I guess, does lower compression pistons necessarily mean more valve to piston clearance??

It really depends how the piston is machined, as far as piston to valve clearance. Some lower compression with bowl work only, this will have no effect on piston to valve clearance.

windrunner408 · Sep 11, 2013

Got ya. Makes sense.

Morgan@Midwest Diesel & Auto · Sep 11, 2013

I don't necessarily agree. Machining the pistons with a 0.050" pocket gives you adequate clearance, and drops about .25 of a point of compression. I doubt you can even see that on a dyno, nor feel it driving. Even with our de-lipped and deep valve relieved pistons there is only minimal haze on a cold start with no actual harder starting than normal at 0*F. The valve reliefs will make no quantifiable difference other than a couple hundred bucks and the fact that you won't have valves hit your pistons if you break an input shaft or u-joint while under WOT conditions.

I have also seen lot of valve contact in engines we've torn down that had no previous issues until we find that. Usually these are trucks that get ran hard, raced or pulled. I'd rather not tear down an engine that was already built once, just because I didn't want to spend a little extra to get valve reliefs.

In the end it's up to the consumer and all we can do is advise them. Yes it will run fine without them. But at least you know the difference.

NathannialD · Sep 11, 2013

dropping compression has a huge effect on truck that see cold temps and/or are at high elevation

Morgan@Midwest Diesel & Auto · Sep 11, 2013

delong_1 said:
dropping compression has a huge effect on truck that see cold temps and/or are at high elevation

Yeah but not @ .25 of a point of compression. Thats like taking your 17-1 stock 6.4 engine to 16.75-1. I agree a loss of two points to a 15.5-1 engine isn't ideal for anything but a competition engine. I would be willing to put money on a .25 compression loss will not be any difference from a stock truck. Not being argumentative, just informative, from experience.

Fast-6.0 · Sep 11, 2013

Sledpull said:
I don't necessarily agree. Machining the pistons with a 0.050" pocket gives you adequate clearance, and drops about .25 of a point of compression. I doubt you can even see that on a dyno, nor feel it driving. Even with our de-lipped and deep valve relieved pistons there is only minimal haze on a cold start with no actual harder starting than normal at 0*F. The valve reliefs will make no quantifiable difference other than a couple hundred bucks and the fact that you won't have valves hit your pistons if you break an input shaft or u-joint while under WOT conditions.

I don't agree. Did you CC that or just guessing. And 6.0's do benefit from every ounce of compression.

Been there done that. Don't do relief's if not needed. We are talking about street trucks here, Stage 1 cam.

Morgan@Midwest Diesel & Auto · Sep 11, 2013

Fast-6.0 said:
I don't agree. Did you CC that or just guessing. And 6.0's do benefit from every ounce of compression.

Been there done that. Don't do relief's if not needed. We are talking about street trucks here, Stage 1 cam.

Once again, these are recommendations. You don't have to follow them if you don't want to. Just speaking from experience here of a lot of cammed powerstrokes that I've seen valve marks in when torn down. Even with stage 1 springs.

And yes, with standard size valve diameter cuts @ .050" deep they are 2.1cc's. on a stock 6.0 displacement engine with .043" piston to head clearance the engine would be 16.3-1. Same calculation puts that same combo at 16.95-1 without valve reliefs.

I agree that the compression is a bigger deal on a 6.0 then a 6.4.

@3-5000 ft elevation it will make a larger difference than our shop @ 500ft.

I can say at our elevation it makes nearly zero difference at all. But it only gets to -10 deg F around here in the winter at most. But hey when I had a brand new 6.0 it wouldn't start at -10 without being plugged in.....

windrunner408 · Sep 11, 2013

Sorry for a dumb question here, but I was under the impression that a stock 6.0 had an 18-1 compression ratio. Is that not the case??

Strokethis34 · Sep 11, 2013

I believe they are 18:1

Morgan@Midwest Diesel & Auto · Sep 11, 2013

Yeah I was using using the calculations for a 6.4 when I ran those numbers. The 6.0 would be the same difference only at a higher number.

I did the calculations

18.01w/o

17.301 with 2.1cc reliefs

Morgan@Midwest Diesel & Auto · Sep 11, 2013

Actual measurements on your given engine may yield a little different results I was using generic numbers from 6.0's I've done before. Depending on deck height, head milling, gasket brand etc your compression may be slightly different.