I tested industrial engines back in the late 90's with ceramic coatings. For all the cost, there was no change in performance or reliability. And we measured peak firing pressures in the engine with transducers to see if there was any change in combustion pressures or temperatures.. Notta. Sorry, I don't think its worth the cost IMHO..

 

Excellent points all around, gents.



Big Swole scares me! He's scattered a few 04.5+ engines in a variety of ways..

I agree with your "fix the root cause" point. The 03-04 piston & bowl design is superior & that addresses the root cause.

 

Mono mono mono mono monotherm! What's that name again? Monotherm!

 

Mono means one, and therm means therm.

 

LOL, I'm not following you at all...


Seriously though, what aftermarket (aluminum!) pistons exist for the CR.
Are they even necessary?

I've heard Mahle but what about others? Arias, Wiseco, Ross, etc?

 

Besides monotherms I don't think there is much for piston alternatives( besides fly cuts for larger cams). The aftermarket cant really do much to the 04.5 piston to keep it from melting. The design is just bad.

 

Everyone you have listed but Wiseco have aftermarket pistons for the 5.9. They are forged aluminum and are a better piston for a race engine. They still do not take heat like a steel piston (I can find some pictures of some aluminum marshmallows from earlier this year). The other issue is without the keystone top ring land (steel ring land) they are a low mileage piston. That top ring takes a ton of abuse in compression engine, and as such without that steel inset found in cast pistons, they wear out fast. I have never run a set on the street, but my guess would be 20,000 - 40,000km's before they were done.

The best choice if you are going aluminum is the QSB marine pistons, they are double heat treated and are 30% stronger then OTR pistons, and they have the keystone ring land. The best choice period is the monotherm.

 

There is no real value in getting fly cuts for a CR engine that only spins 4000 rpms and the flow pretty much stops increasing at .500

We seen actual decrease in flow with bigger camshafts at the lower lifts. Once I find the graphs, or the thread I'm post them. For 5.9/6.7 CR crowd, the colt stage 3/4 is enough.

Forgot about the forged pistons not having the keystone lands for the top ring. The metal piston cooler jets has been discontinued, and all you can buy is the plastic jet. Still trying to source QSB jets, hopefully they are metal.

QSB pistons are 3-4 week custom order from the factory. Just ordered mine on Friday.

 

Just throwing this out, heard a few issues with the colt stage 2 cam's. The cam has a more aggressive ramp rate than stock or stage 3 (Similar lift but has more duration, which slows down tappet ramp rate). If your going to run a stage 2 cam, its a good idea to check for piston to valve clearance. You might have to adjust stuff.

I've only used stage 3 stuff.

 

Buddies 06 has gone down. So be doing research on engine parts, etc. Called about the monotherms, less than a month ago there was no pistons avaiable. Spoke with Mahle, there were building some, but dont be in any type of a hurry to get them.

 

Well you pretty much have the dead reliable down, not a lot to make it better. A cam isn't a bad idea, but I doubt it would effect your reliability.

Good, clean oil, reasonable coolant temps, reasonable EGT's and not letting the cylinder pressure exceed the holding capacity of the HG/bolts(studs).

I presume your EGT's are a little lower than mine since you have twins.. but I can pull WOT up a 6% grade at 6K feet plus and be just on the edge of my EGT comfort level at 16K in 6th. Above that weight I need to downshift, but that's fine.

With the parts you have EGT's will be your downfall, and it sounds like that's not an issue.

But if you were to do a build and money wasn't a concern, on top of what you have now...

Coated QSB480 pistons
03-04 50hp Nozzles
Pushrods
Cam
Balanced bottom end
6.7 fuel system
BB Twins (GT3782/GT4202)
4.10's (less torque output from the motor for the same wheel tq)

 

I'm building a 06 CTD engine right now with 480 marines, brand new head, oringed, colt stage 3 cam, available with 12V or CR rods, 425 ARP's head/mains. Its available if you want. Everything is brand new included the head, 480 pistons, oil pump, and so on. I just got this stuff laying around. I was planning on throwing on a steed manifold T-4 and run my S366. My plans was to use it for an older chevy project that I was dreaming.

 

I just wanted to mention, we have a customer that has decided he wants the ultimate street engine. So we will be building just what I was talking about here in the next month or so:

-R&R's
-Monotherms
-Ported & Milled head with Hellmann intake
-Balanced
-Steed exhaust manifold
-Decent sized twins

Looking for a reliable 800hp, with the ability to go over 1000hp.

I will try and post up some "spy" pics as we build it.

 

Mahle only builds monotherm's once a year according to Eric at Mahle, they are doing the production run right now. We have a couple sets on order.

 

Anyone running a 5.9L CR should run Monotherms or the 480 pistons as a minimum. The CR325 piston just isn't a decent option. As expensive as the billet rods are they really aren't that bad, if you have to buy 12V and R&R them so you can use them.