Aftermarket Cylinder Heads?

[RTillery]

I know there is a 12 valve head that is being reproduced, has anyone heard of a 24 valve head that is available through the aftermarket?



Any experience, comments or pricing on the 12 valve would be appreciated too. Thanks.

 

[bmoeller]

You mean other than one that has been modified, as in porting and such?

 

[RTillery]

No, there is a 12 valve aftermartket head that is not made by Cummins that is on the market. I saw it in a shop today. The owner did not know if a 24 valve was available and I wondered if anyone on the board had heard of such an animal.

 

[Piers]

We can get the aftermarket 12v heads no problem, but no one other than Cummins, so far as I know, is making the 24v one. I've got so many cracked 24v heads here, I've been trying to buy just a new bare casting from Cummins... . no luck so far

 

[Gary - K7GLD]

Piers - or others - what might be the advantages of such an aftermarket head casting? Price alone, or better materials and construction?



"Different" is not necessarily "better" - but it sure doesn't hurt to investigate...

 

[WCounts]

What is causing the cracking on the 3rd gens? I have one.

 

[Piers]

There are many different suppliers and models of aftermarket 12v heads, so one has to watch what you're buying, also none of them that have come to me, are up to our spec's, we end up checking each head out and at the least, resurfacing them, before we feel comfortable sending them out.



Too much heat is the main culprit. Where is your 04. 5 head cracked? The 98. 5 to late 2001 had no real seats, so they were prone to cracking, but the late model 2nd gen and the 3rd gen heads have real seats in them, so cracking doesn't appear to be as bad a problem.

 

[supersonic]

Piers, are you talking about a custom performance cyl head or just a new aftermarket recast?

 

[SRadke]

I understood there are RV heads available through Cummins with a higher nickel content. Should make a tough casting.



-Scott

 

[J.R. Adkins]

The 98. 5 to late 2001 had no real seats, so they were prone to cracking, but the late model 2nd gen and the 3rd gen heads have real seats in them, so cracking doesn't appear to be as bad a problem.

Yes sir I agree. But since the valve seat is not intrugal(sp?)... . some of the valve seats are coming out with the high heat that some of these motors are producing. The 12v has seats that are a part of the cylinder head. Unlike the 24v.



J. R.

 

[Gary - K7GLD]

"

Yes sir I agree. But since the valve seat is not intrugal(sp?)... . some of the valve seats are coming out with the high heat that some of these motors are producing. The 12v has seats that are a part of the cylinder head. Unlike the 24v. "



While there is always the remote risk of a valve seat insert coming loose, *I* would FAR rather have the greater hardness and typical durability that insert provides over the rather thin localized surface hardening of previous heads.

 

[RustyJC]

But since the valve seat is not intrugal(sp?)... . some of the valve seats are coming out with the high heat that some of these motors are producing.

Valve seat inserts, like replaceable cylinder liners, are commonplace on large industrial engines. If the seat is dropping out, it either has:



1. Insufficent interference fit, resulting in low clamping forces.



2. Excessive interference fit, causing the seat to collapse due to excessive hoop stress, resulting in low clamping forces.



There's nothing wrong with valve seat inserts if they're properly engineered and installed. In fact, the insert allows one to use premium heat-resistant materials such as Triballoy, Inconel and other superalloys, some of which don't lend themselves to weld placement on the head casting.



Rusty

 

[WCounts]

Mine has not cracked yet. I just want to prevent it from happening if I could.

 

[Piers]

I'm referring to aftermarket heads.

J. R. , I agree with you on the seat problem... ... we just need to convince everybody of the damage that is done by running tooooo much heat. Cut back the fuel and run bigger or twin chargers so you won't hurt your engine. My 04 runs a 13. 3 at 102. 5mph & I'm sure it would run mid 12's if I didn't keep the pyro to 1350 or less

 

[J.R. Adkins]

Yea we need to talk cummins into adding some Inconel seats!! Dont they know were are gonna BOMB these things anyways????

 

[RTillery]

Some of you guys seem pretty sharp on installing aftermarket seats. What kind of interference do you like? I have always heard about . 006" is close to right on cast iron. Do you have a brand of seat you prefer, J loy, Martin Wells, etc? Had any experience with the sentered metal seats.



Piers, what kind of flatness to you like to see on the heads before acceptable? What kind of surfacing machine do you use? Do you have an RA range you like to shoot for? Pretty smooth, kind of rough? What type of surface works best with the new gaskets not including orings. Yeah, lots of questions but this stuff is interesting. Thanks

 

[Jim Fulmer]

I'm referring to aftermarket heads.

J. R. , I agree with you on the seat problem... ... we just need to convince everybody of the damage that is done by running tooooo much heat. Cut back the fuel and run bigger or twin chargers so you won't hurt your engine. My 04 runs a 13. 3 at 102. 5mph & I'm sure it would run mid 12's if I didn't keep the pyro to 1350 or less

Hey buddy, just so everyone knows my head has/d no cracks in it what so ever, valves looked good for wear (side load) springs and seat pressure were fine with no changes and no warpage as it is . 002 for the total length... ... . rememeber were talking 2 years of abuse... ... 40K.



Jim

 

[nickleinonen]

Yea we need to talk cummins into adding some Inconel seats!! Dont they know were are gonna BOMB these things anyways????

don't them new "600" engines have those????

 

[ThomasLawrence]

don't them new "600" engines have those????

The 600's have inconel exhaust valves. The valve seats are stellite - a cobalt alloy.



-Tom

 

[nickleinonen]

The 600's have inconel exhaust valves. The valve seats are stellite - a cobalt alloy.



-Tom

i knew i remembered something was inconel up in there... stellite is some strong stuff too... [i know it is used in unit injectors to deflect the HP fuel when the spill ports open]