The KB/Diamond Saga

[jsawduste]

First off I want to be clear that we all have opinions and ideas. Some are cultured by experience, need or simple $$. Yes there is more then one way to skin a cat. Please understand that my background comes from a long career in engine development for one of the big 3 automakers. The amount of time and testing that goes into a finished product is immense. Again please understand that my comments are based on the I6 engine and may or may not apply to other engines or types of engines.

jsawduste wrote:Diamonds are forged not cast.


Now thats news to me, that's a good price then and I take back all my comments. I could have sworn I'd read about the Diamond pistons and heard that they had some ring land issues and inconsistent quality, now that I think about it that was Venolia's from Accurate Power and not Diamond's from HESCO.

In that case let me comment on this remark you made:
jsawduste wrote:Do you really think that KB is going to come in cheaper or better ?


Yeah, maybe. If HESCO isn't the sole supplier of the new KB's they may very well be shooting for a price point closer to cast, remember cast pistons by their own words cost more for limited production runs so they always start with forged. This at least IMPLIES that they aren't trying to market a golden piston.

I certainly hope they have at least done enough research to know that HESCO is offering the Diamonds already, couple that with the fact that HESCO is notorious for price gouging ESPECIALLY when they are the only source of something.

Could not agree more. Hesco has taken advantage of there position in the I6 market place. In fact when I ordered from Diamond, TThe sales engineer was very surprised as to what Hesco was selling the pistons for. Hopefully the KB`s will not be marketed through Hesco and be available for a reasonable cost.
The thing I do not understand and is the basis for my KB comments. Diamond does not sell an “off the shelf piston”. They have a very detailed spec sheet which must be filled out in it’s entirety for them to make you a set of pistons. Thus with the variables that are built in each stroker build. Diamond can accommodate them. Again if this service is available now and the fact that you can buy them from direct Diamond. Why is KB entering the picture ? There is a reason but I do not fully understand it.

jsawduste wrote:Diesel CI, while still reduced (by diesel standards) is much more fortified then SJ.


That's a little out of date now. Many Diesel Oils for the last year are just about in the same boat as SM motor oils (ie. 600 to 800 ppm Zinc and Phos). There are a couple good non-diesel formulations at the moment, Mobil 1 High Mileage which is an SL because of 1200 and 1100 Zn and P is probably the best option, commonly available on shelves. You can find fresher information on BITOG http://www.bobistheoilguy.com including the few diesel weights that still are good and Virgin oil analysis on other better weights for the 4.0 (the AMC I6's all seem to like 5/40 and 10/40 for lowest measured wear metals, in published UOA's (used oil analysis)
Good important information. Indeed with the “new” diesel emission regulations. They to have to meet stringent requirements. Oil development is always ongoing as needs change. This leaves us folks with specific applications out in the cold, sorta speak. The oil company’s will sell many times the latest and greatest formulations as compared to “older” formulations. Thus we need to stay abreast of what is happening in the field. Did not know that the I6 seems to like 5/10/40`s. As opposed to other weights. But if you think about it. It makes sense. These I6 engines were design at a time when there was not as many oil choices to be had. Be it weight or formulation. In addition emissions and mileage (until recent years) was not a big issue. Thus they had oil galleys and ports designed with the flow rates of the then commonly available oils.
jsawduste wrote:The I6 has a prov-en know rpm design. With proper lubrication a stroker will last as long as a stocker. The benefit of the roller is to induce a more severe cam dynamics. Something this engine doesn't need based on it`s design parameters and limitations.

Allow me to expand on this.
First even with a stroker crank and longer rods. The mean piston speed is still well within the industry standard of a maximum of 4,000 FPM. Proper lubrication is to mean oil formulated with enough additives so as not to wear the cam and valve train components prematurely.
Secondly, “severe cam dynamics” was meant to be a description of the much steeper opening and closing ramps allowed by a roller cam. Nothing to do with higher power.

This seems so oversimplified as to barely merit commenting. You could write the exact same thing regarding Stroking the 4.0. Lets try and see if it illustrates whats wrong with your generalization: Lengthening the stroke of the 4.0 induces more severe crankshaft dynamics. Something this engine doesn't need based on it`s design parameters and limitations....

This is true BUT what if the rotating mass is lighter then stock ? Granted you do have a greater amount of rod angularity then stock. In addition what if the rotating components are balanced to a higher degree of precision then a stock engine ? How is it that crank of the earlier 4.2 with its additional counter weights (and mass) deemed as reliable as a later 4.2 crank with the lighter counter weights ? Is there a difference in materials, manufacturing process, heat treat ? Would not some of these factors help to nullify the effects of adding stroke, thus piston speed ?

Wow... Sage wisdom... Lets go one step further:
Modifying the 4.0 in any way from factory stock induces more severe performance dynamics. Something this engine doesn't need based on it`s design parameters and limitations...

Wow that's the spirit.... By even slightly modifying the 4.0 we are introducing all manner of potentially unsafe usage to the detriment of reliability, longevity, emissions, fuel economy, all intended "design parameters" of a bone stock factory engine.

Now I know for sure you aren't seriously intending to advocate any of those, but your comment about roller cams amounts to the exact same thing, I only took it to the extreme.



Already happened, quietly and with a thoroughness only black helicopter EPA agents can manage all the ZDDP containing oil supplements have either been taken off the shelves (STP red, SLOB, and two other CD-1 oil treaments) or are forumlated to contain very little ZDDP (STP blue)

This may be true but it has not hit out in Michigan.
Castrol offers
http://www.castrol.com/castrol/generica ... Id=7032644

AC-Delco 10-421. Which is the repackaged GM EOS. The web site does not show an image but it is a good part number. Purchased a case last month.

Lucas Break In Oil Additve 2007 SEMs show winner in the new products catgorey
http://www.lucasoil.com/products/index.sd

Joe Gibbs, Brad Penn, Redline, Crane and Comp Cams Additive


jsawduste wrote:Diamonds are forged not cast.

ZDDP has been an issue since SG/SH when the oil companies stared reducing levels.

Diesel CI, while still reduced (by diesel standards) is much more fortified then SJ.

Did you know that the Comp Cam and Crane additives are repackaged GM EOS. Which is still available under the AC-Delco name ?

The I6 has a prov-en know rpm design. With proper lubrication a stroker will last as long as a stocker. The benefit of the roller is to induce a more severe cam dynamics. Something this engine doesn't need based on it`s design parameters and limitations.

Flash, what I mean is a steeper opening and closing ramps. To the degree that a flat tappet would never handle.

That last statement is kinda miss leading.........and just not TRUE.

First of"induce a more severe cam dynamics" i take it you mean it would make more power......thats a good thing
But reading farther on down you statement, you taking about the roller being designed for High RPM with our 4.0L/strokers won't live at.....Ummm True Would you consider a full size Buick, Cadillac or Lincoln town car to be.....a high rpm race car........No, but they all us a roller cam and lifters........

No, there are a number of reasons why current engines use rollers. Agree that RPM is not much of a factor in these quoted applications.

Lets use your cam for and example......274 duration and .480" lift
With a roller cam we can close the exhaust valve sooner and delay the intake valve opening latter.....= less over lap = more bottom end torque then your cam................
I can close the intake valve(IVC) at the same time as your cam........= Same DCR
I can open and close the intake and exhaust valve must faster(allowing the valve to be at full lift longer) then any flat tappet cam could even dream of......and will live!!!! The longer the valve is open in it full lift state, the more cylinder fill and or more top end HP
Now, that means that my cam would have less duration.......lets say it 264* compared to your 274* and has the same lift .480"
If my eng was built identical to yours, except the cam, my cam, would be smaller then yours and make more torque at the same rpm and more HP at the same RPM.......O here is and added bonus!!!!!!!!! I WOULD GET BETTER EMISSION THEN YOU!!!
There is many reason why almost(all that i know of) all auto manufacturer have switched to roller cams....... and better controlling emissions and having some power left over........Is a big one
Mind you this is not a 7000 or Even a 6000 RPM cam!

Much of what you say is indeed true. But I do take issue with several of the statements. But is what makes this forum a learning experience for all of us.
My issue with roller cams on an I6. Is simply based on a cost per gain factor.
Now before we jump and say that custom pistons have a questionable gain. Let’s look at the bigger picture. The cam itself is a very expensive component. Rivalling the cost of pistons. Now add in the cost of the roller lifters and the pushrods. IMHO the benefits of the roller cam are way overshadowed by other engine parts that could be more beneficial. This is of course taking into account that the correct oil formulations are used in the flat tappet cam.
Flash.

[Flash]

I can except all that you have added to this conversation...........and i fully agree that the roller cam is way way $$$$$$$ and there is a lot more thing that this cash could be spent on......that would yield a better power to $$$$ ratio

The roller cam has grate benefits as you well know, Better power, emission, and durability,.....even milage come into play. let alone being able to put the power curve were it fits the vehicle best.(Yes i know that this can be done with any kind of cam.......But a roller cams do it better)
If the roller cam ever make it off the ground floor, it will come down in price and will be more viable option.
No body is willing to spend the hi price tag, and are waiting for some one else to do it so they can buy one when it becomes a product with a part number and a much smaller price tag.(Witch will probably never happen and is only wishful thinking on my part )

If i had the cash i would be buying 3 of these just so i could experiment with different cam profiles on my 300,000 miles stock 4.0L jeep..................but thats why i own a 300,000 mile jeep (Even have enlarged to push rod hole in my spare head so that the lifters can be remove with out removing the head!

Flash