Rockwell Hardness of Cyl Bores.

longball

I fought the lawn...
Dammit, Steve. Just Google the hardness of the material the bores of made of. I believe for cylinder heads they use the Brinell Scale rather than the Rockwell scale. Iron has a maximum hardness of 65 Rc on the Rockwell scale. Don't forget to PM me. I am more familiar with the Mohs Hardness Test. LOL
 

HighMileage

Albany,NY
Let me rephrase this question.. Has anything been done to raise the hardness such as a nitriding process?

I’m in an off-forum discussion with someone who says these engines can’t take the boost without wearing out prematurely.
 

NY Twin Turbo

All the good stuff.....Times 2.
Let me rephrase this question.. Has anything been done to raise the hardness such as a nitriding process?

I’m in an off-forum discussion with someone who says these engines can’t take the boost without wearing out prematurely.
Just tell them they are retarded.

That should some it up for them.
 

HighMileage

Albany,NY
Thanks for the replies. Here’s what I’m dealing with:

“Modern trucks can handle this level of boost (I think a bit less) for extended periods, but they have super hard cylinder liners. You can bet your ass that you will have Rockwell Hardness 60 cylinders on any big diesel. The hardness of automotive liners (includes Mr black) is under 20. The trucks also have 3 mm plus thick compression rings (my baby Cummins is 3mm, a 6 inch bore engine will have thicker yet). Your Mr Black Buick is probably 2mm, maybe less. Also, the piston skirts in automotive engines are short. The Buick is really a toy engine, that with steroids, it can be made to sprint well for brief periods.
 

Pronto

Believe nothing you hear and half of what you see.
Seems to be plenty of TBs around that have 100k + miles on the blocks and they only need a good timing chain to keep going...
 

rag231

Well-Known Member
When they said that the engine cant take boost without wearing out prematurely was he making a reference to a race engine or daily driver? I would tell him that we have eclipsed the weak links of our motors and cylinder hardness of the bores was never in the top 100. If I only need 38-43 pounds of boost to run a 7 second time in the quarter what difference does it make. On that forum are they referencing boost in terms of how fast or how much power something makes or are they just a boost addict looking for a number?
 

rag231

Well-Known Member
Tell him also that I would be more concerned with cylinder roundness and cylinder cross hatch patterns for piston ring sealing. We also do sonic bore testing for wall thickness for high performance applications.
 

salvageV6

Daily Driver
Both my 31 year old V6's would have 2 Cummins "high mileage badges" each, in daily driven cars. 200K and 235K miles.

Both 11 second pump gas and alky. cars, 24 psi., neither raced until 140K miles on the clock.

I'm sure both have a little ring and valve seal blowby, with absolutely no loss in power.

I'd be much more worried about the transmissions in both vehicles standing up to higher than stock power levels.
 

earlbrown

runs with scissors
LOL. You know what's harder than cast iron?... glass.


Tell your diesel guys to run glass liners if they want to up the boost levels. Since hardness alone is what determines wear.




-he says sarcastically.
 
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