dnkynrbk

iTrader: (34)

Has anyone built one of these? I was intrested in what kind of power they put out and I know its like a 4.125 crank I think. What would be the bore size?

Just seems like a good budget motor. any imput?

KCFormula

iTrader: (4)

bore would be a 4.060. Not much room for error there but doable.
Mine is a 4.125" stroke and a 4.030 bore. I don't know how "budget" you can consider it by the time you get all the machine work done. I'd say you save a few hundred over a LS2 block but by the time you figure horsepower loss via alum. block its not all that much % of total cost. Iron block should make more power because of the way it holds heat though.

dnkynrbk

iTrader: (34)

So what cubes is yours?

KCFormula

iTrader: (4)

http://www.race-cars.net/calculators...alculator.html

elias_799

iTrader: (8)

how do you come up with holding heat in making more power ?

yes aluminum alloy block will release heat quicker then an iron block, but that is a good thing. an aluminum alloy block does require different building technics because of the aluminum alloy expanding more then cast iron.

but both block will make the same amount of power providing they where built the same way, and the alloy block has proven itself to hold up to the same power levels as an iron block.

blue00ZZleeper

iTrader: (5)

x2!....those ls2 blocks have seen 1000+ wheel many many times in turbo and prochargers. What material do you think the LS7 blocks are made of? 1 guess....not iron lol

KCFormula

iTrader: (4)

Building techniques are different due to the expansion rates of the materials.
Iron holds more heat which means less heat transfur during combustion which means more heat is transfured into energy. Take a class in thermal-dynamics.

KCS

iTrader: (20)

Too much heat also causes detonation.

bww3588

iTrader: (49)

the heat retention of an iron block over an aluminum block can be tuned around to counter detonation. iron blocks are more suited to nitrous or boost. not that an aluminum block cant handle it, just more reliable.

bww3588

iTrader: (49)

stick with a 4.00 stroke. in the 6.0 block, a 4.00 crank is a tight squeeze. a 4.125 stroke is even tighter obviously. you would have so much time clearencing the block it wouldnt be worth it in the end over 19 cubes.

elias_799

iTrader: (8)

i know i have stated that in my last post, you do not need to repeat it.

both an iron block and an aluminum block will pretty much run at the same temperature, that is why we have thermostats.

your theory is a load of **** when it comes it internal combustion engines. why do you not see any drag racers heating up their blocks with torches before they do a pass ? form what you are saying is that if you make it red hot the motor will make a billion horsepower.

1CAMWNDR

iTrader: (21)

Back on topic---I have an iron 6.0 motor that is filled with Hard Blok up to the waterpump ports and bored to 4.0745" (4.07" Wiseco pistons with .0045" clearance) and a Compstar 4.100" crank. It is awesome and the ring pack on the pistons keeps the bottom ring from coming out the bottom of the hole since they were originally designed for a 4.125" crank.

Do it. Make sure you have a reputable machine shop familiar with LSx motors.

KCFormula

iTrader: (4)

They will run at the temp. the thermostat allows them to run. However the (hold on this is an important word here..) *RATE* at which the engine dissipates the heat will change. If it didn't you wouldn't need a 'stat, you could calculate flow and thermal exchange and just run a specific sized restrictor.

Its not MY theory bud. Output is dependent upon thermal efficiency. You live where its cold, don't you ever see diesel trucks cover their radiators in the winter? You had better tell them they don't know what they are doing!!

bww3588

iTrader: (49)

diesel trucks put covers on their radiator because the blocks and heads are so thick and it takes forever for them to warm up, so long they would never get to operating temp if airflow thru the radiator wasent restricted.

one fast zo6

iTrader: (490)

bore is to short on a 6.0 iron block for a 4.1+ stroke, the motor will
suck oil like crazy. the promblem will be piston rock at TDC and BDC.

ATVracr

iTrader: (5)

Not going to be N20 friendly going bigger than 4.0
Hell we use the 3.9 crank for better piston design for N20.

KCS

iTrader: (20)

What? How so? How does heat retention counter detonation, which is caused by too much heat? Are you implying that we could run more compression with iron heads, rather than aluminum?

bww3588

iTrader: (49)

no, thats not at all what i was getting at. i guess i didnt word it right.

what i was saying, is the detonation caused by more heat retention of the iron block can be tuned around by changing timing and fuel tables under certain loads. the result will be negligable and in no way will justify choosing an aluminum block over an iron block based soley on the heat soak/retention factors of the two different metals.

now, if the 2 blocks in question were two old school carbed/distributer motors, the argument might hold water.

PowerShift408

iTrader: (44)

The only problem I've encountered is that when using a 4"+ stroke in an iron block, you run into the problem of pulling the piston too far out of the bottom of the cylinder. It caused problem in my 408. With a 4.125'' stroke, I only imagine it would be worse.

KCS

iTrader: (20)

From similar scenarios I've seen in the streetcar stuff, where someone is trying to run too much compression for pump gas, it's usually advantageous to run a lower compression ratio, rather than to band aid the tune (or cam timing) to avoid detonation/preignition. It's not uncommon to see an engine make more power with 11:1 than it did with 12:1 on pump fuel. Adding fuel to cool the charge and pulling timing to delay the peak cylinder pressure is wasteful, and generally results in lower IMEP, BSFC's, and higher EGT/coolant temps. The difference between an iron block and an aluminum block in a streetcar probably is negligable though.

However, the racecar scene may be different. To expand further into "the big picture", the iron block's inability to dissipate heat as well as an aluminum block, puts more demand on the cooling system. I think it was either the RO7 or FR9 NASCAR engine that was so much more efficient at cooling the engine than it's predecessor, that the team found a large aerodynamic advantage sealing up the front of the car since the radiator was smaller and required less frontal area in the bumper.

Basically, what I'm trying to say is that too much heat can be a bad thing.

But so can too little.