Milling material from iron LS

[peejay]

Just curious, I know there are people who mill a ton of material out of smallblocks to get them super light. Is anyone doing this for the iron Gen III engines? I hear that the iron blocks are 80lb heavier than the aluminum ones, that's a lot of weight to mill out but when the blocks are starting out as heavy as a Mopar RB block then there's got to be a lot there for the taking.

I look at the block structure and see a lot of material that simply doesn't need to be there like massive overhangs at valley gasket surfaces or areas near the water pump boss where the iron is maybe 2" thick.

[pamotorman]

with the manufactures looking to lose every pound of weight to get better MPG I would guess there is not much cast iron there that is not needed.

[ProPower engines]

Just curious, I know there are people who mill a ton of material out of smallblocks to get them super light. Is anyone doing this for the iron Gen III engines? I hear that the iron blocks are 80lb heavier than the aluminum ones, that's a lot of weight to mill out but when the blocks are starting out as heavy as a Mopar RB block then there's got to be a lot there for the taking.

I look at the block structure and see a lot of material that simply doesn't need to be there like massive overhangs at valley gasket surfaces or areas near the water pump boss where the iron is maybe 2" thick.

You may try carl at CNC blocks. He does have cnc programs to lighten sm blks and may have a similar programs to do an gen III block as well.
Unless there is a minimum weight you are fighting the machining cost to lighten a block can be costly and that sticker shock may keep you from doing it.
It would suck to find an air pocket in the cast and ruin the block or at least require further repair which I have seen in some stock blocks I had done some years ago.

[mag2555]

Material that looks like it does not need to be there by Eye, or by computer strees sim's ?

Your Eye can't predict G force loads that increase with the square of the rpm!

If your looking to handle over 550 hp with rev's topping 7K for non road race usage I would think that running Aluminum Rods and a lite Crank would by you very close to the weight savings of milling a cast iron block, plus reap the performance benifits of a faster reving motor which the rework of the iron block will not provide!
Also do not forget the performance gain from lighter rotating mass of the rims and tires!

[peejay]

I'm talking spare nights in the garage with wireless headphones playing rock n roll, making dust and shavings with an angle grinder and carbide burr, trying to save a few bucks over a $$$ aluminum block.

There's a lot of bosses and knobs and stuff that don't need to be there (if there are four engine mount bolts, and eight bosses on the side the block... that's four that don't need to be there) there's a lot of places like around the water pump where it was probably cheaper to run extra metal than try to make a complex casting core... Stuff like that!

[roc]

I'm talking spare nights in the garage with wireless headphones playing rock n roll, making dust and shavings with an angle grinder and carbide burr, trying to save a few bucks over a $$$ aluminum block.

There's a lot of bosses and knobs and stuff that don't need to be there (if there are four engine mount bolts, and eight bosses on the side the block... that's four that don't need to be there) there's a lot of places like around the water pump where it was probably cheaper to run extra metal than try to make a complex casting core... Stuff like that!

That's certainly an enjoyable option. Another option is to skip breakfast on race days.

Are you weighing the block before and after the grinding job?

[peejay]

It's a thought exercise at the moment combined with a good deal of "has this road been traveled before". I'd also like a 20lb crankshaft but I've been told that my expectations are too high

Losing weight would be a great idea if the driver sat over the front axle A friend of mine was able to drop something like 50lb from an engine by judicious use of a milling machine. That was 50lb that the front tires don't need to fight in cornering, that's 50lb less force on the steering axis which translates to lighter/better feeling steering.

I'm also reminded of the JGTC teams running Nissan Skylines who would machine 66kg out of one of the RB26 blocks since they had a 400hp limit and didn't need the 1000+hp capable block that Nissan produced. 66kg of material is the entirety of a Ford 5.0 block. Iron Gen III motors are 1500hp blocks, lot of material that doesn't need to be there if you only want to make 300-400hp....

[carmakerevive]

So just get an aluminium block if you want to make that level of power and lose weight?

66kg would NOT come out of an RB26 block. That's 2KG shy of the entire block weight...

[jsgarage]

Sounds like a fun few weeks work after the racing season ends. If you're sure of your stress levels and have a milling machine available, I'd like to see what you come up with. Remember to factor in heat effects when the engine is warmed up and working hard, and use a ball-end mill for chopping away so there's no sharp edges for stress risers in your sculpturing. NASA spends millions doing this to cut launch weights and some of their creations are pure metal artwork. You probably won't win races based on this 'cause pretty much whatever you do, an alloy block WILL be lighter. Cast iron blocks are stiffer with less heat-rejection to the cooling system, so at low power, the less-stiff alloy block will be better. But if your ride improves next year, you can bet some of your competition will sculpture their iron blocks (and heads) too.

[leahymtsps]

Just curious, I know there are people who mill a ton of material out of smallblocks to get them super light. Is anyone doing this for the iron Gen III engines? I hear that the iron blocks are 80lb heavier than the aluminum ones, that's a lot of weight to mill out but when the blocks are starting out as heavy as a Mopar RB block then there's got to be a lot there for the taking.

I look at the block structure and see a lot of material that simply doesn't need to be there like massive overhangs at valley gasket surfaces or areas near the water pump boss where the iron is maybe 2" thick.

You may try carl at CNC blocks. He does have cnc programs to lighten sm blks and may have a similar programs to do an gen III block as well.
Unless there is a minimum weight you are fighting the machining cost to lighten a block can be costly and that sticker shock may keep you from doing it.
It would suck to find an air pocket in the cast and ruin the block or at least require further repair which I have seen in some stock blocks I had done some years ago.

Actually Dennis Wells Racing out of Texas does his block lightening.

Tom