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CNC lightening of engine blocks for racing.


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#1 NeilR

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Posted 27 April 2012 - 03:18

I've noticed that CNC programs exist for Ford and GM blocks to take up to 15/20kg out of a cast iron block. Quite a big job really. But the Mopar R3 block gets no love and the R3 block is supposed to be much heavier...does no one race Mopar stuff on the circuits in the US?

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#2 ray b

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Posted 27 April 2012 - 16:06

http://www.summitrac...-Engine-Blocks/


LS-1 ALLOY BLOCKS

OR NEW 4 CAM 4 v FORDS OR GM NORTHSTARS ARE CHEAP and light and junk yard prices

why mess with old iron push-rod stuff in 2012 ?

#3 MatsNorway

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Posted 27 April 2012 - 16:21

http://www.summitrac...-Engine-Blocks/


LS-1 ALLOY BLOCKS

OR NEW 4 CAM 4 v FORDS OR GM NORTHSTARS ARE CHEAP and light and junk yard prices

why mess with old iron push-rod stuff in 2012 ?


Because you can still get more power for less cash than any 4cyl around can..

And push rods are compact designs.

Edited by MatsNorway, 27 April 2012 - 16:40.


#4 ray b

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Posted 27 April 2012 - 18:24

Because you can still get more power for less cash than any 4cyl around can..

And push rods are compact designs.


sure but any chevy ls1 is lighter and cheaper then a mopar iron race block

if you want cheap power the northstar is eazy and cheap to get out of wreaked caddys

and why the old 340 mopar wedge that never was a fully developed race motor
unlike the ford or chevy v8's that have a ton of aftermarket goodies

#5 bigleagueslider

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Posted 28 April 2012 - 01:44

The only reason for CNC machining a cast iron block is due to rules requiring use of a production block. Production block castings have lots of excess wall thickness to allow for things like core shift. If cost was no object, an iron block could be cast with wall thickness less than half that used on production blocks.

Back during the F1 turbo era some teams like Ferrari actually used cast iron blocks for strength and stiffness. The iron blocks used by Ferrari were cast using a process that allowed 3mm wall thicknesses.

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#6 Magoo

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Posted 28 April 2012 - 02:23

I'm not a huge fan of milled iron blocks. The weight savings tend to be overstated and it's not terribly cost-efficient even with CNC. I agree with Slider: it's mainly for those rare rules-driven applications where an iron block is required but lightening is permitted -- and you have plenty of the OE's money to throw around.

Also, with later model blocks you get into diminishing returns. Newer castings are pretty close to the bone. With a 1970-ish block it might be worthwhile but with a 1990-ish casting, not so much.

#7 Kelpiecross

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Posted 28 April 2012 - 04:28

[quote name='bigleagueslider' date='Apr 28 2012, 12:44' post='5691172']

Back during the F1 turbo era some teams like Ferrari actually used cast iron blocks for strength and stiffness. The iron blocks used by Ferrari were cast using a process that allowed 3mm wall thicknesses.

BMW also used cast-iron production blocks in the turbo F1 days. I think the blocks were high mileage second hand blocks.


#8 NeilR

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Posted 28 April 2012 - 10:47

Car must used a 'production' iron Mopar block under the rules, only thing is that the iron mopar R3 block seems more intended for drag racing. There is one place that claims to be able to machine out 54lbs of iron from one...seems a lot. It is not a budget category.

#9 Magoo

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Posted 28 April 2012 - 11:50

Quite so, the R3 iron block was developed for applications where weight wasn't critical -- weight class drag racing, etc. In other applications in the USA aluminum blocks are more prevalent.

I am slightly skeptical about a 54 lbs weight savings in machining the iron block. If so, the R3 must be porky indeed in as-cast form. I believe a standard Chrysler LA block is around 160 lbs.

#10 Fat Boy

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Posted 01 May 2012 - 04:14

I'm not a huge fan of milled iron blocks. The weight savings tend to be overstated and it's not terribly cost-efficient even with CNC. I agree with Slider: it's mainly for those rare rules-driven applications where an iron block is required but lightening is permitted -- and you have plenty of the OE's money to throw around.

Also, with later model blocks you get into diminishing returns. Newer castings are pretty close to the bone. With a 1970-ish block it might be worthwhile but with a 1990-ish casting, not so much.



We used to lighten up the Toyota Atlantic blocks. It cost several grand and was worth 5-6 pounds...and then we started breaking blocks. It made me wonder what was going on to the (stressed) block while is was on track. Couldn't have been good.

#11 Lee Nicolle

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Posted 01 May 2012 - 07:58

sure but any chevy ls1 is lighter and cheaper then a mopar iron race block

if you want cheap power the northstar is eazy and cheap to get out of wreaked caddys

and why the old 340 mopar wedge that never was a fully developed race motor
unlike the ford or chevy v8's that have a ton of aftermarket goodies

The old 340 Mopar is a good engine and in its day had lots of goodies advailable. Really there still is but a little overshadowed by Fords and Chevs.

As for the aluminium Ls1s and Northstars they are a far more expensive engine to play with than the older engines.And without special castings etc a far bigger handgrenade too.

Early 70s SBC are up to 40lbs heavier than the late ones as a long bare engine., about 1/2 in the block so a diet is probably not a great idea on the later ones. Especially if used as a stresses member.
I am one who has always mounted them on original rubber in racecars. Solid mounting for me is a no way. Front and rear engine plate maybe but that has just added 15lb! And that only really works on a SBC as they have the ears on the front of the block for that purpose.

#12 Canuck

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Posted 02 May 2012 - 02:28

Grenade? When was the last time you saw a small-block of any brand withstand the punishment being meted out to the LS series? Did you read the Hot Rod article detailing the turbo abuse they subjected a lowly 4.8 to?

#13 ray b

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Posted 02 May 2012 - 04:27

northstars are junk yard cheap 500-1k
add reground cams and trick springs
standard port tricks and clean up or replace the intake
do the time-cents just in case
and sand rail guys rev 7-8-9k and live
on stock lowers



#14 gruntguru

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Posted 02 May 2012 - 05:15

Iambic pentameter Ray?

#15 pugfan

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Posted 02 May 2012 - 06:57

Iambic pentameter Ray?


It's obviously too long but it does have a Haiku flavour to it.

#16 Tony Matthews

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Posted 02 May 2012 - 07:45

Sonnet, innit?

#17 Magoo

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Posted 02 May 2012 - 10:46

I hear it as a country swing tune. Imagine Bob Wills' falsetto interjected here and there: reground cams and trick springs, yeah boy hot cha.

#18 Tony Matthews

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Posted 02 May 2012 - 10:49

North Star and the Junk Yard Boys.

#19 NeilR

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Posted 03 May 2012 - 05:45

This is the place that claims the 54lbs:
http://www.shadydell...p.com/index.htm

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#20 carlt

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Posted 03 May 2012 - 18:12

The iron blocks used by Ferrari were cast using a process that allowed 3mm wall thicknesses.

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This casting process carried over to production Fiats
The 'Fully Integrated Robotised Engine' or FIRE engine fitted in the 80's Fiat Panda , Punto etc has an amazingly light iron block with thin bore walls and intricately laced Main brg bridges [ beautiful iron casting]

#21 Magoo

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Posted 03 May 2012 - 22:27

This is the place that claims the 54lbs:
http://www.shadydell...p.com/index.htm


To me, the 54 lbs and its meaning depends mainly on the R3 block's bare weight in original form. The GMPP LSX iron block, a beefy piece indeed (designed to contain 2500+ hp), weighs 221 lbs, so it's not hard to imagine whittling 54 lbs from it for use in less demanding applications. On the other hand, the recent Ford FRPP Boss 302 casting weighs 160 lbs, so 54 lbs wouldn't appear to be possible. With the unaided eye, the R3 looks to be somewhere between these two. Two items worth noting are the siamese bores and the tall decks. We can also note that the source above says *up to* 54 lbs.


#22 NeilR

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Posted 04 May 2012 - 04:25

fair point, but even removing say 35lbs is a fair bit.

#23 bigleagueslider

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Posted 04 May 2012 - 04:47

To me, the 54 lbs and its meaning depends mainly on the R3 block's bare weight in original form. The GMPP LSX iron block, a beefy piece indeed (designed to contain 2500+ hp), weighs 221 lbs, so it's not hard to imagine whittling 54 lbs from it for use in less demanding applications. On the other hand, the recent Ford FRPP Boss 302 casting weighs 160 lbs, so 54 lbs wouldn't appear to be possible. With the unaided eye, the R3 looks to be somewhere between these two. Two items worth noting are the siamese bores and the tall decks. We can also note that the source above says *up to* 54 lbs.


54 lbs of cast iron is 180 cubic inches of material. That would be a 1" thick plate 13.4" square. That's a lot of metal to remove. Even though it's a production block casting, I can't believe there's that much excess material. Metal costs money, and a modern production block casting would not likely have that much extra material.

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#24 Magoo

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Posted 04 May 2012 - 10:14

54 lbs of cast iron is 180 cubic inches of material. That would be a 1" thick plate 13.4" square. That's a lot of metal to remove. Even though it's a production block casting, I can't believe there's that much excess material. Metal costs money, and a modern production block casting would not likely have that much extra material.

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As I said, it depends on the original casting. For example, with the 221 lb LSX casting, 54 lbs is feasible.

Blocks like the Mopar R3, the GMPP LSX, and the FRPP Boss are low-volume castings specifically designed for severe duty and sold at a premium price in the performance aftermarket. The LSX bare casting weighs over 70 percent more than a production LS iron block. Cost and weight are traded for durability and displacement potential.

Now obviously, there is little point in starting with the LSX block and essentially reverting it back into a standard duty block via expensive and time-consuming machining. May as well start with the production block if weight is critical. And that's the issue with the Mopar R3 block as well...except that the R3 has raised decks and siamesed bores. If you need these features in an iron block, you need the R3 (or successors).

The latest Dodge Motorsports NASCAR block (umm, that would be R6, I suppose) new this season is a compacted graphite casting with closed decks. It will be fairly expensive and I have no idea if it would be accepted in the race sanction above.






#25 NeilR

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Posted 04 May 2012 - 12:33

The people I know purchased an R5 engine from Ernie Elliot racing, but even though they were going to only use the bottom end (there is a 7200rpm rev limit) the engine was banned once the organisers saw it sitting on the workshop floor.

#26 Magoo

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Posted 05 May 2012 - 07:52

The people I know purchased an R5 engine from Ernie Elliot racing, but even though they were going to only use the bottom end (there is a 7200rpm rev limit) the engine was banned once the organisers saw it sitting on the workshop floor.


What is the series if I may ask?


#27 NeilR

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Posted 06 May 2012 - 05:25

Touring Car Masters

http://www.touringca...com.au/news.php

Edited by NeilR, 06 May 2012 - 05:26.


#28 Lee Nicolle

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Posted 06 May 2012 - 09:02

Touring Car Masters

http://www.touringca...com.au/news.php

The category with little resemblance to what the car was. But a modern Nascar block is a bit unrealistic even in that category. Maybe a performance version of the original LA block. Lets hope it is going to end up in a Chrysler product. Unlike Richards Mopar powered Javelin.

#29 NeilR

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Posted 07 May 2012 - 03:31

if you mean they are no longer historic cars, then no they are not. They are much more a cross between an old pan style sports sedan and an old Trans-Am car.
The Ford and Chev runners use a motorsport block, in fact I doubt you could find a production part in the running gear...so I'm not sure why a Nascar block is an issue.