Moparts

Aluminum Vs. Graphite Block

Posted By: HitIt

Aluminum Vs. Graphite Block - 08/09/10 08:45 PM

Looking at the aluminum and CG blocks. What are the pros and cons of each for a 625hp-ish street strip engine? Is the CG block way overkill for this much power? Why do they no longer make these CG blocks?

Thanks!
Posted By: Bill_LBSR

Re: Aluminum Vs. Graphite Block - 08/09/10 09:06 PM

I would say that a CG block would be way overkill for the HP your talking about. Actually I would say the aluminum block would be too. A stock block or one of the World iron blocks would be fine for that hp.
Posted By: fullmetaljacket

Re: Aluminum Vs. Graphite Block - 08/09/10 10:41 PM

A little abstract in explanation, but here goes.

Like said above, you don't need any of the fancy stuff for that level.
Some here are pushing 700 plus HP on stock well tanked, cleaned, pressure tested, wall thickness consistency tested and machined to good round straight,squared and flat surfaces.
Posted By: HEMIFRED

Re: Aluminum Vs. Graphite Block - 08/09/10 10:41 PM

Quote:

I would say that a CG block would be way overkill for the HP your talking about. Actually I would say the aluminum block would be too. A stock block or one of the World iron blocks would be fine for that hp.



x2 stock would be the best bet. ligter than aftermarket steel less costly tan the others can withstand near double your 600 HP
Posted By: Diablo

Re: Aluminum Vs. Graphite Block - 08/09/10 10:57 PM

Quote:

Quote:

I would say that a CG block would be way overkill for the HP your talking about. Actually I would say the aluminum block would be too. A stock block or one of the World iron blocks would be fine for that hp.



x2 stock would be the best bet. ligter than aftermarket steel less costly tan the others can withstand near double your 600 HP



X3 save you money for other things....
Posted By: Dragula

Re: Aluminum Vs. Graphite Block - 08/10/10 12:04 AM

The reason CG block might become obsolete, isn't because of the any issues with the block itself, its the cost to machine it. They are very nasty on tool life. Also, if you did get one and wanted to go +.030" in the future, your engine builder might not like it either.
Posted By: We The People

Re: Aluminum Vs. Graphite Block - 08/10/10 01:12 AM

If I had a bunch O'cash I might use an alum. block on the street just for the low weight. but you dont need it for 625 hp. I run 660 in a stock 72 hp2 at the track.

Attached picture 6131676-goodenginepic.JPG
Posted By: HEMIFRED

Re: Aluminum Vs. Graphite Block - 08/10/10 01:20 AM

using aluminum does have horsepower loss issues
Posted By: DusterDave

Re: Aluminum Vs. Graphite Block - 08/10/10 01:32 AM

Quote:

using aluminum does have horsepower loss issues


Fixable, though. I'd choose the aluminum block over the CG just for that.
Posted By: go green

Re: Aluminum Vs. Graphite Block - 08/10/10 03:42 AM

Quote:

using aluminum does have horsepower loss issues



Far outweighed by weight loss and repairability .


Buy a block you can run and fix forever or buy a CG and hope for the best .
Posted By: 70blackfish

Re: Aluminum Vs. Graphite Block - 08/10/10 05:55 AM

I would say the World block
Posted By: BIG BEAR

Re: Aluminum Vs. Graphite Block - 08/10/10 12:29 PM

Quote:

The reason CG block might become obsolete, isn't because of the any issues with the block itself, its the cost to machine it. They are very nasty on tool life. Also, if you did get one and wanted to go +.030" in the future, your engine builder might not like it either.






Posted By: HitIt

Re: Aluminum Vs. Graphite Block - 08/10/10 04:58 PM

Great info guys, thanks very much.

The reason I ask is that I can get a screaming deal on a new alumnium block wedge block, and the guy offered the GC block at the same price. Might still go aluminum but like you all say money could be spent in better places...

Thanks again!
Posted By: Slingshot383

Re: Aluminum Vs. Graphite Block - 08/10/10 05:10 PM

Carbon graphite takes diamonds, tungston, or carbide tooling to machine it. It also grows and shrinks much differently than aluminum or iron.
Posted By: MRMOPAR622

Re: Aluminum Vs. Graphite Block - 08/10/10 05:17 PM

HEMIFRED, I have heard of the horsepower loss with a aluminum engine. But with the new castings like the Indy Maxx blocks is this still true? This is only a question I am not disagreeing with you.
Posted By: HEMIFRED

Re: Aluminum Vs. Graphite Block - 08/10/10 05:48 PM

Quote:

HEMIFRED, I have heard of the horsepower loss with a aluminum engine. But with the new castings like the Indy Maxx blocks is this still true? This is only a question I am not disagreeing with you.


yes to a point they all have some loss the only evaluation comes from similar combos as no one I know of ever did a mirror build to compare the two.
Posted By: HitIt

Re: Aluminum Vs. Graphite Block - 08/10/10 05:54 PM

Why the difference in power?
Posted By: Cab_Burge

Re: Aluminum Vs. Graphite Block - 08/10/10 06:24 PM

Quote:

Why the difference in power?

ring seal due to the differences in the expansion rate between the aluminum block and steel sleeves is what I have been told. I heard this from a relaible source that has used both types of block that the aluminum block would only hold minimum (less than 5 inches)vacume on start up cold and end up with positive crankcase pressue at the end of the run, 45 seconds to a minute and fifteen seconds later The iron block holds 17 inches on start up and crooses the finish line at 15 inches or more depending on how many runs are on the rings and pistons. This is on a boosted 2000+ HP motor IHTHs
Posted By: Diablo

Re: Aluminum Vs. Graphite Block - 08/10/10 06:38 PM

Quote:

Quote:

Why the difference in power?

ring seal due to the differences in the expansion rate between the aluminum block and steel sleeves is what I have been told. I heard this from a relaible source that has used both types of block that the aluminum block would only hold minimum (less than 5 inches)vacume on start up cold and end up with positive crankcase pressue at the end of the run, 45 seconds to a minute and fifteen seconds later The iron block holds 17 inches on start up and crooses the finish line at 15 inches or more depending on how many runs are on the rings and pistons. This is on a boosted 2000+ HP motor IHTHs



Completely agree there is a loss with Alum blocks but i'm wondering how much closer a solid alum block is to a iron one compared to the water ones.

Both my TS engines have solid KB blocks. (but if i had the choice and there were iron 4.840bs blocks out there i probably would have gone with steel.
Posted By: MRMOPAR622

Re: Aluminum Vs. Graphite Block - 08/10/10 07:29 PM

I have one more question. Do you think there is enought horespower advantage in a steel block to make up for the extra 100 lbs or so? Indy says the Maxx aluminum block is a 110 lbs lighter than the cast iron block.
No one has mention that yet. I was just curious.
How much extra horsepower would it take to make up a 100 lbs? I can't find my Moroso(sliderule) calculator.
Posted By: moparniac

Re: Aluminum Vs. Graphite Block - 08/10/10 08:22 PM

Quote:

If I had a bunch O'cash I might use an alum. block on the street just for the low weight. but you dont need it for 625 hp. I run 660 in a stock 72 hp2 at the track.



did you cut down your vent tubes or something?
Posted By: LA360

Re: Aluminum Vs. Graphite Block - 08/10/10 11:42 PM

Quote:

I have one more question. Do you think there is enought horespower advantage in a steel block to make up for the extra 100 lbs or so? Indy says the Maxx aluminum block is a 110 lbs lighter than the cast iron block.
No one has mention that yet. I was just curious.
How much extra horsepower would it take to make up a 100 lbs? I can't find my Moroso(sliderule) calculator.



Unless the rules dictate otherwise, Pro Stock would be all over Aluminium blocks if there was an advantage. The Compacted Graphite Iron block are much more stable, hence why they are used in Diesel engines and Pro Stock, Comp Eliminator and the like.
Posted By: Chris'sBarracuda

Re: Aluminum Vs. Graphite Block - 08/10/10 11:53 PM

Quote:

Why the difference in power?



The weight makes up for it. Don't worry about that.

It really depends mostly on what your long term plans are.
If you are happy with 650 hp and never plan on going any faster, then a stock block is a good choice. If you want to go real fast later, the Aluminum Block is a great choice for expanding your horizons..

It's ultimately your choice..

I have Aluminum Block, and would never go back.. But that's me.. Just my opinion..

Have Fun either way.



Chris...
Posted By: BB 70 Challenger

Re: Aluminum Vs. Graphite Block - 08/11/10 08:42 AM

Quote:

I have one more question. Do you think there is enought horespower advantage in a steel block to make up for the extra 100 lbs or so? Indy says the Maxx aluminum block is a 110 lbs lighter than the cast iron block.
No one has mention that yet. I was just curious.
How much extra horsepower would it take to make up a 100 lbs? I can't find my Moroso(sliderule) calculator.




This is an interesting topic. I have been thinking this very same thing myself, also. So, I found this info on "Mopar Engines West" pages:

* (4/16/04) Okay, okay... We have had several emails from people that feel there's another "con" we need to mention if your building an all out race motor. Everything else being equal, the aluminum motor will make a little less horsepower. We have seen as much as 20 HP, on the dyno, on 900 HP motors. This is because the engine is basically an air pump AND a heat engine, and it's harder to keep heat in an aluminum motor. Also, aluminum moves around more, so ring seal varies at very high cylinder pressures. But this only affects all out race motors. On a street motor it would be hard to measure any difference, and any slight decrease in HP would be more than offset by the decrease in weight.

http://www.moparengineswest.com/No_Blocks.htm
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