Aluminum vs, Cast Iron Block

[82ACAUTOCRAFT]

I would like feedback from people using the new aluminum blocks, problems, durability issues, stretching, leaks overheating, etc.
For example aluminum rover V8 have a problem with sleeves moving down the block and coolant entering the combustion chamber.

[STCinc]

When I built my engine, I went iron.. Yes, the alloy block is cool, but it's only 80lbs lighter, but cost is a fair bit more. (I went with a DART Iron 351w block with a 9.5in deck)

For street use, I didnt see any benefits. For the track, the 80 or so lbs will make a difference, but I dont plan to track.

[82ACAUTOCRAFT]

Also, aluminum is not great for threads which are usually weak compared to iron. For a street motor, aluminum does not have great advantages except for bragging rights. I think iron is better for durability!

[Jamo]

Originally Posted by 82ACAUTOCRAFT

Also, aluminum is not great for threads which are usually weak compared to iron. For a street motor, aluminum does not have great advantages except for bragging rights. I think iron is better for durability!

So, if you're so committed to your beliefs, why in the hell did you start this thread?

You cite the Rover (nee Buick) arruminum motor as having problems...I'll go one better and cite the Vega motor. Course, in those days we didn't have computers or the internet.

Since then, most, if not all mfgs have been using aluminum motors for production cars...which go through a bit more in their lives than we can put on Cobra motors. Most race mfgs, in every series of racing, now use aluminum.

My own opinion...most folks end up sleeving iron FEs, they are getting more difficult to find in good shape, the really good ones are as expensive as new aluminum blocks, the aluminum motors tend to run cooler, you can run slightly higher compression on pump gas...and the list goes one (including being lighter where it counts...up front).

If you don't want aluminum, then by all means, get what you want...you evidently have already made up your mind, so why start a thread asking for opinions?

[82ACAUTOCRAFT]

Originally Posted by Jamo

So, if you're so committed to your beliefs, why in the hell did you start this thread?

You cite the Rover (nee Buick) arruminum motor as having problems...I'll go one better and cite the Vega motor. Course, in those days we didn't have computers or the internet.

Since then, most, if not all mfgs have been using aluminum motors for production cars...which go through a bit more in their lives than we can put on Cobra motors. Most race mfgs, in every series of racing, now use aluminum.

My own opinion...most folks end up sleeving iron FEs, they are getting more difficult to find in good shape, the really good ones are as expensive as new aluminum blocks, the aluminum motors tend to run cooler, you can run slightly higher compression on pump gas...and the list goes one (including being lighter where it counts...up front).

If you don't want aluminum, then by all means, get what you want...you evidently have already made up your mind, so why start a thread asking for opinions?

Except for your thread above, no one has come up with valid reasons why I should use an aluminum block! My car is original and it is currently fitted with a 428!

[Jamo]

Maybe because it appeared you weren't being receptive to their opinions giving your own explanation to your own satisfaction.

[82ACAUTOCRAFT]

Actually, the only guy who answered the thread preferred the iron block! You refer to most car manufacturers using alloy blocks, yes but they spend millions designing engines from the ground up! not copying an existing design in alloy! the only one which seems to have improved the design is Shelby by running stud all the way down and improving the oiling system!

[Jamo]

I give up.

[blykins]

I think we have another rsimoes on our hands.

[JBo]

he answers all his own threads if you go back and look at the last week or so

[82ACAUTOCRAFT]

What wrong with rsimoes? I have looked at his threads and I don't see anything wrong with them. When I ask a question, I am hoping to get useful feedback from people. Yes, it is true I already know quite a bit about the subject but I am trying to get more feedback to make up my mind!

[ffindling]

I'm not sure the Vega block should be included in a discussion of the merits
of aluminum blocks. The Vega block was linerless and practically all aluminum
blocks on the market these days have cast iron liners. GM developed the
Vega block conjunction with Reynolds who developed an alloy known as 390
and a heat treatment process to go along with it. The idea being that the
390 alloy could heat treated to give cylinder bores good wear characteristics.
It actually worked quite well and in testing, GM ran the engines for over 150K
miles with good results. But the engine suffered for two reasons, first was
abysmal build quality which plagued the entire industry during those times.
The engine needed to be built to fairly exact tolerances and instead they
were slapped together with a degree of sloppiness never seen before. The
other reason was overheating. Consumers often let their cars overheat,
traditional cast iron engines could tolerate that to a degree but the Vega
engine could not tolerate overheating in the least because overheating destroyed the heat treatment on the cylinder bores and once that was
destroyed the engine would gall itself to death. The Vega debacle pretty
much ended the industry's foray into linerless blocks although a few manufacturers have reintroduced linerless blocks in recent years such as
Mercedes and BMW.

....Fred

[Ant]

I have an alloy windsor 9.2 deck Dart block, built by KC, these blocks are good quality and dont give the thread problems etc like some of the old 1960/1970/1980 blocks. Plus I cant emagine the sleeves moving down the block especially when the motor engineers do this work all the time, and follow the correct procedures, surely if the sleeves are seated properly and I am not sure if the block is heated up to further assist this process, and then machined true, there shouldnt be any problems!

Further to that driveability improves, even on the road because you dont have to move the same amount of weight, especially on a road with some nice corners, and the cost isnt really that much more than a new cast iron block, in my opinion buy once and get what you want, and get a reputable engine builder.

[Anthony]

Originally Posted by 82ACAUTOCRAFT

I would like feedback from people using the new aluminum blocks, problems, durability issues, stretching, leaks overheating, etc.
For example aluminum rover V8 have a problem with sleeves moving down the block and coolant entering the combustion chamber.


Except for your thread above, no one has come up with valid reasons why I should use an aluminum block! My car is original and it is currently fitted with a 428!

The aluminum block is lighter (obviously), and can be repaired much more easily than an iron block if your engine builder screws up. Ask me how I know.

In your case, I'd keep the original 428 block, same one they put in the galaxies.

[Manowar]

At World Products, slightly more than 25% of our complete engines are aluminum block options. The percentage of shorts is slightly less. We have several hundred in use over a ten year period by customers and have virtually zero warranty claims on them and very few issues we've seen on the race engines. It's important to remember that unlike other builders, we manufacture our own castings and build our engines from them exclusively.
All of our sleeves are ductile with top flanges and o-rings. All are press fit by heat/cool method. Our brand new Warhawk LS engine uses this method which drastically improves GM's sleeve installation problems of falling out and/or ballooning. The GM sleeves have no flange, using ribs on the sleeve instead,which is then inserted into the tooling (mold) and the aluminum is poured around it. Obviously cooling causes a dimensional change and often high HP, boost or spray use causes the sleeves to fall or fail.
Further, no issues about thread holes for frost plugs or stud attachment are experienced unless the end-user is careless about anti-seize or proper torqueing.
Iron or aluminum, the choice should not be based on fear of aluminum's properties-all the reputable builders (including us!) offer high quality blocks and can build a trouble free engine for you.

[scottj]

Originally Posted by Ant

...Plus I cant emagine the sleeves moving down the block especially when the motor engineers do this work all the time, and follow the correct procedures, surely if the sleeves are seated properly and I am not sure if the block is heated up to further assist this process, and then machined true, there shouldnt be any problems!...

I've had one Dart block where the sleeves sunk .002" in a time period from new to the first freshen. There were no symptoms. The builder took .002 off the deck and they never moved again.

[undy]

My 482" Pond aluminum block S/O engine's great!! No leaks, drips or any other maladies. It runs cooler than the cast iron 428 it replaced too. The build quality and attention to detail is unsurpassed.. 80 lbs off the front end of a Cobra is huge..

I don't think my 494 rwhp 07 Z06 is suffering from a weak block either...

Dave

[ChipBeck]

The biggest problem in a 427 or other big block Cobra is too much weight up front. I've driven both iron bock and aluminum block 427 Cobras and although I can't tell a difference in power the aluminum block cars steer easier and handle better. I think a 289 street car with an aluminum small block would be best of all. My Shelby American all aluminum 427 (CSX460)has been trouble free. In modern motors the only advantage to iron is that it's cheaper to build and buy. IMO

Chip

[Jamo]

Originally Posted by ffindling

I'm not sure the Vega block should be included in a discussion of the merits
of aluminum blocks. The Vega block was linerless and practically all aluminum
blocks on the market these days have cast iron liners. GM developed the
Vega block conjunction with Reynolds who developed an alloy known as 390
and a heat treatment process to go along with it. The idea being that the
390 alloy could heat treated to give cylinder bores good wear characteristics.
It actually worked quite well and in testing, GM ran the engines for over 150K
miles with good results. But the engine suffered for two reasons, first was
abysmal build quality which plagued the entire industry during those times.
The engine needed to be built to fairly exact tolerances and instead they
were slapped together with a degree of sloppiness never seen before. The
other reason was overheating. Consumers often let their cars overheat,
traditional cast iron engines could tolerate that to a degree but the Vega
engine could not tolerate overheating in the least because overheating destroyed the heat treatment on the cylinder bores and once that was
destroyed the engine would gall itself to death. The Vega debacle pretty
much ended the industry's foray into linerless blocks although a few manufacturers have reintroduced linerless blocks in recent years such as
Mercedes and BMW.

....Fred

Fred...I had one. After I added sleeves, it ran forever.

BTW...the Porsche 928 used essentailly the same technology beginning in the early 70s...few problems (at least with the cylinders, that is).

The obvious intent for referring to the Vega motor was that, like the RoverneeBuick motor...citing fairly wide spread issues from decades ago is hardly worthy as support that aluminum motors are problematic.

[Commander]

It's nice to hear about the wonders of aluminum blocks from the Southern Brigade, but anyone have experience living with an aluminum block from a northern clime?