Aluminum vs. Iron FE block longevity

[lippy]

I'm considering either an iron or aluminum Pond block for my ERA build. I'm a big fan of the weight savings associated with the aluminum, and the cost differential isn't that much in the context of the cost of the whole project. But I am wondering about the long-term reliability and longevity of these aluminum blocks. It took Ford and others several years and significant resources to design all aluminum engines, and I wonder if the aftermarket blocks may be good in the beginning but fail to hold up over the longer term. I hear great things about Pond, but the resources and testing capabilities of a small aftermarket vendor are very limited. It would be great to know the longest anyone has used one of these blocks in service, what their experience has been, and of course, their opinion on one vs the other. Thanks!

[patrickt]

My seasoned iron FE block is about 40 years old... and is as good, maybe even better, than new.

[lovehamr]

"Long term" you mean putting 200k+ miles on your Cobra? If that's the plan, really, more power to ya! I don't think that they're looking that far down the literal road. That being said, I do know of guys with 50k+ miles on Pond blocks. If you post that question over on the FE Forum you'll prolly get some good feedback as well.

[lippy]

Ok, by long term I'm thinking 50-75k miles.

[FWB]

with either choice it's safe to say they will both outlive you and maybe your children as far as the inherent design goes......

[patrickt]

You know, at one time an older iron block that was "seasoned" from a couple of zillion heat cycles commanded a premium, at least with older engine builders. I guess folks just don't think that way no mo'.

[347stroker]

Patrick we who build 15 liter high performance diesels alway look for a seasoned block. As you state they have heat cycled thousands of times and are a more stable base for line boring the crank and other machining operations. I would always used a seasoned block! Tom

[fordracing65]

In a glass car iron is fine, but it seems silly, to put an iron block in an alunimum roller, like a Kirkham, keep it all the same metal.

[Silversmith]

Having never owned a alum. FE sideoiler. I can only speak of my experience with a iron FE sideoiler. A well built 65-67 sideoiler will turn 7,500 rpm for 500 miles on avg. with no problem before requiring inspection and refresh. but it may also let go! As might any engine under that type of load. However, if you keep the same engine built the same way @ say 6,500 rpm. per shift (occasionaly) during general street or occasional track use. Then you can expect solid performance for 50,000 miles before inspection and refresh! Lee Holmon relayed this info to me on the 65-67 sideoiler nascar/block engines. This I believe, because of my prior experience with CSX 3116 with a 66 Holmon Moody built sideoiler! Also because of my present ERA (C5AE-H) Holmon Moody built nascar/block sideoiler. She is not pampered! But if the Pond alum. block is just as strong?, and with the weight savings! That would be just awsome! I must say thou; in the end, I just prefer a well seasoned iron block. But who knows, if I loose this hart. I may think of Alum.

[undy]

I believe the Pond aluminum block is stronger and more durable than any original iron S/O block. There seems to be a hell of a lot more "repaired" OEM S/O blocks out there than unmolested ones, understanding that they're nearly 50 years old.

[RICK LAKE]

lippy It doesn't matter if the block is make from plastic,( save this for another thread). Good machinist, good parts, and good maintainance will extend the motors life 3 fold. There are some more important things like, ABUSE. beat the crap out a motor all the time, it is going to come apart. There is something to be said about running seasoned blocks over new blocks. It doesn't matter what material they are make of. I have been running a Shelby block for 15+ years with 1 rebuild for a bigger motor. From 452 to 482 in size. 7 years on the 452 of 98% racing and no failures to block. I did have 2 failures of valve train in heads. 2 broken rocker shafts. Both broken at mount hole between #7 &#8 cylinders. Went with a Erson setup and no failures since. I did improve mounts for rocker shaft asemblies by going to time serts in the heads instead of helicoils. Other 2 notes are this, limiting rpms to 6,000 -6,200 max. Get gearing of the car with a 3.07-3.31, you don't need any thing more unless a small block would goto a 3.54. Trans, 5 speed overdrive with a 2.80's first gear and a .80's 5th gear. Forget HP and build torque motor. Here the last thing and IMO building an FE with a preoiler and running an #80 psi spring in an HVHP oil pump. This is for a street motor with a little fun at times. This is also with a storker kit of BBC rods in the bottom end. I have lived with a #100 pound spring for 15 years. Warming up the motor is important before driving. Having oil pressure before starting IMO is also important. I am running a BBC rod bottom end. You can go any way you want from building a great 390 in iron with side bolts for the caps to a 527 aluminum beast. Paint the motor and no body will know. Build the motor on paper with the parts you want and we will see what power comes for this. Shelby block are built over the top. The engineering is unlike any other motor for strength and power limit,( about 2,800 hp last heard ). You can save money by buying a 390 and boring it to a 445. This will give you 500/500 at the crank and a hand full in the drivers seat to start. After this you may want to try something bigger. I can explain how different my car was to add another 150 hp and over 150ft of torque to it. This is crank numbers. Rick L.

[bret a ewing]

Originally Posted by fordracing65

In a glass car iron is fine, but it seems silly, to put an iron block in an alunimum roller, like a Kirkham, keep it all the same metal.

You can alway paint the aluminum block black or blue.

[mdross1]

The one thing about aluminum is that the expansion rate has to be considered when setting up clearances.As long as the builder is vigilant and knows the ins and outs of building a motor like this longevity should not be an issue.Not knowing Pond products but certain the blocks are far superior to early aluminum offerings in alloy, density,even sleeve material,not to mention weight savings over iron.

[lippy]

Thanks. This is a ton of help. It would also be good to hear who has the most miles out of a Pond or Shelby aluminum block, and whether you've had cooling or leaking problems.

[bret a ewing]

After 2700 miles, including 17 hours of open track, the Keith Craft motor was pretty tired. Overheating and leaking everywhere, but it didn't break. Pretty darn durable IMHO. I believe the 30 minute track sessions at VIR/SAAC36 vs 20 minute on prior events sped up the aging process, live and learn.

Had my local engine builder do the complete rebuilt. It did not take any major parts to complete. 5 angle and bigger valves icing on the cake.

[tirod]

The OEM use of aluminum in blocks is pretty much the long term solution for them. It's cheaper to cast, cheaper to machine, and they get engineering and gas mileage out of it.

One area that is more problematic with aluminum blocks - overheating. If you let them get hot - really hot - the torqued bolts will pull the threads in the block. You can rebuild them to your hearts content, they won't hold the threads after that, and they are junk. It's a significant issue for street cars these days - they get new head gaskets but they won't hold.

Used aluminum heads and blocks from the competition scene are on the market for a reason, too - if they were any good, the team would recondition and reuse them.

Iron won't do that, it'll crack, as the thread on F4TE 351W's relates on TOS. If you look for it, you find it. Most of us can't find soft aluminum in threaded holes.

If you want to run aluminum and enjoy it's many benefits, you need to take more precautions with the cooling system, and it wouldn't hurt to be paranoid about overheating. Aluminum blocks make expensive man cave tables.

There's a another trend that just hit visibility, the use of compacted graphite iron blocks. These are supposed to offer a lot of advantages, and may become a big player. Remains to be seen, but there are folks casting and running them. If World or others offered them in the next five years, it would be nice, I'm not planning on it.

The roadster has a rear weight bias already, the 150 pound difference off the front is likely less significant than a good set of ported heads, brakes, or six speed. In a car already pushing 6.5 pounds per hp, overall handling won't be as affected by an aluminum block alone - the money could get you a lot further in other areas. It's a matter of balancing the design and spending money where it gets the most bang for the buck.

If it was a choice of aluminum block with carburetor and donor brakes, vs iron block, tuned EFI, six speed, and big rotors with 6 piston calipers, it wouldn't be a choice. I'd run an iron block.

What you'd likely get with an aluminum block are all the other goodies - and 650 hp, but that can be done to iron, too. Aluminum doesn't bring that much to the table all by itself, it's just one part of the overall recipe to a performance level.

[Dominik]

Good day!

I don't want to sound clever, but the 150lbs weight savings will not affect your daily driving, unless you do some serious racing.

I love weight savings as much as the next guy - probably more (1950lbs in the 90s with a 496cui alu Chev), but the cost doesn't justify it.

There is one bonus: Aluminium cools better.

Also, you would be surprised where you can save 150lbs on your car. Start with rotating parts which give you a higher "return of weight savings" and then reduce your unsprung weight.

Thirdly: how much do you weigh ;-)

[RodKnock]

Originally Posted by patrickt

My seasoned iron FE block is about 40 years old... and is as good, maybe even better, than new.

I wasn't aware that they make a modern day aluminum 428 for comparison purposes. For comparison accuracy, we should only consider aluminum 427's and iron 427's.

BTW, there are at least several examples of aluminum 427's with over 10,000 miles and going strong. I think my aluminum 482 is wonderful......when I pass by it in the garage.

[patrickt]

Originally Posted by RodKnock

I wasn't aware that they make a modern day aluminum 428 for comparison purposes. For comparison accuracy, we should only consider aluminum 427's and iron 427's.

Uh, agreed... the added wall thickness of my 428 block does make it an unfair comparison.

[undy]

Originally Posted by patrickt

Uh, agreed... the added wall thickness of my 428 block does make it an unfair comparison.

I bet a Pond or Shelby aluminum block has thicker cylinder walls than your 428. Heard of s-i-a-m-e-s-e blocks??