Aluminum vs Iron Block ?

comparing the 2 blocks how much more on average is the cost to build an aluminum deal ? what are the pros and cons? Just looking into the idea of aluminum for weight savings

Aluminum for weight savings other than that it really doesn’t do anything better than iron.

dfree383 wrote:Aluminum for weight savings other than that it really doesn’t do anything better than iron.

Usually about a 2% loss in power for that weight savings.

...and how much do you have to take into consideration the aluminum block moving around as it heat cycles? More of a question than an answer here...

An aftermarket aluminum block is typically about double the cost of an aftermarket iron block.

The aluminum blocks can be had in a number of different deck heights and configurations so you have a bit more flexibility. They can also be more easily repaired if they get damaged.

bigford632 wrote:An aftermarket aluminum block is typically about double the cost of an aftermarket iron block.

The aluminum blocks can be had in a number of different deck heights and configurations so you have a bit more flexibility. They can also be more easily repaired if they get damaged.

so is that it ? just double the cost on the block itself ? or is it double the cost to build an entire deal ?

rmcomprandy wrote:

dfree383 wrote:Aluminum for weight savings other than that it really doesn’t do anything better than iron.

Usually about a 2% loss in power for that weight savings.

why is that ? tolerances ?

bruno wrote:

bigford632 wrote:An aftermarket aluminum block is typically about double the cost of an aftermarket iron block.

The aluminum blocks can be had in a number of different deck heights and configurations so you have a bit more flexibility. They can also be more easily repaired if they get damaged.

so is that it ? just double the cost on the block itself ? or is it double the cost to build an entire deal ?

The cost of head studs is some what more than the iron block stuff. Lots more labor on the block also.

Bruno ,
Aluminum blocks "move" with heat and move more where there are higher concentrations of aluminum. That translates to the sleeves which don't stay as round as iron blocks ( obviously without sleeves) do. So maintaining ring seal in an aluminum block is always more difficult. The aluminum block flexes more than an iron block too ( torsionally).

I just sold a Dart 9.5 deck Windsor block and on my scales i think it was 93 lbs.

I should have added that was an aluminum block.

bruno wrote:

rmcomprandy wrote:

dfree383 wrote:Aluminum for weight savings other than that it really doesn’t do anything better than iron.

Usually about a 2% loss in power for that weight savings.

why is that ? tolerances ?

on avg the alum block will make about 8 less hp when hot. As compared to same ci
ring seal, trade off for the weight is a win. Build it big

Plus If you window it ,It can be repaired Easier
plus If you wear it out,just buy new sleeves

biglucky wrote:I just sold a Dart 9.5 deck Windsor block and on my scales i think it was 93 lbs.

damn that is lite .... what a svo bbf deal comes in around 250 ish if i remember

Alum block have good resale used, easier to repair, never had a problem with ring seal.
Don't think anybodys going to notice 8 hp, a degree of timing will make more difference.
And it's nicer on the back to unload an alum block, compared to a cast iron block.

Something I didn't like about the aluminum block C Head combo was having to lash the valves almost at zero cold, and a constant battle keeping the thing sealed up water wise. Maybe it was a combination of 10.300 deck height, TALL height of C Heads with 10" + pushrod or whatever. That engine grew so much that you had to lash them tight to get it where you would have .024 or. 026 lash hot. I constantly chased water sepage and it was really noticeable if you had to change a valve spring on the engine. If you put air in the cylinder while it was cold it would eventually pressurize the coolant system. We had to heat cycle the crap out of that thing to get it to seal up before making the first pass. The engine would actually change tones slightly if you listened to it once it hit the seal point as well. Speaking for myself only, I wouldn't do an aluminum endeavor again. They might be repairable but for twice the price you can always buy another iron block and come out the same. If your looking for every pound maybe, me I would just look to make more power to overcome the slight weight reduction and not have all the extra headaches that come with the aluminum.

TravisRice wrote:Something I didn't like about the aluminum block C Head combo was having to lash the valves almost at zero cold, and a constant battle keeping the thing sealed up water wise. Maybe it was a combination of 10.300 deck height,  TALL height of C Heads with 10" + pushrod or whatever. That engine grew so much that you had to lash them tight to get it where you would have .024 or. 026 lash hot. I constantly chased water sepage and it was really noticeable if you had to change a valve spring on the engine. If you put air in the cylinder while it was cold it would eventually pressurize the coolant system. We had to heat cycle the crap out of that thing to get it to seal up before making the first pass. The engine would actually change tones slightly if you listened to it once it hit the seal point as well. Speaking for myself only,  I wouldn't do an aluminum endeavor again. They might be repairable but for twice the price you can always buy another iron block and come out the same. If your looking for every pound maybe, me I would just look to make more power to overcome the slight weight reduction and not have all the extra headaches that come with the aluminum.

Well that certainly paints the picture. For someone that fought water issues with the last deal , i want to make this as much a low maintenance deal as possible .

Realistically between the difference in the cost of the blocks, head studs and other changes plan on spending $4000 more to build a 385 series engine with an aluminum block vs. a Cast iron. The Aluminum block is going to be 99 lbs lighter than the Cast Iron. It is more reparable and will allow you to make changes easier. Run a little stop leak through it if you're having issues but you shouldn't be leaking water regardless.

TravisRice wrote:Something I didn't like about the aluminum block C Head combo was having to lash the valves almost at zero cold, and a constant battle keeping the thing sealed up water wise. Maybe it was a combination of 10.300 deck height,  TALL height of C Heads with 10" + pushrod or whatever. That engine grew so much that you had to lash them tight to get it where you would have .024 or. 026 lash hot. I constantly chased water sepage and it was really noticeable if you had to change a valve spring on the engine. If you put air in the cylinder while it was cold it would eventually pressurize the coolant system. We had to heat cycle the crap out of that thing to get it to seal up before making the first pass. The engine would actually change tones slightly if you listened to it once it hit the seal point as well. Speaking for myself only,  I wouldn't do an aluminum endeavor again. They might be repairable but for twice the price you can always buy another iron block and come out the same. If your looking for every pound maybe, me I would just look to make more power to overcome the slight weight reduction and not have all the extra headaches that come with the aluminum.

the lash deal comes with all alum blocks, And its not a issue.

for sealing them up we dont have a problem with water leaks. haven't in over 20 years

Ours was a Oring deal. Full bodied car with hinged hood. I'll disagree that it's not a big deal chasing lash. I checked lash after every weekend of racing. If I skipped I took the chance that the pushrod would jump out of the cup if it was .006 or .007 cold. I didn't have a crew to help. Mainly me or my dad. So working over the fenders and chasing issues are problems if you dont have a lift off front end chassis car. Car weighed 3906# with driver as well. <<<
We filled the oring grooves, tried cometics, even liquid glass. Nothing cured ours. It was not a fresh new engine either. We bought it freshened and it was probably 10-12 years old when we got it.

Some things are bigger deals to different kinds of racers. I wouldn't do it again for 90# that's for sure.

I guess I'll chime in......

Like Rich said, the lash deal just goes with the territory..
I set them cold at .015 , so they are .022-.024 when hot...
Mine doesn't leak....With Cometic head gaskets...js

But you can tell the difference is the "sound" of it, cold vs warm...
Cold she sounds a little rough, but warm... she's ready to get it on !

Well I have 5 - 11.200 deck blocks and love them !!! Yes FIVE !!!!! also have 3 sub 7.50 -200 mph cars !!! and dam I've worked 400 hour months for most of my life also !!
Frank

Is it true that the billet machined aluminum blocks are more stable, and dont "grow" or move around as much as a casting does??

I've got a fresh 4.65 bore A96 for sale if anyone is interested Located in Northern Virginia and the work was done by C and C Motorsports.

TravisRice wrote: I'll disagree that it's not a big deal chasing lash. I checked lash after every weekend of racing. If I skipped I took the chance that the pushrod would jump out of the cup if it was .006 or .007 cold.

You had something else going on causing that. On a 12" Deck block with Hemi heads the valves are open when it's cold, and the lash doesn't jump out when running at operating temp. You may have had an issue with your rocker system or adjusters. Once initially set (and everything settles in) you shouldn't have to adjust the lash again unless something is going away (rocker arm, pushrod, lifter or cam). Ran an engine the other day that hadn't been fired up in 15 months, started it double checked the lash and valve springs and run her to 8500 + no movement on lash or water leaks.

You may be blaming the issues you had on the aluminum block while it may have been the engine itself if it were that old not knowing the history of it.

Carbguy wrote:

TravisRice wrote: I'll disagree that it's not a big deal chasing lash. I checked lash after every weekend of racing. If I skipped I took the chance that the pushrod would jump out of the cup if it was .006 or .007 cold.  

You had something else going on causing that.   On a 12" Deck block with Hemi heads the valves are open when it's cold, and the lash doesn't jump out when running at operating temp.  You may have had an issue with your rocker system or adjusters.  Once initially set (and everything settles in) you shouldn't have to adjust the lash again unless something is going away (rocker arm, pushrod, lifter or cam).  Ran an engine the other day that hadn't been fired up in 15 months, started it double checked the lash and valve springs and run her to 8500 + no movement on lash or water leaks.  

You may be blaming the issues you had on the aluminum block while it may have been the engine itself if it were that old not knowing the history of it.

VERY TRUE, ONCE you heat cly the eng once or twice they dont change much unless there is a prob