OK, it's a given that an otherwise similar engine will be lighter when made of aluminum. My question is this: are there any advantages to having an iron block? I believe they are less expensive and stronger than aluminum. In addition, they seem to have greater heat retention properties. I noticed the other day that the work van warmed up a great deal faster than my Teg. Would this have anything to do with aluminum's ability to conduct heat? Does an aluminum engine block have more effective heat sinking (I may be making up words, but I think you know what I mean ) effect?

 

For what it's worth, I find that my CRX warms up faster than any of the 3 GMC trucks I've also driven. I've attributed it to the Honda being a sleve engine and the others not. Probably a design thing more than the metal.

I guess I'd say iron block would be stronger and last longer than aluminum....but what do I know...

 

Well, it's hard to know for sure. The gauges on the van work so much better than the ones on my Teg...

 

Iron blocks are stronger..

4G63 ( GS-T DSM )
SR20DET ( turbo JDM 240sx )
2JZ ( Supra )
6g72 ( stealth/ VR4 )

All the "big dogs" use iron blocks for a reason....

Hondas were meant for gas mileage, so we got alum. light-weight blocks, that really hold a lot more HP then a lot of people prob. thought at frist...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRXSi90 &raquo;</TD></TR><TR><TD CLASS="quote">For what it's worth, I find that my CRX warms up faster than any of the 3 GMC trucks I've also driven. I've attributed it to the Honda being a sleve engine and the others not. Probably a design thing more than the metal.</TD></TR></TABLE>I think it's from the total amount of coolant & the size of the radiator & heater core, compared to the heat produced. If your CRX carried 3 gallons of coolant it would take longer to warm up, too.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRXSi90 &raquo;</TD></TR><TR><TD CLASS="quote">I guess I'd say iron block would be stronger and last longer than aluminum....but what do I know...</TD></TR></TABLE>Strength, corrosion, heat transfer are all different. Cost is probably different, too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 89dxhunchback &raquo;</TD></TR><TR><TD CLASS="quote">Iron blocks are stronger..

4G63 ( GS-T DSM )
SR20DET ( turbo JDM 240sx )
2JZ ( Supra )
6g72 ( stealth/ VR4 )

All the "big dogs" use iron blocks for a reason....

</TD></TR></TABLE>

Well the sr20det is an aluminum block, but I got what you meant. The KA24DE is (in the USDM 240s) an iron block. Thats why that engine is great to slap a turbo on. Mad amounts of torque

Mike

 

Aluminum transfers heat much better than iron; this causes an aluminum block to have more even heat distribution and less hot spots. This can help reduce detonation and pre-ignition problems.

The problem, I think, with Honda blocks in regards to forced induction is that they have floating sleeves, whereas in iron blocks the block needs no sleeves since it's already iron (iron is necessary for the sleeves because it has extremely long-wear properties unlike aluminum).

I believe Dart makes a B-series block which is machined out of aluminum and has cast-in sleeves, rather than floating sleeves. A design like this should be able to handle much more pressure than a standard floating-sleeve Honda block.

Anyone know what the Porsche Turbo 911's block is? I'm thinking aluminum. I believe the bottom line is that aluminum is really a better material technically for blocks, in all cases, but is more expensive to use especially in high-boost situations.

 

starts saving for a Dart block.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dwolsten &raquo;</TD></TR><TR><TD CLASS="quote">Aluminum transfers heat much better than iron; this causes an aluminum block to have more even heat distribution and less hot spots. This can help reduce detonation and pre-ignition problems.

The problem, I think, with Honda blocks in regards to forced induction is that they have floating sleeves, whereas in iron blocks the block needs no sleeves since it's already iron (iron is necessary for the sleeves because it has extremely long-wear properties unlike aluminum).

I believe Dart makes a B-series block which is machined out of aluminum and has cast-in sleeves, rather than floating sleeves. A design like this should be able to handle much more pressure than a standard floating-sleeve Honda block.

Anyone know what the Porsche Turbo 911's block is? I'm thinking aluminum. I believe the bottom line is that aluminum is really a better material technically for blocks, in all cases, but is more expensive to use especially in high-boost situations.</TD></TR></TABLE>

What you really mean is open deck vs. closed deck blocks. Closed deck = stronger. honda blocks are open deck thats why the problems under boost.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by virginia_dude &raquo;</TD></TR><TR><TD CLASS="quote">What you really mean is open deck vs. closed deck blocks. Closed deck = stronger. honda blocks are open deck thats why the problems under boost. </TD></TR></TABLE>

Not exactly. The thing is that, with few exceptions, cylinder sleeves need to be made of iron because it's long-wearing. Aluminum cylinder walls would wear out very quickly (there are methods of avoiding this which I won't go into here). So with an iron block, it's simple to make it a closed deck--just make the whole block out of iron and drill some holes in it for the cylinders and you're done. There's no really good reason to make it an open deck since that would take more work.

But with an aluminum block, the standard practice is to have separate cylinder sleeves made of iron. I'm not really an engine expert, but my guess is Honda decided an open deck had some advantages, and since they already had to have separate cylinder sleeves, that it was better to go with the open deck design. Of course, they weren't counting on people slapping big turbos on these engines and trying to double the horsepower...

So, in practical terms, iron blocks tend to always be closed decks, and aluminum blocks tend to usually be open decks (at least in the case of Hondas). What I'm trying to point out ultimately is that the notion that iron blocks are much better for forced induction is flawed: there's nothing wrong with aluminum blocks, only with open-deck designs that are prevalent with Honda aluminum blocks.

 

I believe cost is the only advantage with open-deck blocks...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 89dxhunchback &raquo;</TD></TR><TR><TD CLASS="quote">Iron blocks are stronger..
4G63 ( GS-T DSM )
SR20DET ( turbo JDM 240sx )
2JZ ( Supra )
6g72 ( stealth/ VR4 )
All the "big dogs" use iron blocks for a reason....
...</TD></TR></TABLE>

Those are mickey mouse motors,the REAL big dogs run aluminum...
Top Fuel
Top Alcohol
IHRA Pro Stock,
Pro Mod,etc etc.....

 

The boxer engine is aluminum and is opendeck as well.
I believe the JDM h22a pre 96 blocks are closed deck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gsrhatch530 &raquo;</TD></TR><TR><TD CLASS="quote">I believe the JDM h22a pre 96 blocks are closed deck. </TD></TR></TABLE>

If I recall correctly, some older Prelude engines (possibly the ones you're talking about here) are closed deck, but are unique in that they don't have iron cylinder liners. Instead, they impregnated the aluminum walls with silicon I believe to give it long-wear properties. I'm not sure how it worked out; probably not that well since they don't seem to do this anymore.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dwolsten &raquo;</TD></TR><TR><TD CLASS="quote">If I recall correctly, some older Prelude engines (possibly the ones you're talking about here) are closed deck, but are unique in that they don't have iron cylinder liners. Instead, they impregnated the aluminum walls with silicon I believe to give it long-wear properties. I'm not sure how it worked out; probably not that well since they don't seem to do this anymore.</TD></TR></TABLE>Aluminum cylinders never went over very well over here. Remember the Vega?? Valid or not, perceptions drive purchases.

Maybe related, Benz had some Al cylinders in a particular engine, but for USDM cars they put in steel liners. I believe it was because of something in our gasoline (sulpher)?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dwolsten &raquo;</TD></TR><TR><TD CLASS="quote">

Not exactly. The thing is that, with few exceptions, cylinder sleeves need to be made of iron because it's long-wearing. Aluminum cylinder walls would wear out very quickly (there are methods of avoiding this which I won't go into here). So with an iron block, it's simple to make it a closed deck--just make the whole block out of iron and drill some holes in it for the cylinders and you're done. There's no really good reason to make it an open deck since that would take more work.

But with an aluminum block, the standard practice is to have separate cylinder sleeves made of iron. I'm not really an engine expert, but my guess is Honda decided an open deck had some advantages, and since they already had to have separate cylinder sleeves, that it was better to go with the open deck design. Of course, they weren't counting on people slapping big turbos on these engines and trying to double the horsepower...

So, in practical terms, iron blocks tend to always be closed decks, and aluminum blocks tend to usually be open decks (at least in the case of Hondas). What I'm trying to point out ultimately is that the notion that iron blocks are much better for forced induction is flawed: there's nothing wrong with aluminum blocks, only with open-deck designs that are prevalent with Honda aluminum blocks.
</TD></TR></TABLE>

What I mean by open deck which is the block type on most honda engines it the deck surface really isn't there mostly you have cylinders sticking up in mid air nothing connecting them. A closed deck is not like that at all.

Aluminum blocks and cylinders get their wear surface from crystaline silica that develops when the blocks cool which has to be at a certain rate for it to work right. Remember the VEGA , same alloy mercedes adn Porshe used only the block casting proccess was wrong it cooled too quickly and you had clinders that wore too quickly because the silica cystals never formed in the metal. THat was not the issue with Porshe and Mercedes, both of wich had alluminum cylinders also, same as honda. Well most honda anyway. You can get 250,000 miles and more when it is cast and cooled correctly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by D-Man &raquo;</TD></TR><TR><TD CLASS="quote">

Those are mickey mouse motors,the REAL big dogs run aluminum...
Top Fuel
Top Alcohol
IHRA Pro Stock,
Pro Mod,etc etc..... </TD></TR></TABLE>True but those blocks are Far from stock configuration,they have massive amounts of webbing to counteract the twisting effect of the large amounts of power they create.

 

Ok,you want a strong *** aluminum production block,you dont have to look no further than the 03 Cobra engine or even more so the upcoming 04 Ford GT engine.There is one guy making 849whp and over 1000wtq on a stock cobra long block,all stock under the valve covers...only real mods are a KB blower and nitrous..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by D-Man &raquo;</TD></TR><TR><TD CLASS="quote">Ok,you want a strong *** aluminum production block,you dont have to look no further than the 03 Cobra engine or even more so the upcoming 04 Ford GT engine.There is one guy making 849whp and over 1000wtq on a stock cobra long block,all stock under the valve covers...only real mods are a KB blower and nitrous.. </TD></TR></TABLE>Much more fitting examples...and DAMN thats impressive I must say.

 

The S/C cobras use an iron block. Only the non-S/C pre-03' cobras have Alum. block..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 89dxhunchback &raquo;</TD></TR><TR><TD CLASS="quote">The S/C cobras use an iron block. Only the non-S/C pre-03' cobras have Alum. block..</TD></TR></TABLE>

89dxhunchback is correct.

Mike

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Regular Series &raquo;</TD></TR><TR><TD CLASS="quote"> starts saving for a Dart block. </TD></TR></TABLE>

&lt;-- already have one hehe...