What are the cons of an iron block?
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From: Lexington, Ky
What are the cons of an iron block? I'm thinking of building a motor, very long term, and I was thinking of an iron block 6.0L so I could run around 422-427 cubes w/out worrying about dropping a sleeve, etc. It'd most likely be a solid roller setup, also. But a hydraulic roller isn't a bad idea either <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
What, other than the more weight, are the cons to this block?
Will it heat soak now that the block is iron as opposed to aluminum?
Thanks.
What, other than the more weight, are the cons to this block?
Will it heat soak now that the block is iron as opposed to aluminum?
Thanks.
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From: Green Oak, MI
Re: What are the cons of an iron block? Weight, thats about it.
I worried about 2 things. Cooling issues and how the head would react with the block because of different rates of exspansion.
Neither if them have been a problem, in fact my car runs unusually cool, at stock levels or just below. With the air on I hit 210 sitting in heavy traffic on a 95 degree day, driving on a hot day with air its 195-200, without the air regardless of temp and moving I'm never over 195.
I worried about 2 things. Cooling issues and how the head would react with the block because of different rates of exspansion.
Neither if them have been a problem, in fact my car runs unusually cool, at stock levels or just below. With the air on I hit 210 sitting in heavy traffic on a 95 degree day, driving on a hot day with air its 195-200, without the air regardless of temp and moving I'm never over 195.
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Re: What are the cons of an iron block? I believe you can only go 4.060 bore with it. Overheating doesn't seem to be an issue. It is almost 100lbs heavier but with the money you save you can put that towards a light weight K-member, a-arms, light weight carpet and battery and be back were you started. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Durability is better and you don't have to worry about the problems of re-sleeved blocks.
Justin
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Re: What are the cons of an iron block? I agree that weight is the only real con. 100 lbs is probably high. I guess more like 50-60 lbs.
Cast iron is stronger than aluminum for blocks. GM's cast iron Bowtie blocks (last gen) are rated by GM for 700-800 hp at 8000+. Winston Cup engines do about 8 at 9300 rpm all afternoon.
Aluminum heads have been used on iron blocks for most of the life of the automobile. I heard that early on in the LS1 truck engine development, the truck guys wanted iron heads for durability. The Powertrain guys/gals proved that the aluminum heads were as durable or more so. It did take a while to ramp up aluminum head production, however.
Aluminum has an advantage as a head because it conducts heat away faster so it can usually tolerate a bit more compression for the same octane and spark advance. I don't think LS1 truck heads are aluminum to save weight!
Cast iron is stronger than aluminum for blocks. GM's cast iron Bowtie blocks (last gen) are rated by GM for 700-800 hp at 8000+. Winston Cup engines do about 8 at 9300 rpm all afternoon.
Aluminum heads have been used on iron blocks for most of the life of the automobile. I heard that early on in the LS1 truck engine development, the truck guys wanted iron heads for durability. The Powertrain guys/gals proved that the aluminum heads were as durable or more so. It did take a while to ramp up aluminum head production, however.
Aluminum has an advantage as a head because it conducts heat away faster so it can usually tolerate a bit more compression for the same octane and spark advance. I don't think LS1 truck heads are aluminum to save weight!
Re: What are the cons of an iron block? The only real issue is weight. iron block/aluuminum head engines have been around for years. I drove my car around in 95* temps and heavy traffic for about an hour on Thursday. Temp never climbed over 200.
The weight difference block for block is 100lbs. If you use lighter internals and go with the lightweight front suspension there really isn't much loss. My car is actually lighter now than it was with the LS1 block...
Shane
The weight difference block for block is 100lbs. If you use lighter internals and go with the lightweight front suspension there really isn't much loss. My car is actually lighter now than it was with the LS1 block...
Shane
Re: What are the cons of an iron block? make sure the block has the alternator mounting holes!!!
mine came with only one out oof three, i had to drill and tap the second one ( there was an ear on the block for that ) and the third one , i couldn't do anything about. the ls1 has a thick section for the third hole that is drilled and tapped, but the iron block i got had no such thing, just the outside of the water jacket <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> .
as far as cooling, it will be a little warmer, but if you're running the stock fans , you'll be ok.
mine came with only one out oof three, i had to drill and tap the second one ( there was an ear on the block for that ) and the third one , i couldn't do anything about. the ls1 has a thick section for the third hole that is drilled and tapped, but the iron block i got had no such thing, just the outside of the water jacket <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> .
as far as cooling, it will be a little warmer, but if you're running the stock fans , you'll be ok.
Re: What are the cons of an iron block? I was told that the iron blocks are 75 lbs more, I think 1000 sounds too high.
I have a 4.060 over and a 4.075 stroke.
I have 10.8:1 compression and run pump gas.
I run about 180F on the highway and 195 in heavy traffic.
I think the only CON is the weight.
I'm putting on 11.7:1 compression LS6 heads let's see how cool it runs then.
I have a 4.060 over and a 4.075 stroke.
I have 10.8:1 compression and run pump gas.
I run about 180F on the highway and 195 in heavy traffic.
I think the only CON is the weight.
I'm putting on 11.7:1 compression LS6 heads let's see how cool it runs then.
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Re: What are the cons of an iron block? Great info, thanks everyone. Keep it coming. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
PSJ, I saw you mention something regarding core shift in terms of the 6.0L block. If I got a brand new block from GM what should I look for on it when it arrives to make sure it's fine? Thanks.
<small>[ July 14, 2002, 01:40 PM: Message edited by: NastyC5 ]</small>
PSJ, I saw you mention something regarding core shift in terms of the 6.0L block. If I got a brand new block from GM what should I look for on it when it arrives to make sure it's fine? Thanks.
<small>[ July 14, 2002, 01:40 PM: Message edited by: NastyC5 ]</small>
Re: What are the cons of an iron block? You look at the core shift around each cylinder.
A typical 6.0 - LQ4 block can take .030 no problem.
I personally would do .030 over I'm thinking the pistons might be easier and cheaper to find.
A typical 6.0 - LQ4 block can take .030 no problem.
I personally would do .030 over I'm thinking the pistons might be easier and cheaper to find.
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Re: What are the cons of an iron block? Assuming a 409 was to be constructed, hydraulic roller, wanting 500 RWHP N/A, which heads would be the best bang for the buck to get me there, the 5.3L heads?
Re: What are the cons of an iron block? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>Without a doubt I would do LS6 heads since they flow more.
6.0 heads are good but you are starting off with a 70cc chamber.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">My thoughts on this are vastly different.
First on a 422 cu in LS1 you are looking at a 11.8:1 comp ratio with -2cc dish pistons (for valve reliefs) with a clearance height (gasket and deck height) of .040 and 70cc heads.
The 6.0L truck heads are by far the best choice IMHO. Why? Well they cost about $700 less for a core. They flow as good or better when ported compared to a LS6 head. And the large chamber is going to give you a better burn because you can run flat top pistons rather than dished pistons. Also if the head porter knows what he his doing the larger chamber can also be used to guide low lift flow and increase flow numbers there adding to an even more effective head. I would say that LS6 heads are better for high compression engines and smaller displacement LS1's. I don't think they make much sense for a street driven large displacement LS1.
Bret
<strong>Without a doubt I would do LS6 heads since they flow more.
6.0 heads are good but you are starting off with a 70cc chamber.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">My thoughts on this are vastly different.
First on a 422 cu in LS1 you are looking at a 11.8:1 comp ratio with -2cc dish pistons (for valve reliefs) with a clearance height (gasket and deck height) of .040 and 70cc heads.
The 6.0L truck heads are by far the best choice IMHO. Why? Well they cost about $700 less for a core. They flow as good or better when ported compared to a LS6 head. And the large chamber is going to give you a better burn because you can run flat top pistons rather than dished pistons. Also if the head porter knows what he his doing the larger chamber can also be used to guide low lift flow and increase flow numbers there adding to an even more effective head. I would say that LS6 heads are better for high compression engines and smaller displacement LS1's. I don't think they make much sense for a street driven large displacement LS1.
Bret
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Re: What are the cons of an iron block? Bret, thanks for your insight as well.
This is what I'm looking for out of this motor for my C5. Give me your ideas, everyone:
At least a 409
500 RWHP/RWTQ N/A
Good idle
Great Driveability
Runs on pump gas
hydraulic roller
<small>[ July 14, 2002, 06:09 PM: Message edited by: NastyC5 ]</small>
This is what I'm looking for out of this motor for my C5. Give me your ideas, everyone:
At least a 409
500 RWHP/RWTQ N/A
Good idle
Great Driveability
Runs on pump gas
hydraulic roller
<small>[ July 14, 2002, 06:09 PM: Message edited by: NastyC5 ]</small>
I can shift faster than you.
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Re: What are the cons of an iron block? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NastyC5:
<strong>Bret, thanks for your insight as well.
This is what I'm looking for out of this motor for my C5. Give me your ideas, everyone:
At least a 409
500 RWHP/RWTQ N/A
Good idle
Great Driveability
Runs on pump gas
hydraulic roller</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I think that is very possible, assuming you do use the LS6 or 6.0l heads and have a very efficient exhaust setup.
I do agree with Brett on the LS6 vs 6.0l heads. From what I have seen, the 6.0l heads offer slightly better mid-lift numbers compared to the LS6 heads, while the LS6 heads do flow better in the upper lifts after porting. For a street driven/hydraulic roller 409ci application (with max valve lift < .600), the 6.0l heads would be an excellent choice.
Jason
<small>[ July 14, 2002, 06:18 PM: Message edited by: Jason99T/A ]</small>
<strong>Bret, thanks for your insight as well.
This is what I'm looking for out of this motor for my C5. Give me your ideas, everyone:
At least a 409
500 RWHP/RWTQ N/A
Good idle
Great Driveability
Runs on pump gas
hydraulic roller</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I think that is very possible, assuming you do use the LS6 or 6.0l heads and have a very efficient exhaust setup.
I do agree with Brett on the LS6 vs 6.0l heads. From what I have seen, the 6.0l heads offer slightly better mid-lift numbers compared to the LS6 heads, while the LS6 heads do flow better in the upper lifts after porting. For a street driven/hydraulic roller 409ci application (with max valve lift < .600), the 6.0l heads would be an excellent choice.
Jason
<small>[ July 14, 2002, 06:18 PM: Message edited by: Jason99T/A ]</small>
