Cast iron block instead of aluminum

[EdKiefer]

Originally Posted by ConnClark

The big advantage of cast iron is less heat loss to the coolant as it doesn't conduct heat as well as aluminum. This keeps more heat in the combustion gasses and allows you to extract more power. The down side is it makes it harder to pass Nox emissions.

yes, but the combustion process happens with piston up, not much exposed cylinder wall, plus most aluminum blocks got steel liners .

you think it makes that much difference with still aluminum head in place ?

[Frank Lee]

Good point, that really applies to cast iron vs alum heads.

[user removed]

Originally Posted by Daox

I know the guys up north have problems with keeping their Insights warm in winter. The small aluminum block coupled with oversized grills, low coolant volume and autostop make for coolant temperatures that are all over the place.

With the start-stop technology becoming a significant factor the blocks heat radiating ability becomes much more significant. If you are going to consider extracting heat from waste heat energy then reducing the waste heat energy amount in the first place makes much sense to me. Eliminate the waste and the recovery or same energy becomes unnecessary.

The iron blocks resistance to heating up and cooling off is supposedly about 25% of aluminum. That's huge when you think of minimizing heat losses.

Another point they touched on is the cooling system itself. I think they are talking about a dual path radiator, which if I understand the concept reduces coolant heat loss by restricting the radiator volume when it is not necessary. In other words adjusting the radiator capacity to suit the ambient temperature and average engine load. When both are low there is a huge difference in the necessary cooling capacity with extreme examples being the heater core itself provides adequate cooling.

It shows they are really looking into ways of preventing the 60+% heat energy losses to the exhaust and cooling systems.

regards
Mech

[EdKiefer]

Originally Posted by Old Mechanic

With the start-stop technology becoming a significant factor the blocks heat radiating ability becomes much more significant. If you are going to consider extracting heat from waste heat energy then reducing the waste heat energy amount in the first place makes much sense to me. Eliminate the waste and the recovery or same energy becomes unnecessary.

The iron blocks resistance to heating up and cooling off is supposedly about 25% of aluminum. That's huge when you think of minimizing heat losses.

Another point they touched on is the cooling system itself. I think they are talking about a dual path radiator, which if I understand the concept reduces coolant heat loss by restricting the radiator volume when it is not necessary. In other words adjusting the radiator capacity to suit the ambient temperature and average engine load. When both are low there is a huge difference in the necessary cooling capacity with extreme examples being the heater core itself provides adequate cooling.

It shows they are really looking into ways of preventing the 60+% heat energy losses to the exhaust and cooling systems.

regards
Mech

I think one of biggest changes is the integrated exhaust manifold built into the aluminum head, instead of a separate header as was the standard .
I would assume this would cool the exhaust more exiting the engine but at same time heat up o2/cat faster as the shorter path .
With turbo, its only way to go IMO and should give very good response times ,less turbo lag .

[user removed]

Ford's old ancient tech I6 engines had integral exhaust manifolds cast with the head. I wonder if they will actually go to a cast iron head as well. Wouldn't it be ironic to see the return to what many may see as old tech when they may have learned that it may actually end up being better tech. With iron blocks and heads heat losses would be minimised at the source, while heat retention would be maximised.

It will be interesting to see what they actually do that is truly new.

regards
Mech

[EdKiefer]

Originally Posted by Old Mechanic

Ford's old ancient tech I6 engines had integral exhaust manifolds cast with the head. I wonder if they will actually go to a cast iron head as well. Wouldn't it be ironic to see the return to what many may see as old tech when they may have learned that it may actually end up being better tech. With iron blocks and heads heat losses would be minimised at the source, while heat retention would be maximised.

It will be interesting to see what they actually do that is truly new.

regards
Mech

yes, or maybe they can go to a thermo-barrier coating at specific locations to keep heat in in these area's .
I kind of doubt they go cast block an head ,well maybe in small engine but not broader range of engine size (V6/V8 ) .

[user removed]

Good thought. Ceramic coating on cast iron, now we have old bathtub technology .

regards
Mech

[EdKiefer]

Originally Posted by Old Mechanic

Good thought. Ceramic coating on cast iron, now we have old bathtub technology .

regards
Mech

Shhh , marketing guy says "high -tech coating " sells

[dwtaylorpdx]

I've had the opportunity to build quite a few race cars for road racing where we try and save weight. In the AL vs iron area we found Chevy Iron vs AL blocks had the 100 lb savings, but very very few others did. In some cases (Nissan 2.0 engines) the Iron version was 30 lbs lighter than the AL version. I've also seen a std 350 chev v8 block lightened up for a dirt track car by almost 100 lbs with very carefully designed CNC programs. They machined every surface making it thin as possible. Lots of the water jacket is filled with epoxy where the water is not realy needed to help stiffen up the block. Would not be surprised if any mid size 4 cylinder could not be lightened significantly.

Dave.

[EdKiefer]

Originally Posted by dwtaylorpdx

I've had the opportunity to build quite a few race cars for road racing where we try and save weight. In the AL vs iron area we found Chevy Iron vs AL blocks had the 100 lb savings, but very very few others did. In some cases (Nissan 2.0 engines) the Iron version was 30 lbs lighter than the AL version. I've also seen a std 350 chev v8 block lightened up for a dirt track car by almost 100 lbs with very carefully designed CNC programs. They machined every surface making it thin as possible. Lots of the water jacket is filled with epoxy where the water is not realy needed to help stiffen up the block. Would not be surprised if any mid size 4 cylinder could not be lightened significantly.

Dave.

a small 4 cylinder (under 2.0L ) iron block is not that heavy . I have rebuilt many types and have no problem picking them up , never weighed any but my guess is in the 75-100lb max , so smaller 3 cylinder cast iron vs aluminum would be pretty small and that was all old engines I worked on (1970-90's ) .