It’s an old thread, but I have noticed something interesting about engine reliability.
If you use both block and head of cast iron, your will have better reliability than an iron block with an alloy head. Also both made of aluminum will result in better reliability.
I don’t find this very realistic. The most popular way of building an engine between '60s and '00s has been iron block + alloy head. Some of the most reliable/durable engines
of all time have been built like this - such as the Mercedes OM600-series, Saab H-engine and the Audi 5-cylinder. So I think this should be changed so that the material itself
has a reliability coefficient, but not the combination of materials.
The earliest aluminium head + iron block engines did have issues, generally in the way of head gasket failures due to the differential expansion rates of iron and aluminium.
It hasn’t been a problem for a long time, so I’d say that the actual problem is that the reliability penalty is too high, especially in the 90’s-00’s period.
Yeah, that would make sense.
The penalty should be negligible in the later years but I do agree the first developments could have a more noticeable penalty.
[quote=“Sayonara”]
It hasn’t been a problem for a long time, so I’d say that the actual problem is that the reliability penalty is too high, especially in the 90’s-00’s period.[/quote]
I agree with this. There were lots of problems in the 80’s but in the 90’s aluminum heads on cast iron blocks were common and Honda revved them to the moon. The head gaskets never leaked, unlike the 80’s Dodge Daytona which had horrendous head gasket issues.
Any word on whether or not the devs will make an adjustment to this?
I’d really like to build some motors with differing metals, like basically every real life car maker does, but the reliability penalties are just too severe, and that’s not fun (or, again, realistic).
Another thing is that at the moment, even when you can mix metals reliably, it strongly encourages you to do the opposite: to use an aluminum block and a cast iron head. This is because it gives a small horsepower bonus for a cast iron head, and the vast majority of the weight and emissions reductions come from the block. I’m not saying this isn’t realistic, but it makes me wonder why so many auto makers chose to go with cast iron blocks and aluminum heads then.
Of course, I’m just speculating… it is an interesting question though.