Cast iron block/aluminum head

[trinacriabob]

I know that when this technology was newer, the cast iron block and aluminum head could be a problem if the engine ever overheated and it warped the head gasket. I know of a friend's parents with a Thunderbird this happened to. However, I don't hear much about this anymore. The Chevy V6s, 3.1, 3.4, 3.5, 3.9 are all cast iron block/aluminum head. Most engines are like this now. Only the 3800 and a few others remain as iron block/iron head.

Do you think this is a cause for concern? Have they addressed the fact that a car can run a little hot? Any thoughts or opinions?

[balthazar]

No solid data here, but I wonder if rampant electronics (overheat: shut-down protection?) safeguards against extreme conditions like this. Assuredly, head gasket improvements also help. Seems to be an early OEM problem.

The Hi-po aftermarket is ripe with alum heads on iron blocks, been available for years & years and I never hear of that problem at all.

Hope not: I spent $1100 on bare alum heads for one of my vehicle's iron block...

[razoredge]

Sunbeam put aluminum heads on all the Alpines starting in 59. I never heard of a head problem with the Sunbeams heads and many were worked to quite high compression, which I believe was one of the reasons for using aluminum. I dont know about all Toyotas or Datsuns engines but they have been using aluminum heads on some of their motors since the early 70's. I drove a L20B some rediculous distance without coolant and didnt warp the head until I added water.................dut da da ! Ah, to be young, ignorant and stupid again...................I'll pass.

I have always felt alot of the "aluminum heads = bad" talk amounst American oldtimers was little more than folk lore and just plain fear of a soft metal. However we are now quite aware of the vast cheapness surrounding the American automakers with that war between engineers and bean counters. If they can save 10 cents on a casting or metalurgy, thats what they will try to do, even if it fails.

Buick 215 is a prime example. quad4 another

One the flip side I have an 64 English Ford 330 ci I6 with a cast iron head that has a bit of an engineering flaw. The head gasket will eventually fail in this one location and pump compression into the water jacket, thereby pumping coolant out the radiator overflow unless you leave the radiator cap loose......................

671 Detriot Diesels, another I6 with a single cast iron head also experienced some head failure

Nothing is carved in stone that will not eventually erode.

Edited July 24, 2006 by razoredge

[balthazar]

How was the Buick 215 an engineering failure?

[trinacriabob]

Razor:

Those applications you speak of are an aluminum head on an iron block, right? That's my concern - different materials, different coefficient of expansion.

I'm not too concerned about all-aluminum, actually. There are now plenty of Cadillacs on the road that are 15+ years old that have all-aluminum engines with steel piston sleeves.

[razoredge]

TricriBob - Yes they were iron blocks/aluminum heads.......not the 215 (all aluminum) and Im not sure what the block in Quad 4 was. I know what you are talking about with different materials and their expansion rates & temps. I dont think any engine fairs well to overheating............oh wait.............I forgot, we had a 89 NYer that ran the 3.0 SOHC V6 Mitzu, aluminum head/cast block and we over heated it bad at a crowded toll booth, now I was older and wise but I knew no way in hell did I want to shut that car off on the interstate, let alone in that traffic. We drove that car another 2.5 years and never had a head problem. At 150,000+ miles it finally developed a rod knock. Another effect of overheating.

The 60* Chevy V6 family, has had aluminum heads for a long time as far as I know and I dont believe there has been problems due to the head material. Im not worried about the 3.9.................that wont go bad until it hits 36,001 miles ....................shoehorn SC3800 ?............just kiddin I hope.

Balthazar - the word porosity seems to keep poping up, I have no first hand experience with the engine but every topic Ive seen or any time the subject comes up it seems to have a certain amount of "not so great" surrounding the life span of the origional (GM) engines. Something about a large % of rejected casting and others making it to market that shouldnt have. Others know the story, Ive only read/heard it a handful of times. I dont know how British Leland did with them.

Heres an interesting little story about coolant and an all aluminum race engine. I read it years ago and now just recently found it again in a different story. Seems unbelievable but interesting if nothing else

DAYTONA 24 HOURS 1970 - Having qualified as 13th the N.A.R.T. Ferrari 312P Berlinetta - chassis 0870 - of David Piper and Tony Adamowicz finished as 5th overall. Years later Tony tells: "I remember that I was very impressed with the strength and integrity of the 312P. I recall that the track surface deteriorated during the last half of the race - revealing coral under the surface. Bits of the coral kicked up and began to eat away at our radiator, which was mounted very low in the nose. Mike Parkes had unfortunately crashed the #24 bubble roofed car during the early morning hours, and the only spare radiator between the two Ferraris had been used in repairing his car. The track conditions would eventually render our own radiator useless, and David and I had to drive for five hours without any water in the system, using the oil temperature as a guide to finishing the race. And so that's racing, not bad for the first ever ride in a Ferrari."