aluminium heads on a diesel

[JUeckert]

since ford axed the 7. 3 and the 6. 0 that replaced it has been plauged with issues, i left them for another dodge purchase back in 05. for the most part i have been happy with the 05 purchase, but in a couple years will be in the truck market again. i found out that the new 6. 7 engine ford has slated for their truck line, will have aluminum heads, and in my book this is a no no! i really dont feel that aluminum heads have any place on a diesel, especially one that is to be worked, and kept for the long term. what are some opinions or experiences on this subject. please keep the truck brand out of the discussion. if your loyal to a particular brand line [gas or diesel] thats your bis, i just want a perspective on the subject itself...

 

[fox]

My opinion is aluminum heads should only be used with aluminum blocks!!!

The expansion rates of aluminum and cast iron are different. This scruffs the gasket EVERY time it warms and cools.

GM knows better, but thinks they can out smart the materials used. So does Ford.

Aluminum also conducts heat away from the combustion chamber faster than iron, puts it into the coolant.

As far as gas motors go, some say you CAN run more compression with aluminum heads, I say you MUST run more. !!!!

 

[Gary - K7GLD]

We all feared the results of aluminum heads when GM started using them - but they seem to be working out OK so far - and for a reality check, look at the rather uncomfortable number of failed head gaskets and dropped valve seats in the Cummins on this board.

 

[GHarman]

30 Years ago, I had a small vehicle with a 4 cyl. diesel, Natuarally aspirated, indirect injected, cast iron block and aluminum head. At 175,000, every paired exhaust/intake port was joined by a crack. It required a new head! Aluminum works, but does have a finite lifespan compared to Cast Iron. Light weight and manufacturing ease may offset its short life. However, an Aluminum head should be paired with an Aluminum block. Essentially, a throwaway motor. IMHO! GregH

 

[Forrest Nearing]

30 Years ago, I had a small vehicle with a 4 cyl. diesel, Natuarally aspirated, indirect injected, cast iron block and aluminum head. At 175,000, every paired exhaust/intake port was joined by a crack. It required a new head! Aluminum works, but does have a finite lifespan compared to Cast Iron. Light weight and manufacturing ease may offset its short life. However, an Aluminum head should be paired with an Aluminum block. Essentially, a throwaway motor. IMHO! GregH

news flash... iron heads crack

 

[Gary - K7GLD]

news flash... iron heads crack

YUP - sometimes with annoying regularity - like GM small block V8 heads between the valve seats... #@$%!

 

[Forrest Nearing]

good way to prevent that is to run a quality aftermarket aluminum head w/ a good chamber design

 

[JUeckert]

We all feared the results of aluminum heads when GM started using them - but they seem to be working out OK so far - and for a reality check, look at the rather uncomfortable number of failed head gaskets and dropped valve seats in the Cummins on this board.

gary, i have seen the valve seat failures on the common rail engines. when i have spare time, i help my brother on ocassion with his wrecker buisness. doing this has enabled me to become friendly with many of the dealers in our region[all big 3]. most of the valve /seat failures seem to deal with the higher output common rails. my theroy is high egt's, is this not an accurate statment? from what i have seen over the years, none of the cummins engines can be labeled bullet proof, but [and keep in mind, i'am a major 7. 3 fan] the cummins is the best diesel under the hood of pickup. the duramax is not a big seller in my part's, as for grocery haulers, there's quite a few, but rarley do i talk with the owner of one in heavy use, or with lot's of miles. form what i have read, the duramax has had a few changes over the years, partialy due to maintaining durability with the heads and such.

 

[RHestand]

IMO, long life, torque, and durability are of the utmost importance, and the life blood of a diesel engine.

How many OTR trucks have alum. heads, blocks, or any combination of both?

Or, for that matter, V-block configurations?

Comparing gas and diesel engines? Apples and oranges.

 

[GHarman]

news flash... iron heads crack

Forrest, All metals have a failure point. The design is critical to the lifespan of any component. Aluminum workhardens as it expands and contracts. Aluminum also has a thermal coefficient of expansion that is 2X that of steel, with C. I. being more thermally stable than steel in a heat-up-cool-down cycle. Aluminum is easier to cast than C. I. as its pour temperature is much lower (~1200*F. , alloy dependent) where C. I. is about 2800*F+.

IMHO, you will get a statistically shorter life from an Aluminum head than a C. I. Head. The only advantages I see are; You may save a little weight and gain manufacturing ease. You will also have statistically high gasket issues mated with a C. I Block and shorten the potential life span of the motor.

Not everyone wants to tear into their motor to do upgrades. Diesels are sold at a premium compared to the gasoline engines available. I would think that the purchaser would desire a return on their investment by expecting a longer engine life. I can get that from a 4 cylinder, all aluminum gasoline motor (223,000 miles) before head gasket failure. I doubt you will exceed that by much, with an aluminum head on a C. I. block, diesel motor, at a premium price. GregH