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Aluminum valve covers on iron heads?

6K views 14 replies 9 participants last post by  DanielC 
#1 ·
I'd like to dress up the LT1 I'm putting in my project with Aluminum or Chrome valve covers. The engine has stock valve covers now. The car will be a daily driver.
1) The engine has iron heads, so is it OK to use alumimum valve covers?
2) Will the engine run noticably cooler with aluminum vs steel chrome covers?
Thanks
 
#2 ·
You can run aluminum valve covers the only limit for them like any other valve cover is fitting over the rocker system. Stud mounted roller trunion rockers can be a space problem for center bolt covers, not always but it happens. The same if running stud girdles or shaft mounted rockers, it gets possible to have more hardware than space with this stuff on an engine. If there's nothing out of the ordinary than space to get all the parts under the covers shouldn't be an issue.

You won't find that the rocker covers have any noticeable effect on engine cooling.

Bogie
 
#4 ·
Thanks for the advice. One rodder said he did not like to mix alum valve covers with steel heads.
For alum valve covers I like chrome plated finned.
If possible it would be cool to have a Buick name plate on the covers.
(The engine is from a 95 Roadmaster and will be going into a 37 Roadmaster).
I would like to buy tall covers with room for 1.6:1 rocker rollers.
I also will need the clearance for the alternator.
Any suggestions for who sells these for a reasonable cost?
Thanks
 
#8 ·
If anything your friend may be thinking of Galvanic corrosion (Click here). Which is a real concern in some conditions of mixing metal and aluminum. It has became a real concern in the autobody industry with the construction of cars moving from all steel to steel/aluminum. And we aren't just talking bolted on parts here, we are talking mating steel body structure parts to aluminum parts. Cars like an Audi TT have the basic body of aluminum then some of the panels like the rear body panel where the trunk striker is mounted and all across the are body behind the bumper that is steel. You can't just rivet them together, what do you use, a metal rivet or an aluminum one? They have special aluminum rivets that are coated so there is no aluminum touching the metal rear body. The panels are bonded together with an adhesive (again, it is bonding but it is also creating a barrier between the two) and then riveted with these special rivets.

So you hear this talk of galvanic corrosion around the autobody industry a lot. But bolting aluminum valve covers on a cast iron engine doesn't create this problem that I have ever seen. Though the Vega's first engine which had a steel block and an aluminum head caused all kinds of problems. But aluminum headed engines are all over the place, what is the difference, you tell me! I am no expert in metallurgy so I can't say why, but aluminum parts on motors is as old as motors themselves so no there isn't an issue with bolting aluminum parts on your motor.

Brian
 
#10 ·
I am pretty sure the aluminium valve cover is touching the cylinder head. Take a test light, and connect the ground lead on the test light to the positive battery terminal, and see if the valve cover is grounded. I bet it is.

Aluminium bell housings get bolted to cast iron blocks in almost all cars. The heat of the engine keeps the water evaporated away form the parts. No water, no galvanic corrosion.
Same with valve covers.
 
#11 ·
The heat of the engine keeps the water evaporated away form the parts. No water, no galvanic corrosion.
Same with valve covers.
Ahhhhh, there is my answer, thanks. :thumbup: I know that aluminum timing chains and thermostat housings will corrode pretty bad. Finding cherry timing chain covers (it houses the water pump) for the Buick Nailhead is pretty tough.

Brian
 
#15 ·
"bet ya it isn't.. the ground test is because of the steel bolt thats screwed into head and touches the v/cover, the cover never touches the head, unless your gasket is out to lunch "

Then this becomes the point of contact between the aluminium and the steel, and the corrosion will happen at the bolt head touching the aluminium valve cover, if there is water or another electrolyte present.

The idea is you need electrical contact, and a conducting liquid, usually water.
My boat has a heater. It is plumbed pretty much like the heater on your car, hoses coming off the intake manifold, and the water pump, and engine cooling water circulates through the heater. They are connected by a rubber hoses. The heater has a electric fan, wired to the same 12 volt source as the rest of the boat engine.

The ground wire for the heater motor fan supplies the electrical contact. The water in the heater hoses is the electrolyte. After about 10 or so years, the heater core starts to leak, due to electrolytic corrosion eating away the metal of the heater core. This is a boat engine, cooled by raw water, so running antifreeze is not easily done.
 
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