Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


NVH of cylinder head material

NVH of cylinder head material

NVH of cylinder head material

I have a design project for an aircooled engine.  There is some impact on the cylinder head which transmits thoughout the engine.  Is there a better material than aluminium for damping vibration, or an alloy of aluminium.

Has anyone tried curving the cooling fins to stiffen and reduce radiation?

RE: NVH of cylinder head material

Magnesium and its alloys have higher damping than aluminium and its alloys.  However, joints/interfaces usually dominate damping properties.



Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: NVH of cylinder head material

HAs anyone successfully used Magnesium on a cylinder head.  Does it burn??  Any other issues?

RE: NVH of cylinder head material

I am unaware of any current production magnesium alloy cylinder heads.  There are large efforts to create new alloys for head/block applications - you can perform a Google search to find more information.

Mg alloys usually burn only if they are in finely-divided form (like chips/powders) while simultaneously near a large heat source.  A bulk object like a head would burn if heated to the alloy's melting point, which is much higher than the operating temperature of a head.  The other issues to consider are strength, stiffness, thermal conductivity, thermal expansion, and creep.



Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: NVH of cylinder head material

If weight is not a problem then go back to old fathfull-flake graphite cast iron.  It has the one of the best damping capacities of all modern automotive materials.  

RE: NVH of cylinder head material

Montesa free-air cooled dirt bikes of the mid 70s had wiggly fins on their aluminum cylinder heads.  

Rubber spacers at strategic locations do wonders at reducing fin ringing, plenty of which will be induced by the events going on inside engines like combustion, piston slap or even clearance in clutch components.

A sheet metal shroud around the head can contain the noise a lot and used to enforce useful air flow.

Cast iron air cooled cylinder heads don't cool very well.

RE: NVH of cylinder head material


How about using the oil itself to damp the critical NVH point? You can try to create some sort of 'oil reservoir' or oil passages passing nearby or at the critical NVH points.

Mg.. the damping characteristic is better than Aluminium but the Young's modulus or the stiffness is not as good as Al. This metal doesnt help NVH much for highly loaded applications like the block and head. I remember one R&D block that I saw made of Mg has a lot of complicated ribbings.

It is ok for block because the cylinder bore can be coated and the crank bearing has bearing shell to avoid direct contact with crankshaft. However, it will interesting to see how Mg can overcome the problem of rotating camshaft in direct contact with the Mg.

There must be some solution for the Mg head. Anyone out there has tried it before?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close