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Construction of Tri-Metal Engine Bearings

Doc Here,

In the spirit of the 2012 NASCAR Race Season beginning next weekend I thought I’d talk to you about Clevite’s TriMetal™ engine bearings. Every NASCAR Cup Champion has used Clevite® bearings all the way back to when Red Byron won in 1948!

You’ll find out below why Clevite bearings are trusted by professional engine builders especially in the world of motorsports. It all starts with the construction of the bearing.

To start with – almost all bearing manufacturers use a similar grade of steel for the backing of tri-metal engine bearings. SAE 1008 and SAE 1010 are the most common ones used.

The difference lies in MAHLE Clevite’s intermediate layer. It is different than any other bearing manufacturer. It is cast onto the steel in a strip process where an alloy of molten copper and lead is poured onto the steel strip in an atmospheric controlled furnace. Copper in the alloy penetrates the steel, forming an indestructible bond. As the strip leaves the furnace, it is quenched and the alloy solidifies.

Clevite Trimetal Bearing Peeled Back

Every bearing manufacturer in the world except for Clevite relies primarily on a means of manufacturing their intermediate layer using a process called sintering. Sintering is a build-up process of applying a layer of powdered copper lead alloy in a controlled thickness, then heating it to a semi-molten state where the alloy bonds with itself and the steel strip.

The strip is then run through a rolling mill to help remove porosity and increase strength. This process is less costly than running a foundry that pours bronze alloy onto a steel strip.The problem with the sintered material is it does not have many continuous columns of copper in the alloy structure like the Clevite TriMetal bearing. Those columns are important load bearers and are what allows tri-metal bearing load capacity that is typically 2000psi higher than other bearing manufacturers.

The overlay of most tri-metal bearings is babbitt, an alloy of Lead and Tin, applied in an electro plating process. The overlay composition used by most manufacturers is 87% lead, 10% tin and 3% copper.

MAHLE Clevite carefully controls the thickness of the overlay and it will vary from application to application, depending on the load the engine bearings are expected to see in the engine.

MAHLE Clevite also produces a lead-indium overlay for some racing bearings. Often referred to as a Vandervell style bearing, which is preferred to babbitt by some racing and performance engine builders.

To hear more about Clevite TriMetal engine bearings watch my colleague, Brett Dayringer’s video below!

If you have any questions related to Clevite bearings, be sure to ask!

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4 Responses to Construction of Tri-Metal Engine Bearings

  1. Seth Flanders says:

    Great article Doc! Never knew Clevite supplied bearings to NASCAR that far back.

  2. Seth says:

    Hey Doc,
    Seth here. Just to let you know, I made an interesting discovery regarding Mahle-Clevite. I live in Bangkok, Thailand (remember I mentioned being an English teacher?) and Mahle has a branch right around the corner from my in-laws’ house. The main website only lists their address, so I’m not sure what goes on there other than distribution of engine parts. Just before finding out about the Bangkok branch, I saw a box truck with Mahle-Clevite on the side in big blue letters. We do have some racing here (including a drag strip outside Bangkok) but it’s not as big here as in the States of course. It’s nice to know that Mahle has made their presence known here in Southeast Asia…perhaps the racing associated with all those quality engine parts will take off. Are there any expat staff from the States here in Bangkok or is the Bangkok branch run by locals? Take care!


    • Hello Seth,

      Wow I can’t believe you live all the way in Thailand! Thank you for sharing your discovery. We do have a piston manufacturing plant there which belongs to MAHLE GmbH, MAHLE Clevite’s parent company. Our business there is represented by Mr. Jim Gan. Jim is one of our key agents and resides in Singapore. He was actually with us at AAPEX in Las Vegas, NV last fall. We don’t source any pistons from the Bangkok plant though, nor do we have any other representatives in Thailand besides Mr. Gan. If you ever get a chance to go to a race be sure to send along some pictures. My team would love to see them!


  3. Seth says:

    Hi Doc,
    I’ve lived here for nine years and have yet to attend a race. Would love to see on someday though and get some pictures.
    Local magazines and word-of-mouth suggest that the racing scene here is gaining popularity. Drifting is a growing sport and featured in many Thai car magazines. Also, turbo, exhaust and mag wheel upgrades are a common sight here in Bangkok (roadside shops are practically everywhere). However, I think a lot of these young guys overdo it so I would certainly be wary of buying a used vehicle that had been modified.
    I’ve never been to Singapore where your rep lives, but it’s a popular travel destination for Thais who have some money and many Singaporeans visit here as well.
    I know you do quite a bit of traveling in your line of work, but has your job ever brought you here to Thailand? The hot, humid, dusty (and sometimes salty) environment would be a great test lab for Clevite engine parts!


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