Big and Main Bearings

[JochemsTR]

1 hour ago, JochemsTR said:

2 hours ago, YankeeTR5 said:

The head of engineering at King Bearings was interviewed and was asked  which was better for classic cars - bi or tri metal bearings.  His response, which surprised me, was the bi metal bearings were best for classic cars.   The bimetals are better at "absorbing" contaminates as there is more material for those to bed in to and not damage the crank journals.  He commented that newer cars due to much tighter tolerances had much smaller contaminates that could flow thru so less needed for them to bed in to.  

This may be valid for your "standard" classic car, but we are looking at a performance engine. At least I consider 180-200 BHP performance. I discussed this with my engine builder, and he also recommends King Tri-Metal. The way the engine is currently build, this applies to modern cars also. In this respect, there is nothing "classic"

I have been reading Kings Website....the Bi-Metal seems to be better for Cast Iron Crankshafts due to its microscopic texture. The Overlay on a Tri-Metal bearing can be damaged and loses all its properties. Modern cars have steel cranks therefore, tri-metal seems to be the right choice.

More confused now.

[Austin Branson]

Hi Jochem, I used County bearings from Chris Witor when I changed the big-end bearings last year - they probably didn’t need changing, but I had a ruined piston. The old bearings were also County. The engine is supercharged, and produces around 200bhp. I hope this helps. Austin 

[PodOne]

13 hours ago, JochemsTR said:

any partnumber you want to share?

 Hi Jochems

Yes if you were building a MX5 1.6 or 1.8 TR6 not a clue but when the time comes I'll probably go for them if they porduce them.

Andy

[JochemsTR]

...nitriding the cast iron crankshaft seems to be the solution for using tri-metall bearings which are normally used on steel crankshafts.

Jochem