New 20 ounce tumblers available now! Forum donation credit with purchase. https://www.wildguzzi.com/Products/products.htm#Tumbler
Around that era, would it be copper/lead?
Probably, lead/copper on a steel backing, AKA Clevite 77 type and still in use for performance and heavy duty use...I believe the bi metal bearing is more recent and is popular in newer vehicles and for performance...Beari ng inserts are a precision product and the material layers are very thin..
Tony F, do you mean you have had main bearings made before? If so, how have they worn?
Morning. There appears to be confusion in the thread. I am not asking about big end bearings (bimetallic) I am asking about main bearings which I consider to be very expensive but simple to make if I had the correct material.i.e. https://www.harpermoto.com/rear-main-bearing-u-s-2mm-12011401.html
Morning. There appears to be confusion in the thread. I am not asking about big end bearings (bimetallic) I am asking about main bearings which I consider to be very expensive but simple to make if I had the correct material.
Main bearing or rod bearing, makes no difference. Are there any high output engines, And Guzzi is high output, using solid aluminum for main bearings? There are many engines with the cams runs directly on aluminum...but the engine crank are bearings subject to reciprocating loads at 7000 plus RPM And as you mentioned, without the ability for debris to embed in the soft bearing material, crankshaft journals may not last too long.. I'm also thinking the two Guzzi main bearings need to be line honed in place unless they are factory made stuff . About 15 years ago , vintage Triumph rod bearings, common split variety, were getting hard to find. Several known long time Triumph tuners along with Baxter Cycle talked to Mahle who took over Clevite bearing production in the USA..They were able to order a certain number and so now high quality bearings for old Triumphs are available for reasonable money..Maybe this won't work for the Guzzi situation...
Well it does, because Guzzi big blocks don't use shell type main bearings. The front and rear bearings are a two part bearing with a cast outer flange with a pressed in 'Tunnel' type bearing. My guess would be that the most important thing would be to use an alloy with a similar C of E to the flange alloy for the bearing tube as too great a difference will cause either the bearing tube to deform or to become loose as the engine heats up.Pete
Pete, what is the material of the pressed in tunnel bearing...? Is a multi layer construction, as in not a piece of aluminum? Pehaps like the right side sleeve bearing used on BSA and a few other Brit bikes?