Hello everyone,

As a geologist, I am a bit lacking in engine assembly knowledge, so perhaps someone could give me some advice about big-end bearings. My TR1 was making loud knocking noises. Stripped it down and the oil pick-up mesh was coated in bits of hardened gasket-goo (thanks to a previous owner) so the motor was starved of oil, or at least restricted.

Below is a photo of the bearings that came out. Can someone explain why one of the bearings has a groove in it, but none of the other three bearings?

The con-rods are #5 and crank#2, so that means brown bearings, but the engineering shop sold me three brown bearings and one green. The green bearing has the groove in it. Is there any reason why three brown and one green. is the workshop trying to fool me or could there be a reason for this?  Why the groove in only one bearing? Why the groove at all? Does it matter which conrod the grooved bearing goes into (front cylinder or rear?)? Does it matter whether the grooved bearing is used or not (i.e. use a plain  non-grooved bearing?) .The microfische catalogue  shows three plain bearings and one odd-numbered bearing.


So many questions, but that is what a forum is for.

If anyone wants advice about shear-hosted gold deposits I would be happy to help!

Regards

Richard

What Ali said - mixing sizes with the bearing shells will create an "unround" bearing and is therefore very, very bad practice.
I'd use some plastigauge and determine the amount of clearance between shell and crank-pin and then choose the new shells accordingly.
I agree with Ali on the grooved shell going onto the #1 cylinder. You may also install TWO rear conrods or drill out the front conrod to implement the oil-spray-jet for piston crown cooling.

Hope this helps
Greg

Quote from RichardThe_Geo on 16.12.15 at 13:03:36:


I will have a look and send you some pictures and measurements of what I still have in stock (should be two sets of cylinders and pistons)

Cheers,
Greg

Will take care of that tomorrow. I honestly forgot!