TheSamba.com :: View topic

Wed Feb 10, 2010 8:27 pm

OK so I am in the middle of my first rebuild of my '74 1800cc engine.

Here's a pic of the rod side clearance... just about at the .027 wear limit.

Is it even worth getting the crank machined or am I stuck with getting a new crankshaft and rods at this point?

Wed Feb 10, 2010 8:36 pm

Bentley will publish side clearance - both the new range and the max tolerance. It isn't a dimension that changes quickly. Frankly I have never seen a crank and rod that is past the wear limit in side clearance unless someone has been sanding on the side to polish them. If you have a mic or dial caliper see if the rods are all about the same. Maybe you can put a wider rod in the wider journal and the narrowest rod in the narrowest journal. Maybe that will get you back closer to the optimal number.

Wed Feb 10, 2010 9:03 pm

SGKent wrote: Bentley will publish side clearance - both the new range and the max tolerance. It isn't a dimension that changes quickly. Frankly I have never seen a crank and rod that is past the wear limit in side clearance unless someone has been sanding on the side to polish them. If you have a mic or dial caliper see if the rods are all about the same. Maybe you can put a wider rod in the wider journal and the narrowest rod in the narrowest journal. Maybe that will get you back closer to the optimal number.

I should have offered some more background... the wide journal is the spot where the engine ran a spent bearing. According to the PO, the engine was shut off right away... The journal will need to be machined if I use this crankshaft, just not sure if it is useable at this point.

Wed Feb 10, 2010 9:56 pm

ouch. When they spin a bearing the case web next to that journal can get deformed from heat. I would at least find another crank. You will want to look at the rod to see if it or the crank jpurnal is blued from heat. If it is not blued you should be Ok. Be sure to have the big ends on the rods redone also.

Wed Feb 10, 2010 9:59 pm

Jake is in Georgia. You might call him to see what he has as to a used crank and who he would recommend to check it. UPS or FedEx ground from Georgia to Tampa should not be too much.