IowaRV9Dreamer
Well Known Member
I've ordered the Lycoming maintenance library from Tdata, but it hasn't come yet...
I mic'd my crank and cam last night. As near as I can tell, the crank is near the top limit of M003, which is what is says on the tag. That means it is 0.003 smaller than a nominal new crank.
Looking at the Lycoming Table of Limits in the overhaul manual, I see there are two bearing types listed: "thin wall (0.09 approx wall)" and "thick wall (0.16 approx wall)".
Looking in the parts catalog for my O-320-E2A, I see two types of bearings - both are marked "crankshaft bearing" and are listed for my model. One has a ** after it that says "thin wall, high crush".
So my question is - when do you use a regular bearing, and when do you use a "thin wall, high crush" bearing? Is the case the same for either one?
Also a related question: The Parts Catalog has a "Oversize and Undersize Parts Listing" that lists both bearings... and it shows what sizes are available. Would I purchase a M03 bearing (aka "undersize") or an "oversize" Pxx bearing. The oversize come in P02 or P05.
All of the above discussion is for the middle and rear bearings. The large, front one-piece bearings don't seem to have a thin/thick/high crush thing going on. I wonder why?
I know there is a Lycoming Service Letter that will help, and I'll get it soon, but I was hoping someone would have some good, general info.
I mic'd my crank and cam last night. As near as I can tell, the crank is near the top limit of M003, which is what is says on the tag. That means it is 0.003 smaller than a nominal new crank.
Looking at the Lycoming Table of Limits in the overhaul manual, I see there are two bearing types listed: "thin wall (0.09 approx wall)" and "thick wall (0.16 approx wall)".
Looking in the parts catalog for my O-320-E2A, I see two types of bearings - both are marked "crankshaft bearing" and are listed for my model. One has a ** after it that says "thin wall, high crush".
So my question is - when do you use a regular bearing, and when do you use a "thin wall, high crush" bearing? Is the case the same for either one?
Also a related question: The Parts Catalog has a "Oversize and Undersize Parts Listing" that lists both bearings... and it shows what sizes are available. Would I purchase a M03 bearing (aka "undersize") or an "oversize" Pxx bearing. The oversize come in P02 or P05.
All of the above discussion is for the middle and rear bearings. The large, front one-piece bearings don't seem to have a thin/thick/high crush thing going on. I wonder why?
I know there is a Lycoming Service Letter that will help, and I'll get it soon, but I was hoping someone would have some good, general info.