Re using cast iron rings?
I it is not an old timers trick. So u have heard the saying do it right or don’t do it at all. It’s a lot of work to go thru having to do it over again. I only ever have time to do it right and not over again. So far that has worked for me for about 50 years. I think ur gonna have an oil sucking pig that can’t get out of its own way. So are u probably use the old bearings and oil pump along with the timing chain and gaskets. Kim
IMHO as a licensed mechanic, I would put new rings in. I would also consider the upgrade to moly rings. Lightly hone the bores to deglaze them without removing much cylinder wall.
Now the bearings and oil pump are a different matter. On heavy diesels we did beating rolls at 250,000 miles. The heavy hammering the bearings get in those engines, especially the old mechanical injection, fatigues the bearings from comptessive loads. Eventually they turn to small particles like sand. The difference between a running engine and a major overhaul out of the frame was minimal miles. But that is heavy diesels.
For automotive, when dismantling the engine, inspect the bearings closely. You are looking for signs of the silver appearing bearing layer having ateas that are a darker color indicating wear. A spot on the bearing could be a particle of dirt or a metal fragment embedded in the bearing or under the bearing. Sometimes wear will syart at the side of a bearing where the major load is. This continues as the bearing clearance increases and oil film is lost. Eventually the bearings will be copper all around. Bearings can have scratches all around, generally aligned with the oil supply holes. The crankshaft or camshaft will likely be scratched as well. Any of these observations dictate bearing replacement, crankshaft pish or grind and complete engine disassembly with all pligs removed to thourghly clean the oil passages. If the bearings look good and are put back in the same position they came from, they can be reused, providing the clearances are in spec.
Oil.pumps. Now this will wind a bunch up. Take the oil pump apart for close inspection and measuring clearances. Use a brass scriber to mark the cover ends of the gears and gear indexing on the roots style pumps. Minor wear marks are acceptable. As long as there are no scratches that catch your finger nail indicating junk has gone through it is OK to reuse. Just do not turn a gear over during assembly. Oil pumps get replaced as a matter of habit during many refresh jobs when not necessary. A lot of times an engine with even compression within tolerances, but low oil pressure at warm idle have the oil pump blamed. Most times there is no problem with the pump, but the main and rod bearings are worn to copper, top and bottom shells. 400 Fords were bad for this due to a poor oil system design. 100,000 miles was about when this showed up. Roll .001 undersize bearings in on the mains and rods. Use a piece of cardboard from the bearing boxes in the 2 and 4 caps to plastigage clearances on 1, 3 and 5. Do not torque the 2 and 4 cap bolts doing this. Just snug with a speed handle or index and bird finger on either side of the socket and ratchet. With odd bearings checked, move the cardboard to 1 and 5 to verify 2 and 4. Now a small smear of sealant can be put on the rear cap. Just snug bolts and move the crank back and forth to center the thrust cap. May be #3 on many engines. The rubber rear oil seal can be rolled in during the bearing roll with the 3 and 4 caps loose and 5 off.
Most of the small block engines timing chains can be checked for stretch with the oil pan off ussing a long screw driver. Now is the time to replace a worn timing chain, before reinstalling the oil pan.
Now with new bearings on the tighter side of the clearance limits and new seals, the engine is likely good for another 75k to 100k miles of fairly troublefree driving. A compression or leakdown test to verify acceptable ring and valve seal prior to undertaking this is a wise time saver.
