frankendat Posted October 3, 2020 Report Share Posted October 3, 2020 Rebuilding high mileage Z24, have it stripped down to the block. Also, have a cheap micrometer and PDF FSM. I lack confidence in my measurements and wonder if there is a standard or general oversize or undersize. I am sure the machinist would have the size after working on the crank. I am spitballing, but if I intend on having the block bored to fit a set of pistons, then is it possible to have the crank honed and balanced to fit the bearings? If either solution is valid then what size bearings (Over or Under) would be best. I ask, because like the pistons, I wish to apply the ceramic friction reducing coating to the bearings, before the block is machined. There are some coated bearings on the market, but looking at the price difference of coated vs not coated bearings, i can buy uncoated bearings and coat them, for less than the purchase price of coated bearings. Thank you Quote Link to comment
datzenmike Posted October 3, 2020 Report Share Posted October 3, 2020 Does it run? Then it's can't be to far wrong. Generally the softer bearings do all the wear (and designed to do this and are replaceable) and the hardened crankshaft, almost nothing at all so if the bearings are replaced with new ones the clearances will be better than not replacing them at all. For about $5 you can plasti-gauge all the bearings and if close enough.... good enough. Don't over think this. The crank does not need to be 'honed' nor does it need balancing. Engines have run on standard bearings for ever. The bearing and the crank never touch as they ride on a cushion of oil under pressure. Exotic friction reducing coatings are a waste of time and money. Use quality oil, keep it full, change it and the filter on time and don't overheat it and you will have no problem with it. Quote Link to comment
frankendat Posted October 3, 2020 Author Report Share Posted October 3, 2020 5 hours ago, datzenmike said: Does it run? Then it's can't be to far wrong. Generally the softer bearings do all the wear (and designed to do this and are replaceable) and the hardened crankshaft, almost nothing at all so if the bearings are replaced with new ones the clearances will be better than not replacing them at all. For about $5 you can plasti-gauge all the bearings and if close enough.... good enough. Don't over think this. The crank does not need to be 'honed' nor does it need balancing. Engines have run on standard bearings for ever. The bearing and the crank never touch as they ride on a cushion of oil under pressure. Exotic friction reducing coatings are a waste of time and money. Use quality oil, keep it full, change it and the filter on time and don't overheat it and you will have no problem with it. Thank you for the reply datzenmike, the engine is disassembled, it came from a truck with over 100k miles (probably 200k) it was removed from the truck, before I acquired it. The original owner pulled it after it lost compression and started burning oil in one of the cylinders. I will invest in plasti gauge. Quote Link to comment
datzenmike Posted October 3, 2020 Report Share Posted October 3, 2020 Plasti-gauge is a simple method that will show if there is excessive bearing clearances on new bearings when tightened down. I really don't expect any. 1 Quote Link to comment
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