- Joined
- Mar 1, 2000
- RO Number
- 6
- Messages
- 231
CYLINDER BLOCK PREPARATION PRIOR TO REBUILD
We would like to share some ideas of block preparation prior to final assembly. These tips will apply virtually to all engines. Lets say we just picked up our engine block from the local machine shop were major surgery was performed. The tired engine block when sent to the machine shop all greasy with worn cylinders, indeed deserving of reclamation.
Starting with an acid dip, bore and hone (note: two stroke chrome bores are not machineable), installation of cam bearings where applicable, main bearing saddles checked for alignment, cylinder head decks checked for flatness and last but not least installation of core plugs and oil galley plugs where applicable. As we know some of these operations apply only to four stroke engines.
Lets start with inspection, on two stroke engines, make sure all intake and exhaust ports have a radius around all edges. On four stroke engines, make sure there is a proper bevel at the top of the cylinder to aid rings entering the bore. Also, at the bottom of the cylinder, a slight radius is desired, sharp edges act as a scraper removing the oil much needed for lubrication. Make sure a pronounced crosshatch pattern has been established along with the proper finish to insure ring seating. Different ring alloys require their own specific RMS finish. Check all core plugs and oil galley plugs to insure they have been removed and new ones installed. If this procedure is overlooked, once the block has been acid dipped this will loosen the grime within the passage and will go through the fresh new rebuild. Remember, core plugs rust from the inside out. Run a thread tap in all high tensile strength bolt holes to insure proper torque values are achieved. Make sure all bearing saddles (housing bores) are burr free to insure correct bearing crush and or seating.
After all these inspections are complete we can begin with cleaning the block. Use a clean five gallon pail of hot soapy water, you will find liquid floor cleaners such as Top Job, Mr. Clean, etc. are a great detergent soap for this. Using a scrub brush, clean all cylinders thoroughly, remember, you are trying to remove embedded abrasives from the cylinder walls. With compressed air dry the engine block, blowing air through all passages to insure no restrictions and don't forget to wear your safety glasses. Now you are ready to final clean the cylinders, tissue paper with transmission fluid is the best. Wrap the tissue paper around your hand, pour a little bit of transmission fluid on the tissue and began wiping the cylinders. I think you will be shocked to see the amount of dirt in need of removal. This seems to be overkill for a cleaning procedure yet crucial to ensure extended engine life.
We would like to share some ideas of block preparation prior to final assembly. These tips will apply virtually to all engines. Lets say we just picked up our engine block from the local machine shop were major surgery was performed. The tired engine block when sent to the machine shop all greasy with worn cylinders, indeed deserving of reclamation.
Starting with an acid dip, bore and hone (note: two stroke chrome bores are not machineable), installation of cam bearings where applicable, main bearing saddles checked for alignment, cylinder head decks checked for flatness and last but not least installation of core plugs and oil galley plugs where applicable. As we know some of these operations apply only to four stroke engines.
Lets start with inspection, on two stroke engines, make sure all intake and exhaust ports have a radius around all edges. On four stroke engines, make sure there is a proper bevel at the top of the cylinder to aid rings entering the bore. Also, at the bottom of the cylinder, a slight radius is desired, sharp edges act as a scraper removing the oil much needed for lubrication. Make sure a pronounced crosshatch pattern has been established along with the proper finish to insure ring seating. Different ring alloys require their own specific RMS finish. Check all core plugs and oil galley plugs to insure they have been removed and new ones installed. If this procedure is overlooked, once the block has been acid dipped this will loosen the grime within the passage and will go through the fresh new rebuild. Remember, core plugs rust from the inside out. Run a thread tap in all high tensile strength bolt holes to insure proper torque values are achieved. Make sure all bearing saddles (housing bores) are burr free to insure correct bearing crush and or seating.
After all these inspections are complete we can begin with cleaning the block. Use a clean five gallon pail of hot soapy water, you will find liquid floor cleaners such as Top Job, Mr. Clean, etc. are a great detergent soap for this. Using a scrub brush, clean all cylinders thoroughly, remember, you are trying to remove embedded abrasives from the cylinder walls. With compressed air dry the engine block, blowing air through all passages to insure no restrictions and don't forget to wear your safety glasses. Now you are ready to final clean the cylinders, tissue paper with transmission fluid is the best. Wrap the tissue paper around your hand, pour a little bit of transmission fluid on the tissue and began wiping the cylinders. I think you will be shocked to see the amount of dirt in need of removal. This seems to be overkill for a cleaning procedure yet crucial to ensure extended engine life.