Mark up the intake and exhaust ports by scribing the areas to remove. If I hit them with a sanding scroll or carbide burr the hope was I would have a little protection before I start cutting into the seat. You will slip, you will make a mistake, so you want to minimize the size and magnitude of the mistake when you do. I used multiple layers of painters tape on and around the valve seats. When doing the bowls you want to be extra careful. Namely you are worried about the valve seats. Lets get started.īefore you start removing material, protect any areas you don't want to accidentally bugger up. This project took me a very long time with several hours spent at each step across all the ports. Match the intake and exhaust ports to the intake and exhaustĬlean up and smooth the transitions in the bowl areaĬlean up and smooth the transitions in port areaĬlean up and smooth the transitions around the valve guideĮven out and finish the intake ports to a 120 grit finishĮven out the exhaust ports to a 600 grit finish Here is my list of work prior to the machine shop:
Then I made a second list for items to be done at the machine shop. I took notes as I went and then condensed them down into actionable items I could undertake. Theory and Practice of Cylinder Head Modification - David Vizard
Harbor freight port and polish kit how to#
How To Modify Your Nissan & Datsun OHC Engine How To Rebuild Your Nissan & Datsun OHC Engine I spent a fair amount of time reading the following books: You are likely to ruin the head by hitting a water passage or worse. Don't jump right in and start grinding away with carbide burrs. Planningīefore you get started you want to come up with a plan. You will be amazed how filthy and dirty the bench, surrounding area and even garage gets. Grinding and sanding will produce a lot of fine metallic particles and dust, make sure you have proper safety equipment safety goggles, gloves and a particle filter respirator mask. If you don't have spare material around you can always try cosmetic clean up on the exterior casting. I also recommend using your tools on a similar material so you can get a feel for the amount that is removed with each pass based on revolution speed, pressure and contact duration. Before you attempt porting you should read up about what you are trying to achieve and watch a few videos.
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