Sunday, October 13, 2013
How to Port Polish Shovelheads
Since 1936, Harley-Davidson V-Twin engines have been named for the shape of the chrome rocker boxes that enclose their cylinder heads. "Knuckleheads" were replaced by "Panheads" and then by "Shovelheads" in 1966. The "Shovelhead" produced significantly more horsepower with significantly less engine displacement than current models. However, Harley was limited by government regulations as to how much power it could give to the engines and production was eventually halted in 1984. The heads were sand cast iron. A slightly smaller version was called the "Ironhead." And, a standard way to make these engines even more powerful was to polish the interior of the heads and the intake and exhaust ports.
Instructions
- 1
Remove the front and rear heads from the engine. Strip the heads of any movable parts including valves and seals.
2Scrape the bottom of the heads with a gasket scraper and soak the heads in a 5-gallon metal bucket containing any degreasing solvent in a well-ventilated room for 6 hours.
3Dry the heads with compressed air. Paint a 1/4-inch-wide line around the outside of the bottom of each head with black touch-up paint. Do not attempt to polish any part of either head that is not within that painted line.
4Attach an abrasive roll to the shank of a rotary grinder according to the instructions for your grinder. Rolls usually attach to the grinder shank with a single, flat head screw. Work on one head at a time.
5Lay one cylinder head bottom side down on a flat surface. Slowly grind the 90-degree edges of the intake and exhaust ports until those edges are no longer sharp to the touch, using a rotary grinder and abrasive roll.
6Smooth the cast surfaces inside each port until those surfaces are shiny and smooth. Turn the head over.
7Smooth the cast surface inside the hemispherical combustion chamber the same way you smoothed the interior of the intake and exhaust ports. Change abrasive rolls frequently. Do not attempt to physically change the shape of the combustion chamber. Do not polish within 1/2 inch of the valve seats, which are the clearly visible, machined area around the ports inside the head.
8Install a polishing wheel on the rotary grinder shank using the same technique you used to install an abrasive roll. Polish the interior of the intake and exhaust ports and the interior of the combustion chamber using a rotary grinder, polishing wheel and polishing compound.
9Repeat these procedures to port and polish the second head. Remove the touch-up paint from both heads with acetone and a shop rag.
10Wipe all surfaces of both heads with new motor oil and shop rags to remove metal and polishing residue. Leave a thin coat of oil on the cast iron heads to prevent rusting until just before reassembly of the engine top end.
11Wipe all surfaces on both heads with degreasing solvent and shop rags immediately before engine reassembly.
Friday, October 11, 2013
How to Port Polish E7TE Heads
An E7TE head is part of an engine block. The amount of air flow an E7TE will allow does not always get the amount of horsepower to the engine that you may desire. You can improve the flow to your engine with a simple cartridge roll clean up and smoothing of the ports, runners and bowls, plus clearing out the smog injector pumps, if necessary. This can greatly increase the horsepower on whatever vehicle you own.
Instructions
- 1
Pop the hood of the car and locate the engine block. The engine cylinder block is located next to the engine. Inspect the ports on the block. Most engine blocks have four holes that are called ports.
2Plug in an angle grinder and line it up with each of the ports on the engine block. Turn on the grinder and move it back and forth in a circular motion over the entire surface of the first port. Do not stay in one place too long.
3Move the grinder until the port begins to thin out. Go on to the next port and repeat the exact same process. Continue in the same manner until all of the engine block ports have been cleaned out and made thinner with the grinder. Turn off and remove the angle grinder from the engine block.
4Wipe the area inside the engine block clean with a rag. Polish the surface of the engine block with sandpaper. Move the sandpaper over the entire surface in a circular motion to remove all the debris and give it a smooth surface. Wipe away the grit left by the sandpaper with a clean rag.
