L83 Piston Notching
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Teching In
Joined: Mar 2017
Posts: 10
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L83 Piston Notching I started to notch my Gen V L83 pistons to fit my new cam.
Right now I only have the first piston started to prove out my concept. I will hop back on the project this week to finish up the rest of the slugs as well as polish out the remaining sanding marks.
1. Create notching tool, I used an old hss reamer that had a .3135 shank and welded it to a piece of cold roll .125 sheet. I turned it down to intake valve diameter + .120". (2.050?). I lastly ground down the face so it was orthogonal to the axis of the reamer.
2. I created a simple cutting stop with a set screw. This stop will locate on the valve spring base and be firmly attached to my notching tool. This will prevent me from sanding too much of the piston off.
3. Measured PTV clearance using a degree wheel and a dial indicator. Also used a modified solid lifter and an adjustable pushrod. (PTV clearance came out to 0).
4. Assembled notching tool, the cutting stop, and the factory cylinder head to maintain valve guide geometry. I used a sticky back 80 grit sandpaper and attached it to my notching tool.
5. I then took this sub assembly and assembled it on the short block with the stock head gasket. I also cleaned the deck and piston with alcohol and taped the surface so that no material would get down the rings. A vacuum was held to the exhaust port to suck any material out quickly.
6. With the stop set to the required depth (total PTV clearance), I rotated the tool with a handheld drill motor until the stop bottomed out.
7. Cleaned and reassembled the set up with stock valves to verify clearance. (I am shooting for .060" radial and depth clearance, .035 was recommended by BTR).
Right now I only have the first piston started to prove out my concept. I will hop back on the project this week to finish up the rest of the slugs as well as polish out the remaining sanding marks.
1. Create notching tool, I used an old hss reamer that had a .3135 shank and welded it to a piece of cold roll .125 sheet. I turned it down to intake valve diameter + .120". (2.050?). I lastly ground down the face so it was orthogonal to the axis of the reamer.
2. I created a simple cutting stop with a set screw. This stop will locate on the valve spring base and be firmly attached to my notching tool. This will prevent me from sanding too much of the piston off.
3. Measured PTV clearance using a degree wheel and a dial indicator. Also used a modified solid lifter and an adjustable pushrod. (PTV clearance came out to 0).
4. Assembled notching tool, the cutting stop, and the factory cylinder head to maintain valve guide geometry. I used a sticky back 80 grit sandpaper and attached it to my notching tool.
5. I then took this sub assembly and assembled it on the short block with the stock head gasket. I also cleaned the deck and piston with alcohol and taped the surface so that no material would get down the rings. A vacuum was held to the exhaust port to suck any material out quickly.
6. With the stop set to the required depth (total PTV clearance), I rotated the tool with a handheld drill motor until the stop bottomed out.
7. Cleaned and reassembled the set up with stock valves to verify clearance. (I am shooting for .060" radial and depth clearance, .035 was recommended by BTR).
Teching In
Joined: Dec 2008
Posts: 36
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Here is a video prior to notching. Please subscribe for future updates.
https://www.youtube.com/watch?v=oEabvBmh1t0&
Dave.
https://www.youtube.com/watch?v=oEabvBmh1t0&
Dave.
