Inorder to correctly reindex the intake cam for the Exintake mod, you have to drill a precision index hole 197.5' clockwise from top dead center.
Since I don't have a machine shop handy, I used my trusty 3d Printer to make a jig to aid drilling the hole.
this Jig can be inserted into the cam gear from the front or the back, and with a drill press will ensure the hole is precisely where it needs to be for the correct timing.
As a test, I first used the Jig from the front position, and made a small drill mark. Then I fipped the work over and inserted the Jig fulliy into the rear of the gear, and drilled using the rear position. I stopped just as the drill was penetrating the work piece to find that the initial center mark was precisely aligned with the hole I was drilling!
I will add more pictures later.
- insert cam jig into front of cam gear, using the 3 pins to align the jig.
- use a 3/16th or 11/64th drill bit to mark the center of the expected exit of the hole. use the hole marked front.
- remove the jig and reinstall in the rear of the cam gear. using the same bit, align and drill the hole, go slow, and use oil.
- as the main bore breaks the surface, you can check that the predicted center matches the actual bore.
- remove the jig, and test fit. at this point the cam should not slip directly onto the gear. the hole will have to be refined with a file or a 13/64ths bit to actually accommodate the alignment pin.
- refine the hole by using a larger bit to chamfer the edge on the rear of the gear.
- install in the car!
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