Quote:
Originally Posted by mb911
Man you are on the search for max HP. Good luck
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Hi Ben,
It's not just about max HP. If it were, I would be done. But I am just not satisfied with the way the car drives - it makes me pissed off every time I come to a stop and have to fight with it to get going again.
I did the original CIS to ITB EFI conversion because I was looking for two things: one, I have always like the look of the 356's and early 911's with carburetors and wanted that look as opposed to the CIS look and two, I wanted the convenience of modern ECU control of the fuel injection and ignition timing (while retaining the distributor, the look).
So when I rebuilt the CIS 2.7L motor, sure I was after more HP, but I wanted to include more modern components for higher compression along with strengthening the case with stud inserts for all of the case studs (not just the head studs) plus balancing all the rotating and reciprocating parts so I could spin the engine faster and bigger camshafts (higher lift and longer duration) so I could take advantage of a better breathing, faster revving engine.
So when I finally experienced first hand what others had been trying to tell me about the driveability of the 911S MFI camshafts, I realized I must correct my mistake by installing a more modern design camshaft.
Anyway, back to the camshaft replacement.
This is a lot of work, but the it is giving me the opportunity to fix issues that I encountered from the first engine / transaxle removal, rebuild and installation.
One issue I had noted was the transmission mounting bolts (the ones with the pointed end, p/n 930-375-317-01) had worn / galled threads and the bolts weren't threading into the mounting points in the body smoothly, so I bought replacement bolts and used a thread conditioner (thread chaser), M12-1.50, on the threads of the blind hole mounting points. Then I applied some anti-seize to the new bolts and ran them into / out of the mounting points to verify smooth thread engagement.
Another issue was I used Locktite on the rocker arm shaft bolts. BIG MISTAKE. As I have found out while I have been removing the rocker arms, the Locktite squeezed off the bolt threads as I inserted the bolt through the bolt head side expanding cup and the rocker arm shaft. So when I went to remove the rocker arms and loosened the rocker arm shaft bolts, the bolt and the bolt head side expanding cup were glued / stuck in the rocker arm shaft. I got the rocker arms removed, but what should have taken me 20 minutes per rocker arm has extending to 40+ minutes as I have had to use Scotchbrite pads and a 90 degree o-ring pick to remove the Locktite residue from the bolt and nut threads - WHAT A PAIN.
If you are a DIYer and you're rebuilding your engine - DO NOT use Locktite on the rocker arm shaft bolts.
I found during the engine build that a 12 mm deep socket fits through the holes in the camshaft tower (carrier) rocker arm shaft flanges and is a good tool to drive the rocker arm shafts into and out of the camshaft tower. For the camshaft swap job, the 12 mm deep socket works great for driving out the rocker arm shafts (with a levering bar) on cylinders #2, 3, 5, and 6 (I am driving the shafts out toward the flywheel end of the motor). But the deep socket is too long to fit into the space provided for the cylinder #1 and 4 rocker arm shafts.
For cylinder #1 and 4, I am using three regular length sockets, one at a time stacked on another, to drive out the rocker arm shaft out of the cam tower. I made a socket holder "tool" out of bent copper wire to place a 12 mm regular length socket into the cam tower flange and use a levering bar to drive the shaft out partially. Then I use the "tool" to place an 11 mm regular length socket into the cam tower and use a levering bar to drive the rocker arm shaft out further. And finally, I use the "tool" to place a 10 mm regular length socket into the cam tower and use a levering bar to drive the rocker arm shaft completely out of cam tower flange.
Some photos:
