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| Cfletch |
Jan 25 2026, 07:38 PM
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#1
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Member ![]() ![]() Group: Members Posts: 223 Joined: 30-January 14 From: Santa Barbara Member No.: 16,941 Region Association: Southern California |
Hey there everyone, Newbie to Cam timing in general and working on putting the engine back together after repairing an oil leak from the Cam Thrust Plate o rings.
I am having what I hope is just a simple issue of misunderstanding on the timing of the cams and can use some help. Engine is a 1974 2.7 CIS that retains the stock camshafts: L:911.105.141.00 R:911.105.142.00 I currently am running into an issue where I am unable to get more adjustment out of my cam because I am hitting the piston with the valves when trying to rotate it in either direction. Current process has been having the engine at Z1, having my distributor facing #1 cyl and having my piston at the top of the stroke confirmed by a whistle adaptor in the cylinder. Camshaft have the "911" at 12 o clock and the part number listed at 6 o clock. I have my #1 Intake Valve installed and set to correct valve clearance and have the timing chains tensioned by the stromksi tensioners. Pin is installed and nut is snugged up to the cam to get a reading for when rotating the engine. I have a drop gauge and z bar set up on the #1 intake valve and when rotating the engine over, the valve does not seem to lift at the correct position on the crank, and I am also not able to get the same lift I once had of 3745 Thousandths. I would like to rotate the cam at this point to get it adjusted slightly to get it to start raising at a better time relative to the crank, but when attempting to rotate it, I can feel interference with the valve and piston. I feel this going either clockwise or counterclockwise. I am stuck at this point and called it for the day and am looking for some help here. Based on various videos and my 911 rebuild book from Wayne Dempsey. I seem to be doing everything correct, but just am not getting it to raise the correct amount and when trying to adjust the cam I run into clearance problems with the valve so I am clearly not in the right spot there. I am looking for any guidance here either in text format or possible a phone call tomorrow to walk through stuff. I have everything more or less set up ready to go and this is my last step before I am able to get it buttoned back up and reinstalled into the car. One thing I had noticed is that we were getting relatively close to the expected measurement, but it was very far away from, Z1, probably about ~100 off from where it would be expected. Today I had the help of Robert A, he drove up and we worked on repairing the leaky seals but had ran out of sunlight and time today. He left me his tools to hopefully wrap this job up and we were both stumped on this after a long day of work. Any help is most appreciated! |
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| sixnotfour |
Jan 26 2026, 03:33 AM
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#2
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914 Wizard ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 11,105 Joined: 12-September 04 Member No.: 2,744 Region Association: NineFourteenerVille
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Is .3745 total lift ? (IMG:style_emoticons/default/idea.gif) (IMG:style_emoticons/default/popcorn[1].gif)
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Cfletch 911 Camshaft Timing Help Needed Jan 25 2026, 07:38 PM
rudedude I don’t know your cam stamping but the key slot ... Jan 25 2026, 09:06 PM
Cfletch
I don’t know your cam stamping but the key slot... Jan 25 2026, 09:13 PM
rudedude Could you have switched sides? Left 1-3, has the... Jan 25 2026, 09:21 PM
Robarabian Not possible.
We only removed one cam at a time.... Jan 25 2026, 09:38 PM
rudedude Are you using z1 on the pulley or flywheel? The z... Jan 25 2026, 09:33 PM
sixnotfour If #1 is at TDC and rotor pointing at firing #1..I... Jan 25 2026, 11:21 PM
sixnotfour 0.03745 ??? #1 at overlap Rotor pointing to #4 at ... Jan 25 2026, 11:29 PM
rudedude My spec book is in the shop but I suspect a cis ca... Jan 26 2026, 07:06 AM
DennisV
Hey there everyone, Newbie to Cam timing in gener... Jan 26 2026, 08:29 AM![]() ![]() |
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Lo-Fi Version | Time is now: 26th January 2026 - 08:34 AM |
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