Checking Cam Timing with Engine In

[boyt911sc]

Originally Posted by yelcab1

Oh man, that thing looks totally non-stock. Turbo and all. Since you are going through the trouble, check both sides.

Bring it to top dead center number 1. See if there is any valve slop on the rocker arm.
Install your dial indicator, and zero it.
Turn it 360 degrees, read the over lap.

Then, bring it to number 4 TDC (technically, you are already there from the last step), check for rocker slop.
Move the dial indicator over to bank 2, zero it
Turn the engine 360 degrees, read the overlap.

To OP,

A version of the above instruction:

If you have two (2) sets of dial indicators, it would be much easier. Set it @TDC @Z1, for cylinder #1 and turn the crankshaft 360°. Read the dial indicator. You are done now for cylinder #1.

Move the dial indicator to cylinder #4: Reset to zero and turn the crankshaft another 360° (back again to TDC @Z1). Read the dial indicator.

Repeat again and get an average.

You are not alone. Even the experienced individual commits same mistake/s.

Tony

[RogueEngineer]

Update:

Took timing cover off the right side along with upper valve covers.

Both banks were definitely timed the exact same.

I moved the crank to TDC on cylinder 1, with the intention of then loosening the right bank's cam bolt and rotating the crank 360 degrees. While the #4 intake valve was closed, I set up my indicator to measure lift.

I loosened all the valve adjuster nuts to max - rotated 360 degrees, pinned the cam adjuster/quarter tightened the cam bolt, and remeasured the timing. It was still in spec at ~1.6mm.

Adjusted valves and buttoned everything up.

Car started immediately! It also cranks much, much faster now that starter isn't trying to push through 2 cylinders in their compression cycle.

Thank you for everyone's help!

- Ian

[yelcab1]

Imagine no bent valves !!!

[yelcab1]

Originally Posted by boyt911sc

To OP,

A version of the above instruction:

If you have two (2) sets of dial indicators, ,,,,

Only the most die-hard of enthusiastic DIYers would have ... two sets of indicators and 2 z-blocks.

[911obgyn]

Whew, nice conclusion!

[Eagledriver]

Originally Posted by JSV798

Wouldn't valves hit pistons if it's that far out? But the ignition timing could be 180 degrees out.

No. Cam 180 out is crank 360 out. Perfect timing except both sides are trying to fire at the same time.

[boyt911sc]

Originally Posted by yelcab1

Only the most die-hard of enthusiastic DIYers would have ... two sets of indicators and 2 z-blocks.

Yel,

There are no z-blocks in my tool box anymore. A switch has been made some years ago to these:







You don’t need these fancy tools to do a good job for your engine rebuild projects. I’ve been using home-made tools from Home Depot, Lowe’s, and Harbor Freight rebuilding more than a dozen engines before owning my first Stomski tool.

You would think that these tools are expensive and extravagant to possess but wait till you use them. Your perception would change. I am cheap and frugal and only bought the wrenches I needed to do the job from HF.

Then one day, I decided to replace my home-made PVC cylinder hold down gadget with Stomski SR-007 and continued adding more. There is no substitute for good quality tools.

Tony

[yelcab1]

Like I said, only the die-hards have those tools. I do cam timing on Ferraris and Porsches all the time and I don't have those high end tools. I finally bought some digital calipers and dial indicators because of the "zero" features. The math was too hard on analog scales. I also bought a fully articulating mounting arm with a single tightener and it really was a game changer.

Still, I can't see myself with that Stormsky set up. Maybe if I do a 911 once a week...

I do have 12 torque wrenches....

[47silver]

great that you found the problem
those stomski's are nice i have the exhaust stud tool but have not splurged on the others

yet.