944S1 vs S2 Camshafts

[Carboy_GT]

The Cams

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So I've been attempting to find what has been making my S1 so down on power and stall coming off throttle the entire time I've owned this car and I found that it has S2 cams installed. The previous 2 owners didn't know and they had replaced the tension-er, my theory is they timed it as a S which throws off the timing for the S2 cams.

What makes me feel like the timing is incorrect:
Sounds like it runs on 2 cylinders
Cylinder 4,3,2 are all black with soot, 1 is a golden color (Less than 24hrs of run time on them)
Engine make's almost no torque throughout rev range
Engine revs fall but then it catches too late and stalls
Engine throttle response is pretty laggy
Vacuum gauge says late timing when idling

If I were to make this work would I just time the engine as a S2? What's the timing difference between the S1 and S2 cams? Would I advance timing for make up for the more retarded cams?

What I've done so far
3 Smoke tests : Passed
New silicon hoses for under the manifold and vac lines. (944 Online kit)
Replaced TPS sensor (Tested with Multi-meter at all points: Passed)
Replace spark plug wires + Rotor and Distributor (Tested Ohm : all at ~3Ohms)
Fuel injectors cleaned, rebuilt, and calibrated (Verified they are getting signal)
New fuel pressure regulator (Fuel pressure now reads within spec per FSM)
Verified the ICV opens and closes on command (Doesn't close all the way but I haven't seen anybody say it's suppose to the adjustment screw still has the factory tamper glue thing on it)
Verified the length between the 2 notches on the cams (113mm per FSM or 7 outer chain links)

[Bergerac]

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This is from the service manual section 1A, unfortunately my copy is missing page 15-101/102 like most copies getting around so you'll have to find those pages for the S timing.

You could get your dial gauges out and check but from way it's running and the difference on the plug on 1 I'd be checking that cylinder is definitely getting fuel and spark

[walfreyydo]

The FSMs are all available to download for free:
http://p914-6info.net/944%20Manuals.html

Check the 16V engine PDF for setting cam timing. I believe the S and S2 have a different exhaust cam. Check to see if there is a different setting for the 2.5 16V vs the 3.0 16V within the FSM -- I am not sure if there is a difference in what distance the intake valve tappet must be between the two. If you are running S2 cams (very odd why someone would do this) then follow the S2 timing procedure, if there is any difference.

A high level summary is that to set cam timing youll need to adjust the exhaust cam to its max setting, lock down the cam gear, then advance the engine until the intake cam lobe depresses the intake valve tappet a specified distance. Then you unlock the cam gear and advance the engine until the crank is at #4 TDC, which will also allow the exhaust cam to stay in position as the cam gear rotates. Once you are at #4 TDC lock down the cam gear, roatae the engine a couple revolutions and measure the intake tappet depression (it should be within spec listed in the FSM) and you should be good. The cam gear should be approximately half way in its adjustment slot. Youll also need a dial gauge with a long L shaped probe attached to the intake tappet/lifter in order to measure that distance. The detailed run-through is in the FSM, so refer to that as well as Jurgen's video on youtube.

That said, your particular issue may or may not be related to cam timing (I cannot say). You could also have an air/fuel ratio imbalance issue (potential causes: bad TPS, AFM contact arms, IAT within AFM issue, Stuck injectors, DME temp sensor, O2 sensor, Vacuum leak). More info on diagnosis can be found on Clarks Garage

Also, I am not sure, but there looks like there could be some forbidden glitter (metal shavings and/or some sort of fine grain debris/particles) all over the inside that valve cover. Am I seeing that right or is it just the lighting/camera? You might have some bigger issues at play if so.

[cda951]

Are you sure that your ignition wires are oriented correctly on the distributor? It's easy to overlook the basics in such cases, but all of your symptoms could be explained by that.

Also, there is an excessive amount of grey RTV silicone on the gasket surfaces, some of which is hanging inside the valve cover area. RTV should not be needed except for small beads on the sharp angles of the cylinder head side----any excess RTV which squeezes out into the interior portion of the valve cover could end up in the oil pan and eventually in the oil pump pickup screen, I've seen this many times . . . . Scrape the old powdercoating from the inside grooves of the magnesium valve cover and use a small amount of rubber-friendly silicone grease on the upper portion of the valve cover gasket to help it squeeze into place as it is torqued down.

[Thom]

It was not uncommon for earlier Ss to go through camshaft sprockets and since the S exhaust camshaft became NLA rather early it seemed not uncommon to replace it with an S2's to just get a car running again. I also heard that the S exhaust cam was a little hotter than the S2's, and perhaps favoured on 16V turbo builds. All FWIW as it has been quite a while since I heard all this.

[barnwerks]

Faulty camshaft timing will not create a difference between cylinders. Have you done a compression test?