Camshaft timing/Durmetric readings/errors

Still trying to figure out if there is really anything wrong with the setting/timing of my cams after fixing my intermix problems. When I first checked the cam timing with my Durametric it was showing the following readings: Camshaft position 1 deviation -10.86 Camshaft position 2 deviation -02.14 So I have been assuming that the bank 1 cam might be pretty far off. I ran the Durametric on my buddies car and the readings for these are about -1 to -2. I had borrowed a cam position tool from another member and went to check/reset the cam timing today. But visually, there is no way it appears to be off by -10+ degrees. Based on this I did not reset the timing but decided to run the Durametric again and now get the following readings: Camshaft position 1 deviation -12.15 Camshaft position 2 deviation -02.45 Actual angle for camshaft bank 1 .1 (at idle) 25.94 (at 2,000 RPM) Actual angle for camshaft bank 2 .3 (at idle) 24.74 (at 2,000 RPM) The actual angles vary a little bit with the engine running, but you can see the advance kick in between 1,500-2,000 RPM. So here is my question. Do the camshaft position deviation numbers mean that the bank 1 camshaft is starting at -12.15, and then advancing 25 degrees so that it is at 13 degrees advance? Not really sure how to interpret these readings. But it sure dons not look like the bank 1 cam is off by 12+ degrees with the engine off. Any help would be appreciated.

Since you have the special tool to do the cam timing I think its best to time the cams and see what happens. Nice thing about cell phones is long distance to places like suncoast or who ever is cooperative with info from their shops would just cost minutes of usage for the month. I think its best to get a dealer or long time race engine worker thats walked down that path all the time between races. Maybe throw a call towards the durametric guys. Page 1-13 of the service manual I believe is saying the range is 0-40 degrees kW. This is kind of a relief since your range isn't way up there. Page 2-8 shows external locations of sensors and such concerning the cams. The Hall sensor and camshaft rotor operates both banks. Some voltage readings for checking operation are mentioned. Yah plenty of things to wonder about. Would be nice to have it sorted with a pro.

if the engine feels strong and pulls hard then maybe its the sensor.... possible to swap a sensor and see if the deviation follows.

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I swapped the sensor on 1 bank...it is still -9.xx. The other side is -2.xx if I remember correctly.

This is my first post and don't have your answer but do have a question/observation . I acquired a 99 Cab in March and have been sorting it out .This Forum is the best tool available -just tremendous ! The question :when you timed it-did you use the auxillary chain tensioner tools ?( I think it's part # 9559 If not that could explain the deviation from spec when running .In a static test-it could look good and under load changes .Also -somewhere in the shop manual is a chart on specs and acceptable deviations -I rember reading 6 degrees -looked this am and couldn't find the chart .Will continue to look . I have a vested interest in resolving this -I have exactly the same issue Dave

just throwing this out.... Im sure you are aware of all this. But, just in case... http://www.youtube.com/profile?user=.../9/7C5E-yAlZwI

Redridge - Thanks for your responses. The advance mechanisms are working, you can see the advance kick in, and I changed out the pads as part of the work. dcdreschel -I know of the pretensioner tools, and thought of getting them, but a set is over $400. In talking with Baum Tools, which sells them, they said very few mechanics buy them at the real tensioners will due the trick unless they are collapsed. The difference between the pretensioners and the real tensioners would not give a 12 degree change. I also spoke to Jake Raby about this and he said the tensioners should work. I think I may have figured out why I am getting a deviation/reading. On the following pictures you can see that each exhaust cam has a pressed on ring with a flange that passes by the sensor. This is what gives the signal of the cam position. When I was doing to many ins and outs of my cams due to the expansion caps blowing out I did bend one of these flanges as you can see in one picture. I did straighten it out, but it might not be perfectly straight so that when it passes the sensor it is showing a slight deviation.

so are you going back in? is it a big deal? no errors?

I am definitely not going to take off the cam covers, etc. at this time. I had the green plug off of the intake cam yesterday preparing to use the timing tool that I was lent. But the cam seems right on based on the markings/groove so I stopped there. It is kind of tight to get the tool in place and get the scavenger pump off to reset the timing, really need to take off the bumper and the exhaust. Visually the cam is right on the proper setting, no way it is off by 12+ degrees, unless it is the tensioner, so I stopped there and started asking questions here and on the other sites. I am thinking of replacing the tensioners as a preparation for the IMS bearing upgrade but thought I would see if anyone had specific knowledge on the readouts.

Doug -thanks for the feedback .My hang up was that Porsche designed and spent money on a tool for a reason .I don't know the reason and I guess it doesn't matter if Jake says it should work . Think I have read almost all your posts and my compliments on taking considerable time to document and share what you learned ......... Dave

I wonder if the numbers it is sensing off the sensor are used for running the vario-cam and adjusting other inputs. That sure was a bend. Cuss words just don't cover every situation.

Dharn, Curious what do you set your timing to?

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If you do replace the adjusters, make sure you get the older style crank to IMS (996-105-180-54). Last month, I pulled out the new style and replaced it with the last old one in the states (there were 19 in Germany). The new one is a touch shorter and it was fully extended. Rick 99 996C4 87 944S

doug, just an fyi, a reading of 10 degrees deviation is at the crankshaft and is half, 5 degrees, at the camshaft. this would make it more difficult to determine visually.

Thanks for everyone comments and thoughts. Pac996 - On the VarioCam engines the systems is pretty simple for the advance, RPM based, and I don't think it effects much else. Paul 996 - You set the cam timing by fixing the crank at TDC and them setting the grooves in the non-driven end of the exhaust cam straight up and down with the narrow side toward the outside of the engine. With the OEM Porsche tools you set the engine at TDC, attach the tool at the non-driven end of the cams, one end fits in the opening of the head/cam cover on the intake cam to lock the tools in place, and the other end actually fits in the grooves on the end of the exhaust cam, and the tools has a lever that allows you to rotate the exhaust cam relative to the crank, this is done after loosening the bolts on the drive sprocket of the exhaust cam. This them puts the cam in the proper position and then you tighten the bolts on the drive sprocket. With the ZDMax tool I was lent it is a little different process as there is no lever to move the exhaust cam. First you rotate the crank unit the exhaust cam is in the proper position, then you install the tool, which also fits into the opening for the intake cam, but merely slips into the grooves in the exhaust cam to lock it in the correct position. Then you loosen the bolts on the drive sprocket, rotate the crank to TDC, then tighten the bolts on the drive sprocket. Same result. rb101 - That is interesting on the Crank/IMS tensioner. This is one of the questions I have been trying to figure out. The 1-3 tensioner has not really been changed, and the change to the 4-6 tensioner is really just a change to the head so that instead of using a sprocket you use an allen wrench. However the Cranck/IMS tensioner has been totally redesigned, and now instead of a closed piston it appears to have an exposed spring. This change was made when the engines went from the VarioCam 3.4 series, which are 5 chain engines, to the VarioCamPlus engines, which are three chain engines. And apparently the Porsche Tech bulletins say to used the old style tensioners. However if you look at the LN engineering site for the IMS bearing upgrade, where they recommend that you replace the tensioners, they say to use the new styles all the way around. And I spoke to Charles at LN the other day and he says that they are using the new style Crank/IMS tensioner in their 3.4 engines that they race. Still trying to figure this out but your comments are appreciated. Maybe I will email Jake RAby and see if he has some input. I also received some input from a member on Renntech.org who had an interesting thought. What if I missed one link on the chain that drives the intake cam off the exhaust cam? This would explain why the cam timing of the exhaust cam appears correct, and yet the sensor, which is on the intake cam, could be off. Unfortunately the only way I can check this is to remove the cam cover on that side, which is doable with the engine in the car, but is a real pain in the XXX. Probably will give this a try next week. Thanks, to all!!

You may already know this -Page 53 of the Porsche Diagnostic Manual provides the DME Setpoints .Camshaft deviation is + or- 6 degrees . Not sure what to conclude from that -except it's a 12 degree swing and that's acceptable . Dave

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I talked to the dealer in Sarasota about the new style adjuster and he could only point out the tech bulletin said to use the old style and it must be for a reason. I decided to order one. When I pulled the new style one out, the piston was fully extended out of it's bore. First picture is removed newer style adjuster. Second is me bending it, piston at end of bore. Third is when I was replacing in December (3K ago). Picture 4 is from tech bulletin. The tensioner pad sets much closer to the adjuster in the new style and that's why I think piston is being pushed out of the bore. Rick 99 996C4 87 944S

That doesn't look good! Charles from LN told me he was running the new style tensioner in a 3.4, but maybe his was after the change to the new style chain, which took place mid 2000 I think. Mine is a 2000, but was actually made in late 99 and has the old style chain. I emailed Jake RAby to see if he can give some clarification but your picture sure look convincing.

I thought I would resurrect this thread and give an update on the cam deviations I have had since I fixed the intermix on my car. Looking back to the first post I had the following deviations showing on my Durametric. Camshaft position 1 deviation -12.15 Camshaft position 2 deviation -02.45 I set the cam timing by eye with my shade tree method. Visually the slots on the end of the exhaust cam seemed to line up with the seam between the head and the cam cover, and looked good with a straight edge. I was unsure if there was a bent tab for the hall effect sensor on the intake cam, if I had missed a link on the cam to cam chain or what. I did not drop the engine and have 5 years and 30,000+ miles since with the engine seeming to run well. So a week or so ago I checked the deviations again and they were still off by approx. the same amount. Having acquired a tool set with an aftermarket version of the Porsche cam timing tool I decided that I wanted to find out if the problem was real. Well the Porsche tools will not fit with the engine in the car, and I wanted to do some other work so i decided to drop the engine and see what was going on. Even with the engine out of the car it was still difficult to get the tool on the 1-3 head as an oxygen sensor and the engine mount frame were still in the way. By loosening some bolts, etc. I did manage to get the tool in place and here is a picture of what I found. https://rennlist.com/forums/attachme...1&d=1398731776 You can see that the cam was in fact off by several degrees. Remember that 12 degrees at the crank, which is what the Durametric reads, is only 6 degrees at the cam. This is hard to see visually without the tool, but with the tool in place the deviation is pretty obvious. The extension of the arm of the tool from the exhaust cam to the intake cam makes the deviation more apparent. By the way I did find that with the eBay version of the tool, which is what I have, the part that fits into the exhaust cam slot was put together 180 degrees out of place. I guess you get what you pay for but it was easy to turn the part 180 degree (two set screws) and then it worked fine. I reset the timing on the 1-3 cams and also checked the 4-6 side, which was off on the Durametric by 2 degrees and it was just slightly off with the tool. Reset that to. So if you are setting the cam timing, and if you want to do it with the engine in the car, it might be best to get the LN Engineering cam locking tool that is part of their bearing installation tool kit or to get the ZDmak cam timing tool. I think that either of these tools would fit wit the engine in the car. They do work a little differently than the Porsche tool. With the Porsche style tool you lock the engine at TDC, then install the tool with the one end in the exhaust cam, loosen the bolts on the exhaust cam sprocket and use the tool to rotate the cams to the correct position, then tighten the bolts on the sprocket. With the other tools you would have to lock the cams in place, then loosen the bolt on the exhaust cam sprocket and rotate the crank to TDC. I am anxious to see what the Durametric shows for deviations now and if the engine runs smoother and stronger. However that is going to have to wait for a few days. I am going to do a ceramic IMS bearing and the new Direct Oil Feed from Tuners Motor Sports/Pedro's Garage and address a few oil leaks before the engine goes back in the car. Still waiting for some parts for this.

Update?

I sent a Message to Doug to ask about the outcome. Note his kind warning about the Ebay tool being 180 degrees off. I also wonder if fitting to new style 1-3 Timing Chain Tensioner helped solve the problems? It is noteworthy that the Porsche OEM tool kit (also sold by Baum # B9612KPLUS) comes with no Instructions for use. They don't even identify the various tools in the kit.See the EWK site if you want the specific part numbers with a photo. The tool shown in Post 19 #9612)above is a good example The black polygon shaped part at the top of the photo shows how the tool can show if the exhaust cam slot is slightly off. The black polygon slides in & out and is retained by set screw with a 3mm Allen hex head.Unfortunately this tool is too large to fit with the engine in place. Most of the Baum tools are un-useable with the engine in the car. They are just too large and clumsy. You may also have to grind off corners that prevent full engagement of the tools. The TDC lock pins are a good example - far too large and an 8mm or 5/16" bolt or drill bit works just as well. An awl helps you locate the TDC hole when you approach TDC. That is not supplied but a 10d common nail works well enough. No wonder they asked Jake Raby for help. The LN tools work great -of course.Jake wrote: "The allocation (lobe separation) of the intake/ exhaust cams is set by the chains and the amount of teeth between the dots. For your engine their should be two discolored chain links that are 7 teeth apart that will align with these dots. After the cams are allocated to each other the camshaft alignment tool then indexes the exhaust cam to the crankshaft after the crank is locked into position. I (Jake, not me!)am in the process of writing some instructions for the folks at Baum for their tool kits as I have assisted them with the fine tuning of these. I also plan to do an instructional DVD on this soon" https://rennlist.com/forums/996-foru...ol-9612-a.html

Been a long time since I did this. I did replace all three tensioners and put in the Direct Oil Feed bearing. I forget if I ran the Durometric and what the read out was. I will have to run it again but mr friend has it right now to clear a code off his engine.

So... Whatever happened with this?

suggest you check on Renntech- lots of detail there. A potentially very exacting and lengthy issue