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Old 06-05-2008, 08:01 PM   #1 (permalink)
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Default Cam/Crank difference in degrees?

Does anyone have a clue what this number should be? I am trying to figure out why my car is misfiring and when I first looked at the scan tool it said the difference was around 6.6 degrees. I have been moving the cam magnet around and the misfires at idle have gotten better but not under high boost. Cylinder one misses like crazy. Now it says the cam/crank difference is 15 degrees after messing with the magnet. I haven't tried it at 0 yet but when I had the car around that range it idled pretty shitty. I've got the best idle I've had with the Crane 16s right now but cylinder 1 still acts like it's blowing out under boost.
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Old 06-05-2008, 11:15 PM   #2 (permalink)
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I got it down to .9 to 1.2 degrees and it's still missfiring hard at 5200RPMs.
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Old 06-06-2008, 01:35 PM   #3 (permalink)
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Not surprised no one here has a clue.
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Old 06-06-2008, 06:39 PM   #4 (permalink)
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Quote: Originally Posted by HCCAFan View Post
Does anyone have a clue what this number should be? I am trying to figure out why my car is misfiring and when I first looked at the scan tool it said the difference was around 6.6 degrees. I have been moving the cam magnet around and the misfires at idle have gotten better but not under high boost. Cylinder one misses like crazy. Now it says the cam/crank difference is 15 degrees after messing with the magnet. I haven't tried it at 0 yet but when I had the car around that range it idled pretty shitty. I've got the best idle I've had with the Crane 16s right now but cylinder 1 still acts like it's blowing out under boost.

are you running the cams straight up, the 16's should idle kinda shity (thats what big cams do).my only recomendation would be not to degree them leave them at 0. as for the other part i do not understand your translation of what the scangauge is saying it sounds like the pick up is on the wrong cam hole or your crank timing pully skiped and is throwing off your whole valve/ignition timing
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Old 06-06-2008, 06:51 PM   #5 (permalink)
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These are 2.0L Crane 16s I bought from BoostLee. When I first installed them the car would not run and kept throwing the cam/crank misalignment code P0016. I contacted RealTune and Aaron told me I might have to cut the tips off the back of the cam magnet and rotate it. This rotation can be read with a good scan tool. I winged it and got mine to 6.6 degrees of difference and never knew it. Once I exhausted every other option trying to find the cause of my missfire I went back to the cam magnet. My friend let me borrow his Solus and the first thing I did was test 98srt4dr's stock 2004 car. His cam/crank difference was 6.2 degrees. I was pretty stoked I got mine so close to stock without anything but luck. I then went and started rotating my magnet. I tried everything from -35 to +25 and kept having the missfire. I then went for the closest to 0 I could get which is .9 degrees where it is now. Honestly the idlewill sound a little different in that broad range of -35 to +25 but as long as the car doesnt throw the P0016 code it runs about the same. I started this thread hoping someone had some idea of what the specs should be for crank/cam difference.

As far as the cam gears...they are still at 0 and 0. I'm talking about the cam magnet. I know my timing is dead on in relation from crank to cam. I have checked and had other people check. That's water under the bridge at this point.
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Old 06-07-2008, 07:39 PM   #6 (permalink)
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Factory cams should be roughly 6 degrees from the crank.

I'll post up some misfire advice later.

Bryan
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Old 06-07-2008, 07:41 PM   #7 (permalink)
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Quote: Originally Posted by SkullingAxe View Post
Factory cams should be roughly 6 degrees from the crank.

I'll post up some misfire advice later.

Bryan

Nice. How can I know how many degrees these Crane 16s should be?
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Old 06-07-2008, 11:02 PM   #8 (permalink)
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You'll need to degree the cams to find out what degree it should be.

The thing I'm wondering is, those cams are setup just like a set of 2.0l stock cams. Seeing as they are designed for the 2.0l. That being said, I wonder if one of your cams is 180 out, particularly the intake cam. Reason being, the 2.0l cams you have to rotate the intake cam 180 degrees from the stock intake cam. That way the machine holes between the number one and number 2 cylinders were pointing up. (The dowel pins for the cam gears would be 180 out from each other). However, one would also think that the car would not fire up, if not take for ever to fire and back fire out the intake.

What is your engine vacuum at idle? You may just have such a radical cam that is fucking with the PCM due to low engine vacuum. Or your out a tooth, but you said it has been verified multiple times over. Do you have the cam specs? Some rough idle will be normal with bigger cams. It will lope because duration is higher and so is lift. So overlap comes into play, especially on N/A cams where overlap is desirable.

You could also be experiencing Valve float with the big cams. Are you running any upgraded springs and retainers? Valve float usually occurs at high rpm because the coils bind with high lift cams(on the stock springs). It will cause the engine to misfire like MAD and sound like a machine gun because the valves don't fully seat. If your not running upgraded springs then i would start there with the springs.

Have you gone through the preliminaries and checked the basics? AKA vacuum leak, bad wires, bad plugs, sticking injectors?

My final question is what else have you done to the car when installing the cams?

Sorry for the long post just trying to paint the picture in my head and asking questions is the only way I'm going to know without looking at the car.

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Last edited by SkullingAxe; 06-07-2008 at 11:12 PM.
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Old 06-08-2008, 08:47 AM   #9 (permalink)
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Thanks a lot man for trying to help me figure this out.

Yes the cams are 180 off from each other. There is a hole on each cam that points up when at TDC and they make one dowell pin go up and one go down when you align the cam gears.

I think the degrees you are talking about is the actual degrees of the cam since you are talking about degreeing the cams. What I am talking about is on a scan tool in the engine data section you can read all kinds of crap. One of those things says cam/crank diff and it's measured in degrees. I was hoping someone else had looked at those numbers or maybe had access to a service manual that mentions what that spec should be.

My vac is pretty consistent with friends that have big cams. It's around -15 at idle.

My cam specs are :
Grind Number CHR-250-6
Advertised Duration Intake/Exhaust 250 / 250
Duration @ .050 Intake/Exhaust 208/208
Lobe Separation 106
Gross Lift 374/374

2.4 Turbo Neon Crane 16 specs are :
Grind Number CHR-250-10
Advertised Duration Intake/Exhaust 250 / 250
Duration @ .050 Intake/Exhaust 208/208
Lobe Separation 110
Gross Lift 374/374

As you can see the only difference is lobe seperation which will cause a few differences but I believe they can be adjusted out by adjusting the cam gears. Usually a lower number in lobe seperation indicates a peakier torque curve, less top end, less idle vacuum, a shittier idle, intake opens and closes earlier, exhaust opens later, and there is a little more overlap. I'm not sure how much difference those 4 degrees make on these cams but I plan to work that out when we start adjusting the cam gears.

I have Crower Springs/retainers etc and the oil flow modifier in the race ported head I am using.

A shit ton of other stuff was done to the car when I installed the cams but the tests I have done verify there is nothing mechanically wrong, at least I think they do. I suppose there could be a cracked harness wire or something since I believe I read somewhere uncommon had to change out his entire engine harness once to get rid of a miss.

I have done the following;
-Compression test (175+ across all 4)
-Changed the wires (MSDs before and after)
-Switched the number #1 and #4 with each other because #1 is the one that misses and #4 rarely ever does.
-Changed the plugs.
-Regapped the plugs.
-Had my mechanic friend spray the shit out of the #1 cylinder area, intake mani, spark plug boot, injector etc with carb cleaner while I watched the idle on the scan tool and it didn't budge.
-Boost leak tested it to 30PSI
-Swapped out the intake manifold with another freshly ported one.

Stuff wasn't done in that order but you get the idea.

The only thing I have not done yet is put in a new upstream O2 sensor and switching the plugs back to the old reliable Champion Hemi Plugs. Believe it or not my car never would run on NGK 4306s and it has the NGK Iridium 2314s in it now. I thought the Iridiums were one step colder and that they were my only option for a colder plug but have since realized that they are the same heat range as the 4306s and that the Champion 570s actually are a colder plug. I have a new 02 sensor and a new set of Champion 570s that I'm gonna put in the night before my next dyno session. If they don't get the miss out of number 1 then I am pretty damn certain it's something in the SCT tune thats on my car.

Last edited by HCCAFan; 06-08-2008 at 08:52 AM.
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Old 06-08-2008, 09:29 AM   #10 (permalink)
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The 570's are the same heat range as the stock 470's but have a different "wide gap designator" meaning the electrodes are designed to be gapped closer (and the Hemi plug is ever so slightly shorter in length just on the plug wire end). Also of note, even if the cam magnet was off a touch is shouldn't make a giant difference in how the car runs. The computer uses the camshaft sensor to determine crankshaft position but uses the crank position sensor for all the ignition timing and exactly when to fire the injectors. In other words, the camshaft position sensor is used to determine which of the two cylinders at the top of stroke is on the compression cycle so that it can determine injector firing order (which is also required for the SFI function). The PCM should also use it to monitor for things like timing belt jumping a large amount and can run using just the cam sensor, although poorly, if the engine is already running and the crank sensor fails. If one of the sensors completely fails, the PCM will kill the ASD relay at startup and it won't start.
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Old 06-08-2008, 10:49 AM   #11 (permalink)
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Quote: Originally Posted by blackbird_R/T View Post
The 570's are the same heat range as the stock 470's but have a different "wide gap designator" meaning the electrodes are designed to be gapped closer (and the Hemi plug is ever so slightly shorter in length just on the plug wire end). Also of note, even if the cam magnet was off a touch is shouldn't make a giant difference in how the car runs. The computer uses the camshaft sensor to determine crankshaft position but uses the crank position sensor for all the ignition timing and exactly when to fire the injectors. In other words, the camshaft position sensor is used to determine which of the two cylinders at the top of stroke is on the compression cycle so that it can determine injector firing order (which is also required for the SFI function). The PCM should also use it to monitor for things like timing belt jumping a large amount and can run using just the cam sensor, although poorly, if the engine is already running and the crank sensor fails. If one of the sensors completely fails, the PCM will kill the ASD relay at startup and it won't start.


Thanks. That helps greatly because I now know the cam magnet isn't what's telling the car when to fire.

Sucks about the 570s. I'm still going to see if they fix the miss. What the hell do people use for a colder plug? I wish spark plugs.com still had that chart that said what was colder.
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Old 06-08-2008, 07:01 PM   #12 (permalink)
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Welp it wasn't the O2 sensor. I figured it wasn't but it was worth a shot. I put the new one on, disconnected the battery for about 10 minutes and then took it for a ride. Once up to normal temp I got on it. It averaged about 60 misses on the #1 cylinder the times I got the car to pull without throwing the overboost or map/tip code. Tomorrow I'll put the Champion 570s in and give it another whirl.
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Old 06-09-2008, 03:04 AM   #13 (permalink)
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There aren't any choices for colder copper plugs for the SRT-4 and that sucks. I'd prefer to run copper Autolite's but we don't even have any other heat ranges in the stock Champion or the NGK V-Power's, let alone any other copper plugs. The 4306's are a little better quality plug in my opinion, and are supposedly a tiny bit colder at best but should be pretty close to stock heat range, but I've never had good luck with them on my S2 car and a lot of other Stage 2 cars. I'd always get an odd ignition miss that would go away on the 570's. Even heavily modified stock turbo cars probably don't need a colder plug (especially since the richer the car is running the more chance of the plug fouling on a plug that's too cold), but due to the plug construction if you have a big turbo I'd at least try the 4306's and then go to the Denso or NGK iridiums if you do need a colder heat range plug.


When you say "switched the #1 and #4", was that plugs or the injectors? If it was the plugs I'd try swapping the #1 and #3 injectors and see if the misfire changes to that cylinder. Also maybe try a cylinder leak-down test. Also reading back I noticed you mentioned a custom SCT tune. If you have it set up for 3 bar sensors and you're on a stock turbo or even a big turbo and can turn down the boost, you might have your tuner send you the stock S2 calibration and give that a try just to see if the miss still occurs. Unless you have some giant injectors and can't turn down the fuel pressure a little to compensate it shouldn't have a problem at least running lower boost for a couple pulls (but be sure to take it slow and data log before you try to crank it up).
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Old 06-09-2008, 04:44 AM   #14 (permalink)
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Thanks again Blackbird. I have a 50 trim with 3 bar sensors and we have tried stock S2 tunes like you said. Right now the biggest pain in the ass is the P2074 code and the overboost code that throws the car into limp mode. I suspect that has to do with the miss and that's definitely in the tune. SCT said last week they knew what was wrong after having me unplug the sensor on the hard pipe to see if the car cut off or not once it was unplugged. I can't remember what that plug is called but it's not the TPS and it's not the temperature sensor. SCT was going to send us a tune to take care of that so when I get it back on the dyno we'll see if it does.

Yes when I said I switched #1 and #4 I was talking about the injectors.

I have not done a leakdown test. That would mean what, the valves were/were not seating properly?

My car has always hated the 4306 plugs. Unfortunantely the day we tried switching the plugs on the dyno that was all I had available so I switched the NGK Iridiums for NGK Coppers and then went back to the Iridiums when it didn't get any better. I now have a new set of Champion 570s to put in. I'll be happy as hell if they get rid of the miss. They used to be the only plug that worked for me but I figured it was just my imagination.
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Old 06-09-2008, 07:11 PM   #15 (permalink)
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So the 570s didn't help. Car still misses about 60 or more times on number one once you get over 5000 RPMs with or without boost.
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