16 Valve Camshaft Mis-Alignment
12-19-2002, 10:51 PM
#1
Racer
Thread Starter
Join Date: Jun 2001
Posts: 250
Likes: 0
Received 0 Likes
on
0 Posts
16 Valve Camshaft Mis-Alignment
Finally getting the motor back together after a T-belt job and I noticed that the drivers side cam was aligned with the wrong notch! After locking the flywheel at TDC the passenger side cam was aligned OK at TDC but the drivers side was at 12:00 and the correct placement of the mark is at about 10:30 facing the engine. Page 15-14 of the manual shows a picture.This was about 2 full inches off to the right of where it was supposed to be and this car had thousands of miles in this condition! The engine turns over by hand very smoothly with no interferance with the valves. Anyway the engine ran beautifull like this and I am wondering if the PO had screwed this up and what is the best remedy? Is there another way to check proper alignment, say if the white paint mark is rubbed off of the cam sprocket? <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />
12-19-2002, 11:08 PM
#2
Nordschleife Master
If the car ran beautefuly, and it was that way before you took it apart, then thats the way it should go back together.
The cam gears are adjustable, and can be moved to fit the cam shaft. There is a way to set the timeing off the camshaft cams. It involves pulling the valve covers, and checking the lift on to of the valves and turning it to the proper lift for TDC. It's entirly possible that your cam gear was set not in alignment with the cam shaft. Just rember to turn the crank to the possion in which you won't hit the valves on the pistions. I've never done it, so I don't know how hard it is. I saw it in the service manual while I was doing my timeing belt job.
Make perfectly sure that the drivers side was that much off. The camshafts will turn just sitting there. They didn't want to stay at TDC on my car. I had to be very careful about that. I like the suggestion to take photos before you take it apart, so you can go back and check. Unforchantly for you, it's too late.
To put it short, if thats the way it was, and it ran wounderfuly, thats the way it's suppost to go. Just make sure thats the way it was. You don't want to try to turn the engine over with out the timeing right. The 4.7l engine can have piston/valve contact happen. Mine didn't, but you might not be so lucky.
Good luck.
The cam gears are adjustable, and can be moved to fit the cam shaft. There is a way to set the timeing off the camshaft cams. It involves pulling the valve covers, and checking the lift on to of the valves and turning it to the proper lift for TDC. It's entirly possible that your cam gear was set not in alignment with the cam shaft. Just rember to turn the crank to the possion in which you won't hit the valves on the pistions. I've never done it, so I don't know how hard it is. I saw it in the service manual while I was doing my timeing belt job.
Make perfectly sure that the drivers side was that much off. The camshafts will turn just sitting there. They didn't want to stay at TDC on my car. I had to be very careful about that. I like the suggestion to take photos before you take it apart, so you can go back and check. Unforchantly for you, it's too late.
To put it short, if thats the way it was, and it ran wounderfuly, thats the way it's suppost to go. Just make sure thats the way it was. You don't want to try to turn the engine over with out the timeing right. The 4.7l engine can have piston/valve contact happen. Mine didn't, but you might not be so lucky.
Good luck.
12-19-2002, 11:34 PM
#3
The cam gears are keyed to the camshaft at least on the 16V cars, I believe you can time the cams on the 32V cars but the only way of changing the gear/shaft relation would be with an offset key.
What you should be looking for is the notch on the back of the gears between 2 teeth;the paint marks should match these but trust the notches.
The engine may run very smooth with the cams this way but that doesn't mean it's supposed to, if one or both of the cams is retarded the engine will run a smoother but won't make proper power.
Same thing with ignition timing; if you retard the timing say 15 deg. it will smooth out very nice at idle but it's not supposed to be that smooth.
Go back and recheck everything and see if the notches in the gears line up the same, I'd time them properly unless you can find a reason where the present setup is NOT wrong.
What you should be looking for is the notch on the back of the gears between 2 teeth;the paint marks should match these but trust the notches.
The engine may run very smooth with the cams this way but that doesn't mean it's supposed to, if one or both of the cams is retarded the engine will run a smoother but won't make proper power.
Same thing with ignition timing; if you retard the timing say 15 deg. it will smooth out very nice at idle but it's not supposed to be that smooth.
Go back and recheck everything and see if the notches in the gears line up the same, I'd time them properly unless you can find a reason where the present setup is NOT wrong.
12-20-2002, 12:15 AM
#4
Racer
Thread Starter
Join Date: Jun 2001
Posts: 250
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the reply guys. I will check for that notch on the back side of the gears. I did not notice them. The water pump and rebuilt tensioner are back on and so is the new belt after scrubing down the whole engine until it was sqweeky cleen! What a marvel of engineering. Like I said, it turns over nicely by hand but I am thinking of gradually correcting the drivers side cam sprocket one tooth at a time and then check with two revolutions of the crank to be safe. I wondered what one would do if the white paint dot wore off the gears. Devek Level II headers are one the way soon with CAT back Borla exhaust as well as Koni external adjustables with Eibach springs and GTS Big Brake upgrade. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
12-20-2002, 12:47 AM
#5
Nordschleife Master
I appologize for missleading you. I could have sworn there was a set up on my car that would allow you to change the timeing. I was very careful not to mess with it, as I didn't want to go through resetting it. Since I didn't mess with it, I could be very mistaken.
Do be careful about the cams moveing though. They did not want to stay at TDC worth anything for me. Since I'd already broken the t-belt on the road, I didn't worry about dammage, if anything could have connected, it would have when the belt broke. If things arn't clean on the inside, you might not have the clearance.
I don't belive it would take much to bend a valve. The pistion wouldn't hit the valve till it was at the top of it's stroke. Then the crank shaft is as the place where it would have the most leverage on the pistion. The amount of force that you have to use to overcome everything else might easily mask the bit thats needed to bend the valve. I'd be realy leary of it.
Be very careful, I would hate to hear of anyone getting contact. It hurts me even to think about that on my car.
Good luck.
Do be careful about the cams moveing though. They did not want to stay at TDC worth anything for me. Since I'd already broken the t-belt on the road, I didn't worry about dammage, if anything could have connected, it would have when the belt broke. If things arn't clean on the inside, you might not have the clearance.
I don't belive it would take much to bend a valve. The pistion wouldn't hit the valve till it was at the top of it's stroke. Then the crank shaft is as the place where it would have the most leverage on the pistion. The amount of force that you have to use to overcome everything else might easily mask the bit thats needed to bend the valve. I'd be realy leary of it.
Be very careful, I would hate to hear of anyone getting contact. It hurts me even to think about that on my car.
Good luck.
12-20-2002, 01:10 PM
#6
Racer
Thread Starter
Join Date: Jun 2001
Posts: 250
Likes: 0
Received 0 Likes
on
0 Posts
CRISIS AVERTED! Thanks for the info on the v-notch BETWEEN the teeth. I had not noticed them before and now can verify that they are where they are supposed to be and the drivers side cam IS aligned perfectly! It is kind of hard to see under the distributor. There still is that white paint dot on a tooth seven teeth to the right at the 12:00 postion that really through me off and no paint where it should be, on the notch. Perhaps it is there so you can look through the upper cover vent hole for the intake tube to make a crude check on the cam timing? Anyway I am sure glad I did not try to move that side 7 teeth over! That mistake would have been Very Interesting. Thanks again for the help! <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
12-20-2002, 01:39 PM
#7
Rennlist Member
Please do a search here and check nichols and pirtle sites, there is also a piece by Wally; print them ALL and combine; I think Pirtle's is "172 easy steps" but includes other stuff like the tensioner; so I won't try to describe it here; I'm sure it is in the manuals as well. You check the marks at TDC (and check tension at TDC), you lock the fly at 45 degrees before TDC and your cams will not turn on you, if you had read these you would know. There is a reason you must set TDC and then turn it thru twice more!! 
