marine928

Hi Guys, in the middle of my 1st TB/WP service on my 1987 S 4. Am using Dwayne's write-up. Rotated to TDC marks lined up. Rotated to 45 used white paint to mark position, locked flywheel, proceeded with rest of directions, removed TB (did the dance) removed WP (did a dance too), removed old tensioner since I am replacing with porken tensioner (airpump delete).
During all this time did not see any cam movement. Went inside came back out 30 min later to begin cleaning prior to install and noticed the cams had apparently moved. I have a friend helping out so we should have seen something. How do the cams move with the flywheel lock in place and how do I get them back into position. Pics attached. 1st pic passenger side, 2nd drv side.

Thanks
Lon

Leon Speed

The cams can move because valve springs push against the cam lobes. With the crank locked at 45 BTDC the cam (gears) can be rotated without danger of hitting the valves. Rotate the cam clockwise to the original position with a 17 mm wrench. You need to remove the rotors first.

You will also need Porkens 32Vr to fine tune the timing, Porkens BumpStick is not really necessary but it makes this task very easy.

Your cam gears look kind of worn, it might be needed to recoat them or get new ones.

marine928

Thanks Leon, I will take some more shots of the gears to get advice on their condition. I am putting in new rotors and wires as well. I still am mystified on how they moved w/o any help. Did they just relax when the tension of the belt was off. It appears that the pass side moved clockwise and that the drv side moved counter clockwise one notch.
Is that normal.

Leon Speed

Some gears move, others don't. I think "normally" they tend to move outwards, meaning counter clockwise on the passenger side, clockwise on the driverside. Anyway, it is no big deal if they moved.

Btw in your pictures, is the white marking the 45 DBTD marking? Or are the 45 DBTD markings the red/brown ones?

marine928

Just some additional pics of my cam sprockets. 109,207 miles. How do you rate their condition.

Thanks
Lon

marine928

White is the 45 the red was from the previous service done in 2008 at 106,480 miles.

Mrmerlin

WARNING ..... Warning.... Read this carefully.


Before you do any more work make sure the crank is at 45 degrees before TDC .
This way you can turn the cams with out any damage being incurred.

WARNING.....
Both of the cams that are pictured are about 180 degrees out from being at TDC.

With the engine at TDC BOTH of the rotors should be pointing to the driver side fender.

That said you need new cam gears,
and the rotors have to come off to turn the cams and or use the Porken tool.

With the rotors off the cams you will see a 17MM bolt and a 32 MM hex nut washer under the bolt, use the 32mm washer to turn the cams,
this so the torque isnt affected on the cam bolts.

Leon Speed

I'm no expert on cam gears but they might be okay for recoating. Ask Colin Jensan (Lizard here on Rennlist), he did mine.

As the white markings are the 45 ones, the harmonic balancer is on backwards. The red ones are the correct markings for 45.

Leon Speed

right, the 32 mm washer, not the 17 mm bolt like I said.

marine928

Thanks Mrmerlin, I flywheel was already at 45 BDTC prior to removing the belt. Take a look at the additional sprocket picks to confirm your assessment please. I will make sure the DC's are set toward the DS fender.

Thanks for the advice and help.

Lon

Mrmerlin

the damper should be on the crank so you can read the numbers while facing the engine,
please take a picture of the damper and post it so it can be determined whats going on.

as an aside to this,
if the crank keyway is facing the the 4 O clock position then the crank will be at TDC,
if its facing 3 O clock then its at 45degrees before TDC, this while facing the engine.

If the crank is at 4 O clock then the cams should be lined up with the hash marks lined up to the rear of each cam pulley and the rotors both pointing to the driver side fender.

Your picture shows the cams are 180 degrees out from TDC so it stands to reason that if you removed the belt with the cams in this position then you have taken the belt off with the engine 180 degrees out of TDC.

SO dont turn anything lets see what the damper position is or the crank keyway position

On a second look at the cam gears I agree with Aryan, they should be OK for further service but they are getting worn

marine928

Ok let me digress. prior to starting this post I had already rotated the crank bolt to TDC made sure the cam marks were lined up. I then rotated to 45 BDTC locked the flywheel in place marked the position with white paint and proceeded to continue with the service. When I posted this I had already removed the crankshaft belt pulleys, the balancer with the numbered markings and the TB.
I will go take pics of everything so everyone can view.

Thanks
Lon

Bill Ball

Those gears actually look pretty good. Minimal wear through the coating - mostly small spots. Just my personal choice - I would leave them alone. The driver side wears faster than the passenger. They definitely need replacement when the coating is worn through most or all the the tooth face. When that happens the aluminum tooth begins to dish and develop sharp edges. Yes, you could have them recoated now.

And as indicated, it is common for the cams to move. 45 BTDC puts the cams near the top of a lobe, under spring pressure.

marine928

ok, here are my real time pics.

1. crank bolt position
2. PS cam position after I rotated to correct movement. ( clockwise)
3. DS cam " "
4. position of PS rotor currently.
5. Position of DS " "
6. Birdseye view.

Are rotors correct? I loosely attached to show position.

Thanks

Lon

Hai gebissen

You can see the notch in the cam sprocket down towards the bottom...that should be just a few teeth away from the notch in the back timing cover at the top. Mr. Merlin is right, they appear to be 180 off, which isn't going to happen from just spring tension...