Glen McCartney

Is there I write up somewhere on changing the cam sprockets without having to do the cam timing? I am about to replace my worn cam sprockets and do not want to have to pull the cam covers on my MY85 (concerned about breaking those 2 piece cam cover bolts). I searched on Nichols and here, didn't see anything. I just recieved the cam timing tool folr the 32V from Porken, have to see if that will help with the installation.

Any tips are greatly appreciated.

Glen

Peter F

Hi Glen,

i will do the same this weekend and there are some instructions in this thread:
Cam gear change
I have also bought the cam timing tool kit from Porken.
Still not received yet though :-( , it would make the job a lot easier for sure.

Cheers/Peter

AO

I don't think you have to worry about it as the gears are indexed to the cam by the woodruff key (I think that's what it's called). You will have to check the timing belt alignment however and make sure they are aligned with the crank. I'm sure others will chime in.

ROG100

Just did mine.
The key allows for a lot of movement so you need to mark its position.
Replace the 5mm (I think) bolts that hold the rotor in place. Measure between the face of one of the flats of the bolt and the leading edge of the slot in which it sits. I did the measurement on two of the bolts for safety.
I was set at TDC when I did it so aligning the new sprocket was straight forward. Just align the V on the gear with the mark on the housing.
Replace the same bolts in the same position and set to the measurement, tighten the main bolt and you are good to go.
This info was given by Marc at Devek, thanks Mark.

Garth S

That is true for all of us with 16v cars with the OEM cam gears - nice & simple. The '85 and on 32v cars have a 3-prong hub indexed to the cam by the key: attached to this by the cam end bolt, and indexed to the hub by the three rotor bolts is the cam gear. These gears have an ~2x wide slot over the keyway allowing for cam timing prior to snugging everything together.
To recapture the same timing, Rog100 has the good answer.

deliriousga

Would it be better to set it to 45 degrees before putting in the flywheel lock? I think I read setting it to 45 degrees eliminate the possibility of valve crash if one of the cam gears moved a little after the crank was locked at 45. I'm planning on the same deal this weekend. Thanks for the links and info guys!

Anyone know of a write up on the crank gear too?

PorKen

Glenn, Peter,

I am away from my computer all day again this week, but I will add a section to the ZVA manual about changing the gear.

Should be a snap with the tool.
~Get the initial measurement with the indicator at #1 TDC.
~Lock the crank at 45 degrees, as if changing the timing belt.
~Replace the gears and belt, clamping the hub to the gear in the center of the adjustment slot.
~Unlock the crank and set to #1 TDC.
~Follow the adjustment procedure to reset to the initial measurement.

You may need a gear puller to take off an old gear. I suggest using 90W oil to coat the cam and the hub/gear hole, to make it easier to remove and adjust later.

Oops, late again!

ROG100

Here are the detailed notes from Marc.
PS: I was doing a 32V engine.
Use 45degrees if you feel better about it just mark the cam gear to the housing and transfer the mark to the new gear.

to put the cam belt back exactly whre it "was" is simple.


1 Mark belt and sprockets
2 remvoe distributor rotor
3 insert 5mm screws
4 measure distance between screw head and leading face of cam sprocket slot. This locks the sprocket to the spyder
5 Remove old sprocket
6 Mark new sprocket with "belt marks"
7 Install sprocket onto spyder and locate with 5mm screws to the distance measured above in step 4

do other side

Simple!

KEEP in mind, that no two cams are identical. By measuring S4 cams, the lobes to keyway are often off. I have found that by measuring 5 sets of cams, that the slot is off by approximately 3+ degrees against #1 lobe.

That si why we have plus or minus 8 degrees of sprocket adjustment.

Marc

Glen McCartney

Thanks everyone, where else can you get this kind of information!!! Makes owning the 928 a piece of cake, gotta love it.

AO

Glen- You obviously see the benefit. Why not pony up for a 2 year membership and keep the dream alive. You know you need to do it.

Edit: I just realized that all of your replies came from PAID members. C'mon and join the ranks.

Glen McCartney

I am a paid member, membership #030225-2780, EXP. 2/24/2006, don"t know why it doesn't show up as Rennmist member... Randy???

Glen McCartney

Make that Rennlist member, defintely not a Rennmist member...

H2

What about PorKen's new tool? Would that help?

Harvey

Glen McCartney

Harvey, yes it would, I just got it in today's mail too!!! Now, just waiting for parts to arrive.

AO

Glad to hear it... I'm sure Randy can help you out.