dougs968

Hi, gang. I've been moving kind of slow on the 968 for various reasons. Anyway, I've got #1 at TDC. The witness marks on the cam sprocket and cover are off by about 1 tooth in the clockwise direction. The marks on the balance shaft sprockets are off by 2 teeth in same direction. Before I used the travel indicator I rotated the crankshaft clockwise to get close to TDC. All the marks lined up nicely. Timing belt does not seem bad in any way. Balance shaft belt seems a little loose. I haven't checked it with the tension tool yet tho. I may be very lucky if it jumped a tooth. Otherwise someone else installed belts wrong. Also, cam chain black links do not line up with the witness marks on the cams but the spacing is 7 links apart. Pads are very dark in color. I've taken lots of pic's so some time I will post. Many thanks to Raj and Arash for the excellent DIY on this project. Doug.

Stephenwz968

The tension on the balance shaft belt is very loose - surprisingly so! I used the cam sprocket mark and the back of the cam housing notch, lined those up and put the flywheel lock in, this way I knew the crank wouldn't move and that I could always put the cam sprocket and line it up - I did lock the timing by using the 3 screws (after taking off the rotor) that way I didn't have to reset after taking it apart. I marked the cams with white out (and the chain, transferred the marks to the new chain) and that was my insurance that it was all lined up when I put it back together. Good luck, and let's see those pics!

dougs968

I was under the impression that since #1 was at TDC that the cam sprocket and the balance shaft sprockets' witness marks should all line up since the variocam is not activated. Maybe I misunderstood. I will review the manual and DIY again tonight. I'll try to get some pic's up tomorrow evening. Doug.

Stephenwz968

At TDC the cam sprocket is at the notch, and the balance shafts line up the notches at the back of the rollers with the marks on the belt covers.

Stephenwz968

Check out this awesome video series (there are 3 videos) that rennlist member Van did, they are very well done and will show you exactly what you're looking for:

http://www.youtube.com/watch?v=nqc0m...os=3h1ZWvRU9N4

RajDatta

As long as you are 7 links apart between the cam notches, you are ok. The blk links are just there for reference, when you put a new chain on.
Raj

dougs968

Finally, here's some pictures of what I was typing about. Sorry it took so long. This has been one hell of a last week. Thanks Stephen for the video link. As you will see mine is off a little from what it probably should be. These photos were taken at exactly TDC as per the service manual. The middle line of the three on the flywheel is as close to the center of the hole as I can eyeball. It also coincides with my travel indicator. As you see the cam gear is one tooth off, the upper balance shaft sprocket is off two teeth and the lower balance shaft sprocket is almost right on except for the previous white mark. Any questions or comments? What do you guys think? Thanks, Doug.

RajDatta

You are 100% correct. You are off everywhere. It is typical for the timing belt to turn a little once the tensioner is let go, but this one is definitely off by a tooth.
This engine couldn't have been too happy to rev. Good thing you checked everything.
Raj

dougs968

Thanks for the input Raj. It seems to me that retiming is in order also. I was glad to see that the cam lobes look excellent and there was no crud built up or settled anywhere. Just normal varnish. My cam shaft sprockets look serviceable but a little worn. If you were me, would you run them or replace them at this point? Doug.

RajDatta

Redoing the tensioner pads will only add a couple more hrs to the job. I would suggest you do them and have peace of mind. You need to lock flywheel to do all your belts anyway, why not take the extra 2-3 hrs and get done with the tensioner pads/chain as well.
We are here to help so don't feel like you will be on your own. Do you know Scott Harrison? He is a well known waterpumper from your area.
Raj

dougs968

Sorry, I guess I failed to mention that I have new pads and chain that I purchased from Zims a while back and the flywheel lock. I will definitely be replacing those. I have seen plenty discussed here warning of the consequences of not replacing these. What I meant was do my cam sprockets look OK. They look a little worn but no missing or damaged teeth. Should I replace my cams or have new sprockets installed at this point? I seem to remember reading somewhere that the heat treatment or the cam material on some of the early cam shafts were a little soft. If they look good to you guys I'll go with that. No biggie to take the valve cover off and check ever so often. Doug.

dougs968

I don't know Scott. Is he local like OKC area local? Doug.

RajDatta

Doug, check your PM. Scott Harrison is a very well known guy from KC and is an active member of KCWS. They have some great wrenches in that community.
Raj

Barike

How is progress going? First post for me and I'm VERY interested in the 968's. Your quite local to where I am which is one of my main reasons for inquiring as to progress. Thanks!

dougs968

Progress is glacial. I have changed the vario-cam pads, chain, camshaft hardware, crankshaft gear,( one of the teeth had a small chip) water pump, four water pump studs, ( they had corrosion) tensioner, timing belt, balance shafts belt, thermostat and spacers, heater valve, and probably some other stuff that I can't remember at the moment.

I have also made some 968 specific tools such as the camshaft tools my daughter is modeling.

Where I am at now in the project is ready to set the timing. Since the timing and balance shafts were out I have set up dial indicators in #1 spark plug hole and one of the intake camshaft lifters per the factory service manual. I purchased the special tool ( really just a bent tube attached to a flange) so that I can pressurize the vario-cam to 45 psi or 3 bar. I am really pretty close to being done with the engine.

I can't believe I've been working on this for over a year now. My apologies to the 968ers. I've had a pretty full plate this last year.

Any other questions, fire away.

Doug