Work was completed using the "3 tooth" method. For the record I'll document what actually worked here in hope it will benefit others.

The measurement between teeth should be taken "valley to valley", meaning there should be three teeth on the cam between the TDC mark on the cam backplate and the V cut into the cam, which is also in a valley. The V on the cam should be three teeth behind the TDC mark on the cam backplate, in the counterclockwise (left) direction on both cams. Do not place the cam gear mark 3 teeth ahead (clockwise) from the TDC mark on the cam cover plate This will result in a locked crankshaft, forcing you to use highly experimental and dangerous methods to re-synchronize the crank/cam.

In my example, I met resistance while turning the crank to TDC at -10 degrees. I chose to rotate the cams counterclockwise to free the crank. A better solution, suggested earlier may have been to attempt to rotate the crank counterclockwise after removing the spark plugs and crank lock. I did not attempt this maneuver as suggested by Mr. Kibort, however I have no reason to believe it would not work if the crank bolt were torqued to specification, the plugs removed to eliminate compression resistance, and the crank lock removed prior to the attempt. It might work.

The take home message is you must place the cam marks three teeth counterclockwise with the crank locked at -45 degrees TDC for this method to work, and if you do, it makes this job much easier.

My engine apparently suffered no damage (other than a few very loud and very unprintable words that scared my dog). This method, if performed correctly, is far superior to the method loosely described in the WSM, I highly recommend it.

Many thanks to MrMerlin (Stan I believe?) and Dad. My hat is off, my car is running beautifully and I just had a very satisfying road test of the results against a stealth Honda Civic driven by someone who obviously knew what he was doing on the most challenging stretch of CA State Hwy 9 I know of. It was a moment. It was good. No red lights on the board. The car is ready.

Thanks to all who helped.

 

Scott, you say a few things that confuse me (which isn't too tough these days it seems...). The crank is set at 45º --before-- #1 TDC and locked there for all initial cam adjustments. So it's counterclockwise 45º from TDC. At that point, the cam gears index 22.5º counterclockwise from the TDC index mark (the notch) on the back of the cam gear. That's half of 45º due to the ratio of gear sizes, still in the same direction (before the TDC mark) as the crank is relative to its TDC mark. With the crank in that spot, the correct indexing mark for each cam gear is to the right (looking from the front top), so that each cam gear will hit its own TDC mark at the same time the crank gets to TDC #1.

You also scare me a bit when you talk about setting tension at the 45º before TDC marks, and 'declaring victory' at that point before actually moving the crank up to TDC. The tension on the various sections of the belt changes as the forces on the cams change at different points in their rotations. For those following along, you should put enough tension on the belt to keep it from slipping/jumping as you move the crank from -45º to TDC #1. Then make your initial tension adjustment with the tool at TDC #1. Rotate the engine through several (even number) of crankshaft rotations and check again. Repeat until no adjustments are needed through three rotate-twice-and-check cycles.

 

Honestly, now I'm more confused...reading along because I'll be doing this this summer, probably. To me it reads like the last two posts say the opposite, yet that can't be or Scott's car wouldn't be running correctly...

 

My terminology (use of + & -) may be incorrect. For clarity, what I did was set the crank shaft to the 45 mark on the harmonic balancer, which is to the right (in a clockwise direction) of the #1 TDC mark. I used the notation "-45" to describe that point, I believe it's also referred to as "45 degrees before Top Dead Center". I then locked the crankshaft in that position using a flywheel lock.

Looking at the harmonic balancer from the front of the car, the mark on the crankshaft lined up with the red plastic pointer on the water pump is clockwise (to the right of) the #1 0TDC mark.

This has me confused. I'm not sure what the precise angle of the cam gears is (22.5 doesn't feel right somehow). The index mark on the cam gear is exactly 3 teeth to the left of (counterclockwise from) the index mark on the backing plate for the cam. I don't think it's 22.5 degrees just from looking at it, though I suppose it could be. I didn't take a protractor to it, I just counted the teeth, measuring the number of full teeth between two valleys in the gear, with the valley containing the index mark to the left (counterclockwise) from the valley directly underneath the index mark on the cam backing plate.

That would be what you might expect if you were looking at the pictures Stan posted earlier in this thread, however that is incorrect. It's what I did the first time and what got me in so much trouble.

The indexing mark for reach cam gear is to the left (not right looking from the top) of the cam TDC mark on the backing plate. If positioned to the right ("advanced" is the correct term I believe), the crankshaft will lock at the 10 degree mark when you attempt to rotate the crankshaft to #1 TDC after installing the belt. After that, you'll likely discover all of those unprintable words I used that ended up scaring my dog.

If I wrote that it was an error. What I did was position the cams as described, install the belt, then rotate the crank two full revolutions to #1 TDC, then tension the belt.

In truth, the belt was so tight after installing it at 45 degrees before TDC I had quite a bit of trouble getting the idler pulley in and when I did there was enough tension on the belt to close the tension sensor circuit (I checked it). I had to turn the crank through two revolutions before there was any slack at the tensioner.

Before you jump to the conclusion I had not worked deliberately to move all slack to the tensioner prior to re-installing the idler, let me assure you I had. There was no slack to speak of anywhere else, and I tried very had to find any I could and move it since it was a true bear getting the idler back in. This may just be a natural feature of the engine in the 45 degree crank position, I don't know.

This may well explain why I had an unusually difficult time installing the idler at 45.

Yes, this is the procedure I used.

 

I think to some extent they do say the opposite. Take a look at my last post and let me know if it clears everything up or not. I'll try to explain anything that's still confusing.

I truly regret not having taken pictures but my camera batteries are dead.

 

After carefully studying Stan's pics, your descriptions and Dr. Bob's descriptions, and visiting a couple other threads that had pics, I think I have it clear. I suspect there are some terms in use that are not consistently defined across posters.

When the crank is at 45 degrees BTDC, the TDC mark on the cam gears will be to the left (standing in front looking at it) of the indexing mark behind the cam gear by about 3 teeth. When you then rotate the crank clockwise to 0 TDC, the cam gears will also rotate clockwise and the cast-in mark on the cam gear will then match the corresponding indexing mark behind it. I think Stan's picture showed this, but the pic of the cam gear was in the TDC position, with the other line of the angle showing the spot that would be lined up were it in the 45 BTDC position, not the other way around. "Before" really means to the right, because as the gears turn clockwise, the 45 BTDC spot hits the indexing mark before the 0 TDC mark.

Ugh. This makes sense in my head now, until someone posts that it's wrong, then I will immediately sell my car and buy a Prius. No not really. Hopefully this is correct and not even more confusing....

 

Jeff you're one of the few people I've talked with who've installed the new tensioner, how does it manage the tension sensor? I chose to rebuild my old tensioner because I had the idea I was keeping this car as close to stock as possible. I'd planned to install the PorKen tensioner on my track car, which I've been cannibalizing for parts during the restoration of my street car. Since then I've abandoned the 928 track car idea and I'm just putting the parts car in boxes, but I'd still like to know how the PorKen unit works.

 

As far as I can tell, you've got it as clear as I have now. I wish I'd had a better understanding of the picture, I'd have saved a day or so and my stomach would be in much better shape...

 

I actually still have the stock tensioner, but I'm giving serious consideration to using the Porken unit along with an Engine Guardian water pump when I do the job.

The Porken tensioner (reportedly) does a better job of managing belt tension, but has no meaningful way of using that sensor, so it just grounds it. One of the knocks against going that route has been that if the water pump seizes, there can be some warning between temp and the tension sensor, but you lose that in this case....which is why I like the Porken/Engine Guardian combo. I don't know of too many folks using that water pump, but the few I do know seem to like it.

 

I haven't heard of the Engine Guardian pump. I installed a Laso pump last time, it has a plastic impeller rather than steel, the idea is that if the bearings fail and the impeller "walks" into the engine block, the teeth won't be able to bite into the aluminum, ruining the block and seizing the pump. I'll have to look up the pump you mention for next time

 

I'm a sucker for community-sourced innovations. For your reading pleasure: http://perfexmfg.com/

I know it was discussed on here at one point well before my time, and then that all stopped, but it's still being made and several people have mentioned that they have one. I believe there were some teething problems early on, but from an email discussion with the pump's creator, they've had good success. I don't know if there was some drama that occurred on the list over it or not, but certainly the idea is fantastic, and helps solve one of the major issues that 928 owners fear.

 

Thanks Jeff, I wish I'd known about this last summer before replacing my pump. It sounds like an excellent idea and the developer is right about us 928 owners living in fear of our water pumps, at least I do. It's bookmarked. Next time I have to take that belt off I'll seriously consider this pump. Now I wish I hadn't tossed my old pump, I expect these folks could have re-built it for me.

 

I have just installed my new Laso WP, PKT tensioner system and the new timing belt. I installed everything with the engine locked at 45 BTDC. I also rotated the engine about 6 times by hand since removing the flywheel lock. This is what my cam pulleys look like at TDC. Does this look correct? Looking forward to getting everything else re-installed and here it run again. This forum has been great for the DIYSers.

 

Here are a few more pictures after I got parts on last night. Special thanks to Ken and Roger for their help, instructions and that PKT, it looks so simple and less complicated than the stock tensioner.

 

Looks perfect to me, but your cam gears are marked differently from mine, have you replaced them? My gears are marked with notch in the valley of the tooth on the back side of the gear; the side nearest the block.