Formula94lt1

Umm is there a 20 deg atdc slot to accurately setup the 32v'r? I feel I am missing something. Also I didn't know you could rotate the crank whithout rotating the cam... very very confused.

PorKen

For retarding, or counter-clockwise adjustment,there is too much valve spring pressure to use the cam bolt to rotate the cam.

Remove 32V’r.

Counter hold cam bolt washer, loosen and remove cam bolt. Reinstall cam bolt without spacer. Counter hold cam bolt washer, tighten cam bolt to specification using torque wrench.

Rotate crankshaft CW using the crank bolt until 20° advance (CW of TDC).

Counter hold cam bolt washer, loosen and remove cam bolt. Reinstall cam bolt with spacer. Counter hold cam bolt washer, tighten cam bolt to specification using torque wrench.

Replace 32V’r, and slide needle into the hole that corresponds to the amount of retard desired.

Rotate crank clockwise using the crank bolt until the needle is centered in the V.

Loosen the clamp ring bolts, and while holding the cam bolt with a wrench, rotate the engine clockwise to #1 TDC.



While continuing to hold cam bolt with wrench, tighten clamp ring bolts. Remove 32V’r.

Counter hold cam bolt washer, loosen and remove cam bolt. Reinstall cam bolt without spacer. Counter hold cam bolt washer, tighten cam bolt to specification using torque wrench.

Using crank bolt, rotate crankshaft CW again to #1 TDC. Use indicator to recheck cam position. For best results, remove EZK relay, and spin engine using the starter, to equalize tension on the belt.

Ed Scherer

Formula94lt1, did you ever get your timing sorted out?

I'm about to set my cam timing (probably this evening) also with a new Gates belt and PKsn'r.

Did you get any recommendations on what to initially set the timing to with the new Gates belt / PKsn'r combination (and new cam gears, if that matters)? Mine is now at 1° advanced (left side, i.e., DSU) and 2° advanced (right side, i.e., PSU); it might not even be worth setting until the belt is broken in. I'd like to have the initial settings such that it's likely to settle down to close to 0° / 0° under engine hot and belt broken in conditions.

I've PMed Ken (awaiting reply) and searched the archives and manuals, but I'm not sure that any of the recommendations I've seen cover the Gates belt / PKsn'r combination.

Ed Scherer

Well, I thought about this some more and I believe that the 1° advanced (left side, i.e., DSU) and 2° advanced (right side, i.e., PSU) is best left alone for now. According to a post from PorKen a few months ago:
So a little bit of that stretch will serve to retard the left side ever so slightly, so I think I stand a pretty good chance of being close to 0° (or at least within 1°) on both cams after the belt stretch. I can check it again in a thousand miles or so, anyway.

I assume that with the PKsn'r, the "hot engine / cold engine" issue is moot, i.e., that the tensioner maintains tension regardless and so the engine temperature is no longer part of the equation: the belt stretches, the tensioner takes up the slack (regardless of temperature), and the cams are thus retarded a bit (the right side more than the left side). Is that right, Ken? So you would not need to "add ~2° retard to the 1-4 side when cold..." if you've got a PKsn'r?

Didn't mean to hijack your thread, Formula94lt1. I'd still like to know what happened with your situation.

mark kibort

the belt tension wont change or effect anything in this static test. all the pressure on the cams is from the other direction, steming from the crank.

76FJ55

Ed,
I believe the timing change is derived from the expansion of the engine more so than the what the tensioner is doing. the original tensioner was designed to slightly retract with increasing temperature to keep from over tensioning the belt as the engine expanded as it heated up (increased belt run length). this still occurs even with the PKsn'r, therefore you still need to take into account the timing change at opperating temp.

blown 87

If you do not think that belt tension will change cam timing during a static test, you need to time more of them with a dial indicator, cause it will just as sure as the sun comes up.

PorKen

With a new belt, if the cams are within a degree or two of 0, I usually leave it until the belt is conditioned.

You still have to compensate for engine expansion when warm for some reason. You can see the difference if you set the cams cold, then recheck them hot (ouch!).


'Tensioner' is a misnomer. It's a belt length manager. Ideally, it only applies enough tension to the keep the belt taught between the 1-4 gear, and the crank gear.

When the engine is running at a constant speed, tension between the crank gear, oil pump gear, 5-8 gear, water pump pulley, and 1-4 gear reaches an equilibrium which is independent of the 'belt manager' (unless the belt is statically overtensioned). Tension varies between each gear depending on the inertia of the next gear. Belt tension increases when the engine is accelerated, elongating the belt up to the limit of it's elasticity.

The stock (de)tensioner system is a poor belt manager. It cannot extend to take up more belt, so you see loose flapping at high rpm, and low tension when the engine is dead cold. Stock belt tension is set higher than optimum to prestretch the belt in an attempt to try and reduce this flapping, and keep the belt from being too loose when the engine is cold/smaller. (It is still loose when the engine is cold, requiring a 3-minute tension warning delay!)

GregBBRD

A Porkensioner leaves the belt loose. The number is actually under 3.7, which is where the light normally comes on. If there was a warning light left over with this system, the light would be on all the time. As the engine is turned by hand, the Audi tensioner piece moves in and out...watch it, as you turn the engine. This is what causes the variation in cam timing.

blown 87

I forgot he was not using the stock tensioner.

PorKen

The belt doesn't need to be overtight to work properly. See post #23.

The Audi tensioner/damper piston moves in and out because there is more or less belt length, depending on the valve action at a particular angle of the engine, stretching the belt more or less.

If you follow the directions in the 32V'r manual, there is no variation either with a PKsn'r or the stock tensioner, if measured at the same point, EG. 0|T #1. Most important is equalizing the belt tension by turning the engine with the starter after the belt is installed, and after a cam adjustment.

GregBBRD

This is French for:

"Although it appears that the cam timing flutuates because the belt is too loose, once you put the covers on and run the car, you won't be aware of the problem. Of course, you will also have no stinking idea of where the cam timing actually is...once it is running."

I've never been able to get beyond the belt being loose and not being able to set the cam timing accurately, on the engine stand. Taking this all back apart and reseting everything after the belt and tensioner settle in is a step I just can't do/understand. Plus that...no matter what you do, the tensioner only holds the belt at 3.7 "belt units" when the engine is sitting there....the piston simply can't push any harder. However, according to the people in the "know" about this system, something magical occurs when the engine is running and the belt mysteriously gets tighter by some unknown superforce. Trying to figure out where the cam timing is, when this occurs, makes my head hurt way too much.

PorKen

You don't need to install the covers to spin the engine over with the starter. Just clear the belt, and unplug the EZF/K.

Turning the engine by hand does not replicate a running engine.



Many things appear as magic to the uninformed.

GregBBRD

I only seem to be uninformed about this one thing....seems like I pretty much understand everything else....got a pretty good handle on things that are mechanical.

BTW....Cranking a 32 valve engine with the starter motor will not bleed the lifters...unless you have couple of days, a bunch of batteries, and a few starter motors. Lifters take as long as 10 minutes to fill and completely bleed on new engines.

Here's the bottom line, as far as I'm concerned:

If Porsche was still making this engine and they changed their belt tensioner design to the Porkensioner design, they would go back to the manufacturer of the actual tensioner piston piece and ask for one that exerted more pressure than the Audi unit, so that the belt was properly tightened. Picking a "pressure unit" off a shelf, changing the geometry and the location of the fulcrum from the original Audi design was great for the "design" stage of the Porkensioner, but left the belt too loose in the real world.

Roger seems to be able to get things done...why don't you see if he can go to the manufacturer and see if they can make some units that do this. Once this happens, the rest of your design seems plenty robust and adequate.

PorKen

Cranking the engine pumps up the lifters just fine on an engine which has been run recently. More importantly, the belt will settle on the gears properly, and the belt will have a better overall tension.

The Audi components are unchanged in their position to each other.

Where do you see it being too loose? It keeps the belt on the crank gear when cranking, cold, hot, to 6700 rpm, acceleration, deceleration, etc. All without the band-aid anti-flap (water pump), and keep-the-belt-on-the crank-gear-during-cold-start (crank) pulley(s).


Too loose is when you see the belt flapping at high rpm, or the belt skips teeth on startup, as happens with the stock (de)tensioner system.