Timing gauge prob: having a repeatable but WAY off number, and weird behavior

[ldeikis]

Having a timing issue on the rabbit (I've never done this before).  1.6 N/A

All the prerequisites are done:  TDC mark on the flywheel lines up perfectly with the locked cam (#1 lobes up/valves closed), pin slips right into its hole on the pump.  I remove the pin and lock, thread the adaptor into the pump and insert dial gauge, giving some preload, and snug up the collar.  Then I rotate the engine COUNTER clockwise (as if I'm trying to loosen the crank bolt) until the gauge stops reading [weird behavior part:  #1 The gauge doesn't begin moving immediately, I get probably 5 or 10 degrees of crank rotation before it moves, but then it moves evenly and smoothly.  The needle on the dial indicator goes around twice and change, then stops moving... #2 but if I overshoot by more than a couple degrees of crank rotation, the dial indicator begins to reverse...  ie, there is very little flat spot there).  Zero the gauge.  Rotate CLOCKWISE until TDC again  [#3 again, it moves smoothly until a good bit before TDC, then it stop moving and remains where it stopped, up to TDC].  This measurement is consistently 2.17mm.  I've nailed it over and over and over and over.

I bought myself a cheapy chinese gauge from H&H that reads metric and has a 10mm range, it has a big hand that counts up to 1mm, and a little face that keeps track of rotations.  It's going around twice, then ending at 17.  I'm reading this as 2.17, no?  I'm also recording that much going in--ie, if I preload the gauge to 3.00 before I begin counterclocking, I'm around .83 when it stops changing).  I also tried this with a gauge from my girlfriend's father which is much nicer and got the same reading (his only goes up to .5mm on each go-round, so it goes around 4 times then reads 17.)  I pulled the vacuum pump to give myself some room and I haven't reinstalled the injection lines yet, so there's definitely nothing exerting pressure on the gauge.  I've also tried inserting the gauge loosely in the adaptor and then threading the adapter in.  No change.

What in the world am I doing wrong?

Backstory:  Just redid the head gasket and pass motor mount, which required me to unbolt the pump... so I had the sprocket off.  I just did the timing belt 1000 miles ago so I didn't replace it this time.  No major hiccups along the way, belt went on reasonably easily, adjusted cam a tiny bit to match TDC.  Pump sprocket has its woodruff key in place, little timing notch on the pump mount lines up.  Engine turns over happily with the wrench.  When I did the timing belt in December I just locked everything and slipped the old one off and the new on because I didn't have the adaptor thing to thread into the pump.  It ran fine before and after that.

Q:  I wasn't careful to not rotate the pump in the removal/installation process (the sprocket was stubborn and required a puller, which meant I had to remove the locking pin to get the puller arms on).  Is it possible that the pump is 360* out of wack--the way the flywheel reads TDC twice for every one rotation of the cam?  I've never been inside the pump, but from my understanding this ISN'T possible--one rotation of the sprocket = 1 rotation of the pump piston = all 4 cylinders have been injected...  so if the woodruff key is indexing the sprocket to the pump and the locking pin fits, the pumps is correctly installed in the ballpark.

I feel like the fact that the gauge doesn't move in the territory immediately shy of TDC means I've got something way off...  but I can't figure out what.  The car ran fine, if a little slow (hey, it's a N/A diesel), for the last 50k miles I've owned it.

Thanks.

Luke

edit:  Maarten had a similar problem in this thread:
http://www.vwdiesel.net/forum/index.php?topic=10466.0

...but there's no clear resolution.

[gldgti]

OK.

I think you are decribing that you are measuring basically the entire cam-plate stroke? If the guage isnt moving much/at all at the start of roatation (remember 5* crank is only 2.5* pump) then it must be riding the top of the cam "lobe" (i use this term loosely for this application).

either way, i suppose its possible that if the pump really is timed to 2.17mm, it might run - if there are enough other factors (pump wear or injector wear) to get away with it. I've seen 1.6's run with timing so advanced  that they wouldnt start with the cold start lever pulled, since the piston was triing to go back down!

just go over the timing procedure properly, adjust it to 1.05mm like most people suggest and see what happens i suppose :-)

[ldeikis]

Would the car even RUN at 2+mm of advance?!

I wish I'd been able to measure it before it came apart.  I know removing the pump and then lining it back up to your scribe mark doesn't guarantee I've got the same timing as before...  but it *definitely* needed the cold start handle out to start when I began.  In even mild temps, if you didn't have that lever out, you weren't starting.

If it's *really* at 2.17, then I'll likely need to skip a tooth to get in the ballpark...  which means I won't be able to get the pin in, right?  It's a pretty snug fit (deep well 1/2" drive 10mm socket that's .600" on the money OD).

Thanks.

Luke

[8v-of-fury]

This is a weird one! i want to play

ok.. so you run in to problems starting with when your trying to zero out the gauge... Insert dial gauge, and rotate engine counter clockwise RIGHT until it stops moving. Going any further and zeroing the gauge will give you a false reading. When the gauge stops reading it has hit the flat spot of the pump camplate (or the high spot of the camplate, i cannot remember).. and this is where you need to Zero. If it stops and you keep going, rotate clockwise slowly unitl it moves a little then go back half that to where it stop exactly again. Zero the gauge, and rotate the engine to TDC. Loosen the 4 pump bolts 13mm, 3 front and one on the lower back of the pump. Either push or pull away from the engine to get the desired reading... of around 1.00mm for an N/a pump.

The Bentley service manuals list the following "official"  settings:

Early Chassis:  (1977-1983)

1.5l non-turbo 1977-1980                                        0.88 +/- 0.05 mm

1.5l non-turbo 1980 with yellow dot                         1.15 +/- 0.05 mm

1.6l non-turbo  1981, 1982, and 1983 pickup            0.88 +/- 0.05 mm

1.6l non-turbo  1983 Rabbit and Jetta                        0.95 +/- 0.05 mm
1.6l non-turbo  1983 Vanagon                                  0.90 +/- 0.05 mm

1.6l tubo diesel (1982-1983)                                       1.00 +/- 0.05 mm

 

MK2 / A2 chassis:  (1985-1992):

Engine ME (1.6l non-turbo) 1985                             0.95 +/- 0.02 mm

Engine ME (1.6l non-turbo) 1986 and up                 0.90 +/- 0.02 mm

Engine MF (1.6l turbo)                                           1.00 +/- 0.02 mm

Engine 1V  (ECO diesel)                                         1.00 +/- 0.02 mm


MK3 / A3 chassis (1993-1997):
Engine AAZ  (1.9l turbo)                                        0.80  +/- 0.02 mm


 

Many performance tuners use the following:

-         non-turbo pumps:  0.95mm to 1.00 mm  (0.037" - 0.039")

-         turbo pumps:         1.00mm to 1.05mm (0.039" - 0.041")

http://vincewaldon.com/index.php?option=com_content&task=view&id=24&Itemid=28

This link may help you a TON!!!

[lovinthedeez]

make sure that your dial indicator is nice and tight on the adapter, and not being pushed against the vacuum pump.  I know with mine that if it isn't tightened enough, when I go to zero it, the needle will move.  and as far as the actual timing;  just put it to tdc for the crank.  go ccw (the needle should start going backwards right from the start if your belt is on right).  when it stops moving (and you can go a little over just to make sure) go back clockwise to tdc, and check your measurement.  I wouldn't think it would even run at 2mm.  Timing has a pretty steep learning curve that flattens out real quick.  I must have timed my car 32 times (the first time i did it ).  but with a little practice, you'll be able to do it in a half hour from start to finish.

 good luck

[ldeikis]

I think you are decribing that you are measuring basically the entire cam-plate stroke?

Can anyone confirm the total stroke of the pump piston?  I guess I'm wondering, Is it possible to actually measure 2+mm of pump piston travel?  I think it is, but I've never been in there.

When the crank is at TDC, the pin slips right through the hole in the pump into the hole in the timing bracket?

Yes, it slips easily into the hole in the injection pump BRACKET, not just into the sprocket   It's not an interference fit, but it's pretty snug.

make sure that your dial indicator is nice and tight on the adapter, and not being pushed against the vacuum pump. 

The vacuum pump and hard lines are removed.  There's definitely nothing at all hitting the gauge.  And the gauge is well into the throat of the adapter, and the collar on the adapter is snug around the neck of the gauge...  which has no play in it that I can feel, and looks visually straight.

I've also read Vince's excellent page tits-to-tail a dozen times, and have it printed out outside with the car.  I've also searched high and low here and on Jack's page, though most of what you find searching timing issues is poor running etc, or people who haven't read their manual etc.  I can recite blind what I'm supposed to do, it's just not working the way it's supposed to.   When I started, the pump was rotated all the way--or darn near--full retarded.  I scribed a clear line to help me realign the thing, and the mark on the bracket from the pump itself is clear as day anyway.  And of course the pin fit.

I'm going to go out and slip the belt off the pulley and try to retard a full notch...  If I can get the gauge to read accurately and it turns over happily, I might forget the pin issue... but it went in before, and ran fine, so I still feel like something's WAY off. 

BTW, what's the range of adjustment on the pump?  Ie, how  many mm's change is there from full advance to full retard on the bracket?

Thanks...

[lord_verminaard]

Sounds to me like the bottom-end is off a little bit.  I know you verified the TDC mark on the flywheel, but if the flywheel is not the original one, it could have several different marks on it.  I made this mistake by improperly marking the flywheel (gasser flywheel on a diesel engine) and therefore I could not get a "normal" reading when doing the timing- the reading was WAY off.

I also noticed after about the 4th time re-doing the timing, that even if the car is on the ground and the tranny is in gear, the crank can still move a bit.  This happened to me twice when I was in the final stages of tensioning the belt, I watched the alt. pulley spin just a little bit, and knew that I had to take it off and start over.

I re-found TDC by finally removing the #1 injector, inserting a plastic wire tie down in there, and visually checking the movement until I was satisfied that it was at TDC.  I then painted a new mark on the flywheel through the inspection hole, and it was about 3-4 mm away from the original mark I had made.  That is next to nothing in actual crank rotation, (actually very hard to move the crank a small amount like that without overshooting) but I think it is close enough now.  I re-timed the engine to 1.05, and it still acted like it wanted a little more advance so I bumped it up a little more.  I guess that shows that it's still not quite there but it should be close enough, and the car is running pretty well now.

I learned my lesson though, that I should have just marked the damn thing when I was putting the engine together.

Brendan

[ldeikis]

For future reference, in order to be sure to return a pump to the timing it was prior to removal you need to scribe TWO relationships.  You need to scribe BOTH the pump body to bracket AND the pump sprocket to bracket at TDC to make sure you return the sprocket to the correct tooth of the timing belt at TDC.

I did, actually, scribe both the pump body to bracket and use a paint pen to make a mark on the bracket body and one tooth of the injection pump sprocket.

Are you SURE that the woodruff key didn't fall out as you were installing the sprocket? 

While you guys were typing I was out wrenching.  Verified my 2.17 again, then moved the belt one tooth this way and one tooth that way.  I got vaguely in the ballpark by going one direction (max advance I could achieve was .71 though) so I went back to the start point again.  Got 2.17 again. 

Then, I, too, wondered about the woodruff key again, so I popped the sprocket again (I'm getting to be pro at slipping that belt on and off).  Woodruff key IS there...  but somehow almost 90 degrees off.  I have no idea how I managed to do that, but I did...  oh-so-careful to make sure it stays in  its slot, then somehow didn't index the sprocket notch to the key... And torqued the sprocket on, no less, scarring the inside of it and squishing the woodruff key to smithereens.   I don't think the sprocket shaft is damaged enough to matter, but I don't think I can trust that key again.  I'm going back out to try and pry it out of the shaft and maybe I can grind a new one out of something.  Stuck at the house until 10pm when my girlfriend gets off work and I'd REALLY like to have this put back together.     I suppose it is at least progress on why my gauge readings are so jacked.

Luke

[lord_verminaard]

Holy crap, that's a new one!     I didn't figure the sprocket could physically get back on there if the key was not in place.

They sell woodruff keys at Advance Auto in the "help" section, other parts stores have a similar section, hopefully they have one the correct size.  Would be a hell of a lot easier than trying to grind one.

Good luck!

Brendan

[ldeikis]

Holy crap, that's a new one!     I didn't figure the sprocket could physically get back on there if the key was not in place.

Yea, you and me both.  The old one wasn't real interested in coming out, but in the process of trying to encourage him I sort of pushed up his squished shoulders into a more normal square profile.  I'd rather replace it, but this will do for now.  Very carefully put on the pulley again, even going so far as to use a mirror-on-a-stick to look in the hole and confirm it's lined up.  Tightened her down, timed the car like cake (was at .83, set it up to .95) buttoned it all back up and realized the battery's dead from leaving the door open and therefore the dome light on for days on end.  I can smell success, though.

Luke

[gldgti]

WOW! Great to hear you found it.

Come to think of it, there isnt much of that key that sticks out of the shaft once its in there, so i guess thats one to be careful of.

This thread makes me happy - you came on with a problem, someone pointed out an option and you solve your problem. Just the way this forum is intended :-)

[ldeikis]

Thanks for the reassurance, Libby.  That was kind of my thought--also, since I can awkwardly turn the pump by hand (with the sprocket), it doesn't seem like it's fighting a huge amount of resistance...  and, unlike the cam or crank, if it DOES slip I'm just stuck, not destroyed.

The timing went easy peasy after that, and the car started right up.  Amazing how quiet it is with the new motor mount--I had no idea.  I'm still flushing water through it trying to get the last of the gunk out from the head gasket failure, but it seems happy enough.

Thanks everyone.

Luke