IP lock tool slop

[tylernt]

Mainly I'm sick of doing the same job 12 times, though of course I have no one to blame but myself.

So, I made my TDC mark by lining up the flats on the crank throws exactly parallel to the flats on the bottom of the #2 and #3 conrods at the bottom of their stroke (cyl #1 at TDC). If these surfaces are accurate indicators (???) then I may already be as close as I can get with the wire-poke method? I would think so, since I replaced the clutch and the belt, and the car was fine until I melted the belt. Then I replaced the belt again and I got into trouble.

[Vincent Waldon]

Hmmmmm... it *is* strange if you were able to set the timing once using your paint-on-the-flywheel mark.

I can't comment on your method of finding TDC... I suppose it all depends on how accurately you were able to measure the flats being perfectly aligned... again... we're talking thousands of an inch...

Tell us about what happened to cause your timing belt to "melt" after you set the timing the first time.. in particular, was your engine running at the time ?

[tylernt]

The belt melted because I have a 1.5L alternator bracket installed on a 1.6L engine. The front timing belt cover bolt is therefore missing and this allowed the cover to sag and the belt rubbed against it. I noticed it when my tensioner started to make funny noises. The teeth on the belt were 100% fine, so I didn't jump time, but the back of the belt was worn away and bits of rubber were vulcanized onto the tensioner.

I run without an upper timing cover, now.

[3Bunnys]

OK-time for Math 101
Pi- 3.141
D- diameter for rabbit flywheel we'll estimate 12"
degrees in a circle - 360
PixD=circumference
3.141x12"/360=0.10"

If your crank TDC is off by 1/10" (0.10") your timing is off by a 1 degree. For a diesel that's a lot.

My experience is that 1 degree (1/10") of flywheel movement will result in a lot of movement in that dial indicator you screwed into the end of your IP.
If you can't nail down crank TDC within the proverbial red hair you are going to expend a lot of time and energy messing around trying to get that timing "Dead On" right. If its right, it starts good and runs good, get a little off and you have a sick bunny.

BTW.. as I recentlly found out when a rebuild shop put my IP back together 180 degrees out of time (yes that is possible) a bunny will start and run and even produce enough power to drive (but you might not get to 35mph) with the timing off by 180 degrees. Also a lot of valve rattle and smoke!!

Close is not good enough for injection timing, you gotta be precise.

[Vincent Waldon]

My hunch continues to be that you got lucky with the timing the first time and now have enough out of whack between the valve train, pump, and crank that it's causing issues.


Four more thoughts about finding TDC:

1) theres a thread at http://www.vwdiesel.net/phpBB/viewtopic ... 480e685863

where basically you pull the valve cover, get close to TDC, and then using a spacer lower the #1 intake valve. Gently bump the piston up against the valve in both directions, marking the flywheel as you go. TDC is exactly in the middle of the two lines.

Probably more accurate than sticking a flexible wire down... just don't ram the valve hard !

2) (a vendor other than Jack) sells a whistle for gassers which goes in the spark plug hole and stops whistling at TDC...might fit in the injector hole, but you might be able to rig up something similar on your own... perhaps drill out an old glow plug and add a whistle?? Not sure how accurate it would be ??

3) drill out a glow plug, attach a length of thin clear tubing and a funnel, and screw it into #1. Get close to TDC and then use the funnel and tubing to fill the cylinder with diesel, ATF, or oil. Continue to advance the piston... the fluid will rise in the tubing, stop, and then reverse. TDC is where the fluid stops rising. Should be very accurate if you use thin tubing. (just thought of that one myself (c)2007 Vince Waldon.... your smilage may vary !! )

4) In fact, it would be messy, but you could just pull the #1 glow plug, fill the cylinder with oil, and then carefully advance the piston until oil just stops being ejected.

With (3) and (4) you'd need to figure a way to get most of the fluid out of the cylinder when you're done... otherwise you run the risk of a hydrolock... could suck it out with a brake bleeder for instance.

And, I'm spent.

Vince

[libbybapa]

The issues with the whistle and fluid in cyl is that for a significant amount of travel of crank the piston is virtually not moving. If you want a more accurate assessment of TDC then having the piston touch something near the middle of it's stroke in both directions and finding the midpoint would be far more accurate due to the fact that the piston is moving a whole lot further per degree of crank and so the margin for error is greatly diminished.

Andrew

[Vincent Waldon]

Yup I'd agree... having the piston bump up against a stop on its way up and down is probably the most accurate by far.... done safely I'd bet the intake valve method would be the best (snaking a wire thru the swirl chamber of an IDI strikes me as tricky to do accurately).

I suppose you could do the same thing by using the tubing and fluid to measure two spots where the fluid is at exactly the same level in the tube... TDC would be exactly in the middle.

[hagar]

Mainly I'm sick of doing the same job 12 times, though of course I have no one to blame but myself.

hagar sez ---- YES accept the blame -----no way can you blame hagar. -----so here is your answer for next time. -----I have been preaching " Hillbilly TUNING " for years. ( I have a 1982 1.6L NA Rabbit two door) Fraulein Bunny Klunk .

No pin needed No dial indicator needed -----" Billy " in this context is a misnomer.

I would clean CLEAN a spot at I P bolt top front. -- steal some nail polish from my girlfriend
. and apply. ---Then with ALL timing marks lined up --scribe with a needle a fine line.

If you need more help well look around it is all ALL on this Forum.

hagar.

PS : SICK ? ---no way this is fun --- and do not worry . Under TUNING injection can NOT be too far advanced , as to do damage to engine.

[hagar]

here is hagars version of making sure that timing TDC mark on flywheel is correct -------I NEVER TRUST PO I VERIFY.

A flat oil dipstick works perfect ----mine is an old GM V8 diesel stick.
With # 1 injector out ---it is Apple Pie.----like Sandy Cameron would say ---it slips in like snot on a doorknob.

IF the mark is not there ? --I make one-----yes the nailpolish again.

hagar.

PS : finding exact TDC is part of " Hillbilly TUNING ".----a VERY VERY important part.

[hagar]

here are a few ---GOSPEL ----points about Rabbits. -----and you can take it to the bank.

Read ALL postings by Andrew in Flagstaff AZ -----about a month will do it.

according to hagar a Rabbit can not be TIMED according to Bentley numbers.----WHY ? --due to wear.

So what does a good old Yankee ingenuity DIY do ? --why simple ---" Hillbilly TUNING " ----does it work ? ask Gary Bangs in Florida --he turns I P with engine running --- I am too chicken-----but maybe some day just for fun.

To get to optimum performance ? --get used to moving pump not a pencil line ---half a line --or when you really get close --just think about moving it , is enough.

Can you advance pump too much ?---not under Hillbilly TUNING you cant. --the slots are very short ----set it fully advanced if you like ---that does NOT advance Ignition point.----or very little.

Under " Hillbilly TUNING " can a Pump be 180 degrees out ? --NEVER have no fear --read my lips.

hagar.

PS : can the pump be too retarded ? YES.

[idhoho]

I'll have you know that I tried the timing adjustment trick- moving the IP with the engine idling~ No Problemo Hagar. Like you say, just a nudge-