Volkswagen Jetta Junkies banner

VR6 12v timing chain question

9K views 20 replies 3 participants last post by  Skimmer0220 
#1 ·
Doing my chains and I'm having an issue with the chain tension between the cams. I have just a tiny amount of slack between them. Enough that when I roll the engine over the front bank cam (2,4,6) lines up, but the 1,3,5 cam is just ever so slightly off and there is good tension between the chains. I mean a tiny amount. When I took it apart I could slide the tool in both cams, now I have to barely adjust the rear one.

After rolling the engine over
Auto part Motor vehicle Tire Automotive tire Vehicle


Auto part Engine


Notice how close it is

Machine tool Tire Auto part Automotive wheel system Wheel


This is the slack in the chain after aligning cam

Auto part Engine Metal Automotive engine part


Auto part Tire Automotive wheel system Wheel Automotive tire


So is that a half tooth off? Is it normal? I doubt that because they're both supposed to align. I've tried everything and believe me that front cam was the bane of my existence to align. For some reason this engine doesn't want to tense on the correct side on the sprocket but I've got it now. Please don't tell me I've gotta take it back apart. Also that camshaft rolled forward twice while trying to align it with the plate out. It couldn't bend a valve just rolling by itself correct? It'll just stop?
 
See less See more
5
#5 ·
Ok the chains are fully tensed across the top, and this is what I see

It almost goes in. In fact it will start to go in
Tire Automotive tire Auto part Automotive wheel system Rim


The cam plate is off the deck by about half a millimeter and as you can see it does still go into the 2,4,6 cam.
Metal Machine tool Machine Steel


Product Tire Automotive tire Rim Automotive wheel system


Is this half a tooth off or will the tensioner take this slack out when it pumps up?
 
#8 ·
Oh yes I followed it and the Bentley manual I have on PDF every step of the way. The bottom does seem to be on, because the little notch lines up with the vertical mark each time I come back around to indicated TDC. However I must admit my stupidity. I didn't check the TDC mark when I tore it apart, just rotated until the cams lined up, but they did align perfectly when I took it apart. I'll mess with the lower in a little while after my dinner settles and report back. And no the trans isn't back in already. The timing covers aren't even on it yet. I want to make well sure that I'm perfect before putting it back together. Too much work to do over and over and over.
 
#10 ·
Alright another update and my final for the night. The crank moves exactly 10.00 millimeters off the tdc mark before the cams start to rotate. I tried setting it 10 millimeters behind the tdc mark and moving a notch on the sprocket, but it was still too tight to move a tooth. Any ideas on this?
 
#12 ·
Yea I put the crank at TDC with the cams aligned and no matter what it goes exactly one half tooth off. The spacing between the teeth on the sprocket is 10 millimeters I found out so at a 2:1 ratio I would need to adjust 5mm on the sprocket. I have no clue. Some people have said that the tensioner pumping up will correct the half tooth and others said that it will run like crap or continue to jump timing.
 
#14 ·
that's my thought. I mean a half a tooth is an awful lot to ask of the tensioner. I can't for the life of me figure out how I've gotten this thing off. And I checked with the old upper chain just to make sure it wasn't the new chain having some sort of issue, and sure enough I was off with it too. I've tried draping it between the cams every way i can think of and there is always slack between them. When I was able to align the sprocket with the crank set behind the actual TDC mark, the chain was way too tight and it was really far off.
 
#15 ·
this was an email reply I got from a master ase tech. His ad on craigslist said master ase VW/Audi and import. His ad:
automotive repair by master ase vw/audi and import tech (Farragut)




I am an master certified Volkswagen tech with master ASE certification and 11 years of dealership experience. I am offering my services for Volkswagen/audi and Import vehicles and can accommodate most repairs and maintenance. I can get discounted parts for you, saving you hundreds over the dealer.Serious inquiries only please. Please understand that not everything can be quoted or diagnosed through email, sometimes I need to look at the car in order to diagnose the problem.

His response:

I'm not gonna sugar coat it it's been several years since I've done one. They are very tricky to get right. At half a tooth you are probably OK as you can really can only be a full tooth off. Most of the time you will not get it to line up perfectly. The tensioners themselves will pump up when oil pressure reaches then should take up the slack. Thanks, Britt
 
#16 ·
Hello, wondering what the result was of your problem. I have the same problem with my sons 2001 Jetta.
Seems like the exhaust cam is 1/2 tooth off.
I didn't do anything to the lower chain, and did t even remove the upper chain, but I think it had skipped a tooth when my daughter was trying to learn how to drive a manual.

Anyways, did you have any problems after putting it all back together?
Thanks
 
#19 ·
So I started thinking, these almost look like marks that someone made. I was trying to find a picture of someone else's car to see if they had them.
Anyone else have these marks on their camshafts?

Right now I have the crankshaft timing marks lined up, the end slots lined up with the tool in place, and the chain is taunt, but not super tight.

Hopefully it's right.
 

Attachments

#20 ·
In my case the car started and ran perfectly fine apart from a miss caused by a bad plug wire, but after I got that sorted the thing didn't have any sort of timing related problem. There is no dedicated exhaust cam on this engine, so I assume you mean the 2,4,6 bank cam. Mine never did line up perfectly with the tool either, and I was pulling my hair out trying to find a half tooth adjustment. For 3 weeks. Finally I said a 4 letter word and threw it back together to see if it would run, and it turned out fine. Now, let me explain what my deal was: There was slack between my chains with both cams aligned to the tool. It would be taut between them when the frontmost (again, 2, 4, 6) cam would slide in, and the rear (1, 3, 5) would be ever so slightly off of slipping the tool in. Finally I realized that the tensioner would most likely take the slack out of the chain. Hope this is of some help to you man, because I've still only ever done one set of chains on this engine, and I'm by no means an expert.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top