Camshaft Timing Question

[Nevada_TDI]

I am a bit embarrassed to post this here, but I believe this is the right area. When I first had my Jetta I was too intimidated to work on it, it threw a timing belt, and I took it to the local VW shop. Franko6 did the head work, and even though the shop did not have the right tools, I provided them to the shop. My engine never seemed to run the same after that, but maybe it was just me. Fast forward to the timing set I currently have installed, we previously indexed the cam so every part was TDC before bolting the engine back up. She ran the same and all was well, it seemed she was prone to the overboost/kill fueling like she always had always been really touchy when it came to trying to dial in the boost curve. She-"Sophie" named from an inside joke years ago.
Back to the point: this time I purchased the entire timing tool set, including the cam lock that bolts into the vacuum pump bolt holes. TDC seemed different in relation to the camshaft position not matching the lock locating: the crankshaft was TDC, the IP was TDC, but the camshaft did not exactly line up to where she should be so I rotated the camshaft a few degrees and then popped the sprocket, realigned the camshaft sprocket and put the engine back together. Driving home she seemed to run better, but I was tired at the time. The next day I went for a test drive, put her in 3rd at a low RPM- without VCDS, and she didn't cough, she didn't put out a huge plume of smoke either and pulled solid until I couldn't afford to pay the ticket and I backed off at 75MPH I believe. For the longest while-before the new timing set- she smoked heavily when cold-and she does not now. I am still working on a fresh tank of fuel to see if there is any difference in FE.
I apologize for the long post, but is it possible the camshaft was a few degrees off ? If you have an idea or personal experience, will you please post it, and suggest which way the camshaft was off?
Advanced or retarded, and why do think so?
I realize this is not technically a Power Enhancement question, but since the engine is modified and acting differently, and I now have more power, it's close enough, I hope.

 

[Nero Morg]

Yes it's possible. The crank and cam need to be 100% lined up. The fuel pump just needs to be in the general area, since you're going to be adjusting it anyways to dial in fuel timing. Sounds like your crank/cam was out of time a little.

Typically when I set a timing belt, I bar the engine over, line up the mark on the crank, and the cam tool should glide right in. I just make sure the timing hole is close for the fuel pump after, but fuel pump not lining up won't hurt it.

 

[Vince Waldon]

What colour was the smoke?

 

[Nevada_TDI]

What colour was the smoke?

Mostly white when the engine was cold, and big plumes of black smoke when the engine was warm. Now at the tip in, the smoke is very minimal.

 

[Vince Waldon]

White is typically unburnt diesel, typically caused by retarded timing, so that's my random interweb guess as to what your valve timing *was*.

Sounds like you've got it sorted now... using the proper jigs is the way to go for sure. Small differences can make a difference.

 

[jmodge]

One of the reasons rotating the engine twice and rechecking timing is suggested, the slack in the belt is evened out, which could change cam timing. As far as gassers go, cam timing moves the power curve. Advance a cam, low end power, retard a cam, high end power. Which way did you have to turn the cam.

 

[Nevada_TDI]

IIRC, facing the camshaft view, I believe it was clockwise, which would be advancing the camshaft, which would make sense regarding my question. Thank you for your clarifying my question.

 

[300D]

It really is a game of checking everything in every which direction. The mark on the flywheel, the notch on the crank pulley, the cam slot, and even a dowel down the #1 cylinders injector hole if you are uncertain about the other positions. Everything and everything to make sure it's in time. Glad to hear it is sorted, that has got to feel great. Reminds of when I was kid with a 1971 MGB and twin SUs. In about 4 years of teenage ownership I think I had them dialed in for one perfectly running test drive. It was a super sweet 15 minutes, never to be replicated again, and always not feeling quite right after that.

 

[jmodge]

My brother had a Sportster with an SU on it, he managed to never start his pant leg on Fire somehow

 

[Nevada_TDI]

I finally had a much needed, long awaited epiphany about the cam timing: I don't believe it was retarded, I believe it had gotten advanced. Here is my thinking: if the camshaft was advanced, relative to the crankshaft the valves would have already opened and been on their way closed when the boost was requested. The over-boost, fuel-cut, can't seem to get the actuator the right length, etc., etc.. The tune was rock solid written, like hundreds of others with the same hardware. Today I grabbed my VCDS and went on a mission to log what was actually happening; I will have to say I was surprised, actual and requested boost tracked flawlessly. No spikes, no cut outs, just watch the boost climb and feel the power come on. I feel almost stupid for all the grief I went through never thinking the problem could be cam timing. I always wondered how the guys that got identical hybrid turbos to mine, and had no problems. None.
I learned a valuable lesson the hard way, but that is really okay with me; anybody I help do timing sets from now on, will be timed correctly.

 

[Franko6]

Ah, we meet again. I lost track of you for a while. I hope you are doing well, or at least better than you were.

The timing as we have done to create better performance, generally is done by advancing the cam about 1-2 degrees. I guess since 'low rpm' is where the TDI's live, compared to gasoline engines, the judgement that advancing seems to fit with my theories.

I don't recall if we did any injectors with your build, but between the pump and injectors, that is where plumes of start-up smoke will come from. Either an injector is leaking the pressure that is supposed to be held in the pump or the pump's pressure relief valve is acting up.

For the pressure relief valve, we found some interesting things you can do with that valve. As it comes from the factory, the roll pin will push out the bottom of the valve if the pump's pressure exceeds 15 psi. It seems every pump we look at, the roll pin is protruding, we we figured out a way to drop the pressure in the valve and it seems to have been validated. Keep in mind, it's a relative pressure, for those who use lift pumps to pressurize before the fuel gets to the pump. By lowering the relative pressure in the pump, it seems to make the engine start faster and the fueling is more consistent.

 

[Nevada_TDI]

Yes Frank, I am doing better, thank you for asking. I have experience with advancing camshafts in gasoline engines and they really do pull down low.
I haven't looked to see if the pin has moved out again, thank you for reminding me.
I sent you a package yesterday that should arrive on Monday. I haven't had a set of nozzles that worked as flawlessly as the .205's you set up for me a decade ago. I am sure I will these will work as well as the first ones you did for me.

 

[[486]]

I had my cam off by iirc 11 flywheel teeth once
it had zero power, would max out at about 40 miles an hour and I had to heat the intake with a propane torch to get it started
there was a thread on here with how far you can move the cam before calculated interference, mine was beyond those limits, but I'd done a valve job so the valves were sitting higher in the head, giving more piston clearance.

 

[Nevada_TDI]

Dang Dawg, you got off lucky! When you were wondering WTFranco was wrong, did you have a light bulb moment what to check?

 

[Nevada_TDI]

Frank,
It was good talking to you again today, I will be waiting for a phone call from you on Monday.. You forgot having to burn the fatty acids off of the head I sent you from a WVO engine. Your comment was along the line of, "my need to be starting a savings account if I planned on continuing the running of WVO" I listened to his advice and have never run WVO since he rebuilt the Jetta head.
For anybody else if you are not familiar with Frank (Franko6) he is a recommended service provider as well he does sell timing kits, injectors, nozzles, etc. He is the guy that came up with best version of aftermarket camshafts, head repair and porting, IIRC. I have learned more in ten minutes on the phone with Frank about TDI's than I have learned by reading and researching for years.

 

[Franko6]

Nevada,

Thank you for your glowing recommendation. Mary and I try to live up to a reputation of quality. We aren't 100%, but we sure try.

We often hear of issues from competitors, who seem to cast a wide shadow and are relatively large companies. We make no claim on that. I and the company are highly opinionated and that knife cuts both ways. But all of our skill-sets and information are based on repetitive and strenuous efforts in R & D, which is my first love... it doesn't pay the bills, it's fraught with mistakes and interminable time spent guessing, with 'failure' as the hallmark, but it is that process of elimination, hopefully and eventually leading to success. I hope my trials and tribulations end up being for the general benefit of the members of the Club.