I'm new to this vw diesel thing. I'm reading what I can find, I'd like some clarification on IP timing.
there is a great sticky here that explains timing by Libby. in a nutshell cam level, crank at TDC, pin in the pump with a tight belt and your good. I have the factory manual, it says the same thing. I think Libby's explanation is easier to follow.
so enter a couple guys with rough running diesels on threads here. someone always suggests advancing the pump. that's where I get lost. it seems to me you should set to the factory marks.
then there is a 1 mm setting on the pump which I'm guessing is the pump stroke? I remember seeing a video somewhere where a guy had a dial indicator in the back of the pump setting something. is this related?
thanks for taking the time to educate a noob. you guys are great!
The dial indicator is how you measure the pumps timing. 1.0mm is usually a starting point as every engine will run a little different. The way the system works your pump can be quite a bit off with the timing but still on the right tooth. The dial gauge is used to be able to place it in an exact position. You wouldn't technically need one but it would be a lot of trial and error with micro adjustments if starting fresh with a not running engine.
Advancing the pump makes the fuel inject sooner which gives it more time to burn and increases performance and lowers smoke levels most of the time. There is such a thing as too much advance though. Its all about fine tuning and getting the engine to run optimally. Yes it should run at factory spec but it'll run better at its optimal settings.
The deal is that the factory spec is for a brand new pump and brand new injectors. As the pump wears it builds pressure slower, retarding timing. Happily enough as the injectors wear they tend to start popping early which advances timing a little. However there's no guarantee that both parts wear such that the book timing number is still correct, especially after 25+ years.
Further the stock settings had to meet emissions regs, which often dictated that the timing be retarded from optimal to keep NOx levels down.
Finally as the engine itself wears and its compression drops it has a harder time lighting off the diesel. All of these factors combine to generally mean an older engine needs its timing bumped up a bit over the factory numbers.
The book number is a good starting spot but generally folks find they need to go at least 0.05mm over the stock number to get an older engine running correctly.
Welcome to the land of clackity clack, Bravo2043/
There is timing, there is spec, and there is wear and tear on some of our parts. All of this and a fuel that no longer is what it was when VW designed the IP. So as you read on here about timing, know this, we all want our cars to run but we all want them to run differently. I at one time was big on MPG. Driving 4.5 hrs to work one way once a week and using mass transit once I got there, I was trying to keep my fuel consumption down. At the time diesel was knocking at 4.5 bucks a gallon. I wanted 50 MPG and I got it, but I had little performance and when you are in the car that long and every other driver is laughing at you or otherwise motioning you to put your foot farther into it you have to wonder, is it worth it.
I started reading about the fuel and realized that the thickness of it mattered to the IP. It causes an internal pressure that controls the advance of the timing at higher Revs. So, just by adding wax to the diesel I was able to get better mileage out of the same fuel. Wax also adds Cetane which adds kick to diesel.
But we all start with things lined up on the marks, but we know that after 30 years, maybe a pump rebuild and a route that is more hills than flat we "adjust it" Some will do advance others retard. If they have a turbo, I don't dang it, they want low exhaust gas temps so they tweak the timing.
I have multiple methods to determining the timing of my engine. But the one that nails it for me is how it starts, how smooth it idles and what sort of mileage do I get out of it.
I used to run on Waste Veg Oil, WVO and I still have that system working in the car if I do a long sustained trip. The difference in how thick that fuel is and how it makes the engine sound is very apparent to me. Most people will smell the difference but once on the road you actually feel it, and hear it. And if you bounce the switch that controls the diesel or the oil back and forth you can really tell which fuel you are on. It takes a bit to fill the pump and make it do that but that is the best way to know when I was back on diesel at the end of the trip.
The factory marks are just that, when the car was new it ran well if on the marks. Now days that isn't where it will run best.
Stick with us and learn something. We all did and we liked it. Most of all we like our cars to run well.
the injector timing pump pin is for initial timing, mainly of the cam, then after turning motor over and locking cam out one more time, to make sure your work at that point is right on, you can set inj pump with dial gauge, i find it easiest to set dial preload with belt off, the preload seems the most difficult part, and its the most important, as youll get a correct reading. the 1.00mm reading varies depending on which engine and if you have turbo or not. for instance my 1.6na is timed at 0.90mm id have to check but it varies from something like 0.88mm-0.92mm i set one to 0.94mm im getting some white smoke from the advance.