Injection pump timing report

[jbg]

Well I checked my pump timing as I have never gotten around to it since buying the car almost 2 years ago. Following the procedure in the FSM my timing is 0.775mm. The book states:

"D24 (exc. USA/Canada) : 0.90mm
D24 USA/Canada 82-83 : 0.80mm
D24 USA Federal/Canada 84-? : 0.85mm
USA Calf. 1984-? : 0.75mm"

So it appears the car is timed to California specifications ... we can do better than that. :D My plan was to time it to 0.85mm, which puts me right at the US Federal specification. Of course the Rest Of World spec. of 0.90mm might be a better choice.

However I did note on the VolvoTurboDiesel blog that 0.95mm was the hot ticket: http://volvoturbodiesel.blogspot.com/2006_09_01_archive.html

So what are the thoughts of the collective? 0.85mm, 0.90mm, or even more advance? My car runs "fine", but its all I've known from it. Peppy, easier starting, better MPG are all attributes I'm hoping for, perhaps > 0.90mm is the way to go?

[IceV_760]

Schaizze it was d24 :P forgot what i sayed, my mistake

[Jason]

I would time it up to .90 or .95 More timming will just give better mileage, more power, etc... About the only draw back is more timing rattle (engine noise) and a rougher idle, though with the straight six the rougher idle is much less noticeable than it is with the 4 cyl vw 1.6. I had the timing on my '85 Jetta Turbo diesel set as high as 1mm, but the idle was a bit rough, and i didn't notice any increase in mileage so I went back to .95mm. Thats where I plan to set mine, I just barrowed the gauge from a friend and plan to time it tomorrow.

Jason

[Jason]

Mine is set at 1.1mm of stroke and it loves it. Not too much more clattery, but much better throttle response and better take off without boost. Easily starts too. I would time it to at least 1mm, why not? It doens't run rough like the 4cyl version does with more timing (or at least you cant feel it).

Jason

[reed]

I set mine at about .90-.95mm. It starts great and decent power.

[jaluhn]

You need to be careful running too much advance, it can cause serious problem. (like melted pistons, etc) I'd say european spec is probably fine, since chances are the us spec is retarted for emissions reasons. Not sure about anything over .95-1.0 though. If you get too advanced it becomes counterproductive because you're injecting too early. There is an optimum.

For anyone who's really serious about tuning, I'd suggest getting a pyrometer to watch your exhaust gas temps because that gives you a pretty good idea what's going on in there and gives you some warning if it's running too hot.

[jbg]

Just posting an update to my initial timing report. I checked the injection pump timing again on Sunday and confirmed it was at 0.77mm advance. After replacing the leaking rear camshaft oil seal I re-timed the pump to 0.90mm advance.

The car seems to have more pep, and it starts easy. There is smoke when starting and when accelerating. Logically I expected smoke, but its not something I desire. My next plan it to remove the injectors and rebuild them (measure pop pressure, re-shim, replace the nozzles), I am hoping that this will clear up some of the smoke. After all its inefficient to have smoke, that's partially unburnt fuel!

Before going any further into the engine I am going to install an EGT. My plan was to EGT to establish baselines, then advance the timing. I guess I got a bit ahead of myself. :D

-Jim

[Jason]

You may need to adjust your AFC housing. Besides the preload, (jambnut on top) you could also crank the star wheel up a little to add more spring pressure on the diaphram. This would make the injection pump need more boost before the pin is pushed down and more fuel is injected. Also, increasing injection timing will increase smoke at your peak torque, but that doesn't always mean it in efficient. Most times, increasing timing results in better mileage. Have you tested your mileage since advancing the timing? That will tell you if your really sending much unburt fuel out the tail pipe.

Jason

[mike]

How do you adjust the timing on this?
Actually, how do you adjust engine timing as well as pump timing?
I have a diesel mechanic who works on lots of big cat and cummins and northstar engines and is used to degrees.
Does anyone have a link that explains this or is willing to post a "How to"
I'd really appreciate it.