Injection timing?

[ngoma]

Not so much resealing the pressure regulator as bumping up its preload.

[sdturbo]

Took the regulator out and the seals were all dry and cracked. I replaced those and tried to bump the pressure. I thought it moved a bit but there is no difference in the timing. How hard are you supposed to "bump" that stop? Anyone ever tap is for a set screw instead?

[745 TurboGreasel]

I have a theory the motors which run stronger on veg oil are the ones with way below par dynamic advance, and ULSD makes it even worse.
When I checked mine it wasn't far off spec.
Being on the bottom where grit collects probably doesn't help any.
I also had one apart where the advance ring had worn pretty significantly into the pump housing.

[ngoma]

Originally Posted by sdturbo

How hard are you supposed to "bump" that stop? Anyone ever tap is for a set screw instead?

Hard to say, I've never done it; it's still theory to me, but in that link I posted earlier, they hint that there can be some stiction to overcome when attempting to tap in the preload, then finally it moves too much and they have to remove it to push it back out, and start all over again.

Too much internal pressure and it will start blowing seals...

Some sort of a screw-down micro adjuster would be an improvement.

NOTE: I would not attempt any of this without getting baseline measurements of the internal pump pressures at various RPMs. Before and after PSI readings, to be sure. Wasn't that your plan?

[ngoma]

Originally Posted by 745 TurboGreasel

I have a theory the motors which run stronger on veg oil are the ones with way below par dynamic advance, and ULSD makes it even worse.
When I checked mine it wasn't far off spec.

Sounds logical to me. The higher viscosity would be helping build more pressure?

How did you measure the dynamic advance?

[sdturbo]

Well that was the plan except for the part where I am limited on time and and don't have the proper fittings to execute it at the moment. Everything points to low pump pressure so I don't feel I am taking too big of a risk in increasing it. The logic is if i increase pressure a small amount it should be evident in the timing advance (or less retard in my case.) If it blows a seal in the process I wont be devastated in finding another pump to go through and swap in.

I am going to pull it again tomorrow and disassemble the whole pressure regulator. I will measure the stock location of the stop and put some effort into getting it to move one way or another. Maybe I will even make an adjuster for it.

[745 TurboGreasel]

Originally Posted by ngoma

Sounds logical to me. The higher viscosity would be helping build more pressure?

How did you measure the dynamic advance?

Yes, and I didn't, just transfer pressure.

Originally Posted by sdturbo

Well that was the plan except for the part where I am limited on time and and don't have the proper fittings to execute it at the moment. Everything points to low pump pressure so I don't feel I am taking too big of a risk in increasing it. The logic is if i increase pressure a small amount it should be evident in the timing advance (or less retard in my case.) If it blows a seal in the process I wont be devastated in finding another pump to go through and swap in.

I am going to pull it again tomorrow and disassemble the whole pressure regulator. I will measure the stock location of the stop and put some effort into getting it to move one way or another. Maybe I will even make an adjuster for it.

Guys on the VW bard are saying their acoustic timers only work right at near idle speeds where advance won't really show.

Don't bother taking it apart just make a punch with a stop, and drive it deeper.003-.005 a shot.

[sdturbo]

The pump sits ~8" under the cowel on the land rover. I have to take it apart to adjust it :-/.

Interesting about it not working at higher rpms. I am going to try it on my 4bt tomorrow and see how that works. That has a brand new pump in it so it SHOULD advance correctly.

[sdturbo]

Tonight I pulled the regulator and used a vise to push the stop .030". Wow its a totally different animal. Pump needs a re tune, nothing but thick black smoke. The egts are still sky high but it now seems very over fueled. Base timing jumped to 17 and it it only goes up a couple degrees when I rev it. Ill sleep on it and make some more adjustments in the morning.

[745 TurboGreasel]

Poor thing was probably starving the whole time.

A wise man would tell you the sweet spot will be right around 12 unless the advance piston is messed up.