Petter Paz one help

Hi guys my current project is a paz1,I've done a fair amount to her so far,now I'm at the point of testing the pump and injector,now I've got flow from tank to pump,I'm getting fuel out of the first bleed hole but it doesn't seem to flow the same out of the top bleed hole and its coming out the top of the pump when I spin the engine over but there doesn't seem to be much pressure there and there's nothing coming from the injector nozzle however fuel is coming from the runoff a slow drip,now under the pump is a load of shims around 12x I think what would happen if I took some out?

Have you removed the injector pipe from the injector while your bleeding it as there might be air trapped there and it won't push it through the injector.

Stu.

Yes I've had that pipe off while I've been cranking her over but there doesn't seem to be much diesel or pressure coming out of it could it be that the pump just isn't filling up enough?

Sounds like it could be a blockage in the pump, could you put an air line to the bleed screw hole and try to blow it back.

Stu.

I'm not sure what you're expecting in the way of pressure. There won't appear to be a lot of pressure through the pipe on it's own, just a little dribble. It's only really under pressure when the whole system is full & all connections are tight.

These single cylinder diesels can take quite a long time to bleed in, when you think about the volume of diesel held in the injector feed pipe, the pump only pushes a tiny amount through each time it fires, so to fill the pipe & get all the air out can take some time, especially if you're turning the engine over by hand.

Thanks so it sounds like my pump may be ok I'm just having trouble getting the fuel to come out of the injector nozzle but it comes out of the return back to the tank no problem????

That could just be old fuel, in the return line, working its way through, there could still be air in the injector line.

When I did my brother's Petter AA1 we pretty much ignored the return line & just concentrated on the rest of the system in a logical order.

IE: tank to pump - fuel through pump - pump to injector end of line - then fuel through injector. Tightening everything up as you go along.

I don't know about the PAZ1 specifically though, but that should be a reasonable way to go through most gravity fed single cylinder diesel stationary engines.

It takes a long time to get there, & it will take even longer to get fuel from the return line I reckon.

Well I've had some good progress tonight I've got fuel spraying from the injector and peeing out of the return to back to the tank,but I'm not sure if what I'm witnessing is correct-if I put the throttle at we're its been set in the past I get nothing but a drip from the nozzle however if I open it up to max I get some fuel vapourised accompanied with a jet of fuel it seems its all or nothing and at this point I can't see me getting a nice tickover,to me it sounds as if the hole/jet in the nozzle is too big????

I never removed the injector from my PAZ1 but I wonder if they are fitted with a PINTAUX injector nozzle whereby a flow of fuel is injected at low speeds until the pressure rises and the conventional spray takes place? The 'starter hole' will still dribble fuel to prevent the jet carbonning up, maybe an email to ex Petter engineer Jim Perkins jimp1115@btinternet.com will provide an answer?

Pete.

Yeah, this is where I kind of run out of info. I know about the basics of visually inspecting an injector's spray pattern, but that's about my limit.

Perhaps Pete's (Foden's) suggestion is best.

I can recommend Jim Perkins, he always seems happy to help. The man must have the patience of a saint.

Just a point of safety, the spray coming out of the injector is very high pressure, I was always told that it's injecting at about 22000 psi and it could easily blow a hole in your finger. I served my time on truck diesels so the pressure must have been higher but still be careful around the injector nozzle.

Stu.

Not sure about a hole, but I know they can certainly get the diesel under your skin & possibly into your blood stream (which I guess amounts to a hole in your finger).

Diesel under the skin or in your blood is a definite hospital job, not very nice at all. Stu's absolutely right to urge caution. I was always told to be careful with injectors, I think eye protection should be used really & definitely keep any body parts well out of the way when testing.

Hi guys I finally got some new oil rings fitted and she's now back together I've been trying to get her going all afternoon but the most I can get from her is a couple of light chuffs and that's with a hot air gun blasting up the intake, is it normal for a paz1 to be quite loud at the intake? There's bags of compression I've set the valve gaps to 15 thou ish,does anyone know what I should torque the head nuts up to?

Rustybullethole wrote:Hi guys I finally got some new oil rings fitted and she's now back together I've been trying to get her going all afternoon but the most I can get from her is a couple of light chuffs and that's with a hot air gun blasting up the intake, is it normal for a paz1 to be quite loud at the intake? There's bags of compression I've set the valve gaps to 15 thou ish,does anyone know what I should torque the head nuts up to?

I would just do them to an even FT.
Have you bled her fully?

blackvanman wrote:
Have you bled her fully?

Yep, bleeding these Petter singles can take an age! We all thought there was something wrong with my brother's AA1 when we had to bleed that in, it was taking so long.

Bleed the system down to the pump as normal once you've fuel there, loosen an injector pipe as you turn it over and see if your getting a good squirt there then tighten the pipe.
A 15thou gap is a bit big it should of been nearer 10thou for a diesel. Did you move the rings so the gaps were spead around the piston? Try a squirt of oil into the inlet manifold as you turn her over or last resort a sniff of Easy Start but just until shes running then throw it away :stick lol: :stick lol: :stick lol:

Stu.