P38 Diesel Injector Pump & Cam Top Dead Centre?

[UnitLandy]

Cheers for that. Just letting the engine cool down before tinkering.

 

[Mark Piercy]

Cheers for that. Just letting the engine cool down before tinkering.

That's an idea
It may be easier to remove the inlet manifold to get to the inner coller nut on the pump and there is the support bracket at the rear lower part of the pump that may need loosening up... It's been a while since I did one

 

[UnitLandy]

Cheers, Mark
I assume you meant bolt not volt?
Yes I'll get all three bolts. Collect them all! Like a kids toy advert.

 

[UnitLandy]

Incidentally, Mark. Would you know what special size socket I'd need to remove the injectors? I'm not sure if it could be a lose olive, leak off pipe or copper washer, but their's a trail of diesel down the side of the engine that drips on the ground. I'll double check when getting the engine up to temp with manifold off.

 

[Flossie]

Incidentally, Mark. Would you know what special size socket I'd need to remove the injectors? I'm not sure if it could be a lose olive, leak off pipe or copper washer, but their's a trail of diesel down the side of the engine that drips on the ground. I'll double check when getting the engine up to temp with manifold off.

Bear with....

 

[Flossie]

This is the one I got, with the window for number 4 injector.

 

[UnitLandy]

That's brilliant. Thanks, Flossie!

 

[Mark Piercy]

It's quite likely the rubber leak off pipes are split at the ends. If not and it's the fourth injector, the seal around the wiring on the injector can give up and a new one needed

 

[UnitLandy]

I'm in luck as it's the 5th injector. I replaced the leak off pipes a year or so back but I'll check them again.

 

[Datatek]

I'm in luck as it's the 5th injector. I replaced the leak off pipes a year or so back but I'll check them again.

PM me with an Email address and I will send you my steel rule timing info.
Depends what you used for the leak off pipes the first stuff I tried only lasted a year. Got the Gates reinforced stuff on there now.

 

[UnitLandy]

Cheers, Datatek. I've already got a copy from you thanks. I've got to put some masking tape on my steel ruler with 16th of an inch increments as it only has 16ths on the first three inches of the ruler.

 

[UnitLandy]

First measurment above was at 12/16 of an inch & that was 86.57% modulation at 94⁰c

Second I knocked it to 10/16 of an inch and that only drew it down to 83.84% - 81.89% modulation at 93⁰c

I don't know if the pump will even rotate enough to get it down to 50% but I'll see.

 

[Datatek]

First measurment above was at 12/16 of an inch & that was 86.57% modulation at 94⁰c

Second I knocked it to 10/16 of an inch and that only drew it down to 83.84% - 81.89% modulation at 93⁰c
View attachment 346773
View attachment 346775View attachment 346774

I don't know if the pump will even rotate enough to get it down to 50% but I'll see.

You only moved it 2 sixteenths, needs to go a good bit more than that, there should be at least another 4 or 5 sixteenths available if not more.
The change in modulation is not linear, as an example:-

A an example these are the measurements I got on the last one I did.
7" 7/16" Modulation 63% @ 95C
7" 5/16" Modulation 60% @ 95C
7" 4/16" Modulation 50.31% @ 95C
One sixteenth of additional movement produced a big change in modulation.
Engine temperature also affects the modulation, ideally it should be at 95C for 50% modulation, a lower temperature will change the modulation. I think I sent you a chart of modulation against temperature?

 

[pwood999]

Shame most US owners have petrol P38's. They would love all this sixteenths stuff !!

 

[UnitLandy]

Thought it would be super sensitive, . I'll move it a good 4-6 16th next time.

 

[UnitLandy]

Incidentally, you were right, Datatek. It was No 5 injector leak off pipes leaking. I've got some braided hose spare.

 

[RangeRoller dt]

Shame most US owners have petrol P38's. They would love all this sixteenths stuff !!

If you tell them it’s half 2, they think it’s 1PM!

 

[UnitLandy]

Engine temperature also affects the modulation, ideally it should be at 95C for 50% modulation, a lower temperature will change the modulation.

I waited for it to get up to 95C but the bugger wouldn't. Bit of a wind up today.

 

[Datatek]

I waited for it to get up to 95C but the bugger wouldn't. Bit of a wind up today.

Remove the viscous fan.

 

[UnitLandy]

Ha ha. I'm reluctant to do so as it's a right pain in the backside to put back on again. As it happens I've got a hairline crack running along the plastic outlet pipe on the radiator. What's the best remedy for this. Araldite?