Timing valves and Lucas CAV DPS pump

[danebrewer]

Hi all, I’s gots a question. I have had to take off the timing case right down to the engine block on my 2.5 NA/D as I sheared of a bolt on the water pump and didn’t manage to drill it out straight (I was using a magnetic base pillar drill called a broach drill? And play in the stand caused the drill to start squiffy, so I had to haul it all off to get to the bolt)

(1)

When I took the timing belt off, I accidentally turned the various pulleys in relation too each other a bit, (not significantly though) when I was taking the belt off (I forgot to turn the pulleys to line up the timing marks, so I had to re-tension the belt to turn them all together), I have turned the pulleys all back to where they should be, just the opposite amount they were turned off of their correct position.

(2)

Having taken the front cover off of the engine with the inj pump still attached, and having not moved the pulley from its timed position, when I put it back on, will the timing still be OK? – I can’t see any reason why not….

(3)

In a theoretical scenario, if I were to strip the engine down, remove, pump and effectively un-time the valves from the crankshaft and pump, how would you ensure that you were able to time them all together so that the valves, pump and pistons all work correctly and in their correct order?

from what the manual says, the position if the pump drive shaft is not too crucial, so long as the pip on the pulley is aligned with the timing mark, and no 1 piston is at the exhaust stroke then you should be OK, and fine tuning is done with the rotation of the pump body. Surely this could mean that the pump might be injecting into an “incorrect” cylinder, one that does not need fuel

(4)

Lastly, is there any offset in the operation of the valves and crankshaft, so: when a particular piston is on the peak of its exhaust stroke, the corresponding exhaust valve is at its highest point. Is this correct?

Tnaks in advance, and I hope it all makes sense!

[Les Henson]

You are correct in that the injector pump is used to fine tune the engine. However - the camshaft and crankshaft sprocket timing marks must be in the correct position, so timing is critical for them as this is mechanical timing (relationship between piston and valve). Replace the timing case, set all 3 sprockets on their respective timing marks (make sure that the injector pump can be rotated a small amount in either direction where it bolts to the rear of the case). Fit the belt and tension it, rotate the engine twice in the normal direction of rotation (clockwise), check the timing marks, adjust if necessary, and rotate twice again if further adjustment was needed. Fine adjustment of the injector pump is generally done once the engine is running.

Les.

[danebrewer]

thanks for the reply, when you say" when the engine is running" I assume that the timing tweaks must be done with the engine switched off?, the engine runs really smoothly at the moment (or it did 'till I pulled it apart), if I get the same smooth running, I guess there'd be no need to adjust the pump, if it sounds off, how would I know whether to advance, or retard the timing of the pump by the sound of the engine?

[Les Henson]

The need to adjust the pump timing is more noticeable when the engine is started from cold. Retarded timing is indicated by puffs of white smoke, which gradually reduces and disappears as the engine warms up. Advanced timing is difficulty to start from cold and a 'sewing machine' rattle that may get a bit worse as the engine warms up.

Les.

[danebrewer]

hmmm, thanks, I hope I don't need to fiddle with the timing as I sure don't want to have to take the pumo off to replace the gasket, having put everything back together, only to then have to haul everything forwards of the timing case off to change the pump gasket!

[RustyNissanPrairie]

when the bolts snap (and they do the 1st time you take a water pump off a NA) you can tap the timing case to 8mm instead and just open the relevant hole in the water pump casting. Mines been like this for 5 years. Slap plenty of copper grease on everything on reassembly

The pump needs to be timed with the flywheel, there is a slot that takes a locking pin thats a right bugger to get to on the clutch bellhousing near the bulkhead, and a small locking pin that sits in the fuel injection pump when everything lines up. This sets the timing.

Periodically recheck the timing or just advance the pump (very) slightly to compensate for timing belt/pulley wear which in effect retards the timing, these NA's need every little bit of help they can get. If you advance too much you get pre injection clatter and lack of power as the fuel is injected on the piston upstroke.

edited to add-the pump position can be altered without buggering up the gasket, just loosen the injector pipes with IIRC a 9/16ths spanner and the 3x13mm headed nuts and twist the pump slightly. The head/top of the pump away from the engine block is advance/towards is retard.

[danebrewer]

aah I see, I think my NA is older as it has a cover for a timing pointer, which I have and not the hole for the timing pin, in the flywheel housing,

does the locking pin for the pump go in the side or the front? as I can't see anywhere it might go in the front, I guess it goes in the side somewhere?

as for the bolts, I have stripped everything back to the block now so I'll fry and get it out, or just tap it out that way, I did try and drill the bolt out, but as I said, the drill wandered off the top of the bolt, owing to play in the broach drill, which made it impossible to start a drill by hand in the centre. aah well, parts have arrived, so I might be able to get things going again by next week!

Thanks for the help!

[Les Henson]

When you come to fit the pump to the timing case, put a thin film of grease between the gasket and pump. That way you won't damage the gasket if you need to rotate the pump to fine tune the engine.

Les.

[danebrewer]

I haven't actually taken the pump off! I left it attached to the back of the timing case, Hopefully the timing will still be in order and I won't have to haul everything back off to get the pump off to fit a new gasket!

[RustyNissanPrairie]

the pump pin goes in the left hand side of the pump-theres a little plug with about a 10/13mm (cant remember) head on it, unscrew this and stick the pin in. My pump locking pin is home made from a drill bit (cant remember that size either)-I can look on monday.

To be honest though I never had much luck doing it with the proper locking pin setup, doing it by ear and tweaking tthe pump a little at a time was the best method.

[danebrewer]

aah yes, I remember reading that in the book, well the front cover is back on now and a new belt on and tensioned, will hopefully manage to throw the rest back together tomorrow! though does anyone know of a way to torque the crank shaft bolt without an impact wrench? the torque wrenh I have is beefy enough, but is it just a case of finding low range first and going aginst the resistance of the gearbox?

[Briarston]

aah yes, I remember reading that in the book, well the front cover is back on now and a new belt on and tensioned, will hopefully manage to throw the rest back together tomorrow! though does anyone know of a way to torque the crank shaft bolt without an impact wrench? the torque wrenh I have is beefy enough, but is it just a case of finding low range first and going aginst the resistance of the gearbox?

Put in the HIGHEST gear, or you will find your efforts will cause the LR to climb over your wheel chocks. Getting a helper to hold the foot brake on (or spragging the pedal down) is worth doing.