Valves?

[Donald360]

My 1.9 DG wbx makes a curious 'puttering' noise while being driven. But only when under load, ie when accellerating or going uphill. I am worried that it might be a valve or piston ring problem. What is the best way to diagnose and rectify?

Cheers
Donald

[Ian Hulley]

Valve = poor compression

Piston ring = poor compression and most likely raised oil consumption & smokey.

Ian

[ghost123uk]

My 1.9 DG wbx makes a curious 'puttering' noise while being driven. But only when under load, ie when accelerating or going uphill.

Won't be valves then as they don't know you are going up hill. Not being facetious there by the way, non of the valve train is affected by the load on the engine.

Does it sound like someone throwing marbles at a tin lid ? I ask as noises under load can often be the timing being too far advanced. If so you need to fix it as when it is making that noise it is hammering hell out of the top of the pistons.
So try and not let it do it by driving gently, with not much right boot !

If there is not a lot of fuel in the tank, and you don't want to mess with timing yourself, try putting a couple of gallons of Shell V Power or Total Exellium or Murco "Super" in, (they are higher octane)and see if that stops the noise on accelerating / going uphill. If it does stop (or reduces it), it is likely timing.

E D I T = Just thought, could be loose drive shaft bolts too = quite easy to check the inners, outers a bit more tricky

[Mocki]

I seem to remember that Donald's bus is LPG powered..... So it won't be "pinking" if I am correct.
It could be an exhaust leak, that could sound when under load, as described....
It could also be worth checking the rocker arm nuts are not loose.

[ghost123uk]

I seem to remember that Donald's bus is LPG powered..... So it won't be "pinking" if I am correct..

Ah, Donald did not mention that

viewtopic.php?f=37&t=114625

It could be an exhaust leak, that could sound when under load, as described....

[itchyfeet]

It could be an exhaust leak, that could sound when under load, as described....
.

I had exactly that with a samll hole right by the head ^^^ it's distinctive as you can only hear it under load.

You could try handbrake on and get somebody to power against it briefly while you listen, a length of flexible tube to your ear ( like a stethoscope ) can help to find the exact spot.

If it's a late van suspect the pipe under the thermostat housing first

[Donald360]

Lpg system was removed when we got welding done. Never replaced as it was no longer legal.
Interesting posyts re valves. I'll check exhaust first as that would be the easiest fix.

Cheers
Donald

[ghost123uk]

Lpg system was removed...
Never replaced as it was no longer legal

Hi Donald, just out of curiosity, why was your LPG system no longer legal ?

[Mocki]

I'm guessing underfloor tanks too close to ground ?

[Donald360]

Right first time about the underfloor tanks. It had two cylindrical tanks that ran parallel to the sills underneath, in addition it had a torroidal tank in the spare wheel mount at the front. The more recent rules for ground clearance rules out the two tanks under the sills. The only part of the system left is a Gaslow tank inside which is still used to supply the cooker and Propex heater. It was all suffering from a lot of corrosion and really was due to be replaced or at least upgraded. No cash at present to get it done. On my wish list is a trip down to Steve and get a nice new system installed.

[Donald360]

'puttering' noise seems to be getting much more pronounced, so I'm suspecting the exhaust. A proper examination needed.

[ghost123uk]

Easier on a warm and dry day eh,

[Donald360]

I borrowed a compression guage and checked cylinder compression. There are the values with the engine cold. No 1 - 8.5 bar. No 2 - 8.5 bar. No 3 - 8 bar. No 4 - 0 bar

I think there might be a problem with a valve after all. Looks like the cylinder head will have to come off (again). I'm hopeful that, since I have the heads off recently, the liners will stay in place when I remove the head. Here's hoping - for some warm dry weather

[ghost123uk]

Before you rip the head off, might be worth just checking the adjusters on the number 4 tappets ? I suppose it's unlikely that it has closed up, but you never know.

[Mocki]

It could also be worth checking the rocker arm nuts are not loose.