series 3 timing problems.

Hi all, I'm having probs with the timing on my Y reg. series 3 2.25 petrol landy. Any ideas would be most welcome. I've set the points to 0.015 inches, the carb is set at about 1.5 percent mixture and the timing set at 6 deg.atdc. at this setting for the timing the engine runs beautifully but theres a lot of popping through the exhaust on run over. If I advance the timing the popping stops but I get pinking. I can't reduce the fuel mixture any more as it does'nt run too well on fresh air. Any ideas? What have I overlooked?

vacum leaks in the manifold carb area but before that try setting the timing by ear, it usually works best on older engines especially if the dizzy is slighty worn

AAAHHH you are so wise, many thanks Tots

no probs matey if that don't help you can always comeback for more

I've just been to hell and back with timing on a series 3 petrol. Consequently, I now know much more than I did. Other experts may disagree, but here goes:

I think 6 deg ATDC is too far retarded. The popping is unburnt fuel being combusted on its way out down the exhauste pipe. You might even burn valves in time. You need something more like TDC or even 3 deg BTDC.

Adjusting the timing may be a response to another symptom. In my case, the mixture was all to pot. First, too rich due to hole in carb float - which I fixed. Then too weak as there was a hole in the emission control diaphragm

The emission control system takes fumes from the valve rocker cover to the inlet manifold - critically downsteam of the carb. A hole in the rubber diaphragm causes air to leak in and weakening mixture. The oil in the fumes from causes the rubber to perish. Solution is to replace diaphram or remove whole emission control contraption and put bsp plug in carb as I did.

Having got this sorted, she still popped and banged when accelerating which has been sorted by replacing spark plugs.

With timing now at 3 deg or so BTDC the truck now runs like a sportscar in comparision to previous performance.

in other words do it by ear, that way it takes account of all the wear and tear in the ign system!..

Slobs about right there,
Just gap yer points whilst on the high spot of the dizzy cam, fire yer landy up then with the dizzy clamp loosened twist the dizzy till she's running lovely (wear a glove while your doing this or you'll get a jolt) then retighten said clamp. They're not critically tuned bits of engineering these old motors.

Regards WP.

Thanks for all the info ya all, I just took the manifold apart and there was a one piece gasket across all openings whereas on this model apparently it is supposed to have gaskets across inlets only, the exhaust manifold was blowing slightly from 2 points so replaced the gasket and a bit of sealant on the exhaust manifold to take up any irregularities and its all together. Whilst on a roll I thought I'd change the points, circlip went ping and 2hrs of sweeping the floor with a welding magnet !!!!! I'll let you know what happens but if I get any more good ideas please feel free to give me a slap. Regards.

Top tip:

When re-assembling manifolds, fix inlet and exhaust manifolds to cylinder head FIRST. When nice and tight, you can join inlet and exhaust manifold's together.

Some folk join manifolds together on bench before offering assembly to cylinder head, which asks for leaks.

Good luck.

hats off to slob, all my probs down to a slightly distorted exhaust manifold but thanks everybody else for your input. Point to remember, if you've got hands like shovels get somebody else to change your points, regards.