Thread: Confusing - distributors for 3.9L V8

If you suck on the Vac. adv. pipe you should feel pressure and the arm on the other side should move, if you get no resistance when sucking, it's buggered, $128 last time I bought one.
Quote:"Timing is now WAY out."
I would be checking your timing chain, sounds like the cam/valve timing may be out.
Do you know how to refit your dissy to the correct timing?? Regards Frank.

MacMan, where are you? I'm in Mooroolbark, and quite happy to lend a hand if you want. Have special tool 5284 to turn oil pump tang to engage with distributor drive if you want it.

Just about any distributor will work in a V8 with the correct control gear.
I'm not sure, however, about any changes to mechanical advance curves between LC and HC applications.

Rebuilt vac advance mechanisms from Performance Ignitions in Nunawading are about $70 core exchange.

HTH

Pete

Vac unit stuffed. Tested. Stuffed.

Yep, I know how to set up static timing. TDC on #1 cyl, both valves closed following compression upstroke.

I guess that to verify the cam timing is still correct I will either need to take one rocker cover off or remove the timing cover. The rocker cover will be less work, but removal of the timing cover will also reveal the state of the woodruff engagement for the distributor drive.

Annoying stuff.

Originally Posted by Pierre

MacMan, where are you? I'm in Mooroolbark, and quite happy to lend a hand if you want. Have special tool 5284 to turn oil pump tang to engage with distributor drive if you want it.

Just about any distributor will work in a V8 with the correct control gear.
I'm not sure, however, about any changes to mechanical advance curves between LC and HC applications.

Rebuilt vac advance mechanisms from Performance Ignitions in Nunawading are about $70 core exchange.

HTH

Pete

Hi Pete,

Thanks for the offer. I am in Sunbury. I've used a steel rod with a slot in it to turn the oil pump tang before. It's not too hard with trial and error, but the key thing will be to ascertain whether or not the change in timing has come from something inside the distributor (preferable) or timing chain/chain wheels.

I can's see why the distributors would change THAT much internally. Springs and weights would most likely be different to suit different capacities, compression ratios and fueling systems. The thing that gets me is that I have found multiple references to complete assembly numbers that contradict eachother. My printed genuine WSM lists the low compression 3.9L V8 distributor as #ERR1250 but I can't find ANY reference to that part number online. The one fitted was #ERR4740.

The vac advance wont cause it to jump out that far. If the vac advance doesnt work, you just wont get any advance, it wont alter your timing. I ran mine for about 2 years without a working advance before I could be bothered replacing it and all I had was a slightly sluggish engine at low revs. It could be something a little more serious or sinister....

Check the spark from each lead at the plug connection and test the strength.
If its dodgy, might just be a dud cap and rotor.

If you want, PM me your VIN number and I can check it on Microcat for distributor part number.

Cheers

Andrew.

Not a dud cap or rotor - unless I am the most unlucky person in the world. I carry a brand new Lucas cap and rotor in the car at all times and neither made a pinch of difference.

I had it running again yesterday. All plugs on drivers side bank were fouled and today I will swap the others. Timing still advanced on what it should be.

More later.

BTW - thanks for the offer Andrew. I had a Microcat disc here but it has died. Going to download a new copy this morning.

If you have the spare coin ($660) turf the lucas system and get a scorcher dizzy from Performance ignitions in Nunawading Vic. And the prince of darkness will return to Hades and never bother you again.

Some possible causes may be the skew drive gear on the end of the cam or the gear on the end of the dissy shaft that engages with it. The skew gears can strip teeth due to lack of adequate lubrication.

Also with that oil pump you do not want to rev the engine too high when the oil's cold as it can place some strain on the distributor drive gears.

You may also want to check the bush in the dissy shaft. I had an Austin 1800 ute that once had the Lucas dissy shaft bind up and that threw the timing right out.

Does it idle ok? Does it fail only when the mechanical advance kicks in. If so it could be broken advance spring.

Those plastic tooth timing gears are also not the best - much better off with a proper double row steel type.

For the price of a new Lucas you may be better off replacing it with a Scorcher.