Thread: Help, what is the timing setting for a 3.9 V8i

The variation has to do with whether or not you have a low compression (8.13:1) or High compression ( 9.35:1) engine, or whether or not it's a catalyst model ( with O2 sensors in the exhaust system), and if you run it on gas, the setting is different again.

Basically, start with 2 degrees and see how it runs. If it's a little sluggish, bump it up a bit. If it pings (knocks) under load, drop it down a bit.

As to the distributor lock bolt, a longish 9/16 12 pt ring spanner works ok, with the engine off. ( You have to reach thru the fanbelt). You can get a thin walled combination socket/uni joint and a 3/8 extension bar in ok whilst the engine is running if you want to do it that way.

between 6 and 9 degrees is fine for our low compression models, even up to 12 degrees but should run premium if going that far.

JC

Originally Posted by justinc

between 6 and 9 degrees is fine for our low compression models, even up to 12 degrees but should run premium if going that far.

JC

I'm running 12 on std (G)ULP and its fine. Mind you, I do have one of those God awful Dynotec PC216 cams in it too.

Hi guys,,
My vac advance has gone on mine, so a mate and I tuned it via a vacuum guage,, not bad power,,,and heaps better on fuel,, but I'm not sure where that has left it degrees wise,, didnt get to check it with a timing gun,,

So how do you tell which compression ratio you have??

Hi There,

I have checked what I have set it is currently 2deg and is running quite well. The engine is a low comp. this was found on the block where the engine number is. I need to buy a better spanner so I can undo the locking bolt and will have a play.

Just got it back today from having sequential LPG fitted, seems to run really well. No perceivable difference between LPG and Petrol.

Cheers, db.