There is a massive amount of misinformation on line regarding the ignition set up of a 3.8 liter Jaguar engine. I am doing a complete ground up restoration of my 1962 Mark 2 and like a fool removed the old DMBZ6A distributor before checking distributor rotation. I will be installing a new 123 ignition distributor. With very little specified info in the official Jaguar Service Manual, here is what I gleaned so far from various sources:

No 1 cylinder at rear of engine near cowl
Firing order 1 5 3 6 2 4.
Distributor rotation counter clockwise

Can anyone confirm this.

Thanks

 

Confirmed, and you may make #1 on the distributor which ever one you want as long as the firing order is maintained, but with out checking I think Jaguar says the closest terminal on the distributor cap to the block is #1.

What is different for many of the models is the actual ignition timing, it varies depending on what pistons are used in relation to the compression ratio, I think it says in the manual.
I have my 340 set at 6 degrees before top dead centre and I have 8:1 pistons.

 

That is one of the (many) things that confuses me about the 3.8 engines. If set-up is based on the compression ratio, how do you find out what ratio you have? I don't see anything on the data plate, and have never seen a table that tells what engine numbers have for compression.

 

Hi,
From the 3.8 S-type shop manual, (and the "operating handbook") : Engine number... Stamped on the right hand side of the cylinder block above the oil filter, and at the front of the cylinder head casting. /7, /8, or/9 following denotes compression ratio.
On my car its also on the body plate directly above the back of the engine on the firewall. Good luck!

 

Thanks- that is vey helpful. My engine number has a -9. I'll go do some more research in the shop manual.