Misfire

[pushrod]

I've just fitted a new set of leads, distributor cap and rotor arm to the Tiger and I can't cure a misfire. The old parts were several years old and in need of changing.

Engine is a 260 with a Mallory D70 33 distributor. The new leads are Moroso Blue Max, with 90deg plug caps.

Engine was running fine before the parts were changed and I changed each lead separately so as not to get the firing order mixed up, or I think I did!

Just so I can check that I've put the leads on correctly, which connection on the top of the cap is No1 in relation to the little cut out in the base of the distributor cap?

Also the plug boots are a really tight fit over the spark plugs so it's possible one or two might not be fully in contact. Any suggestions how to get them fully on?

Thanks

Lou.

[gtsmrt]

Hi Lou,

On my setup, my no. 1 connection on the distributor is at approximately 11 o'clock looking from the front of the car. You could probably use a small amount of petroleum jelly to help slide the boot over the spark plug. There may even be a special lubricant for the spark plug boots.

Regards, Robin.

[Tomaselli]

Lou,

When is the misfire, first thing when engine cold, or when hot or lower down in the revs, throughout the rev range or when under load?

What fuel you using, and is it old? I find fuel that has been sitting over the Winter is always giving me flaky performance.

Don't you just love owning classic cars......

[pushrod]

Robin:
No.1 on my distributor is at 1 o'clock as it was before I changed the leads.
I've looked at a few websites fo Ford 260 v8 ignition timing and some show diagrams of it being at 11 and others at 1 o'clock - most confusing!

Tomaselli:
Fuel is only a week old, it ran fine before I changed the leads. The misfire is from start up when the engine is cold.

My only consolation is that the weather is crap!

[Tomaselli]

I think if it ran fine before, it will be a process of elimination until you replace the 'older' components with the just serviced item to find the weak link.

Make sure that the fuel pump is doing its job, that's often overlooked

The small block ford can be very sensitive, I even find a difference in the manufacturer of plugs can make a huge difference to the performance - very bizarre!

[gtsmrt]

I remember when I installed my new distributor and leads, the boots were also quite tight so it may be possible it hasn't seated correctly.

[H, Sunny 65]

Hi
The number one lead should be about 1 o'clock as you look from the front of the car. take off dist cap, turn engine untill timing mark lines up on front crank pulley, the rotor will then point to either roughly 1 o'clock or 7 o'clock if at 1 o'clock, fit no 1 lead on where the rotor points to on cap, and then fit in clockwise direction leads 8 7 3 6 2 4 5. try not to let leads 7 & 8 touch as this can cause a missfire.
The best stuff to help leads slide on easy or any rubber for that matter
is good ol Mr sheen or any furniture polish, it also has silicone in it to help seal. Prob wise to fit a new set plugs while your at it.


Hope that some help
Harry.

[pushrod]

Finally found out what the problem was - the choke!

The previous owner of the car never connected the choke cable to the carb, (it always starts with just a dab of the throttle even in winter).

When fitting the new leads I inadvertently closed the choke, initially causing the misfire then non-starting.

Moral of the story - wire it open!

Thanks for all the helpful suggestions.

Lou.

[gtsmrt]

Hi Lou,

Thanks for the update, so it was just too rich for the engine to fire. Good find.

Regards, Robin.