Timing

[Mike J]

Engine running without leaks and mixture spot on. (From Colour of plugs and recent MOT) When warm and driving at around 40mph when I try to accelerate there is a relucatance. I'm pretty sure this is a timing issue. does it need advancing or retarding? Currently its on 12 before set by strobe on tick over at 800rpm.

I'm using Luminition Optical and Stag Webers.

Mike

[Stagdad]

I set mine at 16btdc on Tickover with vac advance capped off for setting up, super unleaded fuel and it pulls great with no pinking but the rom says 12btdc so be careful you don't over advance it.if the engine is to retarded it will get hotter. Try pulling the choke a bit when you want to boot it, if it improves it could be too weak.
cheers Steve

[jleyton]

Have you got enough oil in your dashpots ? - this, effectively, acts as an accelerator pump, by damping the movement of the carb piston.

Cheers

Julian

[staginhiding]

12-14 used to be the setting,changed a bit for unleaded..
Have you made sure you diaphragms are not split,also i have found that the Stag set up spot on runs a little weak .
Try richening just a tad to see if it improves..

Sam

[Stagdad]

Have you got enough oil in your dashpots ? - this, effectively, acts as an accelerator pump, by damping the movement of the carb piston.

Cheers

Julian

On a weber Julian?

[jleyton]

On a weber Julian?

Oops - these people with non standard cars .

Cheers

Julian

[staginhiding]

Oops twice,I didnt see that either..

[jleyton]

Oops twice,I didnt see that either..

Great minds think alike

[staginhiding]

Or dont think at all more like it....
How was the Mendip run ?

[Lingen]

Steve. Just being picky, but there is no need to cap off the vacuum advance at tickover with Strombergs, as there is no vacuum there when the throttle butterflies are closed. Try it and see. I think 16btdc is a bit much, especially for people happily running on standard unleaded. You seem to have to wildly over advance the timing before you actually get any pinking, and performance might in fact be worse..
Mike.

[jleyton]

How was the Mendip run ?

From a pretty wet start it, surprisingly, turned good weatherwise and the hood came down.

Good to meet up with Malcolm, Steve, a couple of other Stag owners and quite a few other peoplke we knew.

All in all, a really good day

Cheers

Julian

[Stagdad]

Steve. Just being picky, but there is no need to cap off the vacuum advance at tickover with Strombergs, as there is no vacuum there when the throttle butterflies are closed. Try it and see. I think 16btdc is a bit much, especially for people happily running on standard unleaded. You seem to have to wildly over advance the timing before you actually get any pinking, and performance might in fact be worse..
Mike.

For my car 16 worked better than say 14 and I always use super unleaded but like I said be careful the rom says 12 so to air on the side of caution stick with that if you are unsure.

[flying farmer]

Unlikely to be a timing issue, more like going weak as the throttle is opened.

Don't really know anything about the Weber set up, but may be similar to the Holley and need the accelerator pump jets increasing in size, or more likely a different pump cam to increase the amount of fuel pumped in rather than a bigger jet which would just increase the amount but reduce the duration of the enrichment.

More advance can sometimes mask the problem as a weaker mixture burns slower, so the spark needs to come earlier.

Neil