Timing advance pinto

[bigtalljim]

Got 2.1 pinto with cosworth pistons, kent fr31 cam and electronic ignition. Weber 32/36 dgav and standard fuel pump. 4/2/1 exhaust manifold

While setting up running it seems to enjoy an advance on the ignition up at 12 to 14 btdc. Is this excessive or do engines with tuning bits vary this much.

At this timing the engine starts fine and runs ok without pinking or overheating. ticks over bit high at about 1000rmp but adjusted idle back to 900rpm and seems ok

any thoughts?

[stevieturbo]

bigtalljim said:

Got 2.1 pinto with cosworth pistons, kent fr31 cam and electronic ignition. Weber 32/36 dgav and standard fuel pump. 4/2/1 exhaust manifold

While setting up running it seems to enjoy an advance on the ignition up at 12 to 14 btdc. Is this excessive or do engines with tuning bits vary this much.

At this timing the engine starts fine and runs ok without pinking or overheating. ticks over bit high at about 1000rmp but adjusted idle back to 900rpm and seems ok

any thoughts?

What makes you think that's a lot ?

[one eyed mick]

Sounds about right similar to my own , r/r set up may find you a bit, megajolt may smooth it 120+

[Nick3point2]

What sort of revs are you expecting to see peak power at? It doesn't sound like a lot to be honest, and if you intend to rev the nuts off it you might even consider more!

[jagracer]

I'd be more concerned how this has affected the mid and top end set up as you don't want it too over advance it higher up the rev range. It also depends on CR and the fuel you use.

[bigtalljim]

i found driving it yesterday that top end was not as good as when advance was about 10 deg. But starting up from cold at that seemed to cause the engine to turn over very slow, making starting difficult. With timing advanced starting better but seemed bit flat up the rev range.

Accuspark trigger in place of points, 2 inch exhaust straight through to back box and k and n filter all the usual mods. Better coil.

Lack of power may be fuel return sucking fuel out of carb as seem to have vacuum building up making the fuel splutter into the clear fuel filter rather than fill it up and flow. This very visible when hot and running after a longish run out.

Clamp off return seems to cure that? Any problem with blocking off return at carb and using return as breather? I think tank breaths through filler or its supposed to..........?

[Mr2Mike]

bigtalljim said:

i found driving it yesterday that top end was not as good as when advance was about 10 deg. But starting up from cold at that seemed to cause the engine to turn over very slow, making starting difficult. With timing advanced starting better but seemed bit flat up the rev range.

Which simply shows that the advance curve of your distributor is no longer suitable for the engine. Either get the distributor re-curved, or ideally throw the useless clockwork in the bin and use a mapped system.


Don't really throw it in the bin though, it drives the oil pump...

[DVandrews]

Maximum advance on a Pinto should be no more than 38 degrees and this should be all in by around 3800-4000 on a modified engine. With an RL31 cam static advance should be around 14 degrees. If your distributor has more than 24 degrees of centrifugal advance then you will need to limit overall advance, aither by adding material to the stops or by having the distributor professionally recurved. As stated above , mapped ignition is ideal and will transform the way the engine runs particularly when off cam and at part throttle, economy will be radically improved too.

Dave