Mis-firing Triumph Spitfire 1500 1980

[Pettifordo]

I took my Triumph Spitfire 1500 (1980) out for a spin on Saturday - the first 15 miles were great - top down zipping along.

Then we stopped to discuss where next and the car stalled.

After a few turns it started but was misfiring under load.

It ran for another few miles - stopped again - this was repeated 4-5 times - I was suspecting the fuel pump.

Eventually it just wouldn’t start and I got towed home 😩

Checked the car the next day and discovered no spark so I re-gapped the points (nothing).

I had used the coil that came with the car before resto so I replace this (nothing).

I had also used the dizzy cap and rotor arm from pre-resto (I had bought new ones but had purchased for a Mark IV not 1500 as this was an early club purchase).

I checked the dizzy / rotor arm and they look ok but as they were the last thing between the spark and the spark plug I replace them and she roared into life !!

For my education - how can you tell if a dizzy cap / rotor arm are faulty by looking at them ? Or do you just check for a spark and then figure out if it is the lead or the dizzy cap / rotor arm ?

This weekend I plan to replace the fuel pump as well as the level of fuel in the fuel filter seems a bit low - which is why I thought it was the fuel pump to start with.

[Iain T]

Have you changed the condenser? 

Iain 

[Pettifordo]

8 minutes ago, Iain T said:

 

Have you changed the condenser

 

Yes the points and condenser are new (well 200 miles since resto new)

[Iain T]

My rotor arm had a small crack which was hardly visible. The plastic parts are prone to cracking. Buy from reputable vendors such as Distributor Doctor to be sure you get quality parts.

Iain 

[JohnD]

The condensor was added very early in the life of the Kettering coil-and-distributor ignition system, as it extends the life of the points, from a few hundred to many thousands of miles.     Condensors can fail in two ways, to fail to 'condense', to store charge, or to conduct the charge.   The first case just wears out the points more quickly, the second acts as a short circuit, bypassing the points, so no spark.   |If you ever doubt the condensor, just take it out.  If all else is well you can get home.

The OP asked what to look for to detect a faulty rotor arm or dizzy cap, and Iain has offered one tip.   Cracks accumulate dirt thatcan cause a short circuit, and another is to look inside the cap, for signs - burning, or white marks - that a crack has developed.   The electrodes in the cap can become dirty too.   Cleaning can get you going again, but a new cap isn't a wallet-fainter!

John

[Pete Lewis]

not much you can do to test a cap  maybe a look in the dark for stray sparking 

any rotor witha rivet in the sweep contact are prone to fail as the spark will jump  from the rivet to the shaft 

condensers are often fake  and have very little inside  see the dizzy docs review Delco condenser: RD7774, CD369, 829111,829107,1861709,1866049,18655972, 1869704,1882239, Lucas Condenser 484249, 400308, 407044, 54411935 / DCB105, 54413006, 23D4 22D 23D DM2 25D DM6 DM4 lucas distributor, Lucas condenser number 423871, GDC101. Condensor 405833 for Ford 8 and Ford 10, Lucas condensers from Distributor Doctor

pete

[Pettifordo]

I got Intermotor ones as this was the brand that the Club supplied with the service kit I bought (for the wrong car 🤣🤣🤣)

Just not sure if I should replace the fuel pump anyway - part of me want to take the car out to see if it is fixed now and it was never the fuel pump and part of me doesn’t want to be broken down again if the fuel pump is the issue 🤔🤔

I guess I could take a new fuel pump and tools required to change with me for a few runs and change at the side of the road if needed ? It is on the “safe side” of the car 🧐

[Pete Lewis]

if you get a decent squirt from the supply pipe at idle  take it to be ok

an air gap in a filter looking only part filled is quite normal and does not indicate a pump problem 

Pete

[johny]

To narrow down more where an ignition fault lies you can pull out the centre lead from the dizzy cap and carefully check if a HT spark is present to earth. If so the problem is downstream ie cap, rotor, leads, plugs....

[NonMember]

1 hour ago, Pettifordo said:

Just not sure if I should replace the fuel pump anyway 

No, you shouldn't.  Your original pump is almost certainly better set up than a new one. 

[Pete Lewis]

I was plagued by a guy off the track about his victor not stating told him (as a joke) stick the coil HT lead in his mouth and crank it over 

next day it took 2 from security to remove him from my office.       you know  some people dont have a sense of humor .

i concluded he was just not that bright  he had been a pain for days  asking all sorts , he didnt come back for more  .

the essence is dont try this at home  its really not recommended unless you want your eyes lite up .

Pete

[Pettifordo]

1 hour ago, NonMember said:

No, you shouldn't.  Your original pump is almost certainly better set up than a new one. 

Ok - will put fuel pump and required tools on the boot so that I can do a running repair

[Pettifordo]

I’m think it is probably the rotor arm where the plastic has cracked ? Would that cause a short ? It’s all quiet finely balanced isn’t it.

With the new coil / dizzy cap and rotor arm, should I check the timing again as I tune up or focus on the carb mix ?

The car runs ok but seems a bit “flat” when you accelerate - that could just be “old” car 🤓🤓

[Pete Lewis]

what with the rivet and the bit fractured off its most certainly the culprit

give the rotor shaft a good firm wiggle  as the top bush needs a squirt of engine oil  this wears and the cam never gives the correct points gap when running 

and yes reset the points gap before you retime the engine 

as  for mixture do youre lifting pins work freely ????  we can expand on that later 

and clean that grey dust  out of the dizzy cap 

Pete

 

Edited April 13, 2023 by Pete Lewis

[Iain T]

1 hour ago, Pettifordo said:

I’m think it is probably the rotor arm where the plastic has cracked ? Would that cause a short

That's exactly what happened to me. To be honest it was brought to my attention at the rolling road tuners. It was tracking and causing a slight miss fire. 

Iain 

[Pete Lewis]

it could well be the fracture was caused by the rotor contacting the cap terminals hence the check the shaft is  firm and no side float 

this oil the top bush problem applies to all our dizzy lucas fair better than delco but a squirt down under the base plate is a service item 

some base plates even have "OIL" stamped on next to a hole 

the top bush is not engine lubricated    some have a felt oiler in the base   some dont     just do it  as part of your service or more frequently is better 

Pete

[AlanT]

No way flat running is just ‘old car’ in a decent 1500 Spit. They feel lively, albeit a bit ‘all or nothing’ on the accelerator (which is what makes them exciting). If compressions are good and even (north of 150psi) then flat running is tuning. Often it’s timing that’s the issue. Mine runs far better 4 degrees out of specs marked than set to spec. 
premium unleaded is essential to decent performance (at least in my car). Spent ages fiddling before working this out.

Edited April 15, 2023 by AlanT

[Pettifordo]

1 hour ago, AlanT said:

Mine runs far better 4 degree

I believe that “spec” is 10 Degrees Before Top Dead Centre (BTDC).

Would your 4 degrees be making it 14 or 6 ?

I assume the vacuum advance is what takes it from the 10 degrees at tick over to the 22-26 Degrees needed at 3200 ? Does this happen via electronics if you have electronic ignition or does the vacuum advance still move the dizzy ?

I ask as I’m thinking that electronic ignition will be my next “modification”.

Fascinating how these systems all work - this afternoon will be spent with a timing light and a colour tune spark plug - hours of fun 🤓🤓

[Pettifordo]

Anyone fitted these “stealth” electronic points ?

It says it replace points and condenser and looks super easy to fit.

My memory of EI from my youth is red or silver boxes with cooling fins and lots of wires 🤣

Do these work well 🧐

https://www.ebay.co.uk/itm/180871977552?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=aceielwaRfy&sssrc=2349624&ssuid=zw41TUiKQsC&var=&widget_ver=artemis&media=COPY

[Paul H]

I use the Stealth on my Vitesse . Works well . You will find a lot of pros and cons here . I do keep a spare though 

Paul 

[AlanT]

Mine is set to 14 degrees. Standard points etc. I’ve had loads of old cars and never found well maintained points to be an issue (re-set gap annually).

[Pete Lewis]

if you followed the problem car witha failed 123 unit the first replacement dizzy unit was accuspark and the module didnt work  they sent out a replacement which seemed a lot better

didnt solve the car problem but it took two accu modules to get a working one 

 

as for dizzy advance   the main controlled advance is done by the bob weights and the centrifugal  relative to rotational speeds of the dizzy spindle 

the vacuum advance has no effect on acceleration and is purely an economy device gaining around 4 mpg  the vac advance is in addition to the centrifugal.

which is why you disconnect it if setting static timing .

the carbs only develop  dizzy vac  at light .cruising throttle openings  made by a small drilled venturi very close to the throttle plates 

so it only works at a cruise type condition at wider throttle openings the vac disappears 

there  wont be much at idle  as the throttle plate will not be anywhere near the port to make any vac 

lucas dizzy mark their vac units with 3 numbers  eg   4-11-21   this is when the vac unit starts to move when its maximum  and the amount of degrees in total 

this varies from model to model .   delco dont mark their units 

if you read the WSM most Dizzy testing is done decelerating nor accelerating   this makes  a lot of difference 

ofet set by ear to the best running and reduce the advance a bit from that works well 

any pinking  then just retard till it stops , always  use 97+  E5 fuel  for effective  performance  not 95 mower fuel 

Pete

 

 

[cliff.b]

2 hours ago, Pettifordo said:

I believe that “spec” is 10 Degrees Before Top Dead Centre (BTDC).

Would your 4 degrees be making it 14 or 6 ?

I assume the vacuum advance is what takes it from the 10 degrees at tick over to the 22-26 Degrees needed at 3200 ? Does this happen via electronics if you have electronic ignition or does the vacuum advance still move the dizzy ?

I ask as I’m thinking that electronic ignition will be my next “modification”.

Fascinating how these systems all work - this afternoon will be spent with a timing light and a colour tune spark plug - hours of fun 🤓🤓

It's the mechanical, centrifugal mechanism that increases advance with engine revs. Two weights that try and fly outwards with increasing engine speed and two springs, a primary and a secondary which restrain this movement and define the advance curve. Also, a stop which limits total maximum mechanical advance. 

When you use your timing light, you should have the vac pipe disconnected but will see that the advance increases with engine revs. You should be able to match it with the chart that you have.

This shows the mechanism

 

 

Edited April 15, 2023 by cliff.b

[Pettifordo]

21 hours ago, Pete Lewis said:

pinking

What does this sound like ?

[Pettifordo]

19 hours ago, cliff.b said:

vac pipe disconnected

Oops - I will have do it again !