Tuning 13/60 engine

[Matt306]

OK I have a 1360 engine with Spit head, standard Stromberg CD125 Carb. How do you all go about checking the fuel mix is good.

I have a normal dizzy with electronic ignition.

Ok it runs and drives ok, but recently I seem to be drinking fuel. I want to run through things but what is the opinion, valves first then carb, or carb dizzy then valves.... a bit of expert advice appreciated.

[JohnD]

Not the first time to be asked.  Here's three, easily found:

Sorry , link no longer available

http://sideways-technologies.co.uk/forums/index.php/topic/6968-herald-1360-tuning-options/

http://forum.retro-rides.org/thread/131605/herald-tuning

Good luck!
John

[Matt306]

Thanks JohnD

[Matt306]

Quoted from JohnD

Not the first time to be asked.  Here's three, easily found:

Sorry , link no longer available

http://sideways-technologies.co.uk/forums/index.php/topic/6968-herald-1360-tuning-options/

http://forum.retro-rides.org/thread/131605/herald-tuning

Good luck!
John

I found those before, they seem to be more about pimping the engine up. I want to know how to get the best out of my standardish 13/60 engine.

[JohnD]

OK.
Ignition timing first, cos its easiest.
Then fuelling.

Valves you don't tune.  Just get'em right.
John

[piman]

Hello John,

if dynamically tuning the ignition timing, I suggest that fuel first is the correct way to go as timing is dependant on fuelling.

Alec

[Clive]

I would be checking the distributor is working correctly. You need a timing light,and check that the timing advances wit revs, and that connecting/disconnecting the vac advance again affects the timing (more advance with it connected!)
When fuelling is correct, set the timing by ear. Take the car for a drive and ideally up an incline see if the car "pinks". If not advance the timing and keep doing so until the car does pink up an incline, then retard it just enough so it doesn't. That setting is as good as you will get, the factory spec may no longer be relevant as everything is worn a bit, fuels are different and who knows what components have been swapped over the years.

To get fuelling correct, it is done by lifting the carb piston a couple of mm. If the speed rises, too rich. If it slows, too weak. If it rises a little and stays, it is correct. The changes are small!  Regularly rev to clear the engine. And make sure it is all warmed up well before you start.
There are aids to tuning, colourtune, and CO sensors up to wideband AFR meters. But simple does work!

[Matt306]

Quoted from cliftyhanger

I would be checking the distributor is working correctly. You need a timing light,and check that the timing advances wit revs, and that connecting/disconnecting the vac advance again affects the timing (more advance with it connected!)
When fuelling is correct, set the timing by ear. Take the car for a drive and ideally up an incline see if the car "pinks". If not advance the timing and keep doing so until the car does pink up an incline, then retard it just enough so it doesn't. That setting is as good as you will get, the factory spec may no longer be relevant as everything is worn a bit, fuels are different and who knows what components have been swapped over the years.

To get fuelling correct, it is done by lifting the carb piston a couple of mm. If the speed rises, too rich. If it slows, too weak. If it rises a little and stays, it is correct. The changes are small!  Regularly rev to clear the engine. And make sure it is all warmed up well before you start.
There are aids to tuning, colourtune, and CO sensors up to wideband AFR meters. But simple does work!

I have colourtune but didnt find it that helpful.
I have read a Vac guage is good for tuning any thoughts?

[JohnD]

Piman, we agree then.
J

[Clive]

Sorry, no experience of using vac gauge....

[JohnD]

Vacuum guage measures the 'depression' in the intake duct behind the butterfly/ies.   Its a function of the degree of opening and engine revs, used to achieve economy rathger than performance.

Ciolourtune works but is subjective, and needs practice.

I'm unclear - do you want to know how to tune your standard engine, in which case getting the ignition and mixture right is all you can do, or in modifying?
John

[JohnD]

Vacuum guage measures the 'depression' in the intake duct behind the butterfly/ies.   Its a function of the degree of opening and engine revs, used to achieve economy rathger than performance.

Ciolourtune works but is subjective, and needs practice.

I'm unclear - do you want to know how to tune your standard engine, in which case getting the ignition and mixture right is all you can do, or in modifying?
John

[Matt306]

Just getting the best out of the standard Herald 1300 engine... when i say standard, it has got a spitfire head on (previous owner) and electronic ignition.

[Straight Six]

All the advice you have recieved is good then; Ensure that all ignition components, including HT leads are in A1 condition. Also as someone has played with the head check you are running the correct needles in the carb.

Having done that set the tappets & carb as per Haynes and then dynamically set the timing, checking that the centrifugal and vacuum advance mechanisms are working at the same time.

My MoT station is happy to take emmisions reading during the test and then (within reason) let me play with the carbs to set them up correctly. I believe this to be the best  way, with my car never going so well or returning such good mpg figures so it may be worth asking next time you take your car in for it's test.

By the way, a vacuum gauge is great for telling you if you have a leak on the intake side of your engine, but I've never been able to set timing and carbs up using mine despite what a lot of sites on the internet claim. The timoing is always way, way too advanced and the mixture too rich I always find.

[Matt306]

I have the standard Stromberg Carb CD 150 I suspect i need to remove the main jet and needle to check? In actual fact thinking about it i brought a refurb kit for the CD150 with seals and jets etc marketed for the Herald so should be ok.

I took the dizzy to bits the weights were stuck but not any more. The vacuum advance holds a vacuum (I tested it with vac pump)

I like your thoughts on MOT test.

One of the problems i find is a lack of oomph coming up the hills. It might be the 40 yr old engine which only had 60HP new or perhaps the OD gearbox and 3:89 diff.

[Nick Jones]

3.89:1 diff and OD will certainly lead to slowing on hills in OD top.

Freeing stuck dizzy weights should make a significant improvement.  Spit head on an otherwise standard Herald 1300 engine won't make much difference.

Nick

[Matt306]

Dizzy weights freed some time ago. I do come out of OD coming up hills.... perhaps i need a 6 pot 1600

[marktheherald]

1500 is the easiest upgrade..