1960 MGA Timing and tuning

[Robert Rundle]

A slightly outside of the space request. But I have a 1960 MGA, which I am trying to get back on the road. I have recently changed it to an electronic ignition, serviced the SU carbs and basically tried to get it into a running state. However, I am having real challenges with getting the static timing set.

Does anybody have an interest in cars of this type or experience of setting the timing and fault finding. Who would consider helping me at some point?

Thanks

Rob

[Eric Rowen]

I can vaguely remember setting the timing on a MK 1 Cortina, but this had points not electronic ignition.  Interestingly I do have a project on the go with the same setup ford block based engine and 30 year old electronic ignition but the whole thing won't be together for a month or two. 

Should be something on the web, but from memory there was a fixed point (maybe several) on a raised curved part of the engine adjacent to the crankshaft pulley, the pulley had a notch in it.  The static timing was set I think with two of these points adjacent. Manual will show what these various marks represent like Top Dead Centre and degrees of advance. 

Fine adjustment (engine running as opposed to static) was made with a strobe light, the fixed point for whatever the advance was at idle speed,  and moving point on the crankshaft pulley were marked with white paint and the then the timing adjusted by moving the distributer one way or the other until the strobe showed the two white paint marks aligned. 

With electronic ignition I should imagine you setup the marks to whatever advance the manual suggests and then adjust the electronic ignition until you get a spark from the number 1 HT lead, then do the dynamic with the strobe light.

You will need some way to check the revs as I guess the MGA didn't come with a rev counter, a basic rev counter can be made with a mono-stable circuit ...

http://www.homemade-circuits.com/2012/05/make-this-simple-tachometer-circuit.html

I quick search on MGA plus static timing strobe light etc. should get some posts............. and most cars have owners clubs and forums.  

One of many hits..

http://mgaguru.com/mgtech/ignition/ig205.htm

--
You received this message because you are subscribed to the Google Groups "Reading Hackspace" group.
To unsubscribe from this group and stop receiving emails from it, send an email to reading-hackspace+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Marcus]

There was a recent post about Open Motor Works, I might be wrong, but would this be in the ballpark of things they're experimenting with?

[Ryan .]

Yep, get in touch with 'em!

R

[Eric Rowen]

The "mgaguru" ref above has all the info you need for static timing adjustment....  The guys at Open Motor Works or anyone with a basic knowledge of engine timing can get you up to speed if the info below does not make any sense.    Sorting out if the MGA is positive or negative earth is also essential............ and,  as on my long gone Daimler V8 it is possible to convert from one to the other so you can't necessarily assume that the way the car was designed is the way it is now. 

It may also help if you can post what make of electronic ignition it is. 

Pertronix ignition can be static timed in the same manner as points ignition. Set the timing mark on the crankshaft pulley to the desired static timing position. Connect a test light to the switched wire running from the coil to the distributor (the one that is not the power wire) and ground the test light. Turn ignition on. Rotate distributor body anti-clockwise until light is out (equal to points closed). Then turn distributor body slowly clockwise just until the light comes on (equal to points open). Lock it down and run it. 

[Alex Gibson]

I am still hoping to make time to visit OMW with my Pontiac. It is still running, but needs tuning up pretty badly.

Tapped on my mobile phone.

To unsubscribe from this group and stop receiving emails from it, send an email to reading-hacksp...@googlegroups.com.

[Robert Rundle]

Thanks Old Raft, 

Its positive earth, which i have confirmed and makes life interesting when wiring, thinking slightly in reverse. It kind of feels like the distributor is 180degrees out. which could be because I have the HT leads incorrectly positioned on the dizzy, but according to all the literature they are positioned correctly. 

I couldnt even get it to OMW without trailing it, which seems avoidable, as it should be possible to get it at the very least firing, even if not lumpy.

I do appreciate all the useful input though.

Rob

[Eric Rowen]

Firing order is easy to get wrong  maybe  1   3    4   2  ?  check the manual  so that running round the distributor (clockwise from above?)  the leads go to those cylinders.  

http://www.mg-cars.org.uk/MGA/mgaspec1.html    confirms   1 - 3 -  4  -  2   

I guess you have to turn the engine over without the distributor cap on to see which way it turns so that then the leads looked at clockwise?    go to   cylinders  1  -  3   -  4   -  2

Is this how it is connected? 

--

[Eric Rowen]

Looking at this post..

http://mg-cars.net/mgtd-mgtf1500-bbs/distributor-timing-firing-order-2013071703581529315.htm

It may not be the same car but the suggestion that even though the leads may be correctly placed to fire  1 - 3 - 4 - 2  is that a No 1  piston is not at top dead centre when the ht fires for that cylinder,  may be relevant.

The timing marks on the block and the crankshaft pulley are usually for the first cylinder at TDC so the correct lead about to get the ht must go to the first cylinder.

If all the ht leads are different lengths and will only fit one way then this would not be a problem but if they have all been removed (and possibly replaced ) from the distributer cap etc then it may be that no 1 isn't getting the spark when it hits tdc (or a few degrees before) 

[Eric Rowen]

Read through the whole post mg-cars.net it's very interesting and informative and shows the leads from distributer (confirmed turning acw) going to the engine  1 - 3 - 4 - 2  and that No1 has to be at tdc for timing. 

[Eric Rowen]

The other silly is possibly that the distributer cap can be fitted 180 degrees out as they just clip at each side. 

[Robert Rundle]

I purchased all new HT leads and connected them in the correct order on the dizzy cap (can only go on one way, due to outlet for wire) timing mark was positioned correctly as far as i could tell at approx -12 degrees (-12 is recommended for unleaded fuel, as -7 was based on the old proper stuff) at TDC for cylinder 1 at the front. worked our TDC based on the valve positions. The dizzy rotator arm, travels anticlockwise.

Thanks for the link, hadn't come across that one. will have a full read through of it as well. I think I have to go back to the start and work my way up through all the connections and ensure i have done it all by the book. I have a spark checkers as well to go inline with the plugs to check that I am getting sparks as well. 

[Eric Rowen]

I would be tempted to have the ignition not too far advanced until you get the engine started.

Are your plugs new and clean and adjusted to 0.025"   Old  plugs that look clean can cause an engine to be difficult to start, plus after a few attempts to start they get wet with petrol so they don't fire very well.

Spark testing can be done with a plug, a spare or one remove from the engine, attached to the ht lead and resting on the engine, just turn the engine over.  You should get a fat spark with electronic ignition regardless of the state of the battery. An ht lead resting on the engine works just as well............beware of petrol and petrol vapour, a well ventilated location is good too.  

Another thought;  is the choke on the SU carb working correctly?  This should pull the tube in which the needle sits, down to get a richer mixture. 

After turning the engine over a few times, take a plug out, it will more likely than not be wet with petrol which will at least tell you that fuel is getting through.

Finally is the battery up to the job?  With electronic ignition you will get a good spark regardless of the state of the battery, but if its not cranking quite fast enough, maybe compounded by wet or old plugs..... (I have been there after rebuilding the head on my Cortina ) 

On Fri, Nov 18, 2016 at 9:30 AM, Robert Rundle <nvng...@gmail.com> wrote:

I purchased all new HT leads and connected them in the correct order on the dizzy cap (can only go on one way, due to outlet for wire) timing mark was positioned correctly as far as i could tell at approx -12 degrees (-12 is recommended for unleaded fuel, as -7 was based on the old proper stuff) at TDC for cylinder 1 at the front. worked our TDC based on the valve positions. The dizzy rotator arm, travels anticlockwise.

Thanks for the link, hadn't come across that one. will have a full read through of it as well. I think I have to go back to the start and work my way up through all the connections and ensure i have done it all by the book. I have a spark checkers as well to go inline with the plugs to check that I am getting sparks as well. 

--