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MG Midget and Sprite Technical - I messed up... timing with pretronix

so i got the pretronix electronic ignition, and attempted to install it. however, i turned the rotor while installing the unit and i'm not sure how to get it back in place. (i'm not the best mechanic, but learn pretty quickly if you explain in small words).

so problem one: how do i get the rotor engaged with the drive slot thingee so the distributor will seat?

problem two: I did attempt to turn the engine, so timing is completely lost now, I assume that means i need to static time the engine?

i have a 73, 1275 engine, standard equipment in all other respects.

I know I will have to turn the engine to line it up to the ignition stroke on the first cylinder? what's the best way to turn it?
Chris Edwards

Chris,

If all you did was to remove the distributor than all you need to do is slide it back into the hole until it bottoms against the drive. Once there, you spin the rotor while gently pushing down on the dizzy. When the slot and the drive cog line up the dizzy should drop in. Since the drive slot and cog are offset, they can only go together one way. Then you have to time it.
Martin Washington

Chris, did the dizzie drive come out with the distributor or did it stay in place? If it stayed in then it's just a case of gently pushing in the dizzie whilst rotating the rotor arm until the offset drive engages. It really is that simple.
If the drive came out with the dissie then you have to refit that first, screw a bolt into the end (can't remember size) and carefully feed the drive (gear end first!)down the "tube" whilst gently rotating the bolt to mesh the gears once seated unscrew the bolt and go back to the first instruction re refitting dizzie. Don't forget that you will have to do a complete retiming session after the refit.
Graham
Martin answered whilst I was writing this :+(
Graham P 1330 Frogeye

Chris,
The good news is that you didn't cause any problems you wouldn't have had anyway. Any time you install a pertronix, it is a safe bet that you will want to static time it to get the car to start and then fine-tune the ignition timing once it is running.

You will want to pull the valve cover off so you can tell the difference between timing marks lined up with #1 by the firing point and 180 degrees out. You want to have the timing mark at 0 and both rockers for the #1 cylinder slightly loose (NOT by loosening them up, simply that when you are on the right rotation, the valves should both be closed, leaving the rockers with a little play in them). At that point, the rotor should be pointing towards the sparkplug wire that goes to the first cylinder.
David "but wait, there's more" Lieb
David Lieb

Chris. First, the distributor drive cannot come out with the distributor on an MG. The distributor drive is held in place by the distributor housing which is, itself, secured to the engine block by a counter sunk screw.

I have a tech article on basic ignition timing on my website, www.custompistols.com/ on the MG side. This might be of use for understanding the basic process. But.

For your problem, recruit an assistant. Install the dizzy into the engine block with the vacuum advance pointing to near where it was when you removed it. The new electronic points replacement system will have changed the timing somewhat. Hook up a strobe light to the spark plug wire for number one cylinder. Have the assistant turn the engine over on the starter while you observe the flash of the strobe and adjust the distributor until the strobe is flashing on the timing marks. For starting purposes, if it is flashing on any of the marks, the engine is capable of starting. When the engine is running, have the assistant run the engine up to whatever rpm the factory manual gives for your initial timing and set your distributor to whatever advance the manual states. Refine as necessary for best operation.

Les
Les Bengtson

Les,
I beg to differ with you. Although it is not supposed to, I have seen situations wherein the dissy went in 180 degrees out and the light would flash just fine, but it was not about to start. Had he not spun the engine over with the distributor out, it would be more likely to work fine, but as it is there is a 50/50 chance of being 180-out.
David "made that mistake before..." Lieb
David Lieb

this is what happens when i get brave and think i can figure things out!

usually if i pull the distributor out, i make a mark on the distributor and a corresponding mark on the clamp plate so i know exactly where it was, and mark where the rotor was pointing when i pulled it out... this time i forgot to do that. so i tried to put it back by memory. I couldn't tell if it was all the way in or not. I tried to start the engine, and it wouldn't start. I'm not even sure if it was firing or not, all i heard was the fly wheel turning. soooo yeah, it definitely won't just slot in now.

a related question that occured to me while i was running errands, there was a black/white wire that went to the spade connector on the condensor from the wiring harness, just below the ignition coil. is that wire no longer used with the pretronix? the directions don't address it. They just say black to negative on the coil and red to positive on the coil. i guess i need to figure that out first, then get the engine in the right position, then static time the distributor, start the engine and check the dynamic timing.

thanks for the help guys
Chris Edwards

Okay Im an expert on this...So trust me! LOL.

Putting the dissy back in at the correct place


1st pull #1 spark plug and turn the engine over by hand or stick in 4th gear and roll the car till you see the top of the piston...then look to see if the timing mark on the crankshaft is somewhre around at TDC, If they are set to TDC....

If the timing marks are not showing in the genral area your 180 degrees out...continue to rotate engine agian untill #1 piston is at top (you can use a long skinny screw to bang on top of the piston to varify. then you can align the TDC marks...

Now put the rotor bug on dissy and point the metal tab of the rotor bug pointing to #1 spark plug and insert in the dissy hole, and hook up all the wiring as should be...your there buddy.

NOW to static time the pretonix chip...

You need a test light the kind that looks like a scratch all it has a sharp point with a clear handle with a bulb inside and a long wire with an alagator clip at the end

put the alagorer clip on the positve post of the coil and the test light sharp spike on the negitive battery post turn on the ignition key

the test light will stay lit and should never never go out as you turn the dissy back and forth but the lite will do a step down to dim lite as you turn the dissy back and forth

Now turn the dissy all the way to clockwise (the lite should be bright) then move the dissy counter clockwise until the test lite steps down to a dim light...BOOM your there thats static time, fire the engine put on a test strobe light and adjust accordingly to haynes. tighten the dissy down...and drive till the smile is permenate...your the man


Prop
Prop

chris

the white and black wire is the ignition wire ...it goes on the positive post of the coil along with the red pertronix wire...and the black pretronix wire on the negitive side of the coil

you should have 3 wires on the coil...Okay 4 if you count the big fire that goes in the middle of the coil to the middle on the dissy cap.

1st. the red AND the white/black wire on the positive side of the coil and

2nd the soild black from the pertronix on the negitive side of the coil


Chris,,,Trust me...Ive known you for several years, your more then qualified to do this...Its much simpler then it appears or even sounds...once you get into it, a little common scence, a haynes manual or better yet this BBS and your going to find this to be a snap...seriously with your talent, your in the kiddy side of the pool. It only look deep.

have fun

Prop
Prop

BTW....Ive found this to be part true on some lucas dissys, and Im not sure why...I think it has to do with after market rotor bugs.

sometimes the rotor bug will rub to close on top of the inside of the top of the dissy pressing the carbon rod fully agianst the spring on the inside of the dissy after you put the magnetic collar on the dissy shaft under the rotor bug, if this happens,,, use a file to file off the bottom of the rotor bug...maybe around 1/4 inch

yeah it happened to me also.

Prop
Prop

Thanks Prop,

I have the three wires on the coil (i didn't remove anything from the coil, just added the pretronix wires to the spare spade connections. I am actually speaking of a wire that comes from the wiring loom and went to the spade on the condensor. I think it is no longer used on this set up, but i hope someone can confirm that.
Chris Edwards

Chis

are you saying you have a white and black wire from the cars wiring harness go to the coil

and then a 2nd black and white wire from the cars wiring harness go to the condenser on the dissy?

meaning 2 wires from the wiring harness.... 1 to the coil and the other to the condenser?

prop...intresting
Prop

prop, yes exactly what I am saying.
Chris Edwards

Hmmmm, you got my atten.

I have to admit, Ive had the pertonix for several years, I cant remeber there being 2 seprate wires comming out of the wiring harness as you desribe

Id be tempted to cap off the cars harness wire that went to the condensor and keep the 2nd wire thats from the cars wiring harness to the positive side of the coil


Are the 2 wires the same wire....the same size and same amount of white vs the black stipe


If you can ... perhaps cut back the harness insalation to see if the 2 seperate wires are actually the same wire,,,they might have a spliter inside the harness...if thats the case discard the wire going to the condensor and keep the now singlewire going to the pos. sde of the coil


Prop...stumped by 2
Prop

Chris.... Im sorry... But I think Im giving you bad advice. I am truly sorry

...Until 5 minutes ago I thought I knew what I was talking about.

After looking at a wiring diagram it appears the White and black wire goes to the ground side of the coil NOT positive side of the coil as I was thinking...and a solid white wire goes to the positive side of the coil...But I still belive the white and black wire are the same wire that has just been split.

here are 3 wirung diagrams for the 73 modle year to look over


1. Car Nos. G-AN5-105501 to 128262 (1971-73)

http://www.spridget-tech.com/wiring_diagrams/Diagram_9.pdf

2. Car Nos. G-AN5-128263 to 138800 (1973)

http://www.spridget-tech.com/wiring_diagrams/Diagram_11.pdf

3. Car Nos. G-AN5-138801 onwards (1973-74)

http://www.spridget-tech.com/wiring_diagrams/Diagram_12.pdf

I hope these help and agian Im sorry for any confusion I have created

Prop
Prop

as near as I can tell chris from the wiring scematics from above

on the positive side of the coil you will have the red pertronix wire and the white wire from the wiring harness

on the negitive side of the coil you will have a white/black wire from the wiring harness and the black wire for the pertronix....and you would cap off or remove the white/black wire from the condenor

Im just guessing the correct wire scematic is ither 2 or 3, you will have to check your vin number.

Prop
Prop

Les, I beg to differ when you say the distributor drive cannot come out! It is held in only by the distributor, gravity and suction around the bottom bearing. If you remove the distributor without giving the rotor a little wiggle and don't rotate it in the correct direction as you withdraw it(to push drive gears into mesh) suction can and sometimes will draw the drive up the tube and out of mesh with the camshaft drive helix and out of the bottom bearing. Usually it will drop off the dizzie before escaping completely, other times it makes it to the top. Very annoying, been there done that several times!!!!
Graham.
Graham P 1330 Frogeye

Graham

Do you have an A or A+ block?

With the A-series, the dissy drive should be held in by the 'distributor housing', to which the clamp plate is bolted.
Dave O'Neill 2

I am stunned by the sheer volume of know-how on this board!
Prop, my car would be diagram 2. (GAN5-138609). So i at least have the wires right. white and red wire on positive, black and black/white wire on negative, extra black/white wire not in use.

to clarify, the drive has not come out of the engine. I am merely concerned with getting the key on the rotor shaft back into the slot that turns it.

oh and it is an A series block. (what is an A+?)

thanks everyone, i probably won't be able to get back to the garage untill this weekend, so i will have time to gather test lights and mental faculties.

thanks!

Chris "One battle at a time" Edwards
Chris Edwards

Hey chris...

The A+ is the transverse version used in the mini cooper, has a differant crankshaft and other odds and ends.

The dissy can only slip into the drive gear slot one way....If your able to look into the dissy hole vary closely you will see the slot that the dissy fits into is NOT centered, But rather off set, meaning one half will be bigger then the other half.

With the #1 piston at the top of the cly. and the timing marks aligned at TDC the dissy drive gear slot will be pointing at 8 o'clock and 2 o'clock when you look at the bottom of the dissy you will notice that the pin is off set accordingly

if the dissy dost slip into place, try loosinging the 2 hex scews that hold the locking plate into place..dont remove them...just release the tension until the dissy slips into place, then retighten those 2 hex screw heads

THE TEST LIGHT...the photo is what your looking for...you can find them at any auto chain parts stores for around $10...and $20 for a high end

Prop


Prop

I'm familiar with test lights. I used to have one, but i either broke it or lost it. (i am clumsy)...
Chris Edwards

sorry forgot to mention on the above

<<<<<<<With the #1 piston at the top of the cly. and the timing marks aligned at TDC the dissy drive gear slot will be pointing at 8 o'clock and 2 o'clock when you look at the bottom of the dissy you will notice that the pin is off set accordingly>>>>>>>>>>


once the bottom pin of the dissy slips into the slot of the drive gear at 8 and 2 o'clock the rotor gear metal contact tab should be pointing at the #1 spark plug hole.

if the rotor bug tab is pointing to the oil pressure nut on the block... then the engne is 180 degrees out.

Prop


Prop

Prop

Marina and Ital 1300 used the A+ block which have found their way into Spridgets - and with a bit of smart machining you can also use Maestro 1300 blocks

Regards

JB
James Bilsland

good to know I got the same problem

I got 4 test lights some where in my shop...If you can find one, your welcome to it.

and the other one thats even worse...the red and black leeds that go to multi-testers, they are ither broke or missing

Prop


Prop

Hey James...

I guess the question I have, Is whats the advantage of using a Marina and Ital 1300 set up...is it because the run of the mill A-series is hard to find in the UK?

here the A-Series is almost as common as bird farts...

you know they are there and that they are fairly common, but it still takes a day to find one. and they are always in a similar nasty condition as the bird fart.


prop
Prop

Prop

Go back to your (no doubt) well thumbed and oily Vizard... A+ blocks have stiffening webs cast in and are reputed to be stronger with an overbored and overstroked engine.

Marina/Ital blocks used to be common 10 years ago... They seem to be slightly rarer now though although I have seen them come up on Ebay recently :)

James
James Bilsland

thats good to know...Im guessing they are NOT as common nor as easy to find as a dastun 5 speed here in the USA. LOL

Prop...Yes, I can get an oil change usig only my vizard bible
Prop

The marina is not an A+. Its different to the midget block yes with alternative mounting points and the moved oil filter but it was only with the Ital it got the strengthening webs etc of the A+.

I have my original block and an Ital in the garage with a Marina in the car. I wish I'd got some pictures of all 3 next to each other when I had the opportunity.

One of the non-technical advantages of the Ital/Marina blocks is for a while the horrendous cars they were in originally were being scrapped regularly so the engines were a cheap source of alternative in-line A series blocks (thats where my Ital A+ block came from in 1990ish). I should imagine thats not happening very often now (despite top gear's best efforts).
Dean Smith ('73 RWA)

speaking of top gear....I know this is WAY OFF the road course....

But was that jeremy clarkson doing the Play by play of USA vs Uk bowling team in the weber X cup tournement? Seriously it sounded just like him.

http://www.webercup.com/

Prop...Okay back to topic at hand


Prop

I could be wrong but I was under the impression that some later Marinas had A+ engines prior to the Ital face lift - certainly the earlier cars had a non A+ block with an inverted oil filter - the Marina and Ital cranks are different to Midget cranks as they have a larger big-end journal size allowing offset grinding to get a greater stroke using Midget/S rods...
James Bilsland

Chris
If you havent solved your problem yet, I would suggest you get on to Petronix. I had the same problem recently and they emailed me back with full instructions within 48 hours. They were exceptionally helpful with further questions I had.
You will find a "contact" section on their web page. For after sales service they were brilliant (and no, I dont have any shares in the company!)
I would post my instructions but my set up is with a positive earth, so unlikely it will help you.
Graham V

thanks Graham. I think i have the ignitor installed correctly, i just have to re-install the distributor. at this time, i have no problem with the pretronix equipment (that I know of). once that is done, i will see if the electronics are right.

one tiny step at a time :)

C
Chris Edwards

Graham...you lucky dog.

I called Pertonix about how to set static timing ... and we played phone tag on voice mail which is how I got the info I needed But I never got any email instructions from them...Must be a UK thing.

Prop
Prop

This thread was discussed between 07/02/2010 and 09/02/2010

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.