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MG Midget and Sprite Technical - 1500 won't start

Please help me find something obvious I must be missing.....
1976,1500 midget engine running fine before removal to replace exhaust manifold, broken timing chain tensioner, thrust washers and other engine 'freshening' items.
Engine back in car and I beleive everything connected and hooked back up, she cranks over nicely but won't start.

I have spark at the plugs and fuel getting to the carb (plugs wet) but get only a occasional misfire out the carb or backfire out the exhaust.

First thought was a timing issue...I have had the distributor drive gear out many times and tried reversing it's position on the camshaft gear. No luck there. I beleive I have it positioned correctly and engaged in the oil pump drive dog as the slots are at 8 o'clock/2 o'clock per manual description with the No. 1 piston at TDC on the compression stroke (no.1 and 2 valves closed, just rocking between open and closing as I turn the crank just a bit).
With the drive gear in the above postion, and the distrbutor inserted, the rotor points to the no. 1 plug wire on the distributor cap. Do I have that correct?

It is a different distributor than the previous one. I now have a pertronix Ignitor and associated coil installed but have the same electronic ignitions in my other british cars so I am familar with their installation, or so I beleive.
I even re-installed the old one but to no avail. Anything to do with the non-ballasted system I have now and did not have before? Other wires needed at the coil besides iginition wires(WLG) and red and black from distributor?

Plug wires correct? 1,3,4,2...Looking down at the cap standing at the driver's fender...No.1 at bottom left, No.3 at bottom right, No.4 at top right and No.2 top left.

When I was freshening engine I did replace timing chain but was careful to keep my timing marks aligned on the gears upon installation.

Other changes were replacing mechanical fuel pump with electric, although this was done prior to engine removal and I do feel I'm getting fuel as I can smell it out the exhaust after cranking. I stick my finger in the carb throat and it does come out wet.

Compression, fuel, spark....What am I missing?

Thanx for any input....
DS





Dennis Silance

try a fresh set of plugs...if your getting that much fuel, they may have fouled


Go back and re-read the hayes manual on the dist. drive dog...I have the 1275 and it says to align it at 8 and 2 also, I find that a little odd that 8 and 2 would be correct for both engines...Its certianly possiable, But im wondering if you got the wrong chapter for that part.
Prop

Here's a picture of my 1500. I see a few differences...my #1 on the distributor cap is at the 3 o'clock position, your's is at 7, also I'm using a solid white wire for coil positive...it gives a full 12 volts for my 3 ohm non ballast coil. On my engine, the WLG wire is a ballast wire and I only get 8 to 9 volts through it. I would make absolutely sure you have the timing right...backfiring sounds like ignition problems.

Also when I installed my Pertronix distributor, set the timing static with a test light to intially start, then used a timing light to set correctly ( I was 12 degrees too advanced with static timing).

Good Luck, hope this helps.

Dave


DL Rhine

After a little more thought, I think you've set #4 at the compression stroke and have the distributor 180 degrees out.

Someone out there correct me if I'm wrong: my thought is if valves 1 & 2 are rocking between open and closed, #4 is ready to fire. When valves 7 & 8 are rocking, #1 should be ready to fire.

I always remove #1 plug, stick my finger in the hole, spin the engine (compression pushes finger) using a jumper on the starter solenoid and get close to TDC on #1 that way.

Let us know what you find

Dave
DL Rhine

Dave, after posting this thread and re-reading it, the same thought occured to me. Maybe I'm wrong with my compression stroke assumption.
Sure enough... I went back out into garage after lunch, made that change and with a little turning of the distributor, she fired up.

Interestingly, my number 1 wire ends up at the 9 o'clock position when engine is running.

Dennis Silance

You are correct Dave.

If the valves are rockng between open and close then the cylinder is NOT on the compression stroke, and you will be 180 degrees out.

Robert (Bob) Midget Turbo

Sorted whilst I was posting. Good job done.
Robert (Bob) Midget Turbo

Don't worry about 3 or 9...don't really know which one's right...SHE'S RUNNING...that's good enough.

Set the timing with a light & she should be good to go!

Dave
DL Rhine

I also had to re-time my engine when I fitted a Pertronix years ago. Apparently the triggering point for the electronic unit is different than for the points, so it wasn't just a simple swap-it-and-go.

Glad to hear you got it sorted!

-:G:-
Gryf Ketcherside

Dave wrote:

>>> also I'm using a solid white wire for coil positive...it gives a full 12 volts for my 3 ohm non ballast coil. <<<

Yes, my car has that same wire - and yes, I once used it to power a coil too. Originally, that particular wire would have led to one end of an external resistor. The other end of the resistor was connected to the original-spec distributor. Once you go to a different dizzy (as most of us have), that wire hangs around with nothing to do, and can be used to power other things, like neon under the car. ;-) (Just kidding, Prop.)

Just FYI - wanted to mention that because the wire shows up on the schematics.

-:G:-
Gryf Ketcherside

Gryf

Yep, that's the wire I'm using now.


Bought the car back in June...got it home & found alot of piss poor repairs & maintenance by previous owners, I'm still in the process of getting it all sorted.

I'm thinking about using relays & additional fuse box in the electrics for ignition, headlights, carb choke (Webber DGV), etc.

Owned a TR GT6 back in the day and did that...took alot of load of switches & circuits.

Dave
DL Rhine

This thread was discussed between 04/10/2009 and 06/10/2009

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