Distributor disaster

[audi321]

Hi all. You may have seen my other posts about my ignition issues but could I ask those that know if you can advise me.

History is that the car wouldn’t start and I narrowed it down to the distributor. After removing almost the entire intake system I manage to get to the distributor and upon removing the cap, the rotor arm has basically come off and must have wedged itself somehow in the mechanism and basically destroyed the distributor inners into a million pieces.

New one is here but I have no idea on timing as the old one was in bits when I took it off.

So I assume i need to start by putting cylinder 1 at TDC (there’s no marks on the crank casing or anything) so I’ll have to do it with a screwdriver in spark plug 1’s hole with a socket on the crank and stop when it’s at the top (unless there’s a better way)? Then putting the new distributor on and ensuring the rotor arm is pointing at number 1 HT lead? It’s counter clockwise so 3 next with 4 and 2 afterwards.

My main question is. It’s a 4 cylinder engine and I assume there are 2 TDCs - one at inlet and one at exhaust? So I have a 50/50 chance of getting it right. But what if I have it wrong? Can I damage things permanently or will it just not start and I start again?

Or is there a better way to find the right TDC?

Thanks all, appreciate any help.

[LordLoveLength]

Yes there are 2 TDCs, yes remove all the plugs and spin over by hand with a stick in number 1 to find a TDC.
Now mark the crank pulley and replace the spark plug in no1
Now when you turn the engine by hand, on one of your TDCs you will be fighting engine compression.
This is the correct TDC

[GreenV8S]

Take all the plugs out, slowly bar the engine over with your thumb over the #1 plug hole until you feel it coming up on compression. Then you know that cylinder is approaching TDC on the compression stroke. It is hard to judge exactly where TDC is with any accuracy since the piston speed is very low over a wide angle. Best to rock the engine back and forth around TDC looking for positions either side of TDC which are equally far below TDC. Ideally you'd use a gauge for this - a wire/stick will only give you a very rough indication of which cylinder is coming up to TDC and you'll struggle to get enough sensitivity to time the engine from it. In any case make sure your probe doesn't get trapped by the cylinder since you may wipe out the threads of the plug hole or even break something.

[audi321]

Ok thanks guys. I’ve bought one of these fancy bluetooth tuneable distributors so am I right in thinking that I just need to roughly get it to TDC then the Bluetooth tuning will adjust the finer details?

Or do I need to be perfect TDC?

[geeman237]

In your other post on the Classic Car sub forum you have said the car is a 1989 Lotus Esprit. These engine do have timing marks to allow you to find TDC. There is a mark on the crankshaft pulley and a pointer on part of the front casing. There is also a TDC mark and pointer on the flywheel. Open the engine hatch and in the rear panel there should be a rubber bung about 3" in diameter (if its fitted) If you remove that you should see an opening in the bell housing that reveals the pointer. When the engine is at TDC or thereabouts you will see the timing degree marks on the circumference of the flywheel. Then to check you are on the compression stroke you need to look at the intake and exhaust cam pulleys. With the timing marks at TDC, look at the face of the cam pulleys facing towards the front of the car. You should see two slightly drilled dots (they may still have coloured paint on them), the dots are about 3-4mm diameter. These dots should be adjacent to each other and in a line across the pulley centres when on #1 piston on compression at TDC. The rotor arm will then be pointing to plug #1 in the distributor cap.

As for the 123 distributor, I don't think it comes with ANY default advance curve pre-programmed. You need to check with the supplier. AFAIK you will have to find out the curve and type it into the distributor via the app on your phone.

Also, if the 1989 distributors are similar to the one on my 1984 Esprit, the distributor body is spring loaded into the distributor body housing so you have to make sure the distributor is fully pushed home before tightening the clamp.

And as I said in a previous post, I don't think you need any vacuum advance connected to the distributor, so cap the unused vacuum connections off.

[julianm]

Crikey - can you phone your distributor these days?

[Polly Grigora]

audi321 said:

But what if I have it wrong? Can I damage things permanently or will it just not start and I start again?

No problem if you get it wrong, you'll get it right first time if following the above help that suggests checking that Cyl 1 is on its compression stroke

[PositronicRay]

Just to add its fairly important to get the TDC accurate, because all the ignition curves will use this as a base line. Failing timing marks a dial gauge indicator will do the job.

They'll have one at the rolling road.

[Cold]

geeman237 said:

In your other post on the Classic Car sub forum you have said the car is a 1989 Lotus Esprit. These engine do have timing marks to allow you to find TDC. There is a mark on the crankshaft pulley and a pointer on part of the front casing. There is also a TDC mark and pointer on the flywheel. Open the engine hatch and in the rear panel there should be a rubber bung about 3" in diameter (if its fitted) If you remove that you should see an opening in the bell housing that reveals the pointer. When the engine is at TDC or thereabouts you will see the timing degree marks on the circumference of the flywheel. Then to check you are on the compression stroke you need to look at the intake and exhaust cam pulleys. With the timing marks at TDC, look at the face of the cam pulleys facing towards the front of the car. You should see two slightly drilled dots (they may still have coloured paint on them), the dots are about 3-4mm diameter. These dots should be adjacent to each other and in a line across the pulley centres when on #1 piston on compression at TDC. The rotor arm will then be pointing to plug #1 in the distributor cap.

[audi321]

Thank you for that picture. However I don’t have coloured dots but I have white dots. You think this means TDC? Also these pulleys must be on wrong way round for me as that says EX but it’s the inlet pulley!

[Polly Grigora]

Good to see you're getting close now

[Cold]

The cam timing was adjusted to suit depending on markets and MY from the factory. The EX cam wheels were used as a ready made solution to achieve the required overlap so don't concern yourself about this. It's normal.

[audi321]

Quick update. I got the 123 tune + distributor installed and it’s running dog rough.

Is the TDC setup just a rough guide and I should get it timed properly by my garage and a timing light?

[PositronicRay]

audi321 said:

Quick update. I got the 123 tune + distributor installed and it’s running dog rough.

Is the TDC setup just a rough guide and I should get it timed properly by my garage and a timing light?

It's a long time since I fitted one, mine came with an LED so finding TDC was a cinch. I did need to fit new HT leads though.

[rigga]

Not fitted one, but assume the 123 has variable advance , but would still think initial set up would need it to be timed correctly at idle.