Refitting distributor

Post by **Forumadmin** » Fri Jan 23, 2015 5:28 pm

Moved by Forumadmin.

by TonyBelcher » 23 Jan 2015 01:04 am
Coming up to three months ago since I stupidly removed the distributor without any forward thinking - like three months since the engine was running! From what I remember from the fifties, the points should be opening (just) at TDC. Hard to 'feel' the piston at TDC but I've noticed a handy white arrow on the pulley which I assume is it. Obviously it needs to be on the compression stroke, but even if it isn't I wondered if swapping the plug leads on top of the distributor would
Re: Refitting distributor

Post by Keith Clements » 23 Jan 2015 10:41 am

Hi Tony,
Well first it is worth putting this post in the correct place in the forum.. so which model are we talking about? Once I know I will move the thread to there. This section is really for help on using this forum.

Anyhow. All of what you say is correct but I will take you through how I do it. There are many topics in this forum on such problems and it is best to first find out whether everything was running well before the distributor was removed. Quite often I ignore such information as , from experience, it will cloud your judgement.

The reason for a distributor is to deliver the spark generated by the coil to the plug on the correct cylinder at the correct time. So first do you have a nice blue spark? The way to check this is to remove No 1 plug (front right if looking at the engine). Connect its high tension lead and turn the engine at least 4 full revolutions whilst watching for a spark across the spark plug gap. The spark plug needs to be grounded somewhere on the engine block of course. Do not hold onto it, as you might feel something! It helps if you are not in bright sunlight to see the spark. But you should hear it. Take the usual precautions if turning by hand, such as removing all the spark plugs and also take all the usual precautions if turning with the starter.

Assuming you do have a good spark, we can continue to see if it is being delivered to the correct cylinder.

When you hear the spark it should come when the NO 1 cylinder is at the outside of its travel (Top Dead Centre) but this occurs also at the end of the exhaust stroke as well as the compression stroke of the engine , so we need to find out which. One way is to turn the engine with your finger in the spark plug hole and feel the compression, or you can just leave the the spark plug in just a couple of turns and you will hear the air rush past more on the compression stroke than the exhaust stroke. A sure fire way of telling (assuming the camshaft has been installed correctly!!!) is to look at the valves with the rocker cover removed, to see that both valves are closed when the cylinder is at the top.

If the spark does come when on the compression stroke then we must now check that it fires at exactly TDC. The marks on the flywheel do help here, or there may be one on the drive belt pulley, however they cannot be relied on. There are two marks on the flywheel, the first in direction of rotation is a 12 degree before TDC used for valve timing, the second at TDC is for ignition timing of cylinders 1 and 2. There is usually a third mark 180deg or opposite this timing mark for cylinders 3 and 4 .

So check the marks are in the correct place by dangling a piece of thin wire into the spark plug hole and slowly move the piston up to TDC. You should be able to gauge exactly when the piston pinches the wire and this is thus TDC. Mark the flywheel and pulley with Tippex or similar at this point. But do double check. We need it accurate to 1 mm on pulley and 2 mm on flywheel. Fitting a pointer to the timing cover helps with the pulley accuracy. To get the engine going such accuracy is not necessary and within 5mm either side should allow the engine to fire, but to get it running smoothly it needs accuracy. Turn the engine to TDC on the compression stroke of No 1 cylinder and leave it there for the next test.

We now loosen the distributor clamp and, with cap off but ignition on, move it until we hear the spark. Thus it it is now firing at about TDC. To do this more accurately you should make sure the backlash in the distributor drive is taken up by checking the rotor arm is back by turning in a counter clockwise direction. But such backlash is unlikely to stop the engine firing.

Adjustment of the timing is then best done with a strobe light and road tests. There are many reasons why even running and good performance cannot be achieved, of course, but this is just to get the engine firing.

If you do not have a nice blue spark then we can take you through that. If the engine only fires on one, two or three cylinders then we can also take you through that.

Keith Clements · Post by **Keith Clements** » Fri Jan 23, 2015 9:07 pm

OK Tony now I know it is a Bradford we are talking about, the instructions need slight modification. I did this all on Jack's Braddie a couple of months ago. It is best to use the wire in spark plug hole to get TDC and mark the pulley and front of the block to give you a timing mark. I used the finger in spark plug hole to give me the compression stroke. You only have two cylinders to worry about, but you still need to get the timing about right.

If you do not have a decent blue spark then check the polarity of the ignition coil with a graphite pencil between the gap where the spark takes place and see which way the orange ions travel. You reverse the wires going to the coil if the orange bit is not between the pencil and the engine block. Obviously take care not to shock yourself. One way to do this (not shock yourself) is to rest the ignition lead (perhaps with a suitable set screw inserted) about 1 cm from the crankcase across which the spark will jump. Then introduce the end of the pencil tip into the spark (holding the pencil with insulated pliers). Obviously if you have a pace maker or any other heart condition it is best not to try this! Dry rubber glooves would improve insulation! You could even build yourself a jig to test this and keep yourself well away.

If the points are oxidised, then gently hone them with a 400+ grade emery or replace.They often oxidise up over winter. You can check resistance of the points with a ohm meter. Power off!
Set to the correct gap when heel of points is on top of cam. This can be checked later with a dwell meter.

If the spark looks weak at the points it could be the condenser or earth leakage via the fragile wires inside the distributor. A meter across the points can tell you a lot, but I will leave that for another day as I am shortly off to France.

george garside · Post by **george garside** » Mon Jan 26, 2015 6:09 pm

there should be tdc mark on the flywheel and bellhousing
george

TonyBelcher · Post by **TonyBelcher** » Thu Jan 29, 2015 12:54 am

Thanks, George. I'll have another look tomorrow. Although it starts now it sounds like a bag of nails. I had hoped it would become much smoother with a bit of gentle twisting of the distributor one way or the other but it doesn't. Surprisingly that incredibly slow tick over still IS there. Also the starter motor has a most peculiar rattly sound, almost as though the engine is already running and the starter is trying to keep up with it.
Tony

Keith Clements · Post by **Keith Clements** » Thu Jan 29, 2015 9:29 am

The starter cog may not be returning. Perhaps a screwdriver in the right place and some WD40 might encourage it.
Have you a good spark on both cylinders? Leads/plugs. Take each plug out after running and see if wet with petrol, or dry and thus firing.
Compression on both cylinders? Valves often stick open. Turn engine by hand with plugs in and feel stiffness at TDC.

george garside · Post by **george garside** » Sat Jan 31, 2015 11:44 am

if its only firing on one pot the slow tickover will sound even slower than normal. (a reason for the relaxed ''unbuzzy'' sound of the Jowett twin is that it sounds as if it is only turning over at half the speed of a four doing the same rpm!)
george

TonyBelcher · Post by **TonyBelcher** » Sat Jan 31, 2015 9:05 pm

Thanks each for the latest advice/info. Finally uncovered the TDC arrow on the flywheel but still can't find the corresponding mark on the bell housing. Is it at the top, which would make sense (although it doesn't have to be) and if so, where? I cleaned all the crud off the vertical face of the ally casting but there's nothing obvious.
The chattering starter motor is a bit more serious: I undid the two top bolts but the third one (underneath) was ominously loose. Not only is the bottom cast iron lug snapped off the motor itself - there's also a wide, 3mm crack running fore and aft right through the ally casting of the gearbox at the bottom of the hole where the starter slips in, so the starter was only held by the two top bolts on a sort of C shaped segment. Anyone any ideas how that could have happened or is it a known weak point? Looks like a box out job to get it welded.

Keith Clements · Post by **Keith Clements** » Sun Feb 01, 2015 10:14 am

If it was a Javelin it could be that the torsion rubber on the gearbox output shaft is not able to rotate.
Maybe the housing was not located properly before being tightened up.

A picture would help diagnosis.

Looks like it is engine out and a bit of welding.

TonyBelcher · Post by **TonyBelcher** » Sun Feb 01, 2015 4:11 pm

So.................Good news and bad, I suppose. I went to take the requested photograph and flooded the inside of the van
( with the floor already removed of course ) with lots of light. Took some good pics and noticed, with all this lovely light, the missing TDC mark deeply engraved into the casting above the bellhousing. (Mental note: buy a new lead lamp first opportunity.)
Well that was about two hours ago. Still trying to work out how to send the pics from my ipad, despite your explicit guide. Might have to ring a 10 year old grandchild................. Hope you meant "gearbox" and not "engine".

Post by **Forumadmin** » Mon Feb 02, 2015 11:36 am

Ah iPad, now there I struggle with the technology.

I know that people have acheived it, but others have struggled, so it may depend on version of software on the iPad.

You might find uploading into the Jowett Gallery works as there are many more ways to do adding items there.

If your grandchild does get it to work then please post solution in JowettTalk tips.

george garside · Post by **george garside** » Mon Feb 02, 2015 11:13 pm

cracking of the starter mounting is usually due to over advanced ignition causing a kickback, It seems to be more prevalent on CA/CB than CC.

george

TonyBelcher · Post by **TonyBelcher** » Tue Feb 03, 2015 3:09 pm

So like rotating the distributor to try to get it running smoothly.......... George, you just hit the nail on the head!