Question; What makes the distributor drive shaft shear off at the oil pump drive. That thin flat shears of, and to remove it you have to take all the front off because it’s jammed in?
This has happened to a Javelin in South Wales twice within 6 months!
On the first occasion the car was cruising at about 65mph on a dual carriageway when all of a sudden the engine stops. On inspection the drive tag was sheared off, , the bob weights were all smashed up, all the plug leads were ripped of the plugs and the distributor turned round.
I supplied a replacement distributor ( early type – one I had in my shed that was in very good condition with little to no wear). It was fitted by a long served Javelin enthusiast and club member, timed and set up, started and it ran well with no adverse effects. The car has been running well since until last Thursday when exactly the same thing has happened, again when cruising on a dual carriageway.
The particular car was rebuilt a number of years ago. It has been maintained and used regularly. On occasions that I have driven it and ‘it pulls like a steam engine’ and far better than some other Javelins I’ve been in or driven. It’s quite and there are no strange noises. Before the two breakdowns no warning noises were reported.
So, whats going wrong. Is it just fait or is there something fundamentally wrong.
Jowett distributor - failure
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ian Howell
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From 1966 to '67 Black deLuxe Javelin LDF 738 (Scrapped with broken chassis)
From 1967 to '87 Black de Luxe Javelin MKC 1 (later 6469TU). (Sold as non-runner with tons of spares, 1987)
From about 1980 to '87 ex WD Jowett stationary engine. (Sold on)
From 1966 to present, 1930 Long Four Fabric Saloon, Dark Blue / Black.
Taken in a part-repaired state to the 2010 Centenary Rally, returned to a roadworthy state by 2013. - Given Name: Ian
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Cause and effect.
I suspect that something went adrift in the upper rotating parts - e.g. the bob weights or their pivots. This locked the rotating parts to the distributor body, pulled it round against the clamp and put an intolerable load on the drive shaft at the point where there is a 'stress raiser' where the shaft thins down to slot into the oil pump.
Twice in a few months seems odd though. Anyone else got any thoughts?
I suspect that something went adrift in the upper rotating parts - e.g. the bob weights or their pivots. This locked the rotating parts to the distributor body, pulled it round against the clamp and put an intolerable load on the drive shaft at the point where there is a 'stress raiser' where the shaft thins down to slot into the oil pump.
Twice in a few months seems odd though. Anyone else got any thoughts?
The devil is in the detail!
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Forumadmin
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1. How many miles had the distributor worked in the car before it broke?
2. Had you oiled all the parts that needed oil?
My guess is that a weight flew off because a spring broke, jammed the cam because the plate moved up. Should be able to tell by looking at the broken parts. A picture?
Could just be a screw fell out ! Easily done. I always fit with Loctite.
New dissies make a world of difference to the running.
2. Had you oiled all the parts that needed oil?
My guess is that a weight flew off because a spring broke, jammed the cam because the plate moved up. Should be able to tell by looking at the broken parts. A picture?
Could just be a screw fell out ! Easily done. I always fit with Loctite.
New dissies make a world of difference to the running.
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David Morris
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Jowett Distributor - Failure
Hi there,
A bit of an update on this problem.
John Airey and I went across to South Wales and helped out this week in getting the Javelin in question running again.
We are as mystified as everyone as to why this has happened to this car twice in a year. From an examination of the failed parts, it looks as if the failure of the distributor was caused again by one of the advance weight springs snapping. At least, there is no sign of the spring now! The second one is still there.
The weights have mangled and probably jammed themselves against the inner body of the distributor and the result was that the tang at the bottom of the distributor drive shaft snapped off. The car was then dead on the hard shoulder of the M4, and needed to be recovered home. On both occasions when this fault occurred, the Javelin was at full throttle....
To get things going again, we have replaced the distributor [which I should add is the early type, with the external advance/retard diaphragm].
At the same time, we have also changed the drive gear on the end of the crankshaft and the oil pump. This is to try and remove possible causes for the distributor 'snatching' and causing the failure, which we would wish to avoid happening again. We tried to pick the best drive gear out of three to hand, but all three were pretty worn. We also made sure the oil jet on the oil pump for this gear wheel was clean.
With these units changed, and a replacement distributor, she burst into life again. I should also add that we needed to change the capacitor to get her running and to simplify matters, we swapped the whole baseplate from a Bradford's distributor, in the assumption that Bradfords and early Javelins shared the same distributor baseplates - they certainly look the same? Is this the case, or are there some dimensional differences that we should watch out for here?
Anyway, she is running again and we hope sincerely that it has been a case of 'lightening striking in the same place twice'.
Any advice would be most welcome.
All the best
David
A bit of an update on this problem.
John Airey and I went across to South Wales and helped out this week in getting the Javelin in question running again.
We are as mystified as everyone as to why this has happened to this car twice in a year. From an examination of the failed parts, it looks as if the failure of the distributor was caused again by one of the advance weight springs snapping. At least, there is no sign of the spring now! The second one is still there.
The weights have mangled and probably jammed themselves against the inner body of the distributor and the result was that the tang at the bottom of the distributor drive shaft snapped off. The car was then dead on the hard shoulder of the M4, and needed to be recovered home. On both occasions when this fault occurred, the Javelin was at full throttle....
To get things going again, we have replaced the distributor [which I should add is the early type, with the external advance/retard diaphragm].
At the same time, we have also changed the drive gear on the end of the crankshaft and the oil pump. This is to try and remove possible causes for the distributor 'snatching' and causing the failure, which we would wish to avoid happening again. We tried to pick the best drive gear out of three to hand, but all three were pretty worn. We also made sure the oil jet on the oil pump for this gear wheel was clean.
With these units changed, and a replacement distributor, she burst into life again. I should also add that we needed to change the capacitor to get her running and to simplify matters, we swapped the whole baseplate from a Bradford's distributor, in the assumption that Bradfords and early Javelins shared the same distributor baseplates - they certainly look the same? Is this the case, or are there some dimensional differences that we should watch out for here?
Anyway, she is running again and we hope sincerely that it has been a case of 'lightening striking in the same place twice'.
Any advice would be most welcome.
All the best
David
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Forumadmin
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One further thought.
I looked at my collection of about 15 Jowett distributors and found most of them had worn stops that limit the travel of the advance and hence may cause the weights to go further than normal. Could this cause then to hit something?
Also springs are made of hard metal which after 50 years is probably fatigued.
I looked at my collection of about 15 Jowett distributors and found most of them had worn stops that limit the travel of the advance and hence may cause the weights to go further than normal. Could this cause then to hit something?
Also springs are made of hard metal which after 50 years is probably fatigued.