There is a loud engine clatter coming from our 1936 ruby, I am unsure where to start looking for problems.

Symptoms are:

The clatter seems to get worse the longer the drive, presumably related to engine temp in some way.
The noise is in time with the engine, rather than the road speed and is a fast clatter (possible one clatter every revolution of the engine)

On full throttle there is no clatter (unless very high revs), likewise when engine braking there is no noise, it is only there when at part throttle. It is present in all gears including neutral when revved up slightly.

Any ideas where to start looking to find the issue?

I can get a video in the coming day if that will help.

Location: Cirencester, UK

Hello George and welcome to the A7 clan.
A possibility is that the noise is caused by the ignition being too far advanced. I am guessing that you have a later, automatic advance and retard distributor. If so, the advance and retard can be adjusted manually.
Have a look at The Dorset Austin Seven Club site under "Technical Pages" - "The Austin Seven Auto-Advance distributor".
It would be ideal if there is an A7 owner near you who could give you some backup if you are at all apprehensive about having a fiddle!

Location: Near M1 Jtn 28

If I had a loud clatter I would be careful about taking the engine to high revs! Hopefully it will turn out to be something sraightforward to sort out.

Hello George,

In my experience, this is a symptom of one of two problems:

1) Big end failure, especially on a 3 bearing with shell rods

2) End float in the dynamo shaft, when you have examined the big ends and found that they are fine.

You might detect that I have been down this very path on more than one occasion!

Regards

Tim R

Location: North Wiltshire

Hi George.

Having first established that your distributor has not moved round (i.e.. the clamp is still tight) what I would do is try and isolate the noise. Use a length of dowel, for example, as a "stethoscope" to determine where the noise is coming from.

You could establish if the noise is coming from one or more cylinders. With the engine running, short out each of the HT leads in turn. If the noise stops with one of the spark plugs not firing, you can probably deduce that the problem lies with the piston or rod in that cylinder.

One of the symptoms of a failed big end bearing is a knock on the over run rather than under load.
Have you checked the oil pressure? Too high a reading can indicate a blocked oil jet.

Location: Derby

My guess would be a loose flywheel. Both driving and over-run torque holds it firmly one way or the other hence no noise in these conditions.

Location: Melrose, Roxburghshire

Hi George,
It is very difficult to diagnose a noise related problem from a description.
It's best to join your local Austin Seven Club and have an experienced Seven owner have a look and a listen, in the mean time, try backing off the ignition slightly and see if that makes a difference.
J

Location: As far east in Kent as you can get

Thanks for all the advice.

I am avoiding driving it at the moment until I have found the issue so hopefully I won't make anything worse. I am completely new to Austin 7's so please excuse any of my silly or ignorant questions!
I have an advance/retard lever on the steering column which has been 'fixed' in place using a hose clamp, the previous owner said not to adjust it unless I knew what I was doing as it runs nicely how it is set. The car did come with some spares, one of which looks like a brand new modern distributor, should I go about fitting it?

I wouldn't know where to start with checking big ends so I will try and eliminate everything else first, I had thought to myself that it might be the flywheel so I will get on and check that if I can.

Location: Cirencester, UK

Hi George,

When you run the engine at the speed which induces the "clatter", press the clutch down. If the noise stops or is significantly reduced then I would suspect a loose flywheel.

Location: Stretham

Hi George

A 1936 Ruby should have automatic advance on the distributor (DK4A), so if you have a lever on the steering column, this is non-original and is an alteration that someone has made.

If the timing is wrong, as others have said, the engine will rumble, the alteration that has been made may or may not be a problem, but I wonder why someone would revert from an automatic set-up to a manual adjustment, a retro-grade step back!

When checking the static timing, care needs to be exercised with the initial setting, the owners handbook (did not get updated...!) & much written info relates to cars with manual adjustment levers (which it sounds as if you have!), but for cars with the automatic advance, the position the flywheel has to be in is different, approximately 3/4" to 7/8" as measured back from the Top Dead Centre point (marked on the flywheel as 1/4, which means cylinders 1 & 4 are at the top of their stroke - make sure that the cylinder is on its compression stroke otherwise will be 180-degrees out), number 1 cylinder should be on the point of firing when looking at the points.

The assistance of a local owner & a methodical approach will help, have you thought about speaking to the previous owner? Might be worthwhile and you could ask about the advance/retard lever that was fitted.

Good luck, a photo of your set up would be interesting to see.

Location: Saltdean, Brighton

The previous owner seemed to have a general knowledge of 7's although he didn't seem to know this one too well as he had only owned it a year and he said he had done less than 10 miles in it during his ownership.

I have taken some pictures of my distributor setup, perhaps this will shed some light on whether I have the auto advance or not! I am very much learning as I go so all info is very helpful.

Thanks,
George





This is the lever on the steering column, ignore the aftermarket indicator switch!




This is the new distributor that came with the car:

Location: Cirencester, UK

Intrigued by the domestic plumbing arrangements from the side water inlet - where / what does the half inch copper pipe lead to on the nearside of the engine ?

The lever attached to the steering column would appear to be off a bike / lawnmower of some description, though the cable does appear to link to the distributor with a spring going forward toward the radiator. This is not as it would have been originally for a manual distributor, though as Gary has said, yours should be an auto advance distributor.

The new Bosch distributor will need some work before you can fit it, for a start the drive dog will need to be replaced by a drive gear - I believe new gears are available. The body may also need machining, if that hasn't already been done, I suspect it hasn't.

Jeff.

Location: Almost but not quite, the far North East of England

Location: Cirencester, UK

This post below and others - key 'Bosch Distributor' into the search box at the top of the page, give an indication of what needs to be done.

http://pub25.bravenet.com/forum/static/show.php?usernum=2099944454&frmid=5&msgid=987821&cmd=show

I'd think most of the Cherished Suppliers will stock the new distributor drive gear - Austin Reproduction Parts have it at £22

From the depth of the body, the Lucas distributor fitted to your car does appear to be an auto advance unit, though whether the weights and their associated springs are working correctly is something that would need to be checked.

Jeff.

Location: Almost but not quite, the far North East of England

Here is a photo of my dizzy, this was re-built by Distributor Doctor, and yours should be the same, I can't see the purpose of that gubbins and if your distributor is properly secured (looks like all the bolts are there as they should be), then none of that will do anything, so you could safely remove that stuff.



Your dizzy should have a plaque on the side and if it has DK4A then it is the correct part for your car! Whether it works well or not is another matter!



There is plenty on the Forum regarding the Bosch distributor and you will have to make your own mind if that is the way to go. I put electronic ignition inside (Aldon), so I have dispensed with points & condensor, I am pleased with this set-up.

Given the arrangement on your car, the spare dizzy that came with it, it might be that the ignition timing would be a good place to start!

Location: Saltdean, Brighton

George on the aluminium dynamo/fan mount on the carb side should be a metal cover with two bolts securing it. If you loosen the bottom bolt and remove the top bolt you should be able to swing this out of the way, this will expose the dynamo gear and the camshaft gear. You can check the backlash on the camshaft/ crankshaft gears by rocking the pulley that drives the fan. Give the top dynamo gear a prod to see if it is secure, you can also twist it to see the backlash. By the colour of your fingers you should be able to tell if oil is getting in there as well. For saftey you may want to disconnect the battery to avoid the possibility of a geared finger. My dynamo gear had come loose and the noise is much less with it secured!
Good luck
Gordon

Location: Surrey United Kingdom

I doubt if spark timing is the cause, but it is something which often baffles newcomers.The topic is spread over a myriad posts and not all easily traced. Try “Piston BTDC query”.

For the old hands it is a non issue but those unfamiliar with the cars, vintage performance and vintage engine, it is a challenge. The two different original auto advance distributors, each with different static setting, the handbook blunder, the mixed and/or worn internals, substitute distributors, the altered heads, crs, etc complicate matters. For crank life the absolute minimum advance for no significant performance loss is the ideal. Those with manual systems can experiment underway. A lockable manual override is similarly convenient for sorting the basic auto advance setting, and it gives you something to play with on boring drives. Seems this is what you have. Possibly worth retaining until you become familiar with the car and its sounds. Performance must not be judged by noise. ¾ inch static advance was advised as conservative setting for 3/6 deg distributor and tdc for the 8/16 deg distributor, in original condition and conditions.

Bob Culver

Location: Auckland, NZ

Looking at the photographs of your dizzy & control lever it appears to me that some previous owner has made a modification to a auto advance dizzy to a manual one. My advice is take off the spring that goes forward towards the rad also the control wire that is attached to the stealing column. Take off the distributor base plate and check the bob weights. Put it all back together as an auto advance unit. Time up the ignition timing and see how it goes.

John Mason

Location: Nottinghamshire

All this talk of timing issues is,I think, a red herring.
Over advanced ignition would surely produce the loudest 'noise' at full throttle - car accelerating.
Without actually hearing the 'loud engine clatter', and from the OP's description, I would suspect big ends.
I sincerely hope I am wrong here.

Location: Bonnie Galloway

I would suggest big end problem.

Try removing one plug lead at a time on moderate revs to identify which rod it might be.

Agree with Dave W and Ruairidh - plenty of guessing about electrickery, but we're not really sure that's the problem. I'm not a doomsayer, but I'd be looking for something more mechanical. Sorry. Cheers, Bill in Oz.