Engine noise

[Brian Cole]

I posted a few weeks ago under 'clutch rattle'. It transpired that I had the clutch rod the wrong way round, it is now the rightr way but I still have the rattle which can best be described as a fairly high frequency jingling scrapy rattle. There is no noise at all when the engine is pulling, it is slightly evident when running on a light throttle and increases dramatically when initially braking on the engine in top or third decreasing again with reduced engine/car speed.
I realise how difficult it must be to diagnose what in effect is a quite alarming noise, from a mere description, but before I start ripping the car to bits, it"s actually running very well at the moment, I thought I would give our knowledgable members a chance to make suggestions as to where I should be looking for the problem, it may be that someone has had a similar experience in the past. I'm losing sleep over this , Please help if you can!

[Forumadmin]

Amy had a tinkling noise in the SC when engine speed altered. It turned out to be the fan had sheared from the boss.
This however could be clutch pressure plate or gearbox input shaft or possibly the fan hitting something when the torque reaction turns the engine on braking.
Is the frequency of the tinkling different depending on which gear you are in? Does it stop when you depress the clutch? This would conclusively prove which side of clutch and which end of gearbox it is coming from. Some substitute clutch pressure plates can foul the operating fork, or if you have the wrong length clutch ball (or it has not seated properly against gearbox housing) this can also cause the operating fork to foul the pressure plate. The other possibility is a layrub hitting the chassis.

[Brian Cole]

Thanks for the quick reponse Keith, I think I have tried dipping the clutch but the rattle is still there. Reverse torque is precisely what I think could be responsible, and I will certainly check the fan blades and make sure all cables etc are out of the area. I did wonder if the reverse torque could be causing a bulge in the timing chain,? thus settting up contact with possibly the oil feed pipe. or the casing. Next time out I will check the frequency in top and third, to see if there is any change, and also have a look at the floor tunnel over the layrub, I know it's close. Your suggestions have got me thinking, I want to nail this down because it is spoiling my motoring, I feel unhappy at the prospect of doing any distance until I have this sorted. Many thanks for being a proactive forumadmin!

[jowettgeoff]

I go along with Keith's suggestion of the fan blades. I had this recently on the Jup, and it turned out that the fan wasn't quite 'square' with the chassis, causing one of the blades to catch on one of the chassis cross tubes. I don't think the timing chain is to blame, as the tension on the chain is the same whether or not the engine is on overrun (because the crank is still turning the camshaft against the resistance of the valve springs).

Happy hunting.

[chapman]

I had a similar problem after a bottom hose burst and the engine boiled and the problem turned out to be the water pump bearings ( the noise at 60mph was unbearable)
You can check this by removing the fan belt and try the car without it .
The water pump will probably leak as well but don't check it with your figer like I did as it takes the end off the second finger and shatters the index finger.
If the water pump is the problem talk to Drummond

[Keith Andrews]

A mechanics stethoscope works majic, even when one thinks there is no noise at kurb speed
And other addition is an elcheapo doctors sterthoscope. held in the enginbay and turned to locate direction of any noise.
The only noise tap whatever I have ever had troubles with locating is a collaspsed piston skirt in a V8...and that was trying to confirm what I thought in the 1st place.

[Brian Cole]

I cant remember, seems to happen a lot in my dotage, whether I have added to my post regarding the glitch I was having with engine noise/ rattle. During a later routine check on the engine timing I noticed that the two tiny screws that hold the distributer points mounting plate in place had loosened. allowing the plate and moving contact to jump around. This would most likely have been the cause of the missing that I was experiencing at certain engine speeds, and possibly also the aforesaid "jingling rattle"?. The two screws had not been fitted with anti vibration washers and so I fitted them and much to my delight the missing and the jingle now seem to have gone. No doubt I shall now hear new noises not noticeable previously !
Forgive me if I am repeating myself, but as this is something that can be easily overlooked, the information could benefit other members who might have had similar problems.
There seem to be fewer postings on the Jupiter site thes days, so I guess are all our cars must all be running superbly. Looking forward to Llandrindod!

[Keith Clements]

Well done Brian. Those screws can be a problem. If they get caught up with the rotating weights all hell can break loose!