The Triumph Dolomite Club - Discussion Forum

RJF_70 wrote:Thanks guys, she runs again!! Followed the explanation to a tee and fired first turn. She does have a terrible rattle, but I did find something unusual when I took the rocker off. The cam sprocket doesn't locate into the hole on the chain guide, instead it's actually rubbing the guide but my worry is
A. it's threaded so should it have a nut on it?
B. if answer to above is yes then where is the nut??
it sounds pretty good idling but above 1500 revs the noise / rattle starts, can't work out where exactly its coming from!
Have taken a picture of my finding in case I have used incorrect terminology for any of the parts mentioned..lol

Thanks Rich

Hi Rich; Something I did notice there in the photo was that the camshaft sprocket fixing bolts appear to have spring washers added. Not sure if this is a good idea as they are not listed in the parts book. The tab-washer also doesn't seem to be standard. It should fit flat against the sprocket but yours appears to have a bend in it on the lower side. The support bracket is sitting exactly as mine does. When you service the timing chain you just lever that back onto the threaded section and secure with a nut.
HTH,
Tony.

Thanks Tony, head was refurbished to unleaded in 2011 by previous owners prefered garage and has done less than 2000 miles since. Obviously they have used what they had available? By the sound of things then the cam sprocket / chain doesn't seem to be giving me the rattling I'm experiencing as although the flat washers aren't standard and have a bend at bottom, cant see them fouling on anything and have rotated the engine several times by hand. Just strange that she will idle almost perfectly with no noise, but as soon as revs are over 1800-2000 very noisy! Weather is against all of us today I think but need to try and get a positive diagnosis so I can get on with getting a replacement engine if needed.
Cheers Rich

My eye caught this sentence:

Just strange that she will idle almost perfectly with no noise, but as soon as revs are over 1800-2000 very noisy!

My guess would be your timing is too advanced. Static timing should be set at 11° BTDC, your distributor advances more when revving: too much advance can give a rattle called pinging(?)

It would be worth getting the ignition timing checked now the engine is running. You shouldn't need to do the static timing. Just put a timing light on and see where it is. The book figure mentioned above is the best starting point.

Toledo Man wrote:....The book figure mentioned above is the best starting point.

At idle an 1850 is not at 11 btdc, so the book figure for static means little.

11 static.
15 - 18 ish idle if on points.
Maybe a bit more (not too much) if on basic electronic ignition.

18 at idle and it will run the wrong way round when you start it again.

Jeroen

I got your PM Rich. I hope my pearls of wisdom are of any help. I've suggested checking the fanbelt because I had the same sort of problem on mine. Removing the fanbelt will confirm it one way or the other. It is worth replacing it if it is worn and/or cracked. See if you can shoot some video. I'm sure it will help with the diagnosis.

How is your car coming along? It looks lovely in your signature photo

Kind Regards

Russell.

Rich has been sending me PMs and the problem is one of the spark plugs threads on the head. We're hopeful that cleaning the thread will cure it. Is it possible to helicoil these?

Plug is now seated properly, but still wasn't the problem , It seems to be timed up right, although I'm very rusty on timing light useage. Revs very smoothly up to 1800-2000 revs then the knocking / rattling starts, off the revs and dissapears!
Rich

Dolly-Dimple wrote:How is your car coming along? It looks lovely in your signature photo

Kind Regards

Russell.

Hi Russell, car in my signature is my 1500 auto, which I will be in tomorrow at TDCIR, my 1850 auto is Carmine.
Rich..

Have you tried running the engine without the fan belt? It will eliminate a slipping fanbelt, alternator and fan pulley problems. It has to be worth a try.

Yeah ran without belt yesterday, but still the same so eliminates pulleys!!

Rich, it was good to meet you at the TDCIR. We reckon that it could be the timing chain. You need to get the cover off for better access. If that problem is with the timing chain it will be lower down where the tensioner is.

Toledo Man wrote:Rich, it was good to meet you at the TDCIR. We reckon that it could be the timing chain. You need to get the cover off for better access. If that problem is with the timing chain it will be lower down where the tensioner is.

Likewise Dave, will hopefully know this week how severe the problem actually is! Was a good day today, thanks for all the advice so far.
Rich