The Triumph Dolomite Club - Discussion Forum

dollyman wrote: ↑Mon Dec 20, 2021 2:49 pm Mmm, remove fanbelt and see what happens? To be honest it doesn't sound serious as i'm sure it would have gone bang when you took it up to 6K

Tony.

Would it go bang instantly? I didn't hold it there for long, just wanted to see if it would rev. I am guessing it is not wise to hold an engine at high revs, with no load, for a long time.

Ok, getting a bit baffled by this. I had ago at running the engine without the cam cover. What I have discovered, is if you do this the engine attacks you with oil, mainly flying off the timing chain.

Alas the oil system appears to working perfectly, with oil dropping out of the ends of every finger. The timing chain is rock steady, with no movement. Pulling the leads makes no difference to the noise.

I have changed the oil and filter, so it is possible that has unblocked something. I was hoping i might find some water in the oil, a nice head gasket failure diluting the oil and explaining the issue. Alas the oil was pretty much perfectly clean, no water, no bit of metal. So I am a bit baffled, unless it is simply the crank is worn and needs replacing.

if you do this the engine attacks you with oil, mainly flying off the timing chain.

Sorry, forgot to mention that

My chain remained tensioned when the slipper pad detached, but I don't think you can see the tensioner location from above, from memory, but the noise there is more of a rattle than a knock...

Some time ago I had a loose bolt on the timing cover which was rattling against the back of the fan pulley.

Here is a link to what I found. It's about 1/3 of the way down.
https://forum.triumphdolomite.co.uk/vie ... lt#p288618

Tony.

xvivalve wrote: ↑Tue Dec 21, 2021 4:48 pm

if you do this the engine attacks you with oil, mainly flying off the timing chain.

Sorry, forgot to mention that

My chain remained tensioned when the slipper pad detached, but I don't think you can see the tensioner location from above, from memory, but the noise there is more of a rattle than a knock...

The conclusion I have come to is the crank is just worn out, it must have been pretty much on its last legs and now it needs replacing. Since it is already been ground to .20, I don't think there is enough meat on it to reground it. So i will have to keep an eye out for a replacement and lift the engine out when the weather improves.

MIG Wielder wrote: ↑Tue Dec 21, 2021 5:46 pm Some time ago I had a loose bolt on the timing cover which was rattling against the back of the fan pulley.

Here is a link to what I found. It's about 1/3 of the way down.
https://forum.triumphdolomite.co.uk/vie ... lt#p288618

Tony.

I would like it to be that and I will have a look but I did point a timing light down there and I would have thought I would have noticed something like that.

You can grind to +30 or +40

I have a selection of used cranks lying about the place if you'd prefer to keep to a shallow grind

xvivalve wrote: ↑Tue Dec 21, 2021 6:24 pm You can grind to +30 or +40

I have a selection of used cranks lying about the place if you'd prefer to keep to a shallow grind

I thought that .20 oversized were the largest bearings available? That is why I didn't get the crank reground before fitting, which now looks somewhat of a blunder.

I have both +30 and +40 good quality bearings on the shelf. I've seen some +60, but would suggest with cranks being available that might be a thou' or two too far

Not really convinced it's crank related to be honest? If was a big end the plug lead trick would tell you. If it was mains you would have low oil pressure..... I don't think i would be pulling the engine out just yet? I would continue driving it and see if it gets worse or let someone else have a listen.. Just another pair of ears.. Where are you based?

Tony.

Does the noise sounds as if it's engine rev related or more of an intermittent knock? Does it get worse when revs rise/revs fall or the same all the time? Any signs of excessive play or seizure in the jackshaft related items? (Dizzy, oil pump. water pump, timing gears)

I know it's stupid... but I'll ask anyway, no excessive dents in the sump or the timing cover?

Not knowing the type of sound youre hearing its hard to say really. Can you see the end of the tensioner where it contacts the chain itslf? If so make certain the rubber pad is attached still. I have pulled a few apart where the sides of the timing cover has wear marks where the chain had been slapping.

With the cam cover off Id be tightening the exhaust shims to get 10- 12 thou tbh (set each set of rockers to where you measure the clearance and get an allen key between the rocker and the valve retainer, pull it back and lift out the shim with a magnet, release spring get new shim and do the same to fit it)

Tony

It is frustrating because everything apart from the noise suggests all is well. There appears to be no loss of oil pressure, no coolant loss, no play or excessive movement. All the tests I have tried so far have said everything is OK.

Yet there is a noise that increases with revs and things do not sound healthy. Neither does it sound like it is coming from the front end, though I guess the next thing to do is to pull the timing cover and have a look.

can you take a video with your phone, upload it to youtube and put the link to here, then we could listen to what you are getting.
i did this when i had a problem knock after a rebuild and instantly was pointed in the right direction.
https://forum.triumphdolomite.co.uk/vie ... =4&t=36083

Manta wrote: ↑Fri Dec 24, 2021 3:33 pm can you take a video with your phone, upload it to youtube and put the link to here, then we could listen to what you are getting.
i did this when i had a problem knock after a rebuild and instantly was pointed in the right direction.
https://forum.triumphdolomite.co.uk/vie ... =4&t=36083

Will do but I will have to put the top end back together before doing that, so it might be a few days.