The Triumph Dolomite Club - Discussion Forum

My car is making a rattling sound when it changes gear (it is an auto).

It only happens when the car is hot and I think that it is the big ends.

What are the chances of the crank being out of shape ?

I'm assuming this is an OHV model?

I'm a bit wary of condemning the crank without more evidence or hearing the noise for myself. Certainly, the 1500 in particular has a bad rep for destroying big ends, but it's not the only thing that can make a noise like that

Sometimes a cracked auto drive plate can give a similar "death rattle" and i've also found that mild crank wear can be exacerbated by too lean a mixture to produce that distinctive growl on upshifts. This in turn can be caused by something as simple as malfitting or split breather hoses!

On the upside, it is relatively easy to remove the sump with the engine in situ and physically check the big end shells for wear and check the crank for ovality with a micrometer.

HTH Steve

Thanks Steve

It is an 1850 so does that mean it is less likely to be the crank? The fact that it comes on when it is hot is what made me think of the crank.

I will look at the plugs but I think that the mixture is OK.

Maybe I should drop the sump anyway.


While I'm here can anybody move this to the @Dolomite Related ' threads. I have put it in the wrong area.

Yes the 1850 is MUCH less likely than an OHV to suffer from crank related problems. Do you have an oil pressure guage fitted? I'm assuming that the oil light goes out promptly on startup and doesn't reappear on hot idle.

Steve

It did appear once on hot idle after I had given it it's head up the motorway.

Other than that no and the oil lamp seems to go out fairly quickly.

Fitting a new set of b/e bearings can make the engine a whole lot better for minimal costs. I am not sure if you can drop the sump in-situ or maybe raising the engine a bit? If so it may be worth a try. (best to drain the oil overnight before starting the work. And a plastic shower cap....

To remove the sump in situ on a slant 4 you need to remove the oil pick up which is a right fiddle to replace!

xvivalve wrote: ↑Sun Dec 23, 2018 9:57 pm To remove the sump in situ on a slant 4 you need to remove the oil pick up which is a right fiddle to replace!

In my experience it's an easy job but you have to lift the engine a bit.

Jeroen

I would investigate further what the cause of the rattle is before attempting anything. Does the rattle occur only when changing up or also when changing down? Is it worse under load? Worn mains are more usually associated with a dull heavy regular knocking whereas big ends tend to produce grumbling/growling and both change depending on load.

when i first got the dolly i had a rattle sound,i found out the downpipe gearbox bracket bolt was loose and the spring washer was rattling,nipt up and all cured,,,,could bolt be loose causing a washer to rattle,go round all bolt and see if any are loose......just a thought