potential engine knocking?

[dudload]

morning all!

had a couple of lovely trips out in the car this weekend, but just wanted to check something I noticed whilst going uphill. When in 4th gear and putting the engine under full load to try and keep at 60mph I noticed that the engine makes quite a rattly/vibration sound.

now it doesn't make this sound in any other gear under partial or full load, only in 4th and pretty much when the pedal is to the floor. is this anything to worry about - could it be the timing advance isn't quite correct (would that only affect one gear?)

one other thing I noticed is that when in a low gear and coming off the accelerator theres sometimes a light tinkle - can't quite tell where it's coming from either. hoping this isn't pinking, although is strange that it's when I'm not putting any load on the engine.

[panky]

It sounds like pinking, try retarding the timing slightly. Could also be caused by a weak mixture so check for air leaks, a damaged vac advance pipe is a good place to look.

[dudload]

thanks panky - do you mean it could be pinking in the first, second or both scenarios?

My fault for asking too many questions at the same time!

[panky]

I've experienced pinking in all scenarios you've described and it would normally occur when struggling under full load in top. Try a slight adjustment on the dizzy (a couple of degrees anti-clockwise) and see what happens.

[dudload]

right, will give it a shot in that case. suppose i'll probably need to adjust the carb if it idles rough after adjustment?

[panky]

You may need to but the engine might actually speed up a little, only slight adjustments on the dizzy and try a test run on that hill if you can get to it

[bmcecosse]

Is the oil pressure good? Should be at least 10 psi for every 10 mph in top gear - up to 60 psi/mph when hot.

[dudload]

not sure - haven't got round to buying or fitting a pressure gauge yet.

one (basic) question - when turning the distributor, i take it the securing bolt needs to be untightened before any free movement of the dizzy is possible? if so - is there any special trick to this i.e. when untightened does the thing move of it's own free will and therefore has to be marked or held in place or does it only move when turned by hand?

[dudload]

or am i being a complete idiot and the timing adjustment is at the bottom of vacuum advance?

[panky]

There is a thumbwheel on the side of the dizzy that will give you very slight adjustments but probably better to loosen the clamping bolt at the base of the dizzy and give it a slight twist.

[bmcecosse]

Loosen and turn - only very slightly. But I suggest an oil pressure gauge is a high priority for you.

[dudload]

thanks all - given that we now have sun I will try it this evening

[dudload]

evening all! so i've bought the smith guage, pipe and t-piece and looking to install. however, i can't get at the oil pressure sender unit nut to unscrew as the vacuum advance is bang in the way!

do i need to take the whole dizzy off to give myself space to undo the nut? would rather not as it could put the timings right out and i've never had to do it from scratch before. is it possible to just remove the vacuum advance??

help much appreciated as always

[panky]

You can take the dizzy off from the block without disturbing the timing. Don't touch the pinch bolt but take out the two bolt that fix the dizzy to the block. Make a note of where the rotor arm is pointing before removing the dizzy so you get it back on again in the same position and don't turn the engine over until it's back in.
I did have the same issue when I fitted a new electronic dizzy, the vac advance actually touches the oil pressure switch when the T piece for the gauge is fitted.

[dudload]

thanks - just had to replace the rocker cover gasket this morning as it was leaking slightly and wanted to clear the breather pipe properly.

also - i think i may have found the problem for knocking too - the vac advance pipe looks like it's broken down at the part where it connects to the carb (picture below). Am i right in thinking its part 12B2095 in this link to moss only that i need?

http://www.moss-europe.co.uk/shop-by-mo ... 46a97.html[frame][/frame]

[bmcecosse]

Well yes that looks well knackered - so I suspect the static timing has been advanced to compensate, and is now too advanced when running. If you trim that connector - is there not enough 'good' left to make at least a temporary connection?

[dudload]

yup, does make sense. will trim it and run as a temporary solution until i get a new one. was that part ref the right one Roy?

[myoldjalopy]

That part looks right, although any piece of plastic tubing will work, as long as it creates an airtight seal.............

[simmitc]

If you do decide to to remove the dizzy by undoing the two bolts that hold the clamp to the block, be careful - (a) very easy to drop them and (b) the slots through which they fit are elongated holes, so it is possible to let the timing slip by a couple of degrees. In your case yo might be lucky and find that loosening them will give sufficient adjustment for what you need; just depends on how the clamp was positioned when being fitted.

[bmcecosse]

The couple of degrees on the timing will be easily recovered by gently turning the dizzy back and forth once it's hot and idling. Or take a pic before undoing to see if it's in the middle of the slot or towards one end or the other. And yes I guess item 37 is the bit you need. £1 + goodness knows for post/packing and vat - unless you live near enough to collect! 'Any' plastic or rubber pipe - provided it doesn't collapse flat under vacuum ! Here you get the whole thing for £2:25 right to your door....
http://www.ebay.co.uk/itm/Classic-Mini- ... vnkGlyc7vw