240 General: Ignition problem

[Bob 1967]

Another view , no marks visible.

[Bob 1967]

There is a line in the casing , could this be it ??

[Othen]

Originally Posted by Bob 1967

Hi , its automatic , so no tachograph.
As Alan correctly stated ,my primary mission (and it has turned into one ) is to check ignition first and work from there.one thing at a time.
I can set ignition and am capable of most jobs on any engine.
unfamiliarity with aspects of Volvo cars is why I ask particular questions on the forum.
That's why we are all here to help each other, from knowledge gained through our own experience.
I've removed fan shroud ,fan and loosened alternator belts so belt cover could be removed.
I suspect the aux wheel is out, but cant see marks on casing
The " Dot" seems to be around the 2 'O clock position . Ill clean it and try to see it.
i'll post a pic asap.

Hi Bob,

The RB is an auto as well, but has a tacho - specifications probably varied from market to market.

It certainly looks as if the auxiliary shaft is out of synch with the camshaft - it should be at about the 3 o'clock position - yours is about 2 o'clock. It looks from your later photos that the metal back plate on your engine is of a different design to the RB. I remember having a lot of difficulty locating the timing mark, it was a tiny indentation I could just feel with a sharp screwdriver. I think that mark you have highlighted in blue on the photo is almost certainly the timing mark on your motor car Bob. I think it would be worth putting a blob of paint so you may identify it easier.

Have you located the mark on the bottom pulley yet? That is somewhat easier to find - again mark it with some paint.

It looks like you have found the problem - the auxiliary shaft is a tooth or even two out - that would be either (about) 9 or 18 degrees. It is unlikely that the belt has jumped (unless it is really worn, but it looks okay in the photos) or the tensioner is slack. It was probably put on that way, with the distributor adjusted to its limits to compensate. If it was running right on the edge of the distributor's adjustment range then perhaps some small change knocked it over the edge causing the poor running the other day?

No matter, it is free to fix it - apart from a bit of your time. I'd suggest starting again: align the bottom pulley with the TDC mark and the camshaft pulley with its mark, then slacken off the tensioner and slide the belt off. Have a look and see if there are some timing marks printed on it - if there are then that will make the job much easier (probably an arrow for the bottom pulley, one line for the cam sprocket and another for the auxiliary shaft sprocket). Without moving the bottom pulley or the camshaft carefully push the belt back on, then align the auxiliary sprocket properly and when you are happy release the tensioner:



... then turn the engine over by hand two complete revolutions (clockwise) and see if the three marks still align.



The whole jobs only takes about 15 minutes, but check it and check it again.

Once that is done it should be possible to arrange the distributor somewhere in the middle of its adjustment range, and so get the timing right so the engine will run properly. There may be other things wrong of course - and they may have contributed to the motor car going outside of its operating range. Once the timing is correct it should be easy to identify anything else that is wrong.

Good fortune,

Alan

[Bugjam1999]

One comment - it's entirely possible that the belt jumped a tooth on startup/attempted startup if the belt is old enough to have stretched a bit and the tensioner securing nut hasn't been released and tightened up again recently.

The cambelt tensioner is not automatic, the nut securing it needs to be released and retightened to allow the tensioner spring to take up slack as the belt wears/stretches - there is a rubber grommet in the cam cover for this purpose.

Since the belts are cheap and you have the front of the engine in pieces already I'd suggest you replace the belt with a new one, carefully lining up the pulleys as others have said, then go from there.

Cheers

[Bob 1967]

Yes , i found the mark on the very bottom pully (right at the back) that lines up so its definitely the Auxiliary pully that's offending part.
I fully intend to change all belts ,tensioner and water pump all together ,just right not now. I've gotten the area cleaned and ready I slackened off the tensioner nut ready for tomorrow.
But as I now know the steps for removal it will make replacement of parts much simpler.

If some of you might remember ,when I bought the car it had the brake bleed nipples removed and replaced with bolts ! (All new calliper's and discs have been fitted since )
So a pully out of alignment doesn't surprise me, much.
Bob

[Bugjam1999]

You'll need to compress the tensioner against the spring and insert a nail or similar into the hole that appears for the purpose in order to get enough slack to remove the timing belt.

Look at this page, about a third of the way down under the title "Timing Belt Tensioner and Belt Adjustment After Installation." which shows a tensioner pulley with a nail inserted as a retainer in the correct place.

https://www.volvoclub.org.uk/faq/Eng...BeltsVent.html

Cheers

[Othen]

Originally Posted by Bob 1967

Yes , i found the mark on the very bottom pully (right at the back) that lines up so its definitely the Auxiliary pully that's offending part.
I fully intend to change all belts ,tensioner and water pump all together ,just right not now. I've gotten the area cleaned and ready I slackened off the tensioner nut ready for tomorrow.
But as I now know the steps for removal it will make replacement of parts much simpler.

If some of you might remember ,when I bought the car it had the brake bleed nipples removed and replaced with bolts ! (All new calliper's and discs have been fitted since )
So a pully out of alignment doesn't surprise me, much.
Bob

Hi again Bob,

This might come in handy for an aide-memoire:

https://www.volvoforums.org.uk/showp...postcount=2169

This is a pretty simple job, so whilst I hear what Bugjam says about changing the belt at the same time I agree with you: just get on and fix this ignition problem. Having then already done a dry run you could change the cam belt, tensioner, water pump, auxiliary belts and coolant all in an hour or two.

I'm really pleased you seem to have got to the bottom of this problem pretty quickly. I can't guarantee it will be the only problem, but that is the fascination of 40 year old motor cars.

Good fortune,

:-)

[Othen]

Originally Posted by Bugjam1999

One comment - it's entirely possible that the belt jumped a tooth on startup/attempted startup if the belt is old enough to have stretched a bit and the tensioner securing nut hasn't been released and tightened up again recently.

The cambelt tensioner is not automatic, the nut securing it needs to be released and retightened to allow the tensioner spring to take up slack as the belt wears/stretches - there is a rubber grommet in the cam cover for this purpose.

Since the belts are cheap and you have the front of the engine in pieces already I'd suggest you replace the belt with a new one, carefully lining up the pulleys as others have said, then go from there.

Cheers

Good points,

I wonder if the tensioner was a bit slack, and that led to the belt jumping. The cam belt is supposed to be re-tensioned after 500 miles, perhaps the previous owner didn't bother and this was the result? That would explain the sudden change in performance of Bob's motor car. It is also plausible that the previous owner mis-aligned the cam belt when it was fitted and had to bodge the ignition timing to make the engine run.

You are right about it being sensible to change the cam belt whilst the front of the engine is off, but this time I agree with Bob: just get it back together and confirm the ignition timing is sorted. I think Bob intends to change the belt/tensioner/water pump at the same time - which he should be able to do in Tesco's car park whilst his wife gets the shopping one Saturday morn :-)

I'm really pleased Bob seems to have solved this problem quickly - it really does show the value of this excellent forum and all its members.

Best wishes,

Alan

[Bob 1967]

Found on YouTube
https://www.youtube.com/watch?v=-OCr7aBYfkY

[Bob 1967]

Part 2.


https://www.youtube.com/watch?v=jg97Yc_A6Wc