project 1980 Austin Princess

[vulgalour]

Proper Princess updates are going to be a long time coming so in the meantime, here's a video that tries to condense nine years of ownership into less than 20 minutes of content.

 

[vulgalour]

It's been a while.  Things are finally a bit more organised here so let's have a look at what's wrong with the Princess' engine and turn it around.

 

[vulgalour]

Another Princess update coming soon, and this one will have words and pictures.  Didn't bother with the last one since it's info you've seen before if you've been reading the thread.  Had the head off and back together again today, got too cold and dark to put the battery on and the distributor in so I'm saving that for tomorrow.  You'll have to wait for the video to see what happens, don't want to give you any spoilers here.

[vulgalour]

Progress has been a bit weird today.  I have an odd timing issue.  On the Princess, you've got a small toothed pulley at the top for the camshaft, a smaller toothed pulley at the bottom for the crankshaft, and a non-spring roller tensioner.  Both pulleys are connected by a belt (Gates 5024).

Now, when I fitted the brand new belt it was very cold indeed and while I thought I'd got the timing correct, today I found the timing was off a bit.  I reset the timing, removed and refitted the belt, and the timing kept going off.  The belt isn't slipping or jumping teeth (camera and Pat confirmed this) and after about a dozen removal and refittings of the belt, the problem has neither got better nor gone away.  With every revolution of the engine, the timing marks get further and further apart until what started as perfectly aligned becomes one tooth out.  I'm sure I could keep going and make it even worse but this is an interference engine so I shan't do that.  Camshaft and Crankshaft pulleys are nice and tight, and the tensioner is staying nice and tight too, the belt appears neither too slack nor too tight.

All I can think is this is caused by a stretched belt.  The one I've fitted is exactly the same as the one I've taken off (which I cut, since re-using timing belts is bad practice, so I can't refit it) so I wonder if maybe I've stretched the new belt because it was so cold when I fitted it, or that it was a bad belt to begin with.  Other than that, I can't think why the timing would be wandering off like this.

I'm going to order a new belt anyway now, I've had this new one on and off so many times that I can't imagine that its done it any favours.  I have had this issue before and was told "they can't do that" variously, I believe a new belt was the solution then too.

[cobblers]

Are you talking timing marks on the pulleys reference the engine, or are you marking the belt?

[vulgalour]

The marks on the pulleys themselves.  So, there's a mark to align on the crankshaft and one to align on the camshaft and those marks are shifting out of alignment somehow.  Everytime you rotate the engine to what should be the same point, the timing marks on the pulleys get 'further away' from each other, if that makes sense?

[cobblers]

Unless one of the pulleys has been changed, the belt has got to be slipping or not riding in it's groove properly. Even if it was stretching, you'd end up with inches of slack eventually,

Has it got the right profile teeth?

[Noel Tidybeard]

has the belt got the wrong number of teeth?

[cobblers]

Even if the belt had a different number of teeth, so long as it tensioned up it wouldn't matter really, there twice as many teeth on the cam pulley as there are on the crank pulley and that's that.

[vulgalour]

The belt is exactly the same as the one I removed, which didn't have this problem.  Same manufacturer, same number of teeth, same teeth profile.  The only difference between this belt and the one that was on is that this one has been slightly easier to fit, it's usually a right old war to get the timing belt on while this one hasn't put up the usual level of fight and been merely annoying rather than making me want to rage-throw spanners.

[Paul-l]

is one of the pulleys rotating slowly on the shaft? - perhaps the key has fallen out, or some engines use a taper fit on the cam shaft and rely on the nut being tight to keep things aligned

[vulgalour]

Not that I can see.  If they were, that would be surprising since I haven't disturbed either pulley since taking the old timing belt off, didn't have to disturb either for doing the head gasket replacement, so it's impossible for a key to have fallen out without something going catastrophically wrong.  Since I've been rotating things clockwise, that would tighten the nuts further if they were going to move so I don't believe either pulley bolt has come loose due to that.

[dozeydustman]

The only thing I can think of is the new belt is faulty or slightly longer. Does putting the old one back on keep the timing in check?

[vulgalour]

It doesn't because I cut the old belt off so I couldn't re-use it.  I've ordered a couple of new belts of the same sort, hopefully I'll get a good one.

[Asimo]

Are you looking at marks on the belt?
The cam rotates once for two rotations of the crank, so for every other revolution of the crank the timing marks on the cam wheel and crank wheel should be back where they were.
Sometimes belts have marks to aid installation but these are only correct once, ie when you fit the belt, but these marks “creep”  relative to the timing marks on the pulleys as the engine turns because the number of teeth on the belt is large and not a simple multiple of the number of teeth on the crank pulley.

A few seconds of video here would reallly help the hive-mind to be useful!

[stuboy]

is something seizing and stretching the belt??

[bunglebus]

I would suggest the belt isn't fitted properly - i.e. the taught side wasn't tight enough so you have an extra tooth on that run of the belt. Might be worth trying to loosen it and put it one tooth out in the opposite direction to what it's doing currently then retensioning,

[SiC]

I'm no expert on cambelt changes by any stretch. But when I did my Clio 172 belt, the procedure calls for turning the engine over by hand quite a number of times. After which you check the timing. If out then relock the engine and re-adjust the tensioner. Then turn it over again by hand and recheck the timing.

[vulgalour]

Okay, I'll try and answer the Qs here to clarify.  Tricky to give you a bit of video on this one, I know it would help, but I don't have the time to sort that out and I know that whatever I put up it wouldn't answer all Qs and I'd have to start again.  I appreciate that suggestions and help all the same, I just hope I don't have to repeat myself too often on this one while we try to get to the bottom of it.

I'll start by saying the folks I've talked to off forum, both enthusiasts and professional mechanics, in the UK, USA, and Canada, have the general consensus both of 'it shouldn't do that' and 'it's probably a bad/incorrect belt', this lines up with my own suspicions because there's only so much it can actually be on this engine.

@Asimo There are no marks on the belt, so I'm relying on the marks on the pulleys themselves and the alignment marks on the engine (a couple of brackets with pointers), combined with the instructions in the manual.  I've put the new belt on in exactly the same location as the old one came off.

@stuboy Everything is free moving that should be, including the tensioner (a simple roller bearing type rather than a sprung one) and the alternator which are the only things that share the pulleys that the timing belt runs on.  No PAS or air con or anything else running on the pulleys on this one.

@bunglebus I would be inclined to agree except that I've tried to fit the belt without any slack and as tight as physically possible on both sides with no difference.  If I make the belt tight on the tensioner side and run it around the pulleys I have exactly the same issue as when I make the belt tight on the non-tensioner side.  It's very difficult to put the belt on, let alone put it on wrong, although this belt hasn't put up quite as much of a fight as they normally do which was my first suspicion that it might be stretched or bad.

@SiC this one doesn't call for that, but I have tried it.  The more you rotate the engine the worse it gets.  I've had the belt on and off about a dozen times (no exaggeration) and the end result is always the same.  The more you rotate it, the worse the alignment becomes, it doesn't get back to where you started.  There's also no way to lock either pulley.  The holes in the camshaft pulley lead straight to air or the rubber seal and the crankshaft pulley has no holes in it to put a locking tool in.

 

---

 

Here's what I posted on RR a few minutes ago, just so the information is here too.  I know it's a lot, but hopefully it will illustrate what I've done (combined with the above answers) to try and find the root cause of the issue.  Remember, the car was running fine on the old belt and the new belt has gone on (several times) in exactly the same place as the old belt was.  Essentially, nothing else has really changed.

I removed the head because of a failed head gasket. Before removing the head, I followed all the instructions to make sure the timing belt was in the correct location as per the manual, and then dismantled everything required to remove the head from the car. The head has not been dismantled or rebuilt, because it hasn't overheated and the issue was purely a bad gasket, there was no need. Therefore, crankshaft and camshaft have not been disturbed. I then rebuilt the engine, new gasket, reconnected everything I needed to, and fitted a brand new timing belt. The crankshaft and camshaft pulleys had not moved from where they were when I removed the head so the new timing belt went on in exactly the same location as the old one came off. Additionally, before doing all of this the car was running properly with no timing issues as you can see in the most recent Princess video (check back a couple of posts for that). Nothing I've done should have affected the timing in any way, I've been extremely careful about that.

I have checked all of these things too, to try and figure out what might be amiss, even things that might not be relevant to the issue:

Distributor setting - removed and refitted as per manual.
Points/Condensor - car is running hall effect electronic ignition, no points gap or bad condensor to worry about
Rotor arm/cap - clean, very few miles, no sign of damage
Plug leads - flexible, no arcing, good connection
Coil - appears to be working as it should, connections clean and good
Spark - Nice and healthy
Fuel - getting all the way to the cylinders
Spark plugs - correctly gapped, healthy spark
Firing order - exactly as the book describes it
Compression - yes, plenty
Head bolts - torqued correctly, and checked twice
Tensioner - roller type, no tensioner spring. Roller is free moving, tensioner isn't moving out of alignment once set, is putting a relevant amount of tension on the belt
Alternator - belt goes around the crankshaft pulley, no belt damage, alternator not seized, V profile rather than toothed
Timing belt - no sign of damage, correct profile teeth, correct number of teeth, brand new Gates 5024 toothed belt of appropriate size and application for this engine. Identical (as far as I can tell) to the belt that was removed which was the same model and design
Battery - in good health
Starter motor - in excellent health
Clutch and hydraulics - operating as they should, not dragging or sticking or leaking (though obviously can't test with the engine running yet)
Carburettor - not leaking, overflowing, or suffering from vacuum leaks
Cam and Crank pulleys - tight, not loose, haven't been disturbed

I will add that a long time ago I have had this problem with this car. When I first got the car in 2014, the timing belt was an unknown quantity (as was the rest of the car really) and while you could get it to be timed correctly, it wouldn't stay put and would drift off like it is doing now. Previous owner/s had adjusted the distributor, the carburettor, and I believe the plug firing order to compensate so the car ran badly rather than not at all. We replaced the timing belt, which stabilised that side of things, corrected the distributor timing, readjusted the carburettor, and corrected the plug firing order and then it ran fine.

That I'm back where I was when I first got the car in terms of running issues is quite frustrating. I know the carburettor is adjusted correctly, the firing order is correct, and the distributor is set correctly for where the timing belt was when initially set correctly. I feel like that elminates everything but the timing belt.

Things I haven't changed:
Head
Crankshaft pulley
Camshaft pulley
Tensioner

I know what it's doing is not something it should be able to do. I know that's not how it's supposed to work. All I can do is tell you that this is what it's doing and that I don't understand why. So far, general consensus from folks I've spoken to outside of the forum has been it's probably a bad belt or an incorrect belt. This sort of problem is precisely why I dislike working on engines.

[bunglebus]

In that case, either the belt or one of the pullies is incorrect - odd though as if the old belt was the same it should have self destructed in about two seconds.

Don't know this particular engine but I'd probably order a belt for it rather than matching the old one. 

Ultimately the bottom turns the top, so with a belt with the right number of teeth, it should just work

A quick scan of ebay suggests Gates 5024. 104 teeth

Cross references: Austin: CAM5231, GTB1024, UO1838, MG: CAM5231, GTB1024, UO1838, Rover: CAM5231, GTB1024, UO1838, AE: TB124, Bosch: 1987948835, Dayco: 104R170, 104RX170, 104S170, 104SX170, 94236, FAI Autoparts: 41104, Ferodo: 4804524, First Line: FTB3401, QH: QTB118

Can't find any alternative lengths, no. of teeth etc as options. Very odd.

[Jikovron]

I had this recently with the 30year dormant O series engine in my ital,in which the belt was slowly creeping over the teeth due to disturbed dirt falling into and being compacted into the crank pulley teeth, once the pulleys were cleaned up with petrol and a stiff brush it fired up on its ancient belt and ran brill! 

[vulgalour]

That's actually damned good advice and good to hear I'm not alone with this problem.  I'll go full Vulgalour on the pulleys and make them as clean as I can before fitting the new belt.

[3VOM]

I have done a handful of timing belts over the years but they all had some form of tensioning. Can you post the engine details (or have I missed them earlier in the thread - sorry).

[vulgalour]

It uses a tensioner that's almost identical to the one found on the pinto engine put in Fords.

[img]https://i.ebayimg.com/images/g/J6QAAOSwU59fEhXk/s-l300.jpg[/img]

And yes, I am tensioning it correctly, and no the tensioner isn't worn out, and no the tensioner isn't moving once tightened up.

My gut feeling is that Jikovron is on the money with the problem because what they describe lines up pretty well with what I'm experiencing.

[PhilA]

One way to see if itls a slip rather than a wrong-pulley would be to dial it over the same number of revolutions forwards then backwards- worn teeth will tend to slip only one way. 

If you end up where you started I would be more concerned...

[vulgalour]

It's too wet out to be fitting the new belt that arrived, hopefully the weekend will be better weather.  The old belt I took off before removing the head felt stiffer than the new one that's one.  The new belts I've not fitted yet both feel stiffer than the new one that's on and more like the old one I took off.  Hopefully all this faff really is just down to a bad belt since I shouldn't really be able to tell a difference in the stiffness of the belts as there shouldn't really be one.

[vulgalour]

Good news: it was the belt at fault!  The one I took off felt weirdly spongy and the tooth profile looked shorter in depth than the new belt.  I guess it was just a bad belt.  New belt on and the wandering timing issue has gone away, the timing marks now stay correctly in relation to one another no matter how many times you rotate the engine.

However, I cannot get the car to run.  I can get it to crank over and misfire and that's all it wants to do.  This suggests a timing issue and it sounds like plugs out of order (I'll upload a short clip later when I've time to edit down a section), it sounds like three pops out of the exhaust and sometimes one pop out of the carb.  The confusing thing is I've followed what the manual directs to do and Pat has double-checked my work against the instructions and everything appears to be as it should.  Maybe I've missed something really obvious here?

I know it'll be asked more than once so I'll say it again here: I've followed the instructions in the manual, and Pat has double checked my work.  It's correct according to the book.

[Jikovron]

 

In theory the manual will have already stipulated all the following but just incase it hasnt:

The distributor timed with the rotor arm 180degrees out to the cam/360 out to the crank can behave like that, and it's really easy to do as piston number 1  set @ ~5degrees BTDC can be either at the end of the compression stroke or the start of valve overlap. 

To check, turn the engine by hand with the plugs out and a finger over number 1 plug hole, and when you feel it trying to compress air take off the dizzy cap and ensure the rotor arm is on its way to plug lead number 1 ,,,it might be headed towards plug lead 4. 

[vulgalour]

Haha, right, I'm a numpty.

You see, the diagram in the book shows the distributor cap and the 'firing order', but that's the firing order of the cap, not the engine.

So that means my firing order is currently 1-2-3-4 which is, er, wrong.  What a silly mistake.  I will correct the firing order tomorrow and I'm going to add some relevant marks on the distributor cap just to make it easier in the future so I know which socket goes to which plug at a glance.

Daft mistake, easily fixed at least.

[bunglebus]

Good news on the belt, what odd symptoms.

On the timing - you had the distributor out at some point? That would be my first port of call, the way I used to static time older engines was to turn the motor by hand until the engine was in the right position according to the timing marks (let's say 12 degrees before TDC), loosen the dizzy and advance it - then with the ignition on and with the cap removed, turn it slowly back until there's a spark across the points. This should be close enough to start the engine and time it with a light.

Other things worth checking are points gap and that the condenser isn't knackered, lots of replacements seem to be junk.

If you've got electronic ignition fitted it's a bit trickier but you can at least confirm the rotor arm is pointing to #1 on the cap when the engine is at 12 before TDC or wherever the book suggests it should be

*edit* wrote all that while others were posting!