project 1980 Austin Princess - Headlights Arms Race

[SiC]

Is there a bit of surface rust to the right of the lower circle?

[vulgalour]

There is, I gave it a stabby-scrape with the screwdriver and it's very minor surface corrosion.  Nothing is crunchy, thankfully, it seems to be fairly localised corrosion so shouldn't be too difficult to deal with.  With the rear wheel removed I should have lots of space to do the repair somewhat comfortably.  Of course, I won't know how good or bad it really is until I get in there with power tools and cleaners, so here's hoping it's not an iceberg tip.

[vulgalour]

Today I got the Princess over to the unit so I could fix the inner arch holes I uncovered.  I also removed the cold air intake pipe to the air filter box and that improved the cold running considerably.  It took me longer to clean off the underseal than it did to do the actual repair.  Happily, the damage wasn't much worse than what was visible and was an easy fix as a result.

 

 

With the rear seat removed it was easier to see just how the rust had occured.  There's a seam hidden under some goop under the rear seat and this had blown.  The inner arch side of it was rotten, the bodyshell side was still solid enough to weld to, so the repair wasn't too bad.

 

I also found a small hole on the seam of the inner arch tub while cleaning off the underseal.  It's a little awkward to repair since I can't get many tools in at it and will require a patch about the size of a pound coin.

 

After a little bit of time I got some new steel let in where required and seam welded.

 

 

Since I'm still running the experiment, I'm avoiding taking the car off the road and doing these repairs piecemeal.  The bulk of the time today was really stripping everything back to see what I had to repair.  Now that I've done that, getting everything cleaned back and freshly painted and undersealed will be much easier and something I shall be making time to do over the course of this week.

[320touring]

Tremendous! #drivethruwelding

[Uncle Jimmy]

Yes, they are that wide and parking spaces don't seem to have been changed since the 1990s.

More likely the 1950s, based on the width of a Bond Minicar and two trilby hats.

[vulgalour]

End of week report: Week 3

 

Weekly checks:

Coolant - no noticeable usage

Oil - no noticeable usage

Fuel filter - New one fitted today as the old one was looking grotty

 

It hasn't been a good week though.  The mystery misfire/stumble has been getting worse and I'm no closer to finding the cause.  I had thought it was fuel related since the fuel mixture screw has taken to unscrewing itself and, once reset, the problem seemed to go away.  Then it reappeared and became worse.  Today, I reset the mixture screw again, just in case, and replaced the fuel filter since it was behaving slightly like it did when the previous filter collapsed.  I also checked the points gap, which was a little large, and went for a drive.  It seemed much better until the car got up to temperature and then I struggled to get above 30mph.  Another go through the various settings to make sure everything was where it was and on my last run I was struggling to get over 20mph.

 

I'm baffled at this point.

 

When cold, the car fires up normally with choke, as you'd expect.  It runs moderately well with the occasional cough if the choke isn't just so.  Once up to temperature with the choke off the car will run fairly happily for about a mile or so and, as it get closer to full operating temperature, the problems really begin.  If you're really slow on the throttle you can creep the speed up but if for any reason you need faster acceleration or prolonged throttle usage - pulling out of junctions, climbing hills, etc. - the misfire/cough gets worse and worse, the car begins to kangaroo and the only way to resolve it is to back off the throttle and gently creep it up.

 

Once up to full operating temperature even creeping the throttle won't let you accelerate much.  It's like something somewhere is restricted once the car warms up.  This isn't a problem its manifested in this way before.  Monday, therefore, Mike and I will go through the timing, the ignition components, the fuel delivery, and see if we can locate the problem.  Fortunately my spare carburettor is with a skilled friend who is currently doing a top notch job on making it like new again and I hope a freshly rebuilt carburettor will help with some of these problems.  I had hoped to drive over to see him and fit it at his place, but I can't imagine the car will be any fun to drive for two and a half hours running like it is at the moment.

 

At the moment this doesn't end the experiment.  The car hasn't left me stranded and has always got me where I need to go.  However, if I can't resolve this problem promptly the experiment will have to be restarted.  At present I regard this more as a general problem, as can afflict any car of any age at any point.  Until I know more about what the problem is, I'm not prepared to bring the experiment to an end.

 

Here's a nice picture of the Princess a few days ago, when it was running much better.

 

 

[Rocket88]

Are you running a mechanical or an electric fuel pump.....

[vulgalour]

In-tank electric and, as far as I can tell, it is doing its job as it should.

[Rocket88]

Have you tried pulling the choke out when it starts to stumble..........

[captain_70s]

Sounds a lot like what the Doloshite was doing when that was up to temp.

 

I'd like to say I know exactly what caused it but I don't. I just fucked around with the ignition system and carb until the problem was lessened... What carbs do these have, waxstat SUs?

[vulgalour]

Colc: I have, and it makes things *lots* worse.

 

Cap'n: SU HIF6.  Let's hope it doesn't do a total Doloshite on me.

[Rocket88]

In that case........possibly running rich...............try leaning it off a little......

[vulgalour]

An small victory!  Glen over on another forum suggested it might be a blocked fuel jet so recommended pulling the air box off, covering the air intake with a hand while revving the engine.  The vacuum should then suck whatever's stuck in the jet, out of it.

 

Gave it a try and the running is improved, I can now put my foot down and it will actually go.  I'll take the carb apart and clean out the jet and that may well fix the issue completely.

[PhilA]

Does this design of carburetor have an emulsion tube on the pickup of the main jet?

 

Sounds like you may have drawn some grubby water though at some point, perhaps some refinery sand particles that are finer than the filter.

 

Reason I ask is you almost need to run a stone filter with emulsion tube jets, the holes are so fine.

 

Hopefully that's just it and you get to enjoy driving it again. Things like this are sent to test us, I'm told.

 

Phil

[vulgalour]

There's no emulsion tube on this carb.  I'm wondering if I've just left the old filter a tiny bit too long (not that it's lasted that long anyway) and it's started to degrade, pulling stuff in where it shouldn't be.  The last filter just collapsed and went to mush inside so it could even be bits from that one were floating around in the carb and have only now got themselves where they shouldn't be.

[PhilA]

That's a possibility. Particularly if something in the fuel (some gas pump additive) has caused the paper filter to fall to bits and start sending paper fibers towards the carburetor.

 

I don't think the flow would be high enough for a centrifugal filter, though would a fine metal mesh be enough to trap particles big enough to block up holes?

 

Phil

[vulgalour]

Like a post-filter filter so I can filter my filter with my filter to stop my filter getting into the carb?

[vulgalour]

Filter.

[PhilA]

Quite possibly.

 

 

Phil

[vulgalour]

Phil-ter.

 

 

 

I may have drunk too much coffee.

[320touring]

Phil-ter.

 

 

 

I may have drunk too much coffee.

Looks like you are spot on with the dosage - life is better with Punz

[vulgalour]

We failed to proceed today.

I started off this morning by removing and cleaning out the carb.  This revealed there was indeed sediment in the float bowl, though I'm not sure how it got in since I always run a filter before the carb, so it lends credence to the theory that the filter had started to collapse and get sucked into the carb.  After a brief driveway test to make sure the car started and idled normally, I decided to take it out for a short test run just to be sure nothing was amiss.

Foolishly, I tempted Fate by forgetting to take my manual with me and inevitably coming off a roundabout the car just died.  I could get it to fire up but not idle, and on opening the bonnet there was petrol just pouring out of every part of the carb it could.  Not great.  With my tools but no manual I wasn't really confident I'd be able to fix a problem if I found one so, since the car was in a good visible location, I stuck the hazards on and walked home.

I informed Mike what had happened before trekking back to the car so that I could attempt a roadside repair.  I'd also left my mobile at home, so I couldn't ask him to bring the manual to me, so we had to do things the old fashioned way.  Mike had a couple of jobs at home to do and once done, he headed over in his car just in case I needed towing home (I carry a tow pole in the boot, just in case). I have AA cover but it seemed a bit daft to use it since I could practically see my house from where I'd broken down.

On dismantling the carb there was nothing obviously amiss.  Nothing was stuck, there was no dirt lodged anywhere that I could see, so everything was cleaned and reassembled at the roadside and a restart attempted.  This time there was no fuel overflowing but without rather more choke than normal, it wouldn't idle either.  After letting things warm up a bit I tried moving the car under its own power and found that any use of the throttle beyond the barest brush would make the car try and stall, so we creeped into a nearby church car park to turn around and creep home, with Mike providing cover by following me home.

On the same roundabout the car died, it suddenly got its act together and ran normally.  It was like someone had flicked a switch.  Normal acceleration returned and the car was behaving as though absolutely nothing was wrong.  I can only surmise that there was some sediment or a component was sticking for some reason which became dislodged once the car had been running for a few minutes.

I'll test everything again tomorrow and see how we get on.  I've always thought there was something wrong with this carburettor and now I'm sure of it.  Fortunately my spare is being rebuilt and should be with me soon which I'm hoping will resolve this bizarre running problem.

[vulgalour]

As mentioned in the News Thread, today, the Princess was incredibly difficult to start.  So much so that a neighbouring workman popped his head around the hedge to ask if it was always so difficult to get going.  I was beginning to doubt the Princess' ability to fire myself until, eventually, it did.  Then the difficulty was keeping an idle, which it really didn't want to do at all. As usual, I went through the usual suspects to try and find a problem and there was nothing apparent.  I was getting fuel, a good spark, the points hadn't closed up, the carb wasn't flooding... it was almost as if there was a massive vacuum leak somewhere which seemed unlikely since on the roadside repair I'd checked for that and there wasn't one.

There's not many places to look for a vacuum leak.  There's the vacuum advance pipe from the manifold to the distributor, and there's the one other location, which is when I spotted the gasket between the carb and the spacer block had a bit of a tuft.  A quick squirt with carb cleaner (it's what I had to hand) highlighted that this was indeed a massive vacuum leak.  A quick squirt was enough to make the revs rise considerably and, as soon as the area had sucked all the carb cleaner in, the revs dropped again.  This same tactic found the damaged carb mounted block on my old Mk2 Polo, a problem that had also eluded me because I thought it was something else at the time.

On removing the carb I found that there was a big chunk of the gasket missing, it looked like it had just been blown out.  I also noticed the inner hole of the gasket was breaking up and the carb had quite obviously been sucking little fibrous bits of it in.  Perhaps I've also found what was blocking the carb internals up and possibly the root cause of the fuel starvation issue.  It would explain how stuff was getting into the carb without going through the fuel filter.  Perhaps I damaged the gasket at the roadside when I did the repair, perhaps it was already damaged and recent fettling was just a bit too much for the gasket.

Flexoid gasket paper to the rescue!  Mike's had this stuff for ages and its really good.  It's probably older than the car too, for that matter.

With the new gasket made I reassembled everything and the car, predictably enough, was much happier.  A short test trundle proved that things seem to be okay, I'll know better when I've gone on a longer run, I just didn't have the time for that today.

[Fumbler]

Needs more Filter with more doses of Phil-ter coffee to help you carry on daily driving it.

[vulgalour]

Today has been rather trying.  After replacing the gaskets the car drove really well when I went out on my errands until I was on my way home.  Poor running began and then the car just died on me, fortunately in a place where I could coast into a car park.  I got the car to fire up again but with a wandering idle and a reluctance to rev.  Creeping around the car park I found that I could use the choke to counteract the wandering idle enough to limp the car fast enough to not be a hazard to other road users so made my way home again.

Within about a mile of home, the problem got worse.  I was struggling to maintain 15-20mph doing a dance of pedals and choke and, since I was slow enough to be a hazard I put the hazard lights on and deployed hand signals.  I hope the learner driver behind me was educated or knew what hand signals were, certainly they were kind enough to give me plenty of space and I was blessed with clear roads to make the journey home safely.

Once home I could investigate more properly and I found that the points are burned badly enough that they need replacing.  That, combined with the way the car was behaving, leads me to believe the condenser has failed, especially so since the problem is worse when the car is up to operating temperature which is when similar symptoms appeared with my previous condenser failure.  I could purchase a new condenser and a new set of points but I decided that instead I should put electronic ignition to the test to see if the recommendations given really would pay dividends.  Personally I still find points and condenser systems perfectly adequate providing you can acquire good quality versions of both, I just haven't had a great deal of luck with condensers over the years.

The other issue that has been becoming apparent lately is that the rear suspension is firmer and bouncier than I'd like.  I suspect they require a re-gas so that's a job for the new year.  I'm hoping the pivot shafts in my spare rear suspension assemblies aren't seized as I'd far rather send those out for rebuilding so I can at least use the car while I wait for them to come back.  I'll do the fronts at a later date as I don't have spares and they're in good order, so I'd rather wait until a time I can comfortably disable the car for a while.

This has certainly not been the best week of the challenge.  Thankfully, I have very little driving to do between now and January so I may well get through the next few weeks without having to stop the challenge.  We shall see.

[PhilA]

Thinks like this had me looking into the use of polypropylene film capacitors (450V 1uF) instead of the nonsense in little metal tins they sell today for car ignition.

 

Phil

[plasticvandan]

Only basing this on my experience of failing condensors,in a myriad of Lucas 25d4 and 45d4 sparked machines,but when they were packing up it would start and run fine until the engine got warm-hot,then misfire,pop and bang and then die completely.using choke to help suggests an air leak,tho the burnt points does suggests electrical.lift the dizzy cap and crank the engine,if you see blue/yellowish sparks at the points,condenser is fucked,tho I'm sure you know this

[Rocket88]

 

If you want to immobilise the poor old thing completely, buy one of these......

[LightBulbFun]

Thinks like this had me looking into the use of polypropylene film capacitors (450V 1uF) instead of the nonsense in little metal tins they sell today for car ignition.

 

Phil

 

I was wondering why Cars dont just use regular high quality high voltage capacitors these days?

 

(ie why do cars still use a capacitor desgined 50 years ago )

[anonymous user]

I can only add that it seems that all new points and condensers are rubbish. Just when you think you have found some reasonable ones they will turn out to be rubbish as well. If you can find new old stock they might be better.