Page 5 of 5
Posted: Fri Jul 26, 2019 2:05 pm
Thank you, Gasman, for your kind words about the banner I made for you (other corners and paint colours are available...)
Posted: Mon Jul 29, 2019 3:38 pm
Job completed with everything back in the car and fully functional. So, in summary, the fuel tank has been cleaned out and sealed. A new genuine BL NOS sender unit with new genuine BL pump has been fitted. All rubber piping up to the carburettors has been renewed although steel piping remains. Yet another new fuel filter put in (the old one had more crud in it than I had thought from casual visual inspection). The fuel pump relay has been swapped and a new oil pressure sensor fitted. I'm not sure there is anything else to change in the fuel delivery department so I am hoping this will cure the problem. Time will tell.
Whilst I was at it I've changed the oil & oil filter and also the antifreeze so should be all set for while (although there's always something....)
Posted: Sat Aug 10, 2019 9:22 pm
I shall have to do exactly the same thing to make my Princess go...could you give me spare parts number for the sender unit and fuel pump ? I think, I shall replace all the steel - piping by copper ones...they will outlast me then.
Posted: Sun Aug 11, 2019 10:21 am
belleprincesse: The fuel sender part number is FAM3348 and the fuel pump is DRC195.
Posted: Sun Aug 18, 2019 10:11 am
Another interesting read guys
well done, keep up the good work
Posted: Sun Oct 06, 2019 4:45 pm
KWacKers has blotted her copy book.
I am sure some of you will have seen Hubnut's test of SMG on YouTube (There have been 90,000 viewings so far!), being part one of a comparison with KWacKers - the oldest surviving against the youngest wedge. ( https://www.youtube.com/watch?v=BWZWukWzO6A&t=77s
). Unfortunately, Mr Hubnut lost all his film files of the footage of the Ambassador so he came back today to re-film that bit. I had checked that the car was running fine and put a bit of BP Ultimate in the tank. Mr Hubnut arrived and drove off in KWacKers. He came back about 3/4 an hour later saying he was having a bit of trouble with poor running and misfiring. On examination it was running incredibly richly, wouldn't idle and was misfiring, coughing & spluttering on acceleration. Virtually undriveable. Plugs 1,3 & 4 were as black as a chimney. Plug 2 is hidden by the dizzy so I couldn't be bothered to get that one out. I wondered if this was related to filling up and I did just wonder if I had put diesel in by mistake but it was fine going home from the garage. There is only one unleaded 97 Octane pump at the garage which is where I filled up from and the receipt did say unleaded on it!
I had had the carbs re-jetted on a dynamometer a couple of weeks ago (the standard carburettors are set up, of course, for the fuel available in the 80s. Modern petrol is far more volatile and really requires different jets). The car, following that, was running much leaner and was more lively and driveable too. So what's gone wrong and how come it's now running so rich?
Answers on a postcard please. I'm assuming it's to do with the dreaded ASU but it seems a very sudden failure. I'll do a bit more investigation tomorrow.
Very frustrating for Mr Hubnut (the poor chap had come 200 miles for goodness sake!) although he was phlegmatic enough to say it was his fauilt anyway for losing the original files! Not sure when he's going to be able to re-re-film as he's off to New Zealand for 5 months in a couple of weeks.... Part 2 of the saga is obviously going to have to wait.
Posted: Sat Oct 19, 2019 11:25 am
I have been investigating KWacKers and came to the conclusion it had to be the ASU. All plugs were running equally very, very rich. Ign & valve timing correct. Compressions all good and equal (albeit I couldn't measure cylinder 2 unless I removed the distributor which I couldn't be bothered to do. Whoever thought putting the distributor immediately above no 2 spark plug was a good idea). Thus, surely it has to be the ASU.
I duly removed the ASU with the carbs in situ and put on my replacement NOS unit. However, try as I might, I was unable to tighten the retaining screws very tight. As I expected, when connecting the fuel pipe it leaked like a sieve so I took the carbs off so I could tighten the 4 bolts properly. That duly done and everything re-assembled it started first time and would now tick over. However, when fully warm it is coughing a bit on low revs acceleration with poor pick up. Definitely not right but at least it's running now.
I fully accept that the ASU is a bit of black magic to me as I don't really know how it works other than being an extra carburettor which switches off by bimetallic strips... On dismantling there are 3 diaphragms in the system: one on the air jet which looked fine and an upper & lower one on the fuel side. The upper one had a load of black gunge on it but otherwise looks in tact but the lower one does not look in tact & I presume is the cause of the failure.
I do have a manual choke conversion but there are a few little, but presumably vital, bits missing! I am still tempted to get rid of the ASU even though I've got a NOS unit on it now...
Posted: Sat Oct 19, 2019 3:43 pm
The bottom picture of a diaphragm looks like it is perished with cracks plus a blister? BTWDIK...
Posted: Sat Oct 19, 2019 5:48 pm
Yep. I am assuming this was the problem.
Posted: Mon Oct 28, 2019 11:34 am
I have been assessing what's wrong with the running on KWacKers. I need to get it sorted as it's on the Vanden Plas Owners' Club stand at the NEC next week and that's 125 miles away with a stranger to the car driving it there!
Cold start was OK and running reasonably OK until warm. Then, when warm, tick over was OK, but v poor low speed pick up although seemed reasonable above about 3,000 rpm. Very lumpy on the overrun which has always been a problem with KWacKers but worse than usual. On turning off the engine ran on. To me, all signs of a weak mixture.
Armed with this info I took the car to my friendly local SU (& other carbs) wizard with a rolling road. The mixture was very weak below 3,000 but absolutely fine at an indicated 100 mph on the RR (round about 5,000 rpm)! He took the dashpots off and performed a bit of black magic on the needles and put it back on the rolling road. Amazingly, this seemed to sort all the problems.
Incidentally, a top tip from him, use hydraulic (jack) oil in the dashpots. 3in1 (which is what I've always used) is too thin, engine oil too thick.
Road test = best it's ever run! Even better he didn't charge me! Let's hope the improvement is maintained.
Posted: Tue Oct 29, 2019 4:59 pm
Good news after all that trouble then, i did see some video one of you guys posted the other day and shared to my facebook wall to show me pals who knew i had this prior
Posted: Tue Nov 19, 2019 8:02 pm
That is good news! Top tip on the dashpots too.
Posted: Sat Apr 04, 2020 8:30 pm
I have done very little mileage in KWacKers since it came back from the NEC in November. I drove it out of the garage today. It took a while to get the petrol up to the carbs but then it started straight away. I let it run on quite a fast tickover for a while to warm things through as I can't take it on the road at the moment with the current restrictions. That's when I smelt the petrol. On investigation there was petrol pouring out of the float chamber cover gasket on the right carb. It was fine when it went into the garage so presumably the rubber gaskets have dried out. Burlen are still partially open so I've ordered some more rubber gaskets on line and will have to take the carbs off for the umpteenth time to replace them. I find it much easier to do the job with the carbs off the car although some of you clever people seem to be able to do this with them still on the car.
There's always something!
Posted: Fri Apr 10, 2020 1:12 pm
This seems to be a recurring problem on the later (HIF44?) carbs. My Allegro has started doing it and it is not as easy to remove the float chamber top like the earlier ones. Likely to be a float issue rather than dried out seals.
Posted: Fri Apr 10, 2020 7:34 pm
It’s not leaking out of the overflow but unquestionably from the float chamber joint. It can’t be the needle valves.
Posted: Fri Apr 24, 2020 12:39 am
There's three culprits I'm aware of for the leak in this area, the first being deformed sealing ring, the second being a warped plate (usually rectified with a flat surface/block and some wet-and-dry paper), and the third being the carburettor itself going porous. The first seems most likely given how well you look after this car.
I've had to deal with all three issues variously, the porous carburettor was dealt with by replacing the whole carburettor, there wasn't really another fix for that. It's also worth checking the correct spring washers are used with the screws that hold the plate on too, if they're mismatched, or just plain washers, it can cause the plate not to seal evenly and can cause the seal to be different at different temperatures and vibrations and thus prove difficult to locate.
They're not a bad carburettor to work on once you have them off the car, they're just a pain to try and do anything on in situ.
Posted: Fri Apr 24, 2020 11:45 am
Although I've got the new rubber seals I've been too busy tidying out sheds and photographing and cataloguing the wedge spares, all 1000 of them! I'll get round to the carbs soon.
That's a very good point about the spring washers Angyl and hadn't occurred to me. As far as I am aware they are all the correct washers but I will check that in due course. The leak is on the RH carb with the dreaded ASU which attaches as an extra plate between the carb and the float chamber bottom piece so there are 2 joins.
As you say, they are easy enough to work on removed from the car which, now I've learnt how to remove/tighten the 2 awkward nuts, is easy enough.
I wonder what makes a body become porous
Posted: Fri Apr 24, 2020 4:35 pm
I'm told it's something to do with the quality of the alloy and the original metals used not being the correct, or high quality enough, composition. Over time, some portions of the alloy corrode away leaving tiny little holes all throughout the casting which then becomes porous, after which there's not really anything you can do to fix it. There's been similar issues with alloy heads and wheels which are likewise impossible to sort out. You don't really see anything amiss with the component when it does this because the holes aren't visible to the naked eye and you don't tend to get the white fuzziness of corrosion that alloy gets when it happens, you just end up with parts that leak with no visible cause for it.