| Author | Message | ||
     Geoff Wootton Grand Master Username: dounraey Post Number: 721 Registered: 5-2012 |
Hi Folks I am currently reconditioning my carbs and have found the supplied jet spring is much longer than the one currently in the carb.  Also the plastic plug on which the original spring sits is not documented in any of the SU kits or on their website. It turns out, from extensive searches, that Rolls Royce issued a service bulletin for S2 Bentleys and Clouds, saying there had been isolated cases of fuel vaporization and a "plug and tube" had been added in place of the longer SU spring to prevent this. The tube is not visible in this photo, but it is a short small dia plastic tube that runs from the bottom of the float chamber to the jet housing. It appears this mod has been carried through into subsequent models. Should I "discard" this plug and fit the new spring? The new spring is stronger and would be my preference, as I suspect the old, tired spring has allowed the jet to float, being as it is quite weak. The service bulletin states fuel vaporization in Isolated Cases. Should this concern me as these reports were isolated? I'm at a bit of a quandary on this. I do not want to wait another week or two for a shorter one to be delivered. That is assuming these springs are still available. I am just wondering what the general opinion is. Regards Geoff | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 12 Registered: 5-2015 |
I would refit the plug and short spring. The spring simply holds the jet against the the adjustor arm. It doesn't move. And doesn't effect the mixture. As long as the spring does its job. However if one decides to fit the new longer spring and a problem arises then simply refit the original. Once one has worked on these carbs they become simples and quick to fix. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 724 Registered: 5-2012 |
Hi Bob Thanks for your reply. In the end I decided to install the new springs. The reason is the old, shorter springs were too tired. The new springs hold the jets really firmly in place. If I do get problems with hot starting the engine it is a fairly easy job to put replacement short springs in. I noticed that Introcar sell the RR short springs, however after reading Christopher Williams' problems with his so called renovated hydraulic pumps I think I will seek out a genuine RR supplier if I need to buy some. Regards Geoff | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 18 Registered: 5-2015 |
Burlin Services is the official supplier of all genuine SU bits. I get all my stuff from them. When I got new needles and main jets. They came in SU boxes but inside the bits were in RR/B plastic bags. 1989. Every genuine SU spare part would have passed through Burlins hands. I have always been suspicious of some reconditioned bits. I reckon sometimes all you get is a second hand unit cleaned up. My pumps are original and are fine. They are quite simple pumps and not a lot to go wrong. Providing the bore and plunger is not scored and a good fit then usually a quick clean out of the non return valve and jacket new O rings and it's good to go. Worth reading the manual first. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 726 Registered: 5-2012 |
Hi Bob All my recon kits (carb and fuel pump) came from Burlen. They are very good and to be recommended. The thing is, the plug and tube assembly (RR part number CD 1864) is a Rolls Royce modification and does not appear (as far as I can tell) on the Burlen website, as it is not an SU part. Neither does the short spring (UE8408). FS does not appear to stock them and I'm a but leary about using Introcar. If I do need to use the RR mod, I will check out Albers etc. Geoff | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1333 Registered: 6-2009 |
Geoff, I can also recommend Joe Curto as a resource for "all things SU carb." Of course, the parts come from Burlen (or the micro-aftermarket for some of the RR specific parts), but Joe is willing to share all sorts of information with you if he has the time when you call. One of the things he appears to stock is the short carb spring you refer to. See the picture at his website. He's truly a pop-only shop and while his website is great it doesn't include an online store. He has done lots of RR/Bentley carb work and it's definitely worth giving him a call. Brian | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 19 Registered: 5-2015 |
The plug looks like a simple lathe job. Aluminium or brass will do. I have never seen this plug. The tension on the spring only has to hold the jet firmly. So its nothing to really worry about. I should think the spring will last for years. I do like the my SU carbs because they are so easy to work on and are pretty well bullet proof. Always keep an eye on those overflow pipes they must be in good condition hanging low down on the engine. Worth reading the manual on these carbs. When I first discovered the long centre bolt I was very pleased that it was so easy. My boss said that RRs are easier to work on than I thought. He was right. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 727 Registered: 5-2012 |
Hi Brian Thanks, I've added his site to my list. As I said, I will go with the supplied spring for the time being. It occurs to me the HD8 was used on many different cars and if this hot start problem had been universal, SU would have included the mod themselves. The RR service sheet says they were only responding to isolated reports on Bentley S2s' and Clouds. This does dovetail into my next project - replacing the viscous coupling. This should help to keep under hood temperatures down. Geoff | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1334 Registered: 6-2009 |
Geoff, Download the RR & Bentley Parts, Repair, Restoration & Other Resources Compilation I maintain prior to your viscous fan clutch project. There's some information you might find handy. Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 728 Registered: 5-2012 |
Brian That document is top of my local list. I have already read it in preparation. I will order the part immediately I have the engine up and running again. The viscous fan has been troubling me for a while now. I think it is on reduced efficiency. It passes Bob_UK's rolled up newspaper test, but I do not get a particularly strong draft off it on startup, when it should be full on for a minute or so. Also on a hot engine, there is not a strong blow. Most worrying is when I turn off a hot engine the fan blades continue for a couple of rotations. The fan is not freewheeling, but I do think it's time to change the viscous coupling. This is the problem with my car. Although it is a rust free low miler, a lot of the parts have not been changed and are simply wearing out. Geoff | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 21 Registered: 5-2015 |
Geoff, One very front of the convertor is a spiral spring which turns a valve or paddles inside the coupling. Check that this is still connected and is actually present. This spring is bimetallic and turns the valve or paddles to make the coupling more viscous when hot thus driving the fan faster. If the spring has fallen off then this spring is also fitted to other makes of cars. A scrap yard may have a spring. Once the car is moving at say 30 mph the fan is redundant. These couplings aren't cheap. Note to other readers. Never drive a fan designed for a viscous coupling direct by Jamming up or removing the coupling. The fan fan can shed a blade which could smash the header tank and go through the bonnet. Should one be leaning over the engine when the fan bursts then a fatal injury is possible. I say other readers because Geoff isn't stupid. Although electric fans seem like a good idea the price of the kit isn't cheap either and fuel saved is very very small if any. I suppose a scrap yard fan could be used but its a Rolls-Royce not a Cortina. However if one must BMW do some good fans. Note a modern electric fan cannot be run backwards because its efficency will be greatly reduced. | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 22 Registered: 5-2015 |
Forgot. Geoff, Dirty fan blades ruin airflow. By dirty I mean in crusted with dust and grease. A wipe is good enough to clean. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1335 Registered: 6-2009 |
Bob, The information I was pointing Geoff toward is alternative viscous fan clutches that can be fitted to some of the Shadow series cars using their original blade set and function perfectly well. There is also a way to use the same one that works on a subset of the SY1 cars with the SY2 cars if you have an adapter ring machined. This little trick was documented by someone on this very forum, including photographs. I also found an alternate SY2 viscous fan clutch and blade set that can be fitted if the original plastic blades are damaged. These are commonly available aftermarket viscous fan clutches that are not expensive and are fitted to millions upon millions of cars out there on the road. Your warning about the potential for disaster with fans cannot be overstated. I know I posted here about the destruction of the original blade set on LRK37110. I had not detected that whoever worked on the fan last had not tightened the securing nuts correctly. After some months of working on other things and starting the car repeatedly, I was sitting behind the wheel and giving her gas when I heard an incredibly loud bang, and immediately turned the car off. The fan blades had come loose enough to allow them to start wobbling and one hit the radiator, cutting through several tubes, then breaking off one whole blade and a part of another, which were thrown out of the engine bay. They could and would have easily caused major to possibly fatal injury to any human being who happened to be in their flight trajectory. I've now added, "Check that the fan is correctly secured to the viscous fan clutch, and that the clutch is correctly secured to the engine," to my list of things to be certain of before ever undertaking repair activities that require one to be in close proximity to a set of whirling fan blades. Brian, whose father was Safety Supervisor for our regional USPS center and who had "better safe than sorry" drilled in from early childhood | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 23 Registered: 5-2015 |
I thought that a coupling from another make could be used but which one. The info is handy should mine go wrong. They last well so fingers crossed mine doesn't go wrong. I have seen a few bonnets with fan damage. Its surprising how much force the blade has. Even a plastic fan bursting can cause damage. I can visualise water pumps ripped off due to a shed blade and out of balance fan. Scary stuff. Many years ago an apprentice built up a face plate fixture for a 6ft swing lathe. Thats big. He didn't follow the drawings properly and didn't add the balance wieght. He started the lathe in the wrong gear , 200 rpm. The out of balance nearly ripped the whole lathe off its mountings. We had too relevel the lathe. A twisted bed can happen like this. Then the lathe is useless for long accurate work. Incidently lathes are common on ships which pitch and roll. Yet they still are accurate. Most ships have a machine shop. The AA don't do ships especially in the middle of an ocean. | ||
| Randy Roberson Grand Master Username: wascator Post Number: 410 Registered: 5-2009 |
I recall from researching the fan coupling on SRH9391 that the unit on my car was bought out, but I do not offhand recall the brand. I never found a replacement, but I did have a good used unit to replace mine when I noticed it seemed to be leaking oil. Some of the earlier Cars had the same unit as Cadillacs, though. Stay away from the "line of fire" of fan blades. We had a runaway turbocharger at work last year. It threw chunks weighing 10 pounds through the roof. One fist-sized piece went through the side of a contractor's JobBox. Fortunately no one was in the line of fire. | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 25 Registered: 5-2015 |
Runaway diesels are 'king dangerous. I had a turbo diesel runaway and it ate the leg of a boiler suit that I stuffed into the air intake. If that had failed we were heading for the hills. It wreaked the engine. The max speed was 2200 rpm I reckon it got to 5000 rpm. The cause was a failed turbo brg seal. Common. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1336 Registered: 6-2009 |
Bob, AA? I know you can't mean Alcoholics Anonymous and I can't pull up anything else as far as what that acronym might be. Brian | ||
| Randy Roberson Grand Master Username: wascator Post Number: 411 Registered: 5-2009 |
Brian I think we would say "AAA", or the Auto Club. Obviously when ships break down they must be pretty self-sufficient; hence they often have capability to repair or even make parts on-board. This was one of the two turbos on a 20 cylinder natural gas compressor engine. The blower wheel is about 12 inches diameter and the max speed is about 12K RPM; best we can tell this one exceeded 25K RPM before the wheel ruptured. Root cause: a piston was holed on top by a piece of broken ring and the oil cooling for the piston leaked out and got into the exhaust manifold and caught fire. | ||
| richard george yeaman Prolific User Username: richyrich Post Number: 292 Registered: 4-2012 |
Brian it means Automobile Association brings you home on the back of a truck or tries to fix your problem at the side of the road. Richard. | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 28 Registered: 5-2015 |
AA is like AAA We call them Automobile Association or boy scouts dib dib. Most sailors I know are in alcoholics anonymous. The other main one is the RAC which is the royal automobile club. Prince Micheal of Kent the queens cousin is the royal bit. The RAC club is in Pall Mall London. They do an excellent roast beef. I have AA membership. One can imagine a 100,000 ton ship broken down and the engineer making a bit to repair some small bit. A storm blows up and the ship is in trouble because no engine no steerage. This why good ship engineers are crucial. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 729 Registered: 5-2012 |
Just to pick up a couple of points: Bob: The plug looks like a simple lathe job. Aluminium or brass will do. I have never seen this plug. Here's a pic of the complete assembly.  The original is made from nylon and is pretty much indestructible. There is a small hole into which the pipe fits. The nylon plug resides at the bottom of the float chamber and the small pipe runs through the channel to the bottom of the jet housing. It is a loose fit and fuel is allowed to flow around it. I would guess it is used to reduce the volume of fuel at the bottom of the float chamber, which is presumably the hottest part, to allow the cooler fuel pumped in at the top to reach it more quickly, since the flow rate will be faster. As I mentioned, I've removed it, as I am too impatient to wait another 1-2 weeks for a new shorter spring to arrive, and will use the kit supplied longer spring. The original short spring is definitely too weak. I re-fitted it and there was hardly any resistance felt when pushing the jet lever. The new spring offers lots of resistance, so I can be confident the jet will be held firmly in place. If I do get hot starting problems, re-fitting the original parts with a new short spring is a quick and easy job. 30 mins to remove the carburetor assembly, 30 mins to replace the springs, 30 min to refit the assembly - 1 1/2 hours (3 if you include coffee breaks). So I'm happy to proceed on this basis. Thanks also for the tips on removing the half shaft. I will look into the puller and chain idea when I get round to it. It may save me considerable time as, if I do use heat, I will first remove the petrol tank. I have a natural, built in aversion to being covered with a tank full of burning petrol while trapped beneath the car. Also, I will check out the spiral spring on the front of the viscous coupling, but it appears the Hayden 2747 is a direct replacement for the SY1 cars. These retail at around 50 bucks, so replacement is a no-brainer. Brian As always, thanks for the resource file. It is a treasure. As I mentioned, it appears the Hayden 2747 will be a direct replacement. Larry has a pic of the two couplings, original and replacement, and they look almost identical. BTW - the link in the resource file no longer works - it must be due to the recent upgrade of these forums. Best Regards Geoff | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1337 Registered: 6-2009 |
Geoff, Thanks for letting me know about the broken link. I feel fairly certain that this was to the original post by the person who had the adapter ring made, but I'll be damned if I can find it now. The good thing is that I did post a photograph of said adapter ring in the thread, Alternate fan and/or viscous fan clutch for the "Two Series" cars, near the end of the thread. I try to point to the original material as much as I can. If anyone eventually comes upon it, please drop me a message with the correct link. I've updated the resources file as well and the latest version, which uses the thread title and the correct link, is now live on my Google Drive. Brian | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 30 Registered: 5-2015 |
I am a dumb arse. The plug is like a cup of fuel insulated from the aluminum carb body heat. So using a metal to make one won't work. So petrol proof plastic nylon best old screw driver handles turn nice. Check with petrol first. Another way is to fit a thick insulated gasket at the long centre bolt joint. Cut with precision a piece of 6mm thick hard board to the shape then a bead of silicon both sides. 50 bucks for a coupling is almost spare change money. Sorted. Taking the final drive out allows very good access to the two metal brake pipes above. Plus a good clean and a coat of black paint will have the diff looking like new. Check the diff cross member mounts For cracks. Theres a mod for this. | ||
| Robert Noel Reddington Experienced User Username: bob_uk Post Number: 32 Registered: 5-2015 |
Forgot. Removing the fuel tank could be the same amount of aggro as the diff. |
