| Author | Message | |||
     Carlos Maenhout New User Username: carlos_maenhout_from_belgium Post Number: 6 Registered: 12-2018 |
conc. my SS drophead coupe 1970 (DRH7762) The engine is stucking from time to time (in idle and when driving). I already renewed fuel filter, distributor cap and rotor, contact points, ignition coil, plugs and cables.Timing was adjusted. All in vain. Can someone give me a tip? carlos | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3179 Registered: 06-2009 |
Carlos, I realize we likely have an "English as a second language" thing going on here, and my intent is absolutely not to make you feel in any way self conscious, but to seek clarity. "Stucking" is not a term I've ever seen used. I suspect you may mean stalling, but I want to be certain. Could you please clarify? Brian | |||
| Larry Kavanagh Frequent User Username: shadow_11 Post Number: 782 Registered: 05-2016 |
Apart from the main fuel filter underneath the floor there are small gauze filters where the fuel pipes enter the carburettors. Have you checked these for blockages? | |||
| Omar M. Shams Grand Master Username: omar Post Number: 2162 Registered: 04-2009 |
Dear Larry, We need to be sure of the carburettor configuration on this two door car because some came with a solex carburettor and others had these retrofitted. | |||
| David Gore Moderator Username: david_gore Post Number: 3992 Registered: 04-2003 |
Carlos, Re Omar's comment re the Solex carburettor, these were not fitted to the UK and other RHD 6.75 litre V8 vehicles in the early 1970's as these were fitted with dual SU carburettors as standard. The Solex carburettors were fitted in later years when the US imposed emission standards for new cars being sold in the American market [first California delivered cars then all US States some time afterward]. Is there any possibility your car has received a tank or more of E10 or similar ethanol-containing fuel? You car is from an era where the various rubber and elastomer items in the fuel system proved to be susceptible to enhanced deterioration associated with the ethanol content. This problem certainly reared its ugly head when owners used our E10 blended fuel in Australia. I never used E10 in DRH14434 for this reason. Burlen have supplied ethanol-compatible conversion kits for R-R/B vehicle fuel systems liable to be degraded by the use of E10 and similar fuels. https://burlen.co.uk/ http://sucarb.co.uk/cf/vehicle/list/?manufacturer=Rolls+Royce+%26+Bentley&vehicle=Silver+Shadow If it was my vehicle, the first step I would take would be checking the fuel system seals, gaskets and other non-metallic items for deterioration. If you are uncertain whether they have been upgraded or not; I would replace them anyway to avoid possible future problems.  | |||
| Carlos Maenhout New User Username: carlos_maenhout_from_belgium Post Number: 7 Registered: 12-2018 |
Dear Brian, It is stalling indeed. I also feel some vibrations during the stalling Dear Larry, I checked the filters at the entrance of the carburettors with good result Dear Omar, it are SU carbs. Dear David, I always use EUROSUPER 98 but as this has no lead, I always add also an additive for replacing the lead. carlos | |||
| Jeff Young Frequent User Username: jeyjey Post Number: 450 Registered: 10-2010 |
Stumbling before a stall ("I also fee some vibrations during the stalling") is slightly more likely to be fuel than electrical. Does it have a twin fuel pump? Are both sides pumping? | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3181 Registered: 06-2009 |
What RPM is your idle set at? It could be slightly low, and I have known of some who've raised theirs slightly from factory spec. Brian | |||
| Larry Kavanagh Frequent User Username: shadow_11 Post Number: 783 Registered: 05-2016 |
I could be wrong but I think RR SY engines already have unleaded fuel compatible heads and don't require lead additive. This is certainly the case with Silver Shadow 11 engines. | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2266 Registered: 05-2012 |
I'm sure you are right Larry. I've always driven my 74 "series 1" on unleaded E10 petrol with no problems. If lead was an issue the forums would be alive with discussions about what additives to use. Here's a thing - I used to use premium 98RON gasoline in my car, not the lower 95RON. After a discussion in which Brian in particular asserted that you don't need to use 98RON in these cars I tried 95RON. There was no difference at all to the running of my engine. No pinking or loss of power. I thought the higher compression ratio of 9:1 would necessitate the use of higher grade gasoline, but have since read that "higher compression ratio" usually means 12:1 +. Nice one Brian - you've saved me 5 bucks every time I fill up. I wonder if it would run on paraffin. | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2455 Registered: 09-2004 |
Does this happen more when the engine hot or when cold? | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3182 Registered: 06-2009 |
The hue and cry about the death of classic car engines with the removal of lead was, much like Twain's death, an exaggeration of the worst kind. What lead used to do was replaced by other less environmentally damaging (or so they thought, one of the early replacements was pretty awful) equivalents. I've been on one of the RROC-US Pre-War tours as a rider and there was no general running around to put lead additive in the cars I witnessed fueling up. Yet they keep going and going and going. Geoff, indeed, one cannot class any of the engines of the SY era and earlier (and even many in the SZ era as well) as "high compression" in the contemporary meaning of that phrase. These cars were shipped to many locations around the world where what was designated as "five star" fuel in the Owner's Handbook was most certainly not available. They do just fine on what is regular unleaded (87 AKI [R+M/2]) fuel here in the USA. Brian | |||
| Hubert Kelly Frequent User Username: h_kelly Post Number: 432 Registered: 03-2012 |
Lads don't forget the dash pots, if they stick even on occasions they can cause problems. Carlos clean both dash pots and report back. | |||
| David Gore Moderator Username: david_gore Post Number: 3994 Registered: 04-2003 |
Brian, The successful use of fuel with varying octane ratings is simple; it is all a matter of timing: Engine timing that is......... Lower octane = retarded timing. Increase the timing for high octane; retard the timing for low octane. Bush mechanics rule 101 - advance the timing until the engine starts to ping under load, retard the timing 1 degree and subject the engine to full load acceleration; if no pinging is heard, the timing is OK. If it pings, continue to retard the timing until the pinging stops. . | |||
| Omar M. Shams Grand Master Username: omar Post Number: 2163 Registered: 04-2009 |
That is a great bush rule David. | |||
| David Gore Moderator Username: david_gore Post Number: 3995 Registered: 04-2003 |
Omar, If you really want to see "bush mechanics" in action, our ABC TV service made a series of programmes some years with this title which is very interesting and more often than not amazing. https://www.facebook.com/abcnews.au/videos/top-five-bush-mechanics-moments/10155265068789988/ First Episode complete: https://www.youtube.com/watch?v=cDeHI3fOlzo Only one series was ever made but it was compulsive viewing. | |||
| Carlos Maenhout New User Username: carlos_maenhout_from_belgium Post Number: 8 Registered: 12-2018 |
Dear all, It concerns the 6.2 l engine (1969- 1970). There is no twin pump. The problem mainly arises when the engine is hot indeed. It is not only at idle speed but also when driving. Hubert, the dash pots are clean. I will try the tip with the timing. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3183 Registered: 06-2009 |
Carlos, There is either a twin SU fuel pump, or something someone's replaced it with. The twin SU was standard issue for most of the cars produced. I can say, though, that I doubt that's the issue as I had a "one side dead" dual SU on SRH33576 that got me across the USA and back. It was only when what had been the only functioning side died that I realized that there had been only one functioning side. When you say "when driving" do you mean literally when cruising along the road, or only when you've stopped at a light or stop sign (or otherwise)? If it's the latter, I'd still suspect a fuel boiling issue. Brian | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2456 Registered: 09-2004 |
Hi Carlos, IMO you have the classic symptoms of an over rich mixture on one or both carbs, when the engine has completed a hot run could you check the exhaust tail pipe for black soot, use a rag! | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2457 Registered: 09-2004 |
Brian you must of driven like a Nun to cross the USA and back with one side of the twin SU pump working without noticing! | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 271 Registered: 07-2018 |
Both pumps do not work at the same time and the dual pump arrangement shares the same diaphragm and the same in and out tubes. If one of the electrical solenoids fail and it's electrical related hardware inside, such as the points and/or condenser, then you are expected to move the electrical connection to the other pump. On a Shadow, there may be a switch inside the car to do this because I don't believe the pumps electrical connection is very accessible. On my Mark VI, it's quite easy to get at the electrical connection and manually switch it over. This should be done on a regular basis to keep the spare solenoid exercised in case it's needed. The pump that is never used becomes susceptible to oxidization on the points. Maybe both ends of the pumps are wired to operate at the same time on a Shadow, but I can't see this being the case. Both solenoids would have to be in sync. for this to work since they are operating off the same diaphragm. NO, it has to be one or the other. | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2458 Registered: 09-2004 |
Jeff what have you been on! I have repaired many and one way to test if the flow is limited by the one of twin SU,s not working is to drive up a moderate hill [not like a Nun] but on 3/4 throttle and feel the engine falter after a short time. BTW each SU pump has a diaphragm between the pump body. Have seem many twin pumps replaced with electronic types that can do a good flow rate! | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3184 Registered: 06-2009 |
Jeff Martin wrote, in part: Maybe both ends of the pumps are wired to operate at the same time on a Shadow, but I can't see this being the case. Both solenoids would have to be in sync. for this to work since they are operating off the same diaphragm. NO, it has to be one or the other. That would be incorrect on all counts. Each side of the dual SU pump has its own diaphragm and the two share a central pump body and single output from same. See these two articles by Gary Phipps of the RROC-US: The SU Fuel Pump: How It Operates The SU Fuel Pump: How to Test It Also, here's an image of the EPK300 SU Pump rebuild kit. You need two of them for the dual SU pumps, one per side.  Both sides do work at the same time and both stop pumping once enough back pressure exists from the carb floats cutting off flow and resume once they allow the next inflow cycle to begin and the back pressure drops enough. Brian | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3185 Registered: 06-2009 |
Patrick, That drive, while not "spirited" was certainly not at a crawl. It covered interstates that climbed through the Rockies as well as back roads doing the same. The return trip involved an ascent of the Moki Dugway though this must be done slowly. Given the condition of the non-functioning side discovered at the time of rebuild, there was zero chance it had ever been functioning prior to my rebuild. I think I posted photos when I was doing the job. She ran just fine, in all common driving conditions, with a single side of the dual SU doing all the work. Brian | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2268 Registered: 05-2012 |
I remember Paul Yorke, a Rolls Royce specialist, advising owners to check the fuel pump annually by disconnecting the two wires alternately to check each side was working. He said some owners would drive round without realizing the one side had failed only to get an FTP when the other side finally gave up. By implication he was saying you cannot tell if one side has failed in normal driving. | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 272 Registered: 07-2018 |
OK OK... Sorry about that, but even with one pump only working, it should stay ahead of the demand no matter how one drives ? With only one pump working it's simply going to operate twice as fast as the float bowls empty ? I always thought the two pumps were there in case one failed, not to keep up with the demand. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3188 Registered: 06-2009 |
Jeff, I can state from direct experience that SRH33576 had no difficulty in all sorts of typical driving with only one of the two "pumping sides" of the dual SU fuel pump working. I don't think that I noticed speed of the pumping changing much, but the amount of time that the pump had to operate once 2 were working in tandem. The relationship also didn't seem to be linear, as far as only half the time once two were operational. I'm sure the relationship between the two pumps as far as volume two can pump rather than one depends on a number of factors. Brian | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3189 Registered: 06-2009 |
I just discovered a photo I posted on rollsroyceforums.com of what I discovered when I took apart one side of the dual SU on SRH33576 in 2010:  I had to get a "donor half" from a different car because this one was so far gone as to be unable to be rebuilt. What you can see was only part of the damage. Brian | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 273 Registered: 07-2018 |
My GOD, what happened to it, it looks like it's been in salt water !? Obviously exposed to the elements _ winter driven ? I've never seen one that corroded. | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2459 Registered: 09-2004 |
OMG do you lot not know that they can overheat going like the clappers till slowdown flow!!! ? Back to the problem running rich maybe. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3190 Registered: 06-2009 |
Patrick, You need to learn that people reporting direct experience, many of them, trump your pet theories. How many people need to report that all evidence points to long periods of operation with "only one half" for you to believe that it's sufficient, and that there are no "overheating issues"? I've lived it, and I'm not the only one reporting that I've done so. Case closed. Brian | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3191 Registered: 06-2009 |
Jeff, I have often wondered what happened, too. from all external appearances before tearing all the external bits off to expose this, that side was indistinguishable from the other one. I have to believe that it was a tiny, cumulative "seep-in" type leak that kept whatever seeped in wet and active for a very long time once it got in. It was totally unexpected. It's funny, but the same thing almost exactly occurred with one of the window motors on LRK37110. Looked perfectly lovely from the outside but was a rusted mess inside and with no evidence of anything carrying rust slowly dripping out. It was replaced with a donor as well. Brian | |||
| Jeff Young Frequent User Username: jeyjey Post Number: 451 Registered: 10-2010 |
Yeah, it does look like the sealing failed enough to let water in, but not back out. This is the great thing about Land Rovers. All the water comes right back out the bottom.... | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2271 Registered: 05-2012 |
OMG do you lot not know that they can overheat going like the clappers till slowdown flow!!! ? Patrick - I cannot believe a manufacturer would fit a faildangerous device rather than a failsafe device. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3192 Registered: 06-2009 |
Jeff, Just as an FYI, I found the page out of the Burlen catalog (and, oddly, can't find the whole catalog) for the SU fuel pump that our cars use. See the note about both sides operating simultaneously.
Brian | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2460 Registered: 09-2004 |
Brian classic example of the pump heating up on a run in the wet, the seal gives way to the heat and bingo on cooling down sucks in water that sinks to the lower position. Drive like a Nun and the the engine will keep going but the other pump now working as not intended will soon give up then all will be revealed unless you drive normally in that case the engine will falter with the one pump failing. Pleased that the twin pumps have worked for many years on many manufactures vehicles. Geoff the one pump running hot will slow the flow down that is the fail safe warning with the engine faltering but not stalling unless that one stops completely. Back to Carlos with the original fault stalling Is the tail pipe black with running rich? | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3193 Registered: 06-2009 |
Patrick, Put most simply, what you're saying is BS, period, end of sentence. The engine does not falter or stall when one of the two dual pumps is not working. And that's whether you're driving like a nun or scaling an interstate at highway speed through the Rocky Mountains. But, with this I'm done, because this is written for later readership. You are never, ever swayed by facts presented by anyone else. Lived experience trumps your pet theories, always. Brian | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 274 Registered: 07-2018 |
Carlos, here is my 2 Cents. If the exhaust is sooty, more then usual, make sure the choke is totally off after the engine is fully warmed up _ choke flap should be fully open. It's very unlikely ignition timing, ignition just doesn't come out of time unless something has broken in the distributor, in which case in would not be an intermittent stalling problem. It would not really run at all, and start very well. Ignition timing that has gone wrong will cause lack of power over all _ "retarded", and on the opposite end, "pinging" under hard acceleration and hard starting _ kicking back because it's getting the spark too soon. Some people think it's a dead battery, but in fact the starter is working against the motor kicking back, because the spark is igniting the fuel mixture too soo. From your symptoms of stalling, none of this applies to your problem. Problem gets worse when it's hot: Check float valves, they may be swollen, allowing too much fuel from not being able to close properly, or they may be stuck shut _ not enough fuel. Both conditions will cause stalling, hesitation and engine vibration. Check weakener device buy disconnecting it, others here will know more on how to do this properly. Very often two problems can happen, like sticky float valves and a faulty weakener device, so both have to be taken off the table, I would start with the float valves first. This assumes that the choke is working properly. All of this assumes that your ignition is healthy _ common problem is bad condenser, it is now a common problem that even new condensers are bad. I get mine from Distributor Doctor. (better quality) The coil is another thing, it will perform fine until it gets hot. I found the only real test is to substitute with a known working coil, bad coils will bench test OK until they get hot in the engine bay. Coils fail because the varnish on the many thousands of windings of copper wire brakes down form heating and cooling cycles. This causes internal shorts in the coil and becomes worse when hot. The shorts cause internal shorting which adds to the heat problem. It eventually "snow balls" and the car will quit altogether. | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2461 Registered: 09-2004 |
Jeff I go along with all you say however one thing before the coil being the most probable cause I would do a test on the coil ballast control they can be a cause of strange engine cutting out etc when hot if fitted. On the drophead ballast fitted from chassis no 1001- 6000! | |||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 697 Registered: 11-2017 |
Swap out the distributor condenser.The root cause is electrical. Many fuel issues are actually electrical in origin. | |||
| Carlos Maenhout New User Username: carlos_maenhout_from_belgium Post Number: 9 Registered: 12-2018 |
Patrick, the tail pipe is ok Jeff, float valves are ok. choke is ok. This car has no weakener device yet. coil was renewed. Robert, I will renew now the condenser and will keep you informed carlos | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 276 Registered: 07-2018 |
If it turns out to be a faulty condenser, then the points will have to be filed at the very least and reset. Don't use emery cloth or any type of sandpaper of any kind, always use a proper points file. Chances are on the low side, but new coils can be defective as well, where did you get it from and what brand ? | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2462 Registered: 09-2004 |
Carlos, correction to my posting= On the drop head ballast NOT fitted from chassis no 1001- 6000! Did you fit a ballast type coil primary 1.43-1.58 ohms secondary 4500 ohms ? Hope the contacts and condenser sort the prob. | |||
| Graham Phillips Frequent User Username: playtime Post Number: 424 Registered: 03-2019 |
G'day everyone,... Not to be argumentative here but I have always used 'wet-N-Dry' fine sand paper with a few drops of Singer Oil to clean points etc. Never had an issue, was taught this by my father who is an engineer since I was first able to stick my head in an engine bay. When you talk about the 'Ballast' in relation to the coil, are you meaning the resistor? Graham. | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 277 Registered: 07-2018 |
Here is what can happen when using any type paper, the carbide bits from the paper get trapped into the contact surface of the points and have a bad affect on the proper contact between the two surfaces _ this can cause misfiring due to the points not allowing full saturation of voltage into the coil. I can see the oil acting as a lubricant to help prevent the papers abrasive getting embedded into the contact area. | |||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 698 Registered: 11-2017 |
One benefit with the file is both contacts are filed by a fixed thickness (file) thus profiling the points for better contact, | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2272 Registered: 05-2012 |
I once read to just replace points as filing them removes the contact surface. I read this on the internet so it's probably wrong. What are your opinions on this. I replace the points annually with a new set but have kept the old ones - would it be just as good to file them. | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2463 Registered: 09-2004 |
Geoff, you must do a high mileage to replace the contacts yearly unless you have other problems running in the background! More important to set the dwell and ignition timing yearly. The plastic heal of the contacts can wear even when the cam is lubricated. If the vehicle is left for years without running the contact surfaces can suffer from oxidisation, fine emery will restore OK. Timing is of the more importance when running LPG. IMO the way to go unless an electric conversion!  No need for a Matt satin wrap, the car keeps up to date with its age!!!!! | |||
| Trevor Hodgekinson Frequent User Username: wm20 Post Number: 254 Registered: 11-2006 |
Jeff, Points are usually tungsten No way for abrasive to get embedded as tungsten is way way way harder. Oxide on the surface is the usual culprit for poor performance . | |||
| Mark Tennison New User Username: fixstuff Post Number: 37 Registered: 11-2020 |
Stalling at idle or higher rpm while driving: "In tank" filter clogged with varnish & oxide particles and/or rubber sections of fuel lines closed up as Ethanol attacks the inner wall of the old original non Ethanol compatible hoses. Easy way to check is to put a pressure gauge in the fuel feed line directly to the carb/s, if you see anything lower than 3 psi you have a fuel supply problem either line restriction and/or weak pump/regulator, ideally you want to see 4-5 psi (Carbs only) | |||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 699 Registered: 11-2017 |
Did you swap out the condenser yet? | |||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 279 Registered: 07-2018 |
Trevor, OK, that makes sense, but here is a real world story. A teenager and his girl friend were stranded with his Vauxhall in the rain near a 7-11 and the guy was furiously sanding the points with emery cloth, and the car would not start. My Dad, dug around and pulled out a book of paper matches and used that to set the points, but most importantly, slid the unprinted sides of the book between the points, and the car started right away. The paper cleaned all the bits of gritty emery cloth from the contact surface. | |||
| Carlos Maenhout New User Username: carlos_maenhout_from_belgium Post Number: 10 Registered: 12-2018 |
dear all, the ballast is a new one. I bought the ignition coil at Brabo, a specialised RR company in the Netherlands. However, there is not any mark or manufacturer printed on the coil. I will be on leave now for my business during a week. After this leave, I will resume my investigation at the hand of your tips |
Burlen Catalog - SU Fuel Pumps