Mack Posted May 27 Report Share Posted May 27 Hello all, I wasn't sure which section to post this in as it covers a few of the sub forums. Sorry in advance for the wall of text! I bought this car a little under a year ago and have driven it a handful of times as it started playing up a few weeks into my ownership. I am very much a beginner at all this so have learnt alot in the last few months after lots of searching on this forum and others. It started by not wanting to crank while we were at Goodwood Revival last year so had to be push started a few times that weekend. Then it would run ok with the occasional backfire from one of the carbs, along with what I can only describe as a hollow whislting sound coming from either the alternator or water pump. After getting it home it then started the bad running behaviour where it would essentially run very lean and only have any kind of power with the choke out. It will start ok but idles at about 1000 - 1500 rpm with idle screws backed all the way off. Idles and revs ok but as soon as it's under load the mixture seems really lean. I cant for the life of me find an airleak. I have tried spraying all the joints with carb cleaner and soapy water but cant find anything. I cant get seem to get the mixture correct by lifting the piston with a screw driver a couple of mm. Specs: 1 3/4 HS6 SU carbs. . Petronix Electronic ignition with flame thrower coil on a lucas dizzy with vacuum advance. Huco fuel pump routed behind the engine. 631 stainless exhaust ( I have heat wrapped it to prevent fuel evaporation problems and to protect the newly installed high torque starter) I had the manifold adapted to fit the carbs as previously it had adaptor plates so only had two studs for the carbs. Now has 4 studs and insulators fitted. New intake/exhaust gasket fitted. I changed the head gasket and set the tappets. While the head was off I checked that tdc corresponded to the timing marks, which it did. I have since double checked this with a borescope. I also checked the valves by pouring acetone into the head upside down and waiting to see if it leaked out. Seemed ok. Compression test, two round average, done cold with the carbs open, fuel pump fuse and ignition lead removed. 147 132 130 132 130 135 Not 100% sure what to make of these readings, do they seem ok? Checked timing, advanced to around 10btdc with the vacuum advance hose removed and taped over. Delrin needles checked and float heights set to 4mm New NGK BP6ES plugs ( same as was in the car before) gapped to 0.033 inches. Checked spark on each ht lead by moving the pickup of the timing gun to each lead. New blue coolant and silicone hoses. I am no longer getting any carb backfires but it has stared having a loud backfire pop on shutting off the engine after running for a while. I thought it was being caused by too rich a mixture but have reset the carbs to 12 flats down from the jet being level with the bridge and it still happens after the car has idled for a bit. I cleaned out the jets as best as possible by sucking the fuel out of the bowls and blowing carb cleaner through the jet from the carb body side. Both jets return properly after the choke it removed. I am very close to calling a garage and getting them to pick it up on a trailer but dont want to be defeated, as well as wanting to avoid the cost! If there is anyone who lives near Tunbridge Wells then I would welcome some help from someone who knows what they are doing, as I have run out of skill. Any advice on what to check/ adjust would be also be greatly appreciated. I have included a picture of the current setup, minus the K&N airfilters as I dont seem to have any lifting pins to use to check the mixture. Many thanks, Matt Link to comment Share on other sites More sharing options...
JohnD Posted May 27 Report Share Posted May 27 (edited) Matt, this sounds to me like a problem that needs hands, eyes and ears on, and I'm a bit far away. But this is the TSSC! With Area Groups all over the country! In Tunbridge Wells, I'm sure there is one near you, and you can find it on the Club Website. Is Sevenoaks near you, my geography is poor: The Triumph Sports Six Club - Areas (tssc.org.uk) Give the Area organiser a call/email and I hope that someone nearby will be contacting you soonest! Good luck! JOhn Edited May 27 by JohnD Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 27 Report Share Posted May 27 if you cant shut the idle down then its getting air from the breather , check smiths valve and rocker gasket and cap as simple places to start with. what needles are fitted ??? s with HS6 and KN + 631 needs something very different to std, whos head gasket did you fit we have some problems with payen on recessed bores sorry more questions than help Pete Link to comment Share on other sites More sharing options...
Mack Posted May 27 Author Report Share Posted May 27 That's a great idea John I will get in touch with them. It would be nice to meet some fellow classic car people around here! Pete the needles are BDM which I belive should be correct as it has a gas flowed head as well. I have checked the hoses to the Smiths valve but not taken the valve itself apart yet. Fitted a new silicone rocker cover gasket. The head gasket was a Payen but it is a non recessed one for my non recessed head. One small update though, it seems as though writing that post has chased away some of the gremlins. I double checked the float heights and they were a bit higher than 4 mm so I reduced them. I also retarded the timing to about 7 degrees before tdc, reducing the idle speed a little. I also found the throttle cable was sticking a little bit. This all reduced the idle speed to about 1000 rpm and now there is only a slight burble from the exhaust on shut down. I rebalanced the carbs and managed to actually drive it round the block. It seemed to run pretty well! The first time running without having to keep pulling the choke! I will have to check the plugs to see how the mixture is looking. The loud whistle/ whine is still there. I cant pin it down to being the alternator or the water pump. Not sure how best to do so. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 27 Report Share Posted May 27 some progress then , i would have used 3 full turns down as a starting mixture setting have the carbs been rebuilt ,the throttle plates are easy to fit back to front or not centralised , when closed there should be no daylight showing when yo look through Pete Link to comment Share on other sites More sharing options...
Iain T Posted May 27 Report Share Posted May 27 (edited) To investigate the whistle take the fan belt off to check the water pump and alternator. What fuel are you using? You've set the jets equally but are the needles equal and not centralised? Iain Edited May 27 by Iain T Link to comment Share on other sites More sharing options...
Mack Posted May 27 Author Report Share Posted May 27 The carbs are a bit of a headscratcher. Setting them both to 12 flats gives a different jet height when measured from the bridge. The adjusting nuts are also different sizes so I guess one jet has been changed in the past. The needles are equal and the pistons drop nicely so I assume they are centralised? Fuel is 97 ron premium. I removed the fan belt and ran the car briefly and the whistling went away, I just cant figure out if it's the pump or the alternator. Putting my ear to them with a socket extension didnt make it any clearer! I am very happy that she drives better now though! Link to comment Share on other sites More sharing options...
Firefly Posted May 28 Report Share Posted May 28 If the battery is not fully charged, the alternator can make "a sort of " whistling sound if working hard. Link to comment Share on other sites More sharing options...
johny Posted May 28 Report Share Posted May 28 Spin pump and alternator by hand to see if one feels rough? And from Fireflys comment run the engine normally but with the alternator electrics disconnected to remove any electrical load from it? Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 28 Report Share Posted May 28 have to say many with HS4/HS6 conversions find they run far better returning to strombergs SU were never specified for the 2 ltr engines apart from the later mk2 2000 triumph tune show needls on HS6 as BDM with 631 with + KN BDQ + head work BDM + cam BAE so bit of a mine field + yellow damper springs its the head ache you get from having "must haves" that dont work Pete Link to comment Share on other sites More sharing options...
Stratton Jimmer Posted May 28 Report Share Posted May 28 Not too sure if this has any relevance but my Sixfire currently has its HS6s fitted. I had a sound that seemed to be a bearing squealing which turned out to be a leaking gasket between the manifold and the front carburettor. I did the "run without water pump and alternator" trick which, in my case made no difference. Once the gasket had been identified as the fault it was easily fixed. Here's the rub though, I had noticed a fine film of oil in the carb to manifold adaptor when I had the carbs off to do the gasket. The rocker box vent pipe led to a tee piece with two pipes from there straight to the carbs. I have since changed this to a universal breather tank as shown in the attached photo in order to limit the oil going to the carbs. Since then, my engine's performance seems to be slightly better than it had been. I can't think why this should be but pick up in OD top is definitely improved. Link to comment Share on other sites More sharing options...
Stratton Jimmer Posted May 28 Report Share Posted May 28 P.S. Needles in the HS6 are BCM. Link to comment Share on other sites More sharing options...
Mack Posted May 28 Author Report Share Posted May 28 Thanks for all the replies. The breather connections on my carbs have been blanked off. I am definitely too far down the road to go back to stroms as that would involve a new intake manifold as well. Sunken cost fallacy I guess! I will take the fan belt off and give everything a spin. Would it be detrimental to unplug the alternator wires with the car running? Link to comment Share on other sites More sharing options...
Stratton Jimmer Posted May 28 Report Share Posted May 28 1 hour ago, Mack said: Would it be detrimental to unplug the alternator wires with the car running? Why take any risk? Just unplug it then start the engine. It's the battery that provides the power to the ignition and starter motor. 1 Link to comment Share on other sites More sharing options...
Mack Posted May 28 Author Report Share Posted May 28 I was more worried about the alternator generating charge and there being no where for it to go but my electrical knowledge is limited so that might not be a problem. Link to comment Share on other sites More sharing options...
johny Posted May 28 Report Share Posted May 28 No youre ok the thing you musnt do is disconnect the battery while running👍 Link to comment Share on other sites More sharing options...
Mack Posted May 28 Author Report Share Posted May 28 Great thanks I will give it a try this weekend and report back. I really appreciate all the help and suggestions. Thanks everyone! Link to comment Share on other sites More sharing options...
Ian Foster Posted May 29 Report Share Posted May 29 (edited) On 28/05/2024 at 13:14, Mack said: I am definitely too far down the road to go back to stroms as that would involve a new intake manifold as well Actually Stromberg CD175s have the same bolt pattern as SU HS6s, so are a straight bolt on replacement, if a tad tall with the standard dashpots. I run Stromberg 175 CD2s on a similarly modified manifold (ditched the adapters about 5 years ago). They have 2E needles in 100 thou jets. The needles are fixed and the jets are adjustable from the bottom. Currently with K&N filters but with a modified airbox planned. The dashpots/side and damper were shortened by 6mm to improve under bonnet clearance. I also have a Huco sucker fuel pump, Pertronix ignition module and a Flamethrower coil, but still have the standard Mk2 Delco distributor. The car runs wells, revs cleanly and gives good economy (+35mpg on the RBRR). When I read your initial post I did immediately think of air leaks through the carb/manifold joint and this was the catalyst for modifying my manifold. Ian Edited May 30 by Ian Foster Link to comment Share on other sites More sharing options...
Mack Posted May 29 Author Report Share Posted May 29 Ah good to know! I will keep them in mind if I cant sort the SU's out. Link to comment Share on other sites More sharing options...
Mack Posted June 8 Author Report Share Posted June 8 (edited) I think I'm getting somewhere. I decided to rule out the water pump by w=exchanging it as there was a tiny bit of play in the bearings. Whistle still there but nice new water pump Therefore now convinced the whistle is from the alternator as it changes in pitch when I use any thing that draws power. It seems to be charging ok so I guess I will live with it for now! I am still unsure if I have the timing right though, it is currently set at about 10 degrees BTDC. I have also managed to get the carbs set up ( I think). My problem was trying to get the mixture right when the engine wasn't up to temp. Rookie error. There is however now a rattle/ knocking sound when I shut off the engine. I have attached a video to demonstrate (sorry for it's size!). Is this anything to worry about? If so what would be the cause/ remedy? Many thanks for all the help so far! rattle2.mp4 Edited June 8 by Mack Link to comment Share on other sites More sharing options...
Paul H Posted June 8 Report Share Posted June 8 20 minutes ago, Mack said: I think I'm getting somewhere. I decided to rule out the water pump by w=exchanging it as there was a tiny bit of play in the bearings. Whistle still there but nice new water pump Therefore now convinced the whistle is from the alternator as it changes in pitch when I use any thing that draws power. It seems to be charging ok so I guess I will live with it for now! I am still unsure if I have the timing right though, it is currently set at about 10 degrees BTDC. I have also managed to get the carbs set up ( I think). My problem was trying to get the mixture right when the engine wasn't up to temp. Rookie error. There is however now a rattle/ knocking sound when I shut off the engine. I have attached a video to demonstrate (sorry for it's size!). Is this anything to worry about? If so what would be the cause/ remedy? Many thanks for all the help so far! rattle2.mp4 5.15 MB · 0 downloads Not sure if it’s me but I couldn’t hear anything Paul Link to comment Share on other sites More sharing options...
Iain T Posted June 8 Report Share Posted June 8 Nor could I, it must be the same pitch as my wife........ Iain Link to comment Share on other sites More sharing options...
Mack Posted June 8 Author Report Share Posted June 8 Hmm it's not as obvious in the video but its the last second after the ignition is switched off. Will try and get another video tomorrow. Link to comment Share on other sites More sharing options...
JohnD Posted June 8 Report Share Posted June 8 Wot? That "ruff, ruff" in the last second? Link to comment Share on other sites More sharing options...
Mack Posted June 8 Author Report Share Posted June 8 Yeah that's it. Sounds less like a small dog and more like a rattle in real life. Link to comment Share on other sites More sharing options...
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