Iain T Posted March 7, 2022 Author Report Share Posted March 7, 2022 28 minutes ago, Pete Lewis said: 22hg is a bit too high i would drop it nearer 18 I thought so and currently have it at 17-18. I need to get some petrol so I'll take it for a spin and see if it pinks. According to the timing marks it's about 20 degrees.....?! Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 7, 2022 Report Share Posted March 7, 2022 with the dizzy vac unit disconnected or left connected ??? Pete Link to comment Share on other sites More sharing options...
Iain T Posted March 7, 2022 Author Report Share Posted March 7, 2022 1 hour ago, Pete Lewis said: with the dizzy vac unit disconnected or left connected ??? I left the dizzy vac hose connected. I could try clamping the hose (it's rubber not the hard plastic pipe)? Driving to the petrol station the engine pinked when at low revs in high gear and then WOT. Put it back to just over 13 degrees and 14hg vacuum but the needle does shake a small amount. Check the compression or disconnect a plug lead? I can't hear any air going into the manifold and the gaskets are all new. Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 7, 2022 Report Share Posted March 7, 2022 you need to just disconnect it when using a strobe /engine idling as there will be some advance which you need to add to the static figure without digging through the manual i would not expect 6 deg from the vac unit but its certainly possible just pull the pipe off the dizzy and a soft rubber pipe will collapse under the max vacuum it supposed to carry a hard tube is far better dont take the HG readings as gospel its an indication , needle vibration as i said fit a short bit of bundy and squeeze it to make a restrictor just keep squeezing till the needle goes steady and its my guess with twin carbs you get a lower manifold vacuum as you have two throttles all sucking air so manifold depression at idle could be less sorry forgot about all this stuff from my emission testing days take it for a drive whats the vac to cruise with a light foot ( to get the highest reading without loosing speed ) stick in 3rd and decel whats that giving ??? Pete 1 Link to comment Share on other sites More sharing options...
Iain T Posted March 7, 2022 Author Report Share Posted March 7, 2022 There shouldn't be much of a vacuum at the ported takeoff by the carb but I'll try it out Wednesday, the wife want to go uptown tomorrow! I'll also check the tappet clearance. Cheers Link to comment Share on other sites More sharing options...
dougbgt6 Posted March 8, 2022 Report Share Posted March 8, 2022 Iain, I have a vacuum gauge on the dashboard and set the timing by it. The most you'll get out a 6 cylinder is 21 and then back 1 bar to 20. (22 and 21 for a 4 cylinder) I suspect if your getting 22 on a 6 cylinder your gauge is reading high. You can check it by ear, turn the dizzy for maximum revs and back a gnats. On mine the "ear" and "eye" methods line up exactly. Most satisfying. I have no idea what the BTDC is, gave up checking that for the reasons Pete's detailed. Doug 1 Link to comment Share on other sites More sharing options...
Iain T Posted March 8, 2022 Author Report Share Posted March 8, 2022 1 hour ago, dougbgt6 said: The most you'll get out a 6 cylinder is 21 and then back 1 bar to 20. Doug, To satisfy my paranoia I've ordered a piston stop plug to check if the tdc pointer and pulley marks line up. The vacuum did just go up to 22 if I set it at 20 the timing, according to the pulley, would be over 20degrees btdc! When I set at 17-18 on the vacuum gauge it definitely pinked under load. I want to check the pulley calibration before I proceed. If the pulley marks are out I'm wondering if the cam is set correctly? I'll do another check tomorrow with the dizzy vac hose (it's thick wall vac hose) blocked as I had it connected when I took the readings. I'm going one step at a time! Please look out for updates! Apologies the max reading was 21! Thanks Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 8, 2022 Report Share Posted March 8, 2022 3 hours ago, Iain T said: blocked as I had it connected no just disconnect it thats all you need to do ...pull it off it wont affect mixture or anything you are measuring pete 1 Link to comment Share on other sites More sharing options...
Iain T Posted March 9, 2022 Author Report Share Posted March 9, 2022 On 08/03/2022 at 16:22, dougbgt6 said: The most you'll get out a 6 cylinder is 21 and then back 1 bar to 20 Been tweaking today. I pulled the vac hose off the dizzy and it made no difference to the timing left to atmosphere or with my finger over the end. I advanced the timing until the vac gauge read 18-19 then backed it of to a reasonably steady 17. I checked the afr gauge and tickover and all seemed fine at about 13.5 and 750rpm. When I checked the timing its about 25btdc. The piston stop should arrive on Saturday and all will be revealed as to if the pulley timing marks are correct! The only other thing I'll do is the valve clearances which according to Newman Cams has to be done cold. I would put the post in say the Engine section but not sure how to do it! VID_20220309_153443.mp4 Link to comment Share on other sites More sharing options...
johny Posted March 9, 2022 Report Share Posted March 9, 2022 Iain, of course the definitive timing set up test is the WSM recommended 'pinking should just end as you get to 2000rpm under full acceleration in top gear on the flat'. Obviously the engine should be as hot as it gets and the fuel octane what you normally use... Link to comment Share on other sites More sharing options...
Iain T Posted March 9, 2022 Author Report Share Posted March 9, 2022 13 minutes ago, johny said: Iain, of course the definitive timing set up test is the WSM recommended I'll try that tomorrow, it was nearly 4pm after I'd tinkered and the traffic around here is not conducive to calm test driving! Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 9, 2022 Report Share Posted March 9, 2022 if you read the wsm you can check std cam timing all you need is feeler gauges and some simple rocker settings from memory set 11 and 12 on the rock/balance adjust 1 and 2 to 0,040" turn to align TDC the gap under 1 and 2 should be the same doesnt matter what size but the same Pete 1 Link to comment Share on other sites More sharing options...
Iain T Posted March 9, 2022 Author Report Share Posted March 9, 2022 55 minutes ago, Pete Lewis said: if you read the wsm Is there a WSM link on the forum? Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 9, 2022 Report Share Posted March 9, 2022 Triumph Car Service manuals - Vitessesteve pete 1 Link to comment Share on other sites More sharing options...
Iain T Posted March 10, 2022 Author Report Share Posted March 10, 2022 16 hours ago, Pete Lewis said: you read the wsm you can check std cam timing all you need is feeler gauges and some simple rocker settings Ta, I'll try it! Link to comment Share on other sites More sharing options...
Iain T Posted March 12, 2022 Author Report Share Posted March 12, 2022 Checked the timing marks on the pulley and tdc is where it should be. Bisecting the two piston stop points on the pulley corresponds to the tdc line. Top tip. Loosen nuts on rocker assy or as your valves open they can hit the piston stop! I have a small nick in the side of the stop.....then the penny dropped why! Hope the valve is ok🤞 It seems so far all is where it should be but I haven't checked the cam timing. The engine was put together by a guy who has assembled hundreds of engines so I'm hoping that will also be fine. I'm going to put everything back and run it up to 2000rpm and see if the vac gauge is stable (I think that's another test for manifold leaks). Then take it for a spin and see if 20 degrees btdc pinks!? Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 12, 2022 Report Share Posted March 12, 2022 pleased the damper ring is in the right place dont get paranoid about the readings youre ears will give the same results as the gauge ie as you increase the dizzy advance it makes the idle increase the gauge shows the same climb in vacuum.most carbs use 18 to 21"hg but this can be too much for some carbed engines on a light economy cruise you should get around 10 to 15"hg with just enough throttle to maintain speed drop a gear and thrttle back expect 28 to 30 "hg puling hard at a full throttle expect near to 0 "hg if the needle vibrates or waggs around damp it by making a supply pipe restriction if you go to the net there are some realy wild ideas of what the readings are, you dont need a gauge to tell you a valve is burnt out or a S plug is failed constant depression carbs often do give lower vac readings than a fixed jet downdraft carb keep playing and to drive with a 10 to 15 is no fun at all dont forget a poor air filter will affect some of the readings Pete 1 Link to comment Share on other sites More sharing options...
Iain T Posted March 14, 2022 Author Report Share Posted March 14, 2022 On 12/03/2022 at 14:58, Pete Lewis said: dont get paranoid about the readings youre ears will give the same results as the gauge I'm learning readings are for a perfect world, Triumphs aren't perfect! As suspected it pinked at 20 degrees, knocked it back to about 15 and it seems OK. Vac is 16. Adjusted the mixture and tickover. Time to stop fiddlin and drive the thing..... Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 14, 2022 Report Share Posted March 14, 2022 Doug has as many do, have a vac gauge mounted in the dash so you can worry about it when driving Pete Link to comment Share on other sites More sharing options...
Iain T Posted March 14, 2022 Author Report Share Posted March 14, 2022 I have to get out of lockdownitis, too much time and nuffin' to do but twiddle and buy must haves on tinternet. Oh well this little episode added to my box of toys...... Ta for everyone's help, I'm virtually back to my original settings! Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 14, 2022 Report Share Posted March 14, 2022 you know i love must haves !!!!! best way to get a headache ha Pete Link to comment Share on other sites More sharing options...
Iain T Posted March 14, 2022 Author Report Share Posted March 14, 2022 7 minutes ago, Pete Lewis said: you know i love must haves !!!!! They'll be useful one day..... Link to comment Share on other sites More sharing options...
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