Jonny TR6 Posted January 7 Report Share Posted January 7 Checked over my valve clearances yesterday and had a couple of queries which I thought the wise old sages could hopefully answer. All gaps were set to 0.010” (they were pretty close, if not spot on anyway) and I followed the procedure in the manual. My issue however, was knowing the exact moment the respective pair of valves were open, which allowed me to set the clearance for the pair of closed valves. So the questions are - 1.) Do the open valves both open at exactly the same time, or does one open earlier than the other. If it’s both at the same time, then I only need to keep an eye on one of them. 2.) The valves are open for a certain amount of time, therefore does it matter where in the open part I am when I’m setting the clearance for the closed valves ? It’s tricky to see what’s going on with 4 valves at a time. Given that clearances are to a very tight spec, I was wondering how critical it is to get the exact moment that the open valves are in a particular part of the cam lobe, to set the clearance for the closed valves. Or am I overthinking things ? Looking forward to the usual informed debate ! Thanks Jonny Quote Link to post Share on other sites
RogerH Posted January 7 Report Share Posted January 7 Hi Jonny, These are not space ships with Nuclear engines. Just lovely TRiumph motors. Many folk set the valve clearance using the rule of 13 (on the 4 pot engines it is a rule of 9) With #1 fully compressed check #12. When #1 is fully (or nearly fully) compressed you have quite a large circumference around the back of the cam to check the gap. Give it a go and see how that affects the timing. - it shouldn't./ Roger Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 7 Report Share Posted January 7 Yep 13 rule is the simplest method. Mark each rocker with a piece of chalk after you have checked/adjusted it. 12 chalk marked rockers means you have done it. Check lock nut tightness then Wipe off chalk after and refit cover Quote Link to post Share on other sites
harrytr5 Posted January 7 Report Share Posted January 7 Never thought of that Peter using chalk. I have always drawn straight lines on a sheet of paper with corresponding numbers and cross off as I go. Not anymore now, thanks for that. Yes rule of 13 (sixpot) rule of 9 (4 pot) Regards Harry Quote Link to post Share on other sites
RogerH Posted January 7 Report Share Posted January 7 Blimey - now that schools have gone over to 'white' boards where do you buy chalk??? Roger Quote Link to post Share on other sites
Motorsport Mickey Posted January 7 Report Share Posted January 7 4 minutes ago, RogerH said: Blimey - now that schools have gone over to 'white' boards where do you buy chalk??? Roger Ask the local Police Station where they buy them Roger, they have to have a ready supply for drawing around bodies ! Mick Richards Quote Link to post Share on other sites
harrytr5 Posted January 7 Report Share Posted January 7 (edited) Plenty in my garden (chalk), I will dig some up and swap for no smoke oil Roger in our meet next Thursday. Regards Harry Edited January 7 by harrytr5 Quote Link to post Share on other sites
Z320 Posted January 7 Report Share Posted January 7 IKEA, big box for childrens Quote Link to post Share on other sites
Jonny TR6 Posted January 7 Author Report Share Posted January 7 1 hour ago, RogerH said: Hi Jonny, These are not space ships with Nuclear engines. Just lovely TRiumph motors. Many folk set the valve clearance using the rule of 13 (on the 4 pot engines it is a rule of 9) With #1 fully compressed check #12. When #1 is fully (or nearly fully) compressed you have quite a large circumference around the back of the cam to check the gap. Give it a go and see how that affects the timing. - it shouldn't./ Roger Thanks Roger - sounds like a much simpler method. More time consuming, but gives me greater confidence that it’s correct. Slowly eliminating the causes of my sooty plugs. Next step after that is to close my plug gaps to .025” from .035, then do the timing. It’s all transpired from having an old school underslung ball jointed throttle linkage that was a pain to adjust and would never have the butterflies fully closed as it had run out of travel. That meant I couldn’t get idle down to 850rpm (it was always around 1100), which screwed up the timing adjustment etc etc. Quote Link to post Share on other sites
mleadbeater Posted January 7 Report Share Posted January 7 I just check and adjust from front to back in order, (saves on buying chalk, important for a Yorkshireman!), easy to turn the engine by starter with the plugs removed. Couple of tips: use a decent ring spanner, maybe grind the lower end of the ring flat, if its chamfered, to get a best possible purchase on the easily-rounded nut. if you suspect the rocker surface on the valve is worn, ie. indented, your feeler will bridge the indent giving a false setting. To get a truer gap measurement, you may consider using a dial indicator, see photo. Mike Quote Link to post Share on other sites
Jonny TR6 Posted January 7 Author Report Share Posted January 7 Thanks Mike - got a dial indicator, will have a fiddle a bit later now I know I don’t need to watch 2 valves at once. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 7 Report Share Posted January 7 4 hours ago, harrytr5 said: Never thought of that Peter using chalk. I have always drawn straight lines on a sheet of paper with corresponding numbers and cross off as I go. Not anymore now, thanks for that. Yes rule of 13 (sixpot) rule of 9 (4 pot) Regards Harry Does an eight cylinder use 17 rule and twelves 25 rule? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 7 Report Share Posted January 7 4 hours ago, RogerH said: Blimey - now that schools have gone over to 'white' boards where do you buy chalk??? Roger Would liquid chalk marker work? Stuff used to add green grocer’s apostrophes’ https://www.ebay.co.uk/itm/262639134020?hash=item3d26832544:g:TWkAAOSwtcZbh9Ch&var=563782583658 Quote Link to post Share on other sites
Kevo_6 Posted January 7 Report Share Posted January 7 I always use a dab of tippex, not sure you can still get it though. Quote Link to post Share on other sites
john.r.davies Posted January 7 Report Share Posted January 7 (edited) Tippex or chalk must contain some very fine but solid material, which may or may not be caught by the filter, but certainly I don't want in my bearings! I use a dab of grease on each adjuster screw as I do it, but use Vaseline, as that dissolves in engine oil where another grease may persist as lumps. John Edited January 7 by john.r.davies Quote Link to post Share on other sites
RogerH Posted January 7 Report Share Posted January 7 'Simon says' all in the memory. But if I had some chalk. Roger Quote Link to post Share on other sites
john.r.davies Posted January 7 Report Share Posted January 7 You recommended Rule of 13, Roger! If you can do al the subtractions and retain the results in series then you deserve the prize! There is another way, The Mirror. Imagine that there is a mirror across the middle of the block. Then when a valve is fully down, adjust the valve that is its "reflection". So, eg: If 4 is down, then adjust 9. You will note that this is the same as Rule of 13, but of course it is! More, it reflects (!!) the nature of a straight six engine, as two three-cylinder engines that are mirror images of each other and 180 degrees out of phase. And, it avoids repetitive arithmetic! John Quote Link to post Share on other sites
RogerH Posted January 7 Report Share Posted January 7 Hi John, I don't recommend any method. The methods where there long before I was breathing. But it is a useful tool to do something easily. As for mirrors - don;t break them - 7 years bad luck. Roger Quote Link to post Share on other sites
Z320 Posted January 7 Report Share Posted January 7 to avoid to „bridge“ any pitting I adjust the rockers by their noise, that works pretty well since years and reduces the push rod engines tick-tick-tick nearly to zero Quote Link to post Share on other sites
RogerH Posted January 7 Report Share Posted January 7 I have often thought that a better adjustment would be by - turn the rocker arm screw out by X degrees. We know the TPI so that will give how many turns or part of turn to give XYZ thou. There is the rocker arm ratio between valve and push rod Should be easy. Roger Quote Link to post Share on other sites
RobH Posted January 7 Report Share Posted January 7 (edited) 12 minutes ago, RogerH said: a better adjustment would be by - turn the rocker arm screw out by X degrees. I have a tool that does just that Roger, similar to this (but a lot cheaper!): https://www.gunson.co.uk/product/G4094/Clikadjust-Tappet-Adjuster Edited January 7 by RobH Quote Link to post Share on other sites
Z320 Posted January 7 Report Share Posted January 7 10 minutes ago, RogerH said: I have often thought that a better adjustment would be by - turn the rocker arm screw out by X degrees. We know the TPI so that will give how many turns or part of turn to give XYZ thou. There is the rocker arm ratio between valve and push rod Should be easy. Roger Tried this, did not work for me Quote Link to post Share on other sites
Kevo_6 Posted January 7 Report Share Posted January 7 3 hours ago, john.r.davies said: Tippex or chalk must contain some very fine but solid material, which may or may not be caught by the filter, but certainly I don't want in my bearings! I use a dab of grease on each adjuster screw as I do it, but use Vaseline, as that dissolves in engine oil where another grease may persist as lumps. John John, it’s the smallest dot of tippex which is then wiped off when all done with a petrol moistened cloth. Quote Link to post Share on other sites
john.r.davies Posted January 7 Report Share Posted January 7 If you're that worried. Why do it? Quote Link to post Share on other sites
John McCormack Posted January 7 Report Share Posted January 7 I write 1 to 12 (1 2 3 4 etc) on a piece of paper and tick them off. The major issue with doing them by ear is you close the gap too much and increase the risk the valves aren't closing properly. Burnt out valves and seats and loss of performance and fuel economy. Quote Link to post Share on other sites
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