trtwo Posted August 12, 2010 Report Share Posted August 12, 2010 Hi again, after some hours, two well versed Triumph bods, and lots of high tech equipment we discovered the following: All ignition parts in good health and working as they should. Valve clearances as they should. Good cylinder compression on all between 168 and 170 lbs, fuel reaching both carbs which are both balanced. What was discovered is very poor vacuum registered off the vacuum advance pipe, with air filters removed the front piston lifting poorly when you try to increase revs and back one is lifting but tends to "dance" a little. The car will start no problem but does not want to rev, the only way is to very slowly and carefully increase the revs and then it will not run clean, hunting and wanting to die. With a colour tune on it was almost impossible to adjust to the proper bunsen blue, with erratic colour and flashes. The consensus is an air leak in perhaps in the inlet, spraying with WD40 did not show anything. Any advice???? John Quote Link to post Share on other sites
TR NIALL Posted August 12, 2010 Report Share Posted August 12, 2010 Come on John,that was last night,have you not got the Manifold off yet. Quote Link to post Share on other sites
TomMull Posted August 12, 2010 Report Share Posted August 12, 2010 Hi again, after some hours, two well versed Triumph bods, and lots of high tech equipment we discovered the following: All ignition parts in good health and working as they should. Valve clearances as they should. Good cylinder compression on all between 168 and 170 lbs, fuel reaching both carbs which are both balanced. What was discovered is very poor vacuum registered off the vacuum advance pipe, with air filters removed the front piston lifting poorly when you try to increase revs and back one is lifting but tends to "dance" a little. The car will start no problem but does not want to rev, the only way is to very slowly and carefully increase the revs and then it will not run clean, hunting and wanting to die. With a colour tune on it was almost impossible to adjust to the proper bunsen blue, with erratic colour and flashes. The consensus is an air leak in perhaps in the inlet, spraying with WD40 did not show anything. Any advice???? John John, Unlike newer cars, there really isn't much on the intake side to leak. Loose manifold or carburetors or disconnected distributor line is all I can think of. That should show up with the WD40. You won't get much vacuum off that pipe if it's missing badly, even if everything is tight.. Did your guys check the carburetors themselves, particularly the dashpot oil, the piston needles, the diaphragms and the mixture setting. Oh, and the linkage to make sure both are working at the same time. The piston "dance" is quite normal and indicative of a misfire but the failure of one piston to lift would strongly suggest a carburetor problem to me., Tom mulligan Quote Link to post Share on other sites
TR NIALL Posted August 12, 2010 Report Share Posted August 12, 2010 We have done our best to check carbs,this is an ongoing problem. John had the same problem with the old carbs they were taken off and sent for a Specialist rebuild on their return thought that the problem was solved but alas same symptoms,the Dizzy also went for a rebuild just to be sure, we are fairly sure that there is a vacuum loss,but where. Quote Link to post Share on other sites
67_gt6 Posted August 13, 2010 Report Share Posted August 13, 2010 (edited) have you tried switching over the carb pistons to see if the behaviour changes? not uncommon for dashpots and pistons to become de-paired over the years. were the throttle shafts re-bushed as part of the re-build? Andy Edited August 13, 2010 by 67_gt6 Quote Link to post Share on other sites
Rhodri Posted August 13, 2010 Report Share Posted August 13, 2010 Going right back to your first post, on the other thread, you say that you have the cam timing at 15* BTDC, and you had difficulty setting the tappets etc. Where did you get this figure of 15* BTDC from, it is almost an ignition timing at full advance, half crank speed, type of figure, and not a valve timing figure ? A valve timing figure would be something like 103* ATDC. You may have your "timing" figures cross referenced. If using a standard cam set the rocker clearances to 0.0165" ( 0.42mm ) and the inlet and exhaust valves should be equally open with the piston at TDC on the exhaust stroke. Then reset valve clearances to 0.010" as normal. This info is from th TR4 manual. If you have an aftermarket cam you should have an installation figure, eg 105*, this is the figure that full lift occurs after TDC for the inlet and BTDC for the exhaust valves. So find true TDC on number one piston, zero your timing disc against a pointer bolted to the engine, then rotate the crank clockwise until the pointer is at the installation figure, eg 105*. Leave crank in this position and rotate the camwheel until the number one INLET valve is fully open, using a dial gauge. (The cam info should tell you what rocker/valve clearance to use whilst setting timing). Move nothing and fit the chain with any slack on the side of the tensioner. The valve timing should now be correct. Sorry if you know all this and have done it, but the figure of 15* rings alarm bells. Rod Quote Link to post Share on other sites
Menno van Rij Posted August 14, 2010 Report Share Posted August 14, 2010 Perhaps an odd question: is there nothing blocking the exhaust? Menno Quote Link to post Share on other sites
pfenlon Posted August 14, 2010 Report Share Posted August 14, 2010 rogue washer stuck under manifold gasket? Quote Link to post Share on other sites
Menno van Rij Posted August 14, 2010 Report Share Posted August 14, 2010 (edited) Perhaps an odd question: is there nothing blocking the exhaust? Menno rogue washer stuck under manifold gasket? After reading Peter's reply: did you put on the airfilters te correct way: i.e. not upside down, blocking two of the four holes at the back. You have done all obvious things and went beyond that point. Personally, I think it's something very unusual that's blocking something. Menno Edited August 14, 2010 by Menno van Rij Quote Link to post Share on other sites
TR NIALL Posted August 15, 2010 Report Share Posted August 15, 2010 (edited) Sorry Menno but it wont run right with the filters off never mind on we shall keep trying. Edited August 16, 2010 by TR NIALL Quote Link to post Share on other sites
stuart Posted August 16, 2010 Report Share Posted August 16, 2010 Have you checked inlet manifold for warpage on the inner face or cracks. There have been instances of poor manifold gaskets as well. If the manifold has a tapping for a servo is this blanked off properly. Stuart. Quote Link to post Share on other sites
TR NIALL Posted August 16, 2010 Report Share Posted August 16, 2010 Have you checked inlet manifold for warpage on the inner face or cracks. There have been instances of poor manifold gaskets as well. If the manifold has a tapping for a servo is this blanked off properly. Stuart. Getting the Manifold checked is our next course of action Quote Link to post Share on other sites
stuart Posted August 16, 2010 Report Share Posted August 16, 2010 Getting the Manifold checked is our next course of action If its NBG let me know before Friday as I may have one that will do and will bring it to Stafford. Stuart Quote Link to post Share on other sites
TR NIALL Posted August 16, 2010 Report Share Posted August 16, 2010 If its NBG let me know before Friday as I may have one that will do and will bring it to Stafford. Stuart Many thanks Stu,Thats 2 offers of help with a Manifold.I really appreciate these offers as TR2 Manifolds are not that plentiful over here,in fact i don't think there any at all Quote Link to post Share on other sites
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