daverclasper Posted September 6, 2018 Report Share Posted September 6, 2018 (edited) Hi. Vitesse Mk1 2 Litre. This is according to plug colour and seems to be getting more so in the past couple of months. Have tried a manifold leak test around no6 area with brake cleaner, though not conclusive (maybe a tiny leak not showing and also I have always had an uneven idle, so maybe difficult to tell a slight change). Any suggestions please, or could it be another issue?. Any help, great, thanks. PS, No difference in how it runs that I can tell, except occasional split second hesitation after say slowing down for a roundabout and then giving it some gas. Dave Edited September 6, 2018 by daverclasper Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 6, 2018 Report Share Posted September 6, 2018 I would suggest a compression test , you may have a valve showing leakage Pete Link to comment Share on other sites More sharing options...
Nick Jones Posted September 6, 2018 Report Share Posted September 6, 2018 2 hours ago, Pete Lewis said: I would suggest a compression test , you may have a valve showing leakage This is one possibility. Also worth trying the compression test with the throttle shut. If 6 gave a higher reading in this situation then it could indicate a manifold air leak. Years ago I also had a cleaner plug on no 6. Initially I thought leaner (though normally 2 & 5 are the leanest running), then I realised it was actually cleaner rather than leaner and wondered about headgasket issues. This was supported by slow water loss, but not by cooling system pressurisation with the engine running or by compression test results. While starting the dismantling process to examine the head gasket I found that there was a little water in the inlet runner for no. 6 and realised that there was a water path to it from the manifold heating jacket. Swapping the inlet manifold solved the problem and the head stayed on. Nick 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 7, 2018 Report Share Posted September 7, 2018 Water inJection was a old idea, I made a coil of brake pipe round the downpipe of my 53 mk5 minx to squirt steam into the carb as a unknowingly idea from a youngster, the pipe furred up and blew a hole are well the best laid idea's was doomed But Nicks clues are well worth a careful look in the manifold area. Pete Link to comment Share on other sites More sharing options...
daverclasper Posted September 7, 2018 Author Report Share Posted September 7, 2018 Thanks chaps. That's brill (always expect the unexpected!). I'll try and find time for some compression tests this weekend. Cheers, Dave Link to comment Share on other sites More sharing options...
daverclasper Posted September 7, 2018 Author Report Share Posted September 7, 2018 Hi. Quick question please. How much oil for wet comp test?. Seems different opinions on this. Ta, Dave Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 7, 2018 Report Share Posted September 7, 2018 About an egg cupful but wouldnt bother until you have a dry test result, , Best on a hot engine throttles open , all plugs out , decent battery crank to bet the best reading may take 5 or 6 turns Pete Link to comment Share on other sites More sharing options...
daverclasper Posted September 8, 2018 Author Report Share Posted September 8, 2018 (edited) Cheers Pete. Not done a comp test before. I had a 250 2 stroke bike way back, that Hydrolicked when I kicked it over, due to petrol flooding and bent a con rod, so just checking oil volume. Dave Edited September 8, 2018 by daverclasper Link to comment Share on other sites More sharing options...
Adrian Saunders Posted September 9, 2018 Report Share Posted September 9, 2018 Dave, I found that an electronic ignition conversion engineered out one of the variables, the good old points. My idle was transformed to even and consistent and gave me confidence in that setup so as then be able to look elsewhere. Try electronic, even if you go back to points, you’ll learn. Also, the pipe-in-the-mouth-of-the-carb to set the flow can be surprisingly accurate, set the balance too. If you’re local to Chelmsley Wood/South Birmingham, I can lend you a proper, graduated air-flow meter and a timing light. Let me know. Link to comment Share on other sites More sharing options...
Adrian Saunders Posted September 9, 2018 Report Share Posted September 9, 2018 Oops. Forgot. No 6 can run hotter due to compromised cooling! The waterways in the block/head get full of crud at the rear first. If you remove the block drain plug and nothing happens, it’s blocked. I ended up removing my head and cleaning out the block from above with a wire and multiple fills with water. Link to comment Share on other sites More sharing options...
daverclasper Posted September 10, 2018 Author Report Share Posted September 10, 2018 Thanks a lot for offer of loan of carb balancer Adrian. Not local to Brum though. Would be interested in trying that as I set mine by ear with a hose pipe to ear, though maybe not as accurate. Did have E.I on for a bit, but couldn't notice a difference. My dizzy shaft play does not seem too bad?. My block drain is very free flowing, maybe a sign that the rest is clean, though not proof I imagine. Cheers, Dave Link to comment Share on other sites More sharing options...
daverclasper Posted September 13, 2018 Author Report Share Posted September 13, 2018 Hi. Well finally found time to do a comp test. Found it bit difficult to get a seal (rubber bung/push in type, maybe rubber hard, as a vintage one) though managed it with the dry test. All 6 cylinders between 190 and 200. Second test with throttle closed showed a difference of 0, or + / - 1 difference from first readings (I guess they should all have been -, as less air)?. Wet test not accurate, as could't get the gauge to seal properly and my helper tan out of time. 1 and 2 cylinders/230 and 220 higher. Did try no 6 ( the one that's running weak, showed 5 higher, but this test was leaking worse and ran out of time at this point. So, not sure what to make of that, except looks like losing comp from the cylinders/pistons on at least some of them. Cheers, Dave Link to comment Share on other sites More sharing options...
JohnD Posted September 13, 2018 Report Share Posted September 13, 2018 Dave, If the dry test was consistent across the block then the wet test is irrelevant. It's only to check if a bore that's down is due to piston ring leak, when the pressure will rise (it alwyas does leak or not) or valve leak when the oil won't help. And if there was only a minimal difference with the throttle closed (Nice one, Nick!) then no manifold leak. BUt the other way to chek that is to spray fuel (well, perhaps A fuel, brake cleaner will do or WD40) at the manifold gasket. If there is a leak then the added fuel may cause a brief blib in engine rate or note. May be worth looking inside your manifold. It has to split the flow from on crab to three cylinders that are pulsing away, and a fault in the inside wall might cause that to go off ('m cluthcing a straws here!) John Link to comment Share on other sites More sharing options...
daverclasper Posted September 13, 2018 Author Report Share Posted September 13, 2018 (edited) Thanks John. I was sort of chuffed with those tests across the bores, as not done this test ever before, and my car does use a bit off oil . So, maybe not compression/valve intake related. Will think about air induction related with the manifold and Nicks possible coolent issue into manifold. I have done the spraying around no 6 intake manifold and didn't notice a difference, though my idle is irregular at around 700 revs and maybe hard to show a difference, could raise to maybe around a 1000 when it smooths out and test, do you think?. The car isn't driven hard, so maybe if it is a bit more fuel weak on one cylinder, maybe not the end of the world (or even my Triumph) ?. Cheers, Dave Edited September 14, 2018 by daverclasper Link to comment Share on other sites More sharing options...
daverclasper Posted September 14, 2018 Author Report Share Posted September 14, 2018 Hi. Just wondering, as I'm assuming those those comp reading are pointing to valves/cylinders being ok and therefore intake manifold small leak still possible, would it be worth nipping the manifold nuts up slightly for no 6 with a torque wrench. I did undo one side nut to fit bracket for the breather valve as car didn't have one a while back and tightened it by feel, on the cautious side (as it looks like those bracket things could bend), as couldn't find torque wrench at time. Even if it improved for a short time only, may tell me something?. Dave Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 14, 2018 Report Share Posted September 14, 2018 book shows 20-22 lbft not overly tight a std hard fixing would be around 29 lbft so a normal hand tight is quite adequate Link to comment Share on other sites More sharing options...
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