Edwin Posted September 7, 2009 Report Share Posted September 7, 2009 Hello (again), After 2 previous posts that helped me a lot I am back with another problem I've got a 1970 TR6 with a standard engine (CC 58189L) and 2 brand new SU HS6 carbs. The car runs very nice but has as problem that is beginning to worry me a bit. About 2 weeks ago I found out that the spark plug in cylinder nr4 had oil on it and was therefore burning oil. Today I did a compression test (after a 30 minute drive) and the results were (from cylinder 1 to 6): 186 psi, 186 psi, 183 psi, 186 psi, 182 psi, 187 psi. I had the throttle wide open. These figures tell me that there is nothing wrong with the pistons or pistonrings. Am I correct in assuming this??? The cylinderhead has had new valve seats (leadfree conversion) installed a couple of years ago when I was restoring the car. The oil pressure begins at about 70 when the enigne is cold and drops to about 50 when the oil is hot. The rocker cover ventilation goes directly into the SU carbs but if oil was going into the cylinders this way all the plugs would show oil and not just nr 4, right? Could it be the valve guides on nr4 that are causing the burning of the oil and how can I tell if this is the case? Or could there be another problem/issue? All types of advise or comments are very welcome. Kind Regards, Edwin Quote Link to post Share on other sites
rpurchon Posted September 7, 2009 Report Share Posted September 7, 2009 (edited) Hello (again), After 2 previous posts that helped me a lot I am back with another problem I've got a 1970 TR6 with a standard engine (CC 58189L) and 2 brand new SU HS6 carbs. The car runs very nice but has as problem that is beginning to worry me a bit. About 2 weeks ago I found out that the spark plug in cylinder nr4 had oil on it and was therefore burning oil. Today I did a compression test (after a 30 minute drive) and the results were (from cylinder 1 to 6): 186 psi, 186 psi, 183 psi, 186 psi, 182 psi, 187 psi. I had the throttle wide open. These figures tell me that there is nothing wrong with the pistons or pistonrings. Am I correct in assuming this??? The cylinderhead has had new valve seats (leadfree conversion) installed a couple of years ago when I was restoring the car. The oil pressure begins at about 70 when the enigne is cold and drops to about 50 when the oil is hot. The rocker cover ventilation goes directly into the SU carbs but if oil was going into the cylinders this way all the plugs would show oil and not just nr 4, right? Could it be the valve guides on nr4 that are causing the burning of the oil and how can I tell if this is the case? Or could there be another problem/issue? All types of advise or comments are very welcome. Kind Regards, Edwin my guess would be the inlet valve guide.you could try a top hat type oil seal on no 4 to see if it cures it. early 1990s land rover discovery diesal j or k reg i think.i saved the old ones from my dads old disco. was going to fit to fit on my inlets when it was run in plus a few thousand miles.now really. anyway just tryed one on a spare head i have.tight fit on the guide, hammer and socket job good fit on the valve not too tight not too loose if you know whot i mean. dont bother with the moss type they are just a o ring.but nothing keeps them down on the the guide. richard Edited September 8, 2009 by rpurchon Quote Link to post Share on other sites
Edwin Posted September 8, 2009 Author Report Share Posted September 8, 2009 Thanks richard, I will take a look at the valve guides this weekend to see if I can fix it myself. Anyone else with some advise?? Edwin. Quote Link to post Share on other sites
Mike G Posted September 8, 2009 Report Share Posted September 8, 2009 Hi Edwin Do you have external oil feed to the rockers? If you do, you may be advised to remove it, or insert a restructure. Also worn valve guides will draw oil into the cylinders, on overrun you usually then see a puff of smoke, as the throttle is opened and extra petrol and air are introduced into the cylinders. Mike G Quote Link to post Share on other sites
johnny250 Posted September 8, 2009 Report Share Posted September 8, 2009 hi Edwin, I posted here about my disaster recently http://www.tr-register.co.uk/forums/index....piston&st=0 I had a mucky plug for ages on my No: 5 cylinder.....compressions were all OK, I eventally burnt out the exhaust valve, and of course lost all compression, but when I pulled the piston it had been seized at some stage. Hope that is not your problem, but worth remembering if you have the head off john Quote Link to post Share on other sites
Edwin Posted September 8, 2009 Author Report Share Posted September 8, 2009 Mike, I do not have an external oil feed. After reading a lot of advise not to install this I decided not to use one. Warn valve guides could indeed be a problem. I don't see a puff of smoke when shifting but I do see it when I restart the car after it has been standing still for a couple of minutes. And I wonder if putting in a top hat type oil seal (like Richard mentioned) will fix the problem or that I have to replace the valve guides? Do you know if replacing the valve guides is "easy" to do myself? ------------------------------------------ John, I did have the head off when I was restoring the TR6. The head has had new valve seats installed (leadfree conversion) and the pistons looked all very good. But when I can't get the problem fixed very soon I will just take off the head so I can examine everything better than I can now. ------------------------------------------ Regards, Edwin Quote Link to post Share on other sites
peejay4A Posted September 8, 2009 Report Share Posted September 8, 2009 (edited) Edwin, As Mike G points out, the sure fire way of diagnosing worn valve guides is to warm her up fully then get up to a fair speed in, say 3rd gear, then come off the throttle under engine braking down to about 20mph then with one eye in the rear view mirror, floor the accelerator. A puff of smoke will tell the tale, or in my case a blinking great cloud. Edited September 8, 2009 by HPA 510K Quote Link to post Share on other sites
67_gt6 Posted September 9, 2009 Report Share Posted September 9, 2009 There are no valve stem oil seals on Triumph 6s so there is always a chance of a little drain down, particularly after parking up - I used to get a little puff on start up even on a rebuilt engine (GT6) andy Quote Link to post Share on other sites
rpurchon Posted September 9, 2009 Report Share Posted September 9, 2009 (edited) Do you know if replacing the valve guides is "easy" to do myself? yes they are easy to replace hammer and a drift the right dia.just knock them out. i changed my inlet guides once without removing the head.smoking really bad on overun. but you cant gurantee the valve will sit central in the seat with the new guide. richard Edited September 9, 2009 by rpurchon Quote Link to post Share on other sites
Edwin Posted September 9, 2009 Author Report Share Posted September 9, 2009 I know the TR6 doesn't have valve seals as standard but I came across these: TR6 Valve Seals from GoodParts Is there anyone out there that has some experience with these? I could try them (costs almost nothing). And if they don't do the job I could always remove the head to replace the valve guides. But first I will try the method of playing with the throttle under engine breaking to see what comes out of the exhaust. Edwin Quote Link to post Share on other sites
poolboy Posted September 9, 2009 Report Share Posted September 9, 2009 Hardly seems worth the trouble, at least you know the valve stem is getting lubricated. But seriously, maybe it's the spark plug itself. Before my rebuild, the engine was consuming, not leaking, 1 quart per 600 miles and you'd never know it by looking at the spark plugs. They were burning clean. Champion RN12 YC. Possibly just the one plug is defective. How much oil are you using, btw ? Quote Link to post Share on other sites
Edwin Posted September 9, 2009 Author Report Share Posted September 9, 2009 Hardly seems worth the trouble, at least you know the valve stem is getting lubricated. But seriously, maybe it's the spark plug itself. Before my rebuild, the engine was consuming, not leaking, 1 quart per 600 miles and you'd never know it by looking at the spark plugs. They were burning clean. Champion RN12 YC. Possibly just the one plug is defective. How much oil are you using, btw ? The plugs are brand new, NGK BP5ES, but it could of course be that one is defective. The car has done about 250 miles since the restoration and I had to put in about 300 ml. Edwin Quote Link to post Share on other sites
Mike G Posted September 9, 2009 Report Share Posted September 9, 2009 Hi Edwin During the restoration, was the engine worked on, re-bore or new rings? If the was the case, then perhaps the rings on cylinder No 4 have not yet bedded in properly. This would allow a small amount of oil the migrate past the rings and into the combustion chamber. Mike G Quote Link to post Share on other sites
rpurchon Posted September 9, 2009 Report Share Posted September 9, 2009 I know the TR6 doesn't have valve seals as standard but I came across these: TR6 Valve Seals from GoodParts Edwin these wont fit if you have double valve springs? richard Quote Link to post Share on other sites
Edwin Posted September 9, 2009 Author Report Share Posted September 9, 2009 Mike: The engine itself has not been worked on by me. But the previous owner probably put in new pistons. A specialist that examined them said they looked too good to be 32 years old, but I can't tell for sure if they were replaced. But I did have some work done on the cylinderhead. I had a leadfree conversion done: new valve seats installed and the head was flattened. But that's about it. And maybe the engine has to be driven more to make sure everything is settled beter.... ---------------------------------- Richard: That would not be a problem: mine has single valve springs... Quote Link to post Share on other sites
ELVEDEN1 Posted September 9, 2009 Report Share Posted September 9, 2009 " But seriously, maybe it's the spark plug itself" Have you tried swapping plugs about i.e #4 to #1 to see if it sill oils up? Clive Quote Link to post Share on other sites
Edwin Posted September 9, 2009 Author Report Share Posted September 9, 2009 Clive, I just got back from a 30 mile drive and I did indeed swap the plugs.... and nr4 was still a bit oily, but not as much as before. And the plug that was in nr4 before was almost dry...... A friend of mine suggested I should try to use the NGK BP6ES instead of the BP5ES that i have now. And I think it is a good idea to start all over with a new set of plugs and see what will happen. Edwin. Quote Link to post Share on other sites
88V8 Posted September 15, 2009 Report Share Posted September 15, 2009 An easier way than looking in the mirror is to let it idle 30 secs when hot, then blip the throttle hard and look for a puff of blue smoke. What you are doing with either method is running it for a period under a high vacuum situation (overrun or idle) then igniting any oil that was drawn down the guides into the cylinder. Ivor Quote Link to post Share on other sites
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