davidgsmith Posted May 6, 2008 Report Share Posted May 6, 2008 I have a '63 TR4 which seems to blow some oil out of the filler cap and I have also noticed on tickover, air blowing out of the breather pipe which comes out of the side of the block, pointing down (you know what I mean). I was wonderinhg if this is anything to worry about or is it quite normal and something I will have to put up with..? Thanks Quote Link to post Share on other sites
Don Elliott Posted May 6, 2008 Report Share Posted May 6, 2008 Check the compression on each cylinder. If one cylinder shows low compression, I would guess that the rings on the piston in that cylinder are worn, or maybe broken. If they are worn, the compression, instead of staying above the piston doing useful work, is leaking down past the rings and trying to pressureise the oil pan area. That's why the air is seen escaping from the vent pipe coming out the lower side of the engine. This also communicates to the top of the engine, so this compressed air in the oil pan also goes up the passages around the pushrods to the top of the head in the valve cover. Then it comes out the oil filler cap. If that's the case, you have to decide how bad it really is and, it the engine runs really rough, and you decide you have to do something about it, it probably means that the rings need to be replaced and the liners honed before putting in the new rings. Basically, it's almost a full engine job, when you get that far into it, you'll want to check everything. Don Elliott, Original Owner, 1958 TR3A TR Register Member since 1987 Quote Link to post Share on other sites
davidgsmith Posted May 6, 2008 Author Report Share Posted May 6, 2008 Thanks Don, the engine sounds and feels OK, not rough at all, so hopefully I can run it for this summer and maybe get it overhauled in the winter, would that be a good idea in your opinion? Quote Link to post Share on other sites
TR 2100 Posted May 6, 2008 Report Share Posted May 6, 2008 Thanks Don, the engine sounds and feels OK, not rough at all, so hopefully I can run it for this summer and maybe get it overhauled in the winter, would that be a good idea in your opinion? TR engines are very robust. The sort of problem you have is annoying rather than a warning of something bad about to happen. When TR engines get a bit rattley and blow a bit of smoke, it's a warning that you may need to rebuild the engine in 100,000 miles or so! AlanR Quote Link to post Share on other sites
Ade-TR4 Posted May 7, 2008 Report Share Posted May 7, 2008 "When TR engines get a bit rattley and blow a bit of smoke, it's a warning that you may need to rebuild the engine in 100,000 miles or so!" It's a sign that it has now run-in. ade Quote Link to post Share on other sites
Don Elliott Posted May 7, 2008 Report Share Posted May 7, 2008 David - I would suggest - like Alan and ade, to leave it alone. You say it runs smoothly and if it doesn't stall at tick-over, leave it for now. It may be that the most of the oil smoke you see is only when you accelerate, in which case it's the rings. When it gets rough and won't idle, the plugs (or just one) get carbonised often and when you have time available, then I'd suggest that it would be time to do the engine. Mine was also getting low on compression values and it had lost about 20% of its zip on acceleration. Also the smoking oil from the engine was polluting the planet a bit more that I would have liked. But watch the oil level. I was using a litre of Castrol 20W50 every 600 miles with the same symptoms as your TR and I drove for another 60,000 miles until last spring when I took it out and all we found were the rings needing replacement. The engine repair shop who measured the pistons and liners for me, then honed the liners, told me that my problem had been caused by the SU carbs being set too rich and the extra petrol left on the sidewalls of the cylinders was washing the oil off the bores and this caused the rings to wear from a lack of lubrication. His experienced eye told him this just by looking at the piston with the rings still on. He also lapped in one exhaust valve for me and he polished the journals on my crankshaft. I put new rings onto the same pistons and put these into the same liners he had honed for me. I also changed the bearing shells even though the others with 40,000 miles on them still looked super. That is the same engine re-builder who converted my head years ago to lead-free and also who ground my crankshaft for the new modern rear oil seal. The power is back up and I used Castrol 10W30 for the next 3,600 miles and during that period, I didn't have to add any oil, but the oil level went from the top line on the dip-stick to the bottom. Quote Link to post Share on other sites
davidgsmith Posted May 7, 2008 Author Report Share Posted May 7, 2008 just had the compression checked today and read as follows: 250 250 248 245 Looks OK?? Quote Link to post Share on other sites
RogerH Posted May 7, 2008 Report Share Posted May 7, 2008 Hi Dave, that seems rather high as you are only compressing atmospheric air (14PSI). So with a 10:1 compression ratio that would give 140PSI - or am I missing something!!! Roger Quote Link to post Share on other sites
davidgsmith Posted May 7, 2008 Author Report Share Posted May 7, 2008 (edited) maybe it was 150 150 148 and 145 sorry - too much sun !! Edited May 7, 2008 by davidgsmith Quote Link to post Share on other sites
davidgsmith Posted May 8, 2008 Author Report Share Posted May 8, 2008 Just checked with the mechanic and fellow Register member who did my compression test and he confirmed that the readings were 250, 250, 248, and 245 Quote Link to post Share on other sites
TR 2100 Posted May 8, 2008 Report Share Posted May 8, 2008 Just checked with the mechanic and fellow Register member who did my compression test and he confirmed that the readings were 250, 250, 248, and 245 Are we talking psi here? I think not. AlanR Quote Link to post Share on other sites
davidgsmith Posted May 8, 2008 Author Report Share Posted May 8, 2008 Hi Alan, not sure, I was just sat in the car and turned the engine while he measured it Quote Link to post Share on other sites
Don Elliott Posted May 9, 2008 Report Share Posted May 9, 2008 David - Those values look about a hundred too high. Maybe his compression gauge is out of calibration. In any case, if the numbers are all that close to each other, that tells you that all the cylinders have equal efficiency on holding the compression so you don't have one piston/rings that is causing the blow-by and the smoke you talked about. If the numbers you report are true, then your engine must have about 12:1 compression ratio and should be putting out about 175 HP on a rolling road. It must go like a bomb ! Quote Link to post Share on other sites
Kiwifrog Posted May 9, 2008 Report Share Posted May 9, 2008 Maybe they have skimmed an inch off of the head Quote Link to post Share on other sites
davidgsmith Posted May 9, 2008 Author Report Share Posted May 9, 2008 I know when i went to a tune-up guy last year it was putting out 180ish so hopefully as you said, my new guy's gauge is a little out !! Quote Link to post Share on other sites
Andy Moltu Posted May 9, 2008 Report Share Posted May 9, 2008 The exact figure is probably not too important - many guages are innacurate - the important finding is that all of the compression readings are within 10% of each other which means you are unlikely to have a significant piston/ring or valve problem. Quote Link to post Share on other sites
davidgsmith Posted May 9, 2008 Author Report Share Posted May 9, 2008 Thanks Andy, peace of mind is a great thing don't you think? Let's hope for more great weather this weekend and see our TRs out on the road Quote Link to post Share on other sites
lexsmit Posted June 3, 2008 Report Share Posted June 3, 2008 I have a '63 TR4 which seems to blow some oil out of the filler cap and I have also noticed on tickover, air blowing out of the breather pipe which comes out of the side of the block, pointing down (you know what I mean).I was wonderinhg if this is anything to worry about or is it quite normal and something I will have to put up with..? Thanks My TR4 63 CT18999lo has had the same problem, after I removed the Moss rocker feed kit ,blowing out oil disappeared. Lex Smit Quote Link to post Share on other sites
davidgsmith Posted June 5, 2008 Author Report Share Posted June 5, 2008 (edited) Thanks everyone for your help on this. I took the car to another rebuilder today who took the compressions between 160 on one cylinder, up to 186 on the others. He also commented about air puffing out of the vent tube, which it shouldn't be, exhaust gases recirculating and also, slight oil seepage from a couple of gaskets (crankcase, sump). All pointing towards too high compression, probably the head been skimmed over and over and probable damage to the rings. Looks like I might bite the bullet and go for a full engine rebuild...... Edited June 5, 2008 by davidgsmith Quote Link to post Share on other sites
Don Elliott Posted June 5, 2008 Report Share Posted June 5, 2008 If it's running acceptably well, leave it until the winter, if you don't need to drive it as often then. Enjoy the summer first. Quote Link to post Share on other sites
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