Gordon Irish Posted October 21, 2019 Author Report Share Posted October 21, 2019 10 minutes ago, Gordon Irish said: Aha...well that all starts to make sense Roger thanks. See my reply to Pete coming up now. G Yes these are all NGK's Roger so I"ll do what you say and get a set of Champion L87's tomorrow Quote Link to post Share on other sites
RobH Posted October 21, 2019 Report Share Posted October 21, 2019 (edited) "There's also a lever under the fuel pump which when pulled up appeared to blow air into the glass bowl and force any remaining sediment out, which it duly did, albeit only a small particle or two" That doesn't sound right. There is a non-return valve in the petrol pump which should prevent back-flow and it sounds like yours is leaking. The lever operates the pump for priming the carbs and the valves should only allow flow in that direction. If there is back-flow the carbs may not be getting the proper feed of petrol. Edited October 21, 2019 by RobH Quote Link to post Share on other sites
Gordon Irish Posted October 21, 2019 Author Report Share Posted October 21, 2019 1 minute ago, RobH said: "There's also a lever under the fuel pump which when pulled up appeared to blow air into the glass bowl and force any remaining sediment out, which it duly did, albeit only a small particle or two" That doesn't sound right. There is a non-return valve in the petrol pump which should prevent back-flow and it sounds like yours is leaking. The lever operates the pump for priming the carbs and the valves should only allow flow in that direction. Hmm..ok RobH duly noted. There was a ripple and one bit of drag got released when I pulled the level yesterday but it wasn't a full blow back of air. I"ll keep a watch and if the new spark plugs don't solve my problem, I may have to check that fuel pump more carefully. G Quote Link to post Share on other sites
stillp Posted October 21, 2019 Report Share Posted October 21, 2019 51 minutes ago, RobH said: "There's also a lever under the fuel pump which when pulled up appeared to blow air into the glass bowl and force any remaining sediment out, which it duly did, albeit only a small particle or two" That doesn't sound right. There is a non-return valve in the petrol pump which should prevent back-flow and it sounds like yours is leaking. The lever operates the pump for priming the carbs and the valves should only allow flow in that direction. If there is back-flow the carbs may not be getting the proper feed of petrol. Sounds just fine to me Rob, the priming lever will force through some fuel, but if the glass bowl has been emptied it looks as if it's blowing air - maybe it is, on the first stroke. Gordon, if you operate that priming lever several times, it should feel different when the carb float chambers are full, and the glass bowl should be full of fuel with no air bubbles visible. Pete Quote Link to post Share on other sites
Gordon Irish Posted October 21, 2019 Author Report Share Posted October 21, 2019 Thx Pete. Yes, that's exactly what happened so think it's all good just a small push back of fuel that dislodged some sediment. Now to the new spark plugs tomorrow and fingers crossed!! Quote Link to post Share on other sites
Bfg Posted October 22, 2019 Report Share Posted October 22, 2019 15 hours ago, Gordon Irish said: Hi all...thx so much for your help. I wish I'd checked the page in past few days but thought I had switched on the bit that tells you when someone adds to the thread. Hence, from Pete's (BFG) incredibly helpful note down, I've only just pocked up all your messages and am now going through all with fine tooth comb :-) And, yes, Pete, I really am a novice and guess this problem is pay back for me getting the car first before spending a year or so apprenticeship to know enough in order to maintain the car to a large extent. Hi Gordon, whether an expert, with long experience, or novice - we all learn something from other owners, members and enthusiasts, so you are most welcome. "pay back for me getting the car first before spending a year or so apprenticeship to know enough in order to maintain the car to a large extent!" Imho the best way to learn is with experience on your own car ..where the issues and components you learn on are then familiar / the same as you might later-on face in the real world. Learning is also motivated by those big bright eyes ! From your report it does sound as if that spark plug is at fault. Well done at finding it. I might add that whatever brand of spark plug you buy nowadays - the electrode gap seems to be preset at about 0.035" (thirty five thousands of an inch), so these need to be gently tapped on end to close the gap to 0.025" (twenty five thou'). If you don't have them then you'll need a set of (imperial) feeler gauges to measure these gaps are all the same. Personally speaking, I also smear a coating of Copaslip (grease with copper dust in it) on the spark plug's threads before fitting them. The grease melts away but the copper acts as an anti-seize compound. Be careful not get this copper grease near the tip of the sparkplug, just smear it around the spark-plug's threads to ease their passage into the cast iron cylinder head. NB. The park plugs have washers which are a soft metal designed to flatten on compression, so they really don't need to be super tight. Fuel filter with the primer sounds fine, but because fuel kept coming through when you removed the bowl - but I wonder if the fuel tank's vent hole might be part blocked ..and so slightly pressurised the fuel in the tank and pipe when disturbed, but then part-restricted fuel flow when driving.? Others might better advise but I think there's either one of two vents on the TR4 & 4A. One of which is a vent pipe down the RHS of the tank, or else there's a small vent through the filler cap. if it's there then the latter will only take 10 seconds to check it's clear. Open the fuel tank's filler and it will be a small hole inside through a metal diaphram plate which holds the rubber seal in place. The seal might prevent pushing a wire right through but it should be apparent that air can lift and get passed the seal. The other vent, from a banjo connection on the top RHS of the tank, should have a pipe leading down to under the car. Occasionally grime (or underseal !) can block the end of that. This vent pipe should be long and pretty much straight down. It's designed in case the car is turned over in an accident - then the pipe will be pointing upright and fuel should not spill out of it. All the best with your checking, and hopefully enjoying learning about car maintenance and diagnostics. Pete. Quote Link to post Share on other sites
stillp Posted October 22, 2019 Report Share Posted October 22, 2019 Pete (Bfg), if the fuel level in the tank is higher than the fuel pump, then it is correct for fuel to flow when the glass bowl is removed. You could be right about a blocked breather causing the misfire. Easy enough to check by leaving the cap open for a short run. Pete Quote Link to post Share on other sites
Bfg Posted October 22, 2019 Report Share Posted October 22, 2019 .. you are correct Pete .. sorry must have been having a blonde-grey moment. My 'other' classic has a fuel tank sitting low down between the chassis rear legs so the fuel had to be pumped uphill, but with the TR the tank sits over the rear axle so most likely, even when nearly empty, is always gravity feed (..unless of course the car is parked nose up an incline). I can't see that a blocked fuel vent would contribute to a misfire ..only to the engine miss-firing on one cylinder, but as you say it's so very easy to check simply by running with the filler cap open. Cheers. Quote Link to post Share on other sites
stillp Posted October 22, 2019 Report Share Posted October 22, 2019 20 hours ago, Gordon Irish said: But this gorgeous Valencia Blue baby was just staring at me with those big headlight eyes! I completely understand, it does look gorgeous! Pete Quote Link to post Share on other sites
ianc Posted October 22, 2019 Report Share Posted October 22, 2019 One of Triumph's "improvements" in migrating from TR3A to TR4 was no longer to fit a fuel tap between bulkhead and fuel pump. Well worth fitting a decent fuel tap as it allows the pump to be disconnected or its filter to be cleaned without loss of precious petrol. Ian Cornish Quote Link to post Share on other sites
Gordon Irish Posted October 22, 2019 Author Report Share Posted October 22, 2019 21 hours ago, Gordon Irish said: Yes these are all NGK's Roger so I"ll do what you say and get a set of Champion L87's tomorrow Being little ole Guernsey, there's no garage that has either the NGK's or the L87's but they are ordering them for arrival on Friday. Can you confirm Roger if the L*&'s have any more serial numbers, as the Motor Spares place here reckons L87 isn't long enough!! Quote Link to post Share on other sites
ChrisR-4A Posted October 22, 2019 Report Share Posted October 22, 2019 Hi Gordon, Moss are listing champion L87YCC which was the direct alternative to NGK BP6HS but some major online spark plug suppliers say that L87YCC is obsolete and the new replacement is L87YC. I cannot confirm that but L87YCC are listed at over £5 each whereas L87YC are less than £2 so if ok then a big saving. Chris Quote Link to post Share on other sites
Gordon Irish Posted October 22, 2019 Author Report Share Posted October 22, 2019 3 hours ago, ChrisR-4A said: Hi Gordon, Moss are listing champion L87YCC which was the direct alternative to NGK BP6HS but some major online spark plug suppliers say that L87YCC is obsolete and the new replacement is L87YC. I cannot confirm that but L87YCC are listed at over £5 each whereas L87YC are less than £2 so if ok then a big saving. Chris Perfect Chris...thx. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 23, 2019 Report Share Posted October 23, 2019 From memory the same plug was specified for Fiat 500/126 and Citroen 2CV Check the specialists for these cars and see what the other manufacturers offer Champion was L87Y NGK was BP 6 H S Ac 42 FF Cheers Peter W Quote Link to post Share on other sites
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