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DFD702K.
Feb 24, 2019 19:34:41 GMT
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Post by rosieuk on Feb 24, 2019 19:34:41 GMT
You mentioned a few posts back that you changed the spark plugs because you didn’t know how long they had been in there. When did the car last have a full service? The issues could be ignition braking down through age. If new plugs improved things I would consider changing the whole ignition side (points, distributor cap, rotor arm condenser and plug leads). All are fairly cheap and readily available parts and at least you will know it’s not an ignition issue. If it’s not had a lot of maintenance I would also give the carb internals a clean and a new air filter. It was supposed to have had a full service when I took it to the garage for one. I suspect it didn't - certainly whatever spark plugs were there were bunged in whether they were right or not. Plugs have all *9s and it's now much smoother, will change cap & leads but the other bits are going to be replaced with electronic, more to the point I physically can't stay in that position long enough to get the bits out let alone get them back in with any chance of them working properly. It's had an air filter and wasn't that a bloody palaver - but I'm going to fab up a long heimholtz type plastic intake with a k&n type filter at the grill end. The intake can won't seal properly but that's going to get some judiciously applied duct tape for the moment. Crud in the jets and at the bottom of the float chamber could be causing fuel flow issues that would confuse things as would bad air flow Once those are done then I would look at timing from a starting point of fuel and spark being correct. It's had a fuel filter on it since I got a new fuel line on it and it's now running clean. I don't have the tools or health to start pulling that sort of stuff off the motor. I have a suspicion the engine is overcooling. Because I now have a cold air intake pipe from grille to trumpet into carb, not with the trumpet sucking past the exhaust it doesn't get hot intake air and after a longer run than usual the odd misfire almost disappeared - it might even be pushing in the choke too early. I think the trumpet pointing down might be a BL bodge - that very tight cowl pulls a lot of air through - I wonder if it pulled too much and a quick bodge "fix" was having a permanently hot intake charge (horrible for power, but helps slightly with pumping losses). If I could pull the octopus plate between the block and radiator - remove the upper cowl - replace the plate & test - I suspect it'd be sitting right in the middle of the N zone on the gauge.
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DFD702K.
Feb 24, 2019 19:58:41 GMT
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Post by rosieuk on Feb 24, 2019 19:58:41 GMT
Dizzy cap, plug leads & rotor arm ordered. See if those make a difference. Might examine the points too if can do in place. Have some 1500 grit paper floating around if I need it.
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DFD702K.
Feb 24, 2019 20:00:03 GMT
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Post by rosieuk on Feb 24, 2019 20:00:03 GMT
Dizzy cap, plug leads & rotor arm ordered. See if those make a difference. Might examine the points too if can do in place. Have some 1500 grit paper floating around if I need it.
Apparently someone has built a landcrab with the Montego diesel engine in it? It's apparently a Morris - anyone know who that might be and how hard it was?
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Post by Penguin45 on Feb 25, 2019 0:06:53 GMT
The diesel/spring Crab was photographed HERE - second post. Chris.
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Post by dave1800 on Feb 25, 2019 3:33:02 GMT
Removing the grille makes access to the distributor much easier, I fitted self tapping screws to the grille back in the early seventies to make it easier. Better to fit new points, once filed they lose their surface hardness. David Dizzy cap, plug leads & rotor arm ordered. See if those make a difference. Might examine the points too if can do in place. Have some 1500 grit paper floating around if I need it. Apparently someone has built a landcrab with the Montego diesel engine in it? It's apparently a Morris - anyone know who that might be and how hard it was?
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Post by dave1800 on Feb 25, 2019 3:48:56 GMT
I agree that the air filter housing is not well engineered. In the early days they stuck the "winter" and "summer" markings in reverse so it took in hot air in the hot? UK summer and that reduced performance on hot days. However, you should remember that the "correct" air fuel mixture was obtained by making a SU needle profile for the original set up. If you improve the air flow by using a different style of filter you will need to change the needle or your engine may run weak. There is plenty on the MGB websites where filter mods are common and the SU needle changes required.
I still suspect your engine's valve and or ignition timing given the position of the distributor vacuum take off that indicates to me that someone has taken the distributor out at some time and /or replaced the timing chain. Remember an engine develops its power by maximising the cylinder pressure at around 14 degrees after TDC. What has the greatest effect on this -ignition and valve timing and compression ratio - air fuel ratio far less unless it's considerably out of adjustment. I still find it amazing the amount of threads on many forums on fine tuning the carbs by people who seem reluctant to understand or get to grips with the importance of the valve and ignition timing. Just ask a professional tuner, the carb is the last item to be tuned, tappets, timing, thermostat must be right first.
David
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DFD702K.
Feb 25, 2019 12:14:37 GMT
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Post by rosieuk on Feb 25, 2019 12:14:37 GMT
Took it out for a run - seems to be much happier with different plugs but pulling the vacuum line made zero difference. Half choke & it'll sit at 70mph happily - either I've knocked it out of true or it needs a richer needle. If I've got the intake lengths "30""right & it's working - then 55mph would be where I'd expect lean running. The diesel one is interesting but I don't want to pull the hydrolastic. I still think that the 1800B supercharged diesel would be a better bet - without major changes but it'd need a *lot* of cash. The supercharger sans carb will fit (because it does with a carb). Am going to call garage tomorrow and book it in to get needle checked amongst other things.
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DFD702K.
Feb 25, 2019 18:40:10 GMT
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Post by rosieuk on Feb 25, 2019 18:40:10 GMT
A quick confirmation - if I go up a jet size - would I be able to lean back on the fuel mixture (its currently very rich at low end but I think lean at the top). I'm kind of confused because if I go up a needle size on the same mixture settings - won't it be excessively rich at low speed and possibly rich at high speed? (if it's fuel issue it's only slightly lean atm) Will phone garage tomorrow morning.
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Post by dave1800 on Feb 26, 2019 0:18:44 GMT
You can't go up a jet size with your HS6 carb, it's made for only 0.1 jets". There are dozens of needles - they have different profiles measured every 1/8" that have to be matched to the engine requirements - it is NOT a linear taper and requires an expert to select. You need to get the problem identified and corrected, changing needles is not the way to go in my opinion. It is possible that the jet and needle are worn and that typically causes a rich mixture at idle which if corrected by weakening leads to a weak mixture above idle /low engine load but your problem seems far more extreme than that. It is important however to ensure the needle is centred in the jet and the piston is free to move. You can check that by raising the piston with the lifting pin and listening for the clunk as it fall back. Get the tappets set, have the valve and ignition timing checked (ignition at idle and 3000 rpm) before touching the carb. Having to run with the choke half out could actually be a valve/ ignition timing issue. As I mentioned before there is evidence that the distributor has been removed - or maybe timing chain replaced - as the vacuum advance is not in the usual position - that to me is a potential warning from a quick visual check which should always be the starting point. The more you try and modify rather than find the problem the more difficult it will be to resolve. These engine in single carb versions are very tolerant to being out of adjustment by a few degrees in the ignition timing or a few turns on the mixture nut. Your car's poor running suggests something more fundamental and if not addressed could lead to engine damage. You need to find a mechanic familiar with these engines, maybe used to working on classic Minis, MGBs etc. It is unlikely that a modern garage will have the skills and understanding. David A quick confirmation - if I go up a jet size - would I be able to lean back on the fuel mixture (its currently very rich at low end but I think lean at the top). I'm kind of confused because if I go up a needle size on the same mixture settings - won't it be excessively rich at low speed and possibly rich at high speed? (if it's fuel issue it's only slightly lean atm) Will phone garage tomorrow morning.
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DFD702K.
Feb 26, 2019 18:08:20 GMT
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Post by rosieuk on Feb 26, 2019 18:08:20 GMT
The mixture is rich at idle because it was richened to see if it solved the problem. It didn't but something has - I've done 30 miles today at up to 65mph - one single solitary pop and it's been perfect all day. It's looking like doing 120 miles for half a tank so the mixture looks about right (ie getting the same mpg). Have a parts list to do the piped intake properly (getting rid of that damn can). Also have gotten a part code for a good new condenser. Ran into a chap with a Morris 1800 III - who lives around my area. It's a very dark purple colour. Have just replaced the rotor on dizzy (it's marked as lucas and I haven't chucked it away) and will probably have them replace cap - almost did myself an injury getting it back on. Need to undo and straighten the steering wheel and have a look at why the headlight flasher mostly doesn't and then it's garage work. Does anyone know where I can get a good rear bumper? Mine is bent.
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Post by Penguin45 on Feb 26, 2019 18:39:42 GMT
Couple of bumpers on the Bay of Evil Things at the moment - HERE. Chris.
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Post by dave1800 on Feb 27, 2019 5:25:36 GMT
Hi Rosie If you just enjoy trying things such as modifying the carb air intake that is fine and understandable. However, if you are seriously interested in improving the performance without spending a large sum of money I can only reiterate that you first need to get it running properly unmodified. In the past, for example, people tried to sort out ignition issues by fitting electronic ignition which not only failed to resolve the problem but made it more difficult to address. Once it is running properly and the valve and ignition timing etc are within spec then you are in a position to evaluate any modifications you make and take advantage of any improvements in efficiency, whether this involves changing carb needles or something else. In the early days of my ownership of your car, my office transferred to a new site and that meant I had a 90 mile a day round trip - cross country. I don't like getting up too early so that meant very hard driving with the engine regularly going over 5,500 rpm and speeds on the straight I would not like to mention here. All with the standard air filter and housing and average speeds no longer possible on today's roads. Surprisingly the fuel consumption never fell below 30mpg as measured over tens of thousands of miles. On a more leisurely run for pleasure it was closer to 40mpg. Remember if the engine runs lean then you can end up with burned exhaust valves or worse and wrong ignition timing certainly if over advanced can break rings, burn pistons, damage head gaskets and lead to catastrophic engine failure. regards David The mixture is rich at idle because it was richened to see if it solved the problem. It didn't but something has - I've done 30 miles today at up to 65mph - one single solitary pop and it's been perfect all day. It's looking like doing 120 miles for half a tank so the mixture looks about right (ie getting the same mpg). Have a parts list to do the piped intake properly (getting rid of that damn can). Also have gotten a part code for a good new condenser. Ran into a chap with a Morris 1800 III - who lives around my area. It's a very dark purple colour. Have just replaced the rotor on dizzy (it's marked as lucas and I haven't chucked it away) and will probably have them replace cap - almost did myself an injury getting it back on. Need to undo and straighten the steering wheel and have a look at why the headlight flasher mostly doesn't and then it's garage work. Does anyone know where I can get a good rear bumper? Mine is bent.
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DFD702K.
Feb 27, 2019 19:23:00 GMT
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Post by rosieuk on Feb 27, 2019 19:23:00 GMT
Mpg around the local area on shortish journeys - 26mpg, coming down to Colchester from Blackpool 34mpg at a steady 70mph - but I know it was leaking petrol on that journey (still don't know how it didn't fireball on me). Surprised it got 40mpg but I imagine it has a sweet spot like the Safrane I had. It would love running at 110mph all day @ 38mpg, pootling around the listing was 22mpg. I've ordered bits for proper version of the pipe intake. What I'm hoping to get is a resonance effect above around 2900-3000 rpm - for a bit more power & efficiency. It's not smokey or anything - I think the top end was fairly recently rebuilt - which is why it's a mystery why the bottom is not happy. It'll be going into the garage and since the engine will be coming to bits I'll get the to check timing etc. It's as far as I can tell +10 to 12 static. Part of the problem with the performance checking is there are so many 30mph wonders on the roads - and that's not to mention the idiots engrossed in their phones playing dodge the Wolseley. And as for those idiots who think the two second rule applies to traffic jams, that should be a capital offence. The number of times I've almost gone up someone's behind because they've stopped two car lengths short of a queue.. My driving instructor would be spinning in his grave at drivers today.
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DFD702K.
Feb 27, 2019 19:36:41 GMT
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Post by rosieuk on Feb 27, 2019 19:36:41 GMT
Couple of bumpers on the Bay of Evil Things at the moment - HERE. Chris. I've seen a couple of those but I need the one with the cut out for the reverse light - I've got a new light (eBay £4.99 if I remember right) but the area where it mounts is bent out of shape - and then the wiring will need doing. I might see if the one I have can be straightened. I saw some hydrolastic adjustment valves on eBay for the rear two - but I can't work out how they work if the system is connected - I can only see that working if the back is disconnected - shame because with a level switch - pump & reserve - self levelling could be installed. It really needs a wash at the moment. Does anyone know btw, what the grille & the strakes are made of? I'm toying with maybe chroming them in the highly unlikely event I get any money.
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DFD702K.
Mar 1, 2019 15:33:44 GMT
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Post by rosieuk on Mar 1, 2019 15:33:44 GMT
I've finally got the bits for the proper version of the tubular intake.
2 * 90° silicon bends 1 * 1250mm steel polylock tube - inside diameter 48mm 1 * HS6 trumpet (+2 from prototype) 1 * intake cone filter
As I understand it the duration of the cam is 230° so the effect should come in around 2300rpm upwards - in gears - 13/21/31/43mph (49mph with accent 5th ratio for 4th). Nice cool intake charge and the tubing is an interference fit into the bends for easy removal.
To vary the resonance effect you change the intake length - shorter length = higher rpm. So a 4000rpm tuned intake would be 27.5 inches long (5000rpm - 21.6in) . Since most driving will be 60mph or below the longer one seems more sensible.
Fitted new plug leads this morning.
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