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Post by Penguin45 on Mar 10, 2016 23:45:48 GMT
Thing is - you're in slightly unknown territory now. 2L engine; I assume that the compression ratio is up a bit, interesting cam (?) - but, you still have an 1800 dizzy and single carb. The advance curves may not match the new configuration and the single carb will have had to be enriched at least slightly, I'd have thought. Having got "THE DAY" out of the way, it's time to start experimenting a bit and find out what works for the new set up. I know that you have twin carbs in mind for the future, so I wouldn't be worrying too much just yet. Get it run-in, then you can get to work on it properly.
AndrewA has gone down this path before you, so you might want to compare notes as to what works and what doesn't.
Chris.
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Post by dave1800 on Mar 11, 2016 1:31:55 GMT
Carb rebuild, not too difficult but definitely worthwhile. The running on could be as simple as the idle being set a little too high to compensate for a tight new engine or it could be running too hot through a combination of weak mixture, wrong timing and a tight engine. However, as Chris says you will need to play around with mixture, maybe a richer needle and the ignition timing to match the larger engine and wilder cam. The latter typically require more advance down low but less at higher rpm. Andrew A may be able to give you some figures as a base line. Remember if you then move to twin carbs you will need to repeat the process. The Golden Rule, excessive ignition advance and weak mixture are the ways to damage an engine fast, so always err on the side of retarded ignition and slightly rich mixture. As I'm sure Andrew A will confirm there is NO substitute to having the carb needle(s) and timing set up on a dyno where mixture and knock detection can be detemined - but it's not cheap. In the meantime don't drive it hard, damage rarely occurs under light load but heavy load like climbing a long hill at wot is another matter! David Thanks for the links. Looks like a fiddly job. I also seem seem to have developed a running on problem. Is this timing ? |
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Post by andrewa on Mar 11, 2016 18:13:14 GMT
Not sure I'm the best person to give advice and not sure where you are geographically or what your budget is but an hour or two on a rolling road with someone who understands SU's, has every possible needle / spring etc to hand is probably money well spent and is certainly quicker than trial and error. Plus you can see what the engine is doing/how it's behaving so it's interesting as well!
Received wisdom is that twin carbs probably unnecessary '60's marketing (!) and my 1860 apparently doesn't have enough go to make full use of my twin carb setup anyway but 2 litres might.
I'm a fan of rolling roads but then I'm a sucker for a quick answer and don't enjoy the tinkering so much.
Running on - well when you go away from stock they all tend to do that a bit..most easily cured by letting it idle a bit longer before switching off IMHO.
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Post by snoopy11 on Mar 22, 2016 19:26:14 GMT
Another new shiny bit bolted on today. Increased to 2 inch diameter to try to help things breath a little better.  Just need to to find a rolling road in Bolton now to get things properly set up. |
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Post by andrewa on Mar 22, 2016 21:03:21 GMT
I used Peter Burgess at Alfreton - I appreciate it's a couple of hours away- but he did a thorough job for me and you only want to do these things once really. He was also pretty reasonable. Probably kiss of death doing recommendations - but just a thought. |
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Post by Penguin45 on Mar 23, 2016 0:33:39 GMT
There is also an "old school" guy in N. Yorks who is supposed to be an absolute genius with SU's. I'll have a word with Ted on the Wolseley Forum and see if I can find a telephone number. I think Snoopy needs to get the car run-in first and then get the twin carb set-up on board before seeing the man.
Chris.
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Post by dave1800 on Mar 23, 2016 3:40:55 GMT
Also get the timing sorted as it and the mixture are interdependent. David There is also an "old school" guy in N. Yorks who is supposed to be an absolute genius with SU's. I'll have a word with Ted on the Wolseley Forum and see if I can find a telephone number. I think Snoopy needs to get the car run-in first and then get the twin carb set-up on board before seeing the man. Chris. |
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Post by snoopy11 on Mar 24, 2016 20:48:01 GMT
I have now had the car set up a little better by a man who has a little more finesse than me at these things. He also had a lot of meters and tuning stuff in the back of his van. It's running a lot better now and doesn't seem to be pinking. I'm a lot happier now to get some miles on it and run it in properly.
However. The running on issue is still there.
I have been told that this may be because of the much higher compression and is a problem with those Austin sport coupe things that Chris likes so much and there is an anti run on valve to cure it.
So good peeps of the forum. 3 questions.
1 Has anyone come across this with mg's
2 What exactly is an anti run on valve
3 Where do I get one from
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Post by Penguin45 on Mar 24, 2016 23:59:20 GMT
Erm... Thanks, Snoopy. I think it's an American gadget. I think it dumps air into the carb to such an extent that the mixture is massively diluted. Moss seem to know all about it - have a read of THIS. Where you get one from, I've no idea. C. |
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Post by dave1800 on Mar 25, 2016 5:19:54 GMT
Before you go spending big bucks and have another source of problems, have a look at the advice in this MGB forum. I would pay particular attention to Peter Burgess' comments as he is the world's expert on MGB engines, tuned or otherwise. MGB forumMaybe the change of plugs Peter recommends is a good starting point? However, before adjusting the timing at idle you need to make sure you won't be over advancing it higher up or it will cause damage. IMOH the only solution to an engine with the cam you have fitted is a programmable ignition if you want it to run well throughout the range. A specialist can modify the weights and springs if you don't fancy the electronic route, and it will need a rolling road set up. In the meantime you could try advancing the ignition 2 degrees at the time and listen for pinking. You could be lucky, but remember this is likely to be worse on hot days. regards David Erm... Thanks, Snoopy. I think it's an American gadget. I think it dumps air into the carb to such an extent that the mixture is massively diluted. Moss seem to know all about it - have a read of THIS. Where you get one from, I've no idea. C. |
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Post by Penguin45 on Mar 26, 2016 20:31:44 GMT
Snoopy came over in GLE today. I have to say the engine bay is a very pleasing sight and the engine wuffles nicely with its new exhaust. It did disgrace itself slightly be tiddling petrol everywhere. It seemed that the float valve/float was out of adjustment, so easily re-set.
Chris.
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Post by charlypm on Mar 27, 2016 3:55:18 GMT
I have found that the running on in most cars is caused by the idle set too high. If the butterfly is allowed to close all the way this usually minimizes the running on. With that said it may be hard to let the butterfly close all the way because of the needed setting for the idle with a particular cam and/or timing setting. I have found you can usually change something just a little and get the idle down low enough. My Mini was running on during the break in process running rich and a high idle and after breaking in, reset the idle, carb and the timing and it went away. I don't think you need a anti run-on valve, these were mostly for emission fitted cars as the system is closed and vacuum goes to a carbon canister and sucks fumes from the fuel tank and carb overflow. The valve opens to allow air into the system, eliminating the fumes from the canister going back into the carb. I would hate to see all this stuff on a Landcrab. |
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Post by andrewa on Mar 27, 2016 10:40:20 GMT
The valve (also called carb vent valve by Austin Rover) was fitted to late Metros and the carb Coopers of the early '90's to get round the increasing problems (running on) caused by fuel and emission regs. On metro's you have a T piece that goes in the vacuum line between the brake servo and the inlet manifold and this has a pipe that goes to the valve. The valve has an earth and an ignition live. The valve is closed when the cars running and when you switch off it opens and dumps all the air out of the carb so it can't run on. When I did my engine I used to get frustrated with the running on but have learned to live with it. Best quality fuel helps as does letting it idle for 15 secs before shutting down and getting idle as low as poss. I gather the valve works ok but can have problems of it's own. My dad had an 1800 from new and it ran on as well - particularly when weather was hot and he wasn't using 5* and his trusty shot of Redex and he hadn't modified that at all. Probably get shot for this but it's a 60 year old engine design and they weren't stunning when new. I suppose it depends how bad it is - if it's still going when you've locked the door and walked away (I had a Rover 2000TC that would sometimes pull that trick) then something must be done - mine is negligible or none existent if I'm on quality fuel and let it idle, and 5 secs if I forget. The only time it's worse than that is in a crowded car show and / or when i've got an audience. If you're after one this crew used to have them but seem to be out of stock - you can see what it looks like though see 99/100 www.mgocspares.co.uk/acatalog/MGOC_SPARES_INLET__MGB__24.htmlJust found better explanation than mine here btw www.mossmotors.com/MemberServices/TechTips/TechTipsArticle.aspx?TechTipID=143&ModelID=31000&SubcompCode=C500They don't seem easy to come by so it may be breakers yards or the dreaded ebay. Be interested to hear how you get on - despite everything I said above may well be tempted myself! Cheers Andrew PS Now found this www.moss-europe.co.uk/anti-run-on-valve-stn127z.htmlAAnd instructions look pretty straight forward... |
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Post by snoopy11 on Mar 27, 2016 16:54:23 GMT
Thanks all for the information and links. Interesting reading
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Post by charlypm on Apr 1, 2016 3:58:18 GMT
believe MGB's, Midgets,TR6's, Spitfires and Jag XJ6's and some E-types all used these valves, at least US spec cars did. They shouldn't be that hard to locate.
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