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Thankyou, Jens.... I am going to assume based upon the information you gave them on compression ratio, they assume you know enough to use the highest legal (unleaded) octane commercially available and in Europe, this is 98RON as far as I know. Did they include any recommendation as to total timing or set-up? Cap'n. Bob '60 :{) PilotRob@... 33609... MORE
Guys, Thanks for your words of encouragement. My carb re-rebuild is awaiting parts for re-rebuilding. I just get tired of making the same kind of mistakes! I have learned a lot and in the immortal words of Chief Dan George in The Outlaw Josey Wales I will "endeavor to persevere." Rob C Webfoot Leisure.com rob@... 866-530-9801 toll free " robbiesg@... " 33511... MORE
Cap;, Thats what I had in mind when looking. I may just find a 3.7 rear end and call it a day. If I want to go long distances I don't think a Midget is the ticket. Rob C-75 Midget it carb rebuild land, again. Jeez I suck as a mechanic. Webfoot Leisure.com rob@... 866-530-9801 toll free " robbiesg@... " 33494... MORE
Thanks for all the carb help. Got the buggers dialed in OK. Now I have timing issues but what the heck. Rob C Webfoot Leisure.com rob@... 866-530-9801 toll free " robbiesg@... " 33423... MORE
Yep .. think of it pushing the jet away from the carb body for richer, just the same as the choke does when you pull the cable. I have the same pleasurable job ahead of me now after getting it to start on Saturday (first time in 8 years !) the dizzy was in a state, but soon cleaned up and setting the timing by eye was surprisingly easy ! the #2 carb choke mechanism sticks though, so have that to fix amongst other things. Cheers, Simon. "Simon Stirley" 33417... MORE
Jens...suggestion? Go out and purchase a simple Facet solid state electric fuel pump with it's own "incoming" filter. You want the low pressure one, around 3-4psi. Cut out a piece of rubber gasket to place between the pump/body and install it where the stock SU pump went (according to your Haynes manual or whatever you are using) in later cars. This pump will work with SU's just fine without a pressure regulator. Cap'n. Bob '60 :{) PilotRob@... 33377... MORE
downwards to enrich (I won't say clockwise or anti-clockwise as you never know - someone could be looking upwards from below!) If you take the air filters off, you can see the top of the jet, so you can see which way it moves as you turn the nut. David "David Jacobs" 33369... MORE
Esteemed Listers, Although of late I have been lurking, I am out of my hole and asking a rather silly (stupid? moronic?) question. Which way does one turn a mixture control nut on an SU to enrich the mixture? I am having my first go-'round with these exotic carbs and getting anything other than garbage out of the motor has been beyond me thus far. The mixture question would help. Yes, I've read the books but I am either illiterate or am just dense. Rob C-75 midget running out of summer. Webfoot Leisure.com rob@... 866-530-9801 toll free " robbiesg@...... MORE
Coil should get warm, but not too hot to touch. If it is getting that hot it may be that as it heats up the insulation breaks down and the spark is failing. This would cause the misfire. Maybe you have 2 unrelated faults? Mixture and spark? Excuse me stating the obvious, but I always have to think hard about which way to screw the jet to richen or weaken the mixture. Lower the jet for richer isn't it - so its clock-wise as you look down at the carb. Guy "Guy Weller" 33255... MORE
Jens....STOP!!! Your chasing yourself in circles here. The variation in cooling temps with the mixture variations, along with appearance of the plugs and most of all, detonation/ pre-ignition (with octane changes thrown in for good measure) suggest the engine is operating on the borderline of self- destruction, in short time. Saving pennies on octane is extremely penny-wise, pound foolish. With a tuned unit utilizing high rpm's a good part of the time, "economzing" on octane can shortly become extremely expensive. Your "tuned" engine is an investment. Feed it a proper and appropriate "nutritional" diet. :):) May I suggest..... ...firstly,... MORE
Jens, If it is SUs then what you describe could be caused by worn throttle spindles. This makes the carbs seem very sensitive to mixture settings. If you richen the settings to compensate at low engine speeds, then at full throttle it will be too rich and will bog down or foul the plugs. If you weaken, then at full manifold depression it will pull in air at the spindle and run too weak, causing it to run hotter Guy "Guy Weller" 33249... MORE
Jens...."harder" (colder) spark plugs After you look after the carbs and intake system in general for vacuum (air) leaks, we should "re-visit" this topic. But, first things first for obvious reasons! :):) Cap'n. Bob '60 :{) PilotRob@... 33251... MORE
Brad 'veering off the true and righteous path'? I never set out to create a concours car, but I did set out to put my car back to as original condition as I could. Originality is important to me, not for concours reasons, but because I never had a chance to buy one of these cars new, and now's my chance to have an 'as new car, as the makers intended it to be'. Having slightly polished Carb dashpot tops does not detract from that goal, even though they were not like that in new cars, it doesn't stop... MORE
Jens I told you it was well worn! The other spindle wasn't nearly as bad, but decided to replace the pair of them while I was doing it. Clean the carbs? Nothing more than elbow grease! I washed them down thoroughly several times with turps (kerosense) using an inch paintbrush and changing the turp's when it got too dirty. I then scraped off the gasket material with a stanley blade and rotary wire brush cleaned the gasket surfaces only. The rotary wire brush is too harsh for the soft metal casting surface of the carb itself and leaves scratches... MORE
Nigel, You are too kind. Most glaring mistake was installing the throttle and choke linkages backwards. My only excuse is that I've never worked with dual carbs before. I also had to reset the float in one carb as it leaked gas out the intake. FYI-I set the mixture at 2.5 turns from flush and was pretty close to right on. The motor runs about 15-20 dgs. cooler and sounds better and is definitely more responsive. Haven't driven the car yet as I have to build a throttle cable bracket tonight or tomorrow. Then it's a road test and... MORE
Thanks Robbie! The carbs are finished - but the engine is yet to go in the engine bay, so I can't test them yet. Don't be so sure on the mistakes - I keep quiet about the real f*** ups I have, and only make them public to amuse dear old Ed who loves those kind of things - so what mistakes did you make? Nigel "amukdigiphoto" 33200... MORE
Nigel, Way to go. I've been following your exploits as I've been finishing off my dual carb conversion. Shared suffering? Doesn't sound as if you made as many dumb mistakes as I did but the "lil devil runs now. Rob C Webfoot Leisure.com rob@... 866-530-9801 toll free " robbiesg@... " 33199... MORE
Hi guys The parts from Burlen arrived this morning and I was able to finish off rebuilding the carbs and mount them onto the manifold and heatshield. For those of you interested I've uploaded a pic of them into Nigels-71Midget folder in the photo's section of the Yahoo group webpage. And yes I know the linkages aren't in position in the picture - they are now! I also uploaded a picture of the wear on the throttle spindle to show just how much wear there was - a lot, but thankfully no wear to the car body. Nigel "amukdigiphoto"... MORE
Jens I spoke to Burlen this morning as I mentioned and they were very helpful. I've ordered up two spindle kits, two rubber washers and two new AN needles from them. For interest and reference for others going down this route in the future the cost of drilling out the spindle holes in the carb body and putting in inserts for the new spindle is about =A320 GBP + VAT. The new spindle kit (comes with butterfly screws and gaskets) was =A36.87 GBP + VAT and the AN needle =A36.33 + VAT. The moral behind this is to avoid... MORE
Jens I spoke to Burlen this morning as I mentioned and they were very helpful. I've ordered up two spindle kits, two rubber washers and two new AN needles from them. For interest and reference for others going down this route in the future the cost of drilling out the spindle holes in the carb body and putting in inserts for the new spindle is about =A320 GBP + VAT. The new spindle kit (comes with butterfly screws and gaskets) was =A36.87 GBP + VAT and the AN needle =A36.33 + VAT. The moral behind this is to avoid... MORE
Jens When I said a mil I actually meant 1mm! not a millionth! That's double what your wear was! It really is badly worn, if I get a moment I'll take a pic of it today and let you see how bad it is. I actually thought initially that the Carb body itself was also worn, but playing about with the spindle in the body it seems that only the spindle itself is worn, so I may get away with just two new spindles with a bit of luck - like you did. I'm going to be speaking to... MORE
Trevor The needles are fixed not sprung, but I take your point on replacing them - I'm replacing them as a matter of course anyway. I think they're .090" ones, they came in a rebuid kit I bought ages ago, which indcludes all the gaskets, jets, needle and sets and disc/throttle spindle screws. Nigel "amukdigiphoto" 33170... MORE
Trevor Are needles and jets matched? Can't you just swop out needles without having to change the jets? I've found more problems with the front carb this afternoon I need to sort out before I worry about changing the needles! Nigel "amukdigiphoto" 33168... MORE
Jens Thanks. I think I may have figured out why the needles may have been changed inthe past. On dismantling the front carb this afternoon I discovered that the butterfly spindle was badly worn - and I mean badly lol. It's worn down by about a mil which is a lot. I can only assume the switch to those needles was in some form of compensation for the worn spindle. No wonder the engine had such a lumpy idle which I could never fix no matter how much adjustment I did - with that amount of wear on the... MORE
For the purposes of discussion on subject engine with 1.25" carbs... There are two types of needles.... "fixed" (no jet interference) & (emissions/later cars) "biased" (spring loaded...runs against jet's inner core...) The fixed needle should experience no wear as long as the needle is correctly centered within the jet. Theoretically, they never contact and in this respect, should not wear. The "biased" needle/jet is a contact set-up and thus wears, requiring replacement from time to time. I forget which metal is softer and what wears first (or most, over time/use). The stock jet is always size .90 for the... MORE
