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Cap'n , Personally I've never heard it called an air valve - always a piston. I have a dim recollection that one of the tuning mods for improved acceleration was to drill two 1/82 (3.125 mm) holes in the piston at 90 degrees to the keyway. The existing hole in the side of the piston would be tapped and an aluminium plug screwed in .That was for the HS2 1 1/4" carb for minis though - might work on the midgets also. Somebody will prolly have an SU tuning book and confirm or deny the above. Just my tuppenyworth... MORE
From: David Jacobs [mailto: mail@... ] Sent: Wednesday, June 23, 2004 13:39 To: midgetsprite@yahoogroups.com Subject: Re: [midgetsprite] Re: misunderstand???? What effect was this mod supposed to have? I would have thought the hole towards the mouth of the carb would allow more air to enter the space above the piston, and reduce the amount of depression, giving less piston lift? David "Duncan Sinclair" 32719... MORE
I just opened my SU book and it calls it the piston and the butterfly close to the head is called the throttle valve. The piston is more of a variable venture and the butterfly is more of a valve that turns on and off the air/fuel flow. FYI, Bob "Robert D. Gardner" 32714... MORE
1. The shortly later models used a 3/4" dual master cylinder with disk brakes. Looks just like the Bugeye 7/8" but takes less pressure. 2. There is a mastercylinder cap? on ebay for the dual mastercylinder that is raised an holds more fluid than the flat cover??? 3. I'm not sure that they will let you race with a later mastercylinder/clutch cylinder system? I don't know, I'm "simi- stock". Bob, Troutdale, OR Capt'n Bob, Quite. "Robert Webb" 32710... MORE
Hi, Just ran my Bugeye in 4 Vintage races but fortunately blew a head gasket, cutting short my last race, because the master cylinder had suddenly lost about half its fluid in a few laps! Guess now is the time to upgrade to a dual circuit cylinder. What is the easiest route to do this? Any "how to" guides on the internet? There is a roll cage tube that goes quite close beside the "box" the master brake/clutch cylinder unit is in, so I don't have a lot of room for anything. Is there a later spridget dual brake/clutch... MORE
OH...and Jens...I forgot!!! Before you get started on a compression check, DO check the throttle cable hookup and be sure when you put the accelerator pedal fully to the floor the BUTTERFLY is FULLY open! :):) Cap'n. Bob '60 :{) PilotRob@... 32706... MORE
Ah HAH.... You may have hit the nail right on the head here, Jens... "If (my engine...tuned or not) cannot SUCK (produce enough vacuum) to open a pair of HS2's....." EXACTLY!!!! It is time to "begin at the beginning", Jens. As in MAJOR tune-up. Step one is checking engine "mechanical health".... with valves properly adjusted...time for a basic compression & leakdown check. Considering recency of engine work, you're looking for 150 or better on compression check and leak-down rates of less than 10%. Remember to hold the butterflies fully open (accelerator pedal fully to the floor) during the compression... MORE
Jens... ...the air valve is the largest moveable part of the SU carb and holds the needle. I have heard people refer to the air valve as a "piston". The butterfly (or it's position) is controlled by your foot and the accelerator cable and is the closest moveable part of the carb closest to the intake manifold. :):) Cap'n. Bob '60 :{) PilotRob@... 32704... MORE
Jens, Fixed needles are held rigidly by a grub screw into the piston, but swinging (or biased spring) needles are retained by a separate collar, they are forced by a light spring so that they contact one side of the jet, so no centering is needed, but the jet and needle both wear more than the fixed type. They're not interchangeable because of the retaining ring on the spring type. HS2s used both types, depending on the year. You can check which yours is by the tag number on the carb float bowl (what do you mean, it's not... MORE
The Purpose of Tools HAMMER: Originally employed as a weapon of war, the hammer nowadays is used as a kind of divining rod to locate expensive parts not far from the object we are trying to hit. MECHANIC'S KNIFE: Used to open and slice through the contents of cardboard cartons delivered to your front door; works particularly well on boxes containing leather goods. ELECTRIC HAND DRILL: Normally used for spinning steel Pop rivets in their holes until you die of old age. PLIERS: Used to round off bolt heads. HACKSAW: One of a family of cutting tools built on... MORE
I have recently acquired a 'new, old stock' crankshaft rear oil-seal kit for an A-series engine, but it did not come with any fitting instructions. Although it looks fairly simple, I want to make sure that everything is fitted correctly, so I wondered if anyone has fitted this kit and still has the fitting instructions? If so, would it be possible to scan or otherwise reproduce? All replies welcome. Thanks in advance Dave "daveo138" 32688... MORE
Willliam, FWIW-I bought an 1975 for $500 and have replaced virtually every mechanical component. I found and freshly rebuilt engine through the MG Club of Chicagoland classifieds for $632 (engine and freight). It need a backplate and dizzy which I pirated from the original. The special designation to the best of my knowledge had little to do with performance and a lot to do with creature comfort ...radio, carpet appearance package etc. My estimation is that the $600 is OK but you'll need to do more than you think. It will take longer and cost more. Rob C 1975... MORE
I'm looking at buying a 1976 MG Midget special 57K with the 1500cc engine it has the Webber carb upgrade new starter and alternator but the connecting rod bolt came out and trashed the lower end of the engine they said it need a crank connecting rod and the block needed to be machined. How much would it cost to rebuild vs. replace with new/used engines???? also what are the specs for this engine stock and with the Webber carb kit??? besides that the car is decent shape minor rust (not bad surface only on seams)and there are a... MORE
The replacement jets arrived this afternoon. My son installed them and measured the gap, right in the middle of the range. The lids were put on the float bowls and the pump turned on..... NO leaks. The engine was started again no leaks. Now I just need to tweek the carbs a little. I believe the car will be running on the road this weekend. Thanks to all who suggested going back to SU jets. I should have know! Martyn "Martyn Eastwood" 32656... MORE
What are the lengths of the two hoses that run between the oil cooler and the block/filter on a 73 Midget with a 1275? Moss Motors informed me yesterday that they sell these hoses as individual lengths only. I don't have a set to measure. Thanks for your help, Jim C 73 Midget 67 MGB "Jim Crowder" 32649... MORE
Have you actually got the wing off? as reading you e-mail it would appear you have only taken three of the six bolts that hold the rear part of the wing on!. In the foot well there are (or should be) 4 bolts, three are at the door pillar end of the wing, and there is a fourth at the front of the foot well. Then there is one at the top of the win in the guttering looking down from the top of the car. and there is one final one that you will find a little awkward,... MORE
Thats how I test them. Moss lists one for the 1275 25D? for 39.95. Bob, Troutdale, OR "Robert Webb" 32638... MORE
I've just fited a 73 Midget motor into my 67 Morris Minor. The smog rails etc have been removed and the ports plugged. Curently, the induction is the stock Minor setup, this will chnage in time, but I want to get the car finished before I go dual carbs and a larger bore exhaust. Anyway, I have 4 distributors, the stock 41400 25D unit, the stock 67 Minor unit, opne from a 64 TR4 and a DM2 from God know what. As far as I can tell *none* of the 4 vacuum advances work. I have removed each and... MORE
On our old Singer Vogue, we could take the key out of the ignition with the engine still running. In fact, once the whole barrel came out and fell on the floor! With lots of old cars, particularily those still using the original key, the keys become very worn. They work, but there is no way that a duplicate could work! The lock & key wear out together. Margaret So much to do, so few people to do it for me. mmbrock88@... 32634... MORE
Jim and Cap'n Rob, Sorry for the bit of delay in response. The dimensions of the new cover are precisely the same as the old, only difference being the air breather tube is straight rather than angled. Not a big deal. As Jim mentions, the chrome fasteners that come with the cover are tubes, but wider than the standard screw in tube type as listed in VB, pg 66 (items 6-9). You can see this entire package by looking at item #2481129573 on eBay, which is currently on auction. I have an extra 1500 on an engine stand in... MORE
Paul, I bought a matched set, 2 doors and boot lock for my '71 Sprite. I then dismantled the ignition lock cylinder and swapped the little tumbler plates around until it matched the new key set. Fiddely, and I think of the 7 little brass plates I ended up having to file 2 to match the key after swapping the other 5 around . You need to be very patient! I then find that in practice I never lock the doors anyway as there really dosn't seem any point - I rarerly have the hood up, and if I... MORE
Hi, Peter... I am no 1500 guy but I've been following the thread on the discussion of longer studs needed for certain valve covers produced for the 1500 Spit motor. I just came across something in my TriumphTune performance manual which apparently deals with this. TriumphTune (TT) Part #105123 "On late 1500 models after '78, longer studs will be required wherein tube nuts are fitted as standard" This pertains to valve covers, all using the standard gasket. Sounds like what you may be looking for? Cap'n. Bob '60 :{) PilotRob@... 32602... MORE
The fuel pump is a new SU one so I would assume that it is set for SU carbs. Is the pressure adjustable or do I have to use an external regulator?. The needles hold pressure until the engine is started and the it starts overflowing. I've order some standard jets to replace the Grose ones. Martyn meastwood1@... 32599... MORE
Jens... Whew!! Glad you found the problem and it's a "cheapo" fix. A new engine will give around 75psi cold and this will drop to about 65-70 @ 3,000 rpm when hot. Even this (when hot) is too high. Shorten the spring until you get the above figures for a start. Then purchase an "oil pressure regulator" and fit this instead, using the aforementioned spring. The regulator will not affect the idling oil pressure, just the max pressure. Set initially to 60 @ 3,000rpm "hot" then as the engine wears over time/miles, you can "dial up" the max, keeping... MORE
Wow was that e relief, we worked at it all evening yesterday until very late, at one moment we thought that we would have to pull the engine. A tap was the solution, we managed to thread it in a good long way as it was only bearly big enough and it took some real pulling with a grip wise plier, but it finaly came. It was badly scared with several long deep markes all the way lenghtwise. And this bugger was made from aluminium. I havnt had time to run the engine good and warm yet with the... MORE
