stuart Posted August 27, 2021 Report Share Posted August 27, 2021 1 hour ago, MikeF said: A post script from me. I found the pump I put away the last time this happened about 10 years ago.. Great news (I think): It' a proper AC Made in England job, so I'll see about getting it done up; Meanwhile please see picture of my two dud pumps and spot the difference! Can anyone explain why? Mike The one on the right is from a different application. Stuart. Quote Link to post Share on other sites
Charlie D Posted August 27, 2021 Report Share Posted August 27, 2021 But if you remove the six screws and turn the bottom bit around 180 degrees, don't you end up with them both the same? Charlie. Quote Link to post Share on other sites
RobH Posted August 27, 2021 Report Share Posted August 27, 2021 Depends which end of the cap the threaded hole is for the pipe to the carbs. Quote Link to post Share on other sites
MikeF Posted August 27, 2021 Author Report Share Posted August 27, 2021 (edited) David Davis confirms this is the right pump for TR as the cam lever has the correct part number. He will bring pump back to original condition and have it back to me in a couple of days tops and for a very reasonable price. And yes I confirm he is a charming gent! So far as mirror image is concerned can't think why its 180 out, screw heads do show evidence of PO interference. Receipt history shows engine bottom end was restored in 1989-91, so I guess it happened then Mike Edited August 27, 2021 by MikeF Quote Link to post Share on other sites
Z320 Posted August 27, 2021 Report Share Posted August 27, 2021 (edited) Hi, this will be a spare part engine for my TR4A, I've been told it's also from a 4A, at least the cylinder head is the correct one. You see the lovely gravy in the filter bowl and the primer lever bended, I guess the engine felt on it anytime..... Working on the car the rear nut is a bit annoying, later you see what I did there for my car. It's a AC pump "Made in England" and if it is the correct one the lever must be made of layers of hardend steel, als Rich told earlier today. Bingo! The "gravy" seems more to be caramel / fudge To the engine I found only one paper seal, nothing "shimmed", BTW that makes no sence. Because lifting the lever by the cam shaft only SUCKS petrol, the pressure is caused by the spring inside the pump on the diaphragm. You can't adjust this and this is why to shim the pump to the engine body causes nothing (against what is often told). On the workbench, sprayed with WD40 The primer lever bended back The" caramel" I made liquid with some petrol to separate the rust from the cream! The bowl cleaned I to my surprice I found the "AC" logo again! The bowl is a great thing to keep the dust (mainly) away from the sieve! I'm shure this sieve worked! Slightly cleaned with a brass brush If you ever have probems to get a new repro pump not petrol sealed check this sieve! It must be only a minimum wider than the rubber seal, if it has the same size you have to cut it smaller, if the Chinese did not. You can imagine why I know.... That's it for today, Marco Edited August 27, 2021 by Z320 Quote Link to post Share on other sites
Lebro Posted August 27, 2021 Report Share Posted August 27, 2021 Shimming the pump from the bode does make a difference.. The further the spring is compressed, the higher the pressure, so if the pump is shimmed the spring will not be compressed as much, so the pressure it exerts on the diaphragm will be less. Bob.. Quote Link to post Share on other sites
Z320 Posted August 27, 2021 Report Share Posted August 27, 2021 (edited) Bob, sorry me, I have been told this so often and never believed it. But to test it anyway I shimmed my pump in steps of 0.6 mm up to 1.8 mm! It caused nothing. It's a membran pump and the pressure is construction related. That makes it very save and easy to use. Ciao, Marco Edited August 27, 2021 by Z320 1.8 mm, not 6.0 mm Quote Link to post Share on other sites
Z320 Posted August 28, 2021 Report Share Posted August 28, 2021 (edited) I remember a thread at the German www.TR-Freun.de with one answer from an experienced workshop owner: the membran pump of the Spitfire Mk 4 1500 has to be shimmed with a spacer, because the lever is to long, it brakes in pieces at the first engine start if you do not shim it with a pacer..... Edited August 30, 2021 by Z320 Quote Link to post Share on other sites
Z320 Posted August 28, 2021 Report Share Posted August 28, 2021 (edited) Testing the pump in a bucket of water I notice: it doesn't pump the fuel way, but it pumps water in and out the breather hole. So the membran works and there must be a oil seal in. On the 6 screws it is visible the pump has been opended already some years ago, and the locking washers are missing. The pump was already in the ultrasonic bath for 30 min and prepared with a brass brush ... In the opened pump all surfaces are covered with crud from the petrol, specially the inlet valve, but all looks OK Twisting the membran 90° left or right the push rod is unlocked and it is possible to pull it gently out of the pump body (through the oil seal). The tin cap holding the oil seal I found not correct pressed in (right side deeper than left). Easy to get it out with a flat screw driver Shaft pressed out after removing the clip on one side, I found a washer / spacer on both sides, But I don't know if they have to be between the lever and the pump body (like on the photo) or between the levers (able in both positions). Time to look on the surfaces, which have to seal the pump with the membran, they look OK. But moving the body over sand paper (glued on a flat surface) shows the truth: the body is made of soft zinc cast and tightening the 6 screws too much bends the flanges up! But this is OK already, next photos are from a "Made in Canada" pump, 2015 on my workshop, totally bended. This surface was only possible to get sealed after many moves over the sandpaper Back to my todays AC pump, the cover's flange also looks good. The marks on the zinc show the valves have been removed before. After cleaning they worked lovely again and I let them in their position Sand paper test shows; no need to do more Body was only to get clean by sand blasting, I used a very fine quartz sand, the levers are only cleaned with petrol and a brass brush The lever was drilled very accurate, not easy with this high quality of steel. I have seen this already different on repro pumps. No special sideward movement, I shimmed the lever anyway, shure not needed. The membran after cleaning I found it in good condition, I further will use it. And it is an original AC! On the photos it is slightly oiled The assambly beginns, I pressed the oil seal with the tin cap in. In my opinion this is also a pertol seal to avoid pertol draining in the engine in the case of al failed membran... To get the shaft in later the use of a 6 mm awl could be helpful - but it is a puzzle anyway. Next fit the main spring. It is relatively soft and makes the fuel pressure by pressing the membran up. Next the membran through and twisted 90° left or right to lock it in the lever. Make this gentle to avoid damage of the seal. Next is the @%$§!!@ job to get the shaft through (no photo of this). Next photo the assambly is already finished, please don't torque the 6 screws (now with lock washers) not to tight. Tested by pulling the lever it works by pumping air. YES, this membran pumps can pump air! Yesterday I mentioned the annoying rear nut, not easy to undo and fix near the road (in the unlikly case of a failture). Next you see my solution of the issue, I already introduced this some time ago (1/2" hex bar reduced to 9 mm on the late) Tomorrow with better light I will make some photos with the pump on the engine. If you decide to keep your mechanical pump and restore it I wish you good luch and much success! Ciao, Marco Edited September 4, 2021 by Z320 Quote Link to post Share on other sites
Z320 Posted September 4, 2021 Report Share Posted September 4, 2021 Sunny weather for photos today I'm pleased, tomorrow I do the rest of the engine Quote Link to post Share on other sites
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