thebrookster Posted April 9, 2011 Share Posted April 9, 2011 OK, I give in. Where the hell do you guys buy your syringes from, cause I cannot seem to find them at all!! I don't have a ruddy prescription, I refuse to be registered as a user of 'recreational' drugs, all I want to do is find out what out what my Compression Ratio is!! Cheers, Phil Link to comment Share on other sites More sharing options...
AlexC Posted April 9, 2011 Share Posted April 9, 2011 Look for oral medication type if your using it to measure your combustion chamber. No actual needle part just nub. I got mine for pennies at Shopper's (if you don't have those just try the local pharmacy) Vet clinics will have them too! Link to comment Share on other sites More sharing options...
Nick Jones Posted April 9, 2011 Share Posted April 9, 2011 Vets clinics sounds like a good call - vets need BIG syringes sometimes. I don't have any problems getting them though, my wife is a hospital pharmacist Nick Link to comment Share on other sites More sharing options...
spitNL Posted April 9, 2011 Share Posted April 9, 2011 No problem at all here? Cost less than 50cents for a 60ml syringe at the pharmacy and no prescription needed. plenty of them on ebay 60ml http://shop.ebay.co.uk/?_from=R40&_trksid=p5197.m570.l1313&_nkw=60+ml+syringe&_sacat=See-All-Categories 50ml http://shop.ebay.co.uk/i.html?_nkw=50+ml+syringe&_sacat=0&_odkw=60+ml+syringe&_osacat=0&_trksid=p3286.c0.m270.l1313 Link to comment Share on other sites More sharing options...
JohnD Posted April 9, 2011 Share Posted April 9, 2011 60mls is bit big. I would use 10 and 2mls sizes, fo a chamber that is about 40mls. 1mls are available (on eBay) so you could measure to less than 0.1ml, but really it's impossible to measure to less than 0.5mls as there is no clear end point. If you do the calculations, a difference of 0.5 mls makes very little change in CR. John Link to comment Share on other sites More sharing options...
mattius Posted April 9, 2011 Share Posted April 9, 2011 I had the same problem, luckily knew a friendly vet who accidently dropped some in my bag. Link to comment Share on other sites More sharing options...
James Posted April 9, 2011 Share Posted April 9, 2011 Local pharmacy. No point in going for the 1ml type as it just takes you forever to measure. I think I used 5ml — that's only 7 or 8 fills then. Link to comment Share on other sites More sharing options...
thebrookster Posted April 9, 2011 Author Share Posted April 9, 2011 Cheers guys!! I think that as John suggests a 10ml and a 2ml should do the trick nicely. Link to comment Share on other sites More sharing options...
mattius Posted April 10, 2011 Share Posted April 10, 2011 my local pharmacy wouldnt give me any, i had to have either a prescription that required them, or a letter from my doctor saying i needed them for medical grounds. Link to comment Share on other sites More sharing options...
James Posted April 10, 2011 Share Posted April 10, 2011 Matt - syringes not needles I've got them from three or four local places without any issue at all (bought, lost, bought, lost etc) You can't do anything naughty with a syringe. Link to comment Share on other sites More sharing options...
GT6Steve Posted April 10, 2011 Share Posted April 10, 2011 I like the big ones as I fill it to a precise level, 50cc's in my case then dispense until the chamber is full and subtract the remainder. Very quick and easy for me. I really don't see where the burette system would help me! :-/ Link to comment Share on other sites More sharing options...
JohnD Posted April 10, 2011 Share Posted April 10, 2011 If anyone can get their hands on old fashioned glass syringes you're laughing. Mineral liquids degrade the rubber of the plunger in plastic syringes, so that when you come back to do another measurement, the rubber has swollen and the plunger is stiff or seized. A glass one lasts for ever, or until you break it. But then plastic syringes are supposed to be single use, so buy a batch (£2 for 10 1mls on eBay, probably similar for five 10 mls, I haven't looked.) and use one per cylinder. John Link to comment Share on other sites More sharing options...
mattius Posted April 10, 2011 Share Posted April 10, 2011 Matt - syringes not needles I've got them from three or four local places without any issue at all (bought, lost, bought, lost etc) You can't do anything naughty with a syringe. thats what i tried to explain to 3 pharmacies, they all classed syringes as the same a needles. Link to comment Share on other sites More sharing options...
spitNL Posted April 10, 2011 Share Posted April 10, 2011 John, sorry but I have to disagree about refilling a smaller one several times instead of using a one fill big one. When checking against a burette the larger single fill was more accurate. By the way burettes aren't that expensive from ebay and much more accurate: http://shop.ebay.co.uk/?_from=R40&_trksid=p5197.m570.l1313&_nkw=burette&_sacat=See-All-Categories Link to comment Share on other sites More sharing options...
thebrookster Posted April 10, 2011 Author Share Posted April 10, 2011 John, sorry but I have to disagree about refilling a smaller one several times instead of using a one fill big one. When checking against a burette the larger single fill was more accurate. By the way burettes aren't that expensive from ebay and much more accurate: http://shop.ebay.co.uk/?_from=R40&_trksid=p5197.m570.l1313&_nkw=burette&_sacat=See-All-Categories Yeah, I quite see the point on burettes/pipettes, however both myself and another gent over on VT have pointed out, these require a reasonable level of skill to use. Despite myself having a pretty reasonable aptitude for sciences, I never managed to fathom the dark art of using burettes!! Well, it was either an inability to use a burette, or I managed to prove a lot of scientists wrong!! Link to comment Share on other sites More sharing options...
JohnD Posted April 10, 2011 Share Posted April 10, 2011 I still would say that the accuracy of a burette is false, as the end point is not clear. And I'm not advocating using 1ml syringes to measure about 40mls - that would be silly! JOhn Link to comment Share on other sites More sharing options...
spitNL Posted April 10, 2011 Share Posted April 10, 2011 You don't use it to the end. Never let all the liquid out. Just read from the bottom of the meniscus to the bottom of the meniscus. http://www.youtube.com/watch?v=P46M65Qq_04&feature=related http://www.youtube.com/watch?v=D_g0U3vxr18&feature=related Link to comment Share on other sites More sharing options...
James Posted April 10, 2011 Share Posted April 10, 2011 That's how I learned to use a burette at school - we never had issues with accuracy?! I can't see how that is any less accurate. Must be more accurate than any cheapo syringe. Not that you need that much accuracy but it sure is easier. Link to comment Share on other sites More sharing options...
GT6Steve Posted April 10, 2011 Share Posted April 10, 2011 I don't dispute that a burette is accurate, merely unwieldy. With a burette I have one more seldom used apparatus sitting around. When needed I must set it up then manipulate a heavy lump of cast iron exactly inline with the discharge to dribble thru the hole in my sealed plate. With a syringe, I take it out of the drawer, fill it with water and inject it into said hole until all the air escapes thru the other hole. Read the difference and Bob's your uncle. Now if I was in a professional shop CCing cylinder heads daily I might opt for the fixture... 8) Link to comment Share on other sites More sharing options...
JohnD Posted April 10, 2011 Share Posted April 10, 2011 No, spitNL, you misunderstand. The end point which is not clear is the point at which the chamber is full. BUT! I'll bet that I can read a 1ml syringe to an accuracy of 0.01mls. Diabetics do this regularly, as they are the major users of 1mls and need to adjust their dose of insulin, which often comes in 100Unit/ml cocentration. So if they need 47 units, they must measure 0.47mls. Not .46 or .48, 0.47. I challenge you, or anyone, to read the burette you linked to, and which would be typical for garage use, to less than 0.1mls! That's an order of magnitude, ten times, bigger than the error of a 1ml syringe. BUT this is irrelevant, as the ENDPOINT IS NOT CLEAR! You cannot tell easily when the chamber is full, so like Ted I use an easy-to-see point, which I know is not correct. The error in that may be as much as 0.5mls, but even that is not significant when calculating CR. Try it! See how much your CR changes if you change the chamber volume by 0.5ml! See: http://www.csgnetwork.com/compcalc.html The important thing is to choose a technique and an end point, point and stick to it, get experienced in using them and use them for all the chambers. Having equal chambers is as importnat if not more than the absolute CR, which is a pile of nonsense anyway, as the dynamic CR is much less. John Link to comment Share on other sites More sharing options...
SimonPearse Posted April 10, 2011 Share Posted April 10, 2011 Perhaps I am missing something about the end point not being clear, but the way I have used to measure chamber involves covering the chamber with a bit of glass (with a small hole) oil the head surface to seal the glass then inject soapy water through the hole. A bit of detergent in the water reduces the meniscus. Position the hole so that it is at the edge of the chamber and tilt the head so that the hole is raised (to let air out as you put the water in. The only difficulty in detecting the end point is due to the minimal meniscus at the injection hole. Link to comment Share on other sites More sharing options...
GT6Steve Posted April 10, 2011 Share Posted April 10, 2011 Sounds exactly right to me! ;D Link to comment Share on other sites More sharing options...
charlieb Posted April 11, 2011 Share Posted April 11, 2011 Position the hole so that it is at the edge of the chamber and tilt the head so that the hole is raised... That is so obvious now you mention it! I had the hole in the middle & had endless fun with the last little bit of air :B BTW you don't have to have a stand with a burette (although it probably helps). Link to comment Share on other sites More sharing options...
JohnD Posted April 12, 2011 Share Posted April 12, 2011 Ah! That last little bit of air! Glad you find it so easy, Simon. John Link to comment Share on other sites More sharing options...
PeteClan Posted April 12, 2011 Share Posted April 12, 2011 I use a burette on a stand with a piece of perspex with two holes, one for filling and one to the air to escape, along with degreaser in the burette. Very easy, accurate and importantly repeatable. I also have the advantage of a light aluminium head which is easily leveled on the stands I have. Pete Richards Link to comment Share on other sites More sharing options...
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