Do carb jets usually MEASURE bigger than stated size?
Discussion
Ordered some 182.5 air correctors. I really need 180 but these are pretty cheap and I understand that air correctors generally go in steps of 20.
Out of curiosity I popped them on an optical CMM...
They measure 1.864, 1.856, 1.862, 1.852 So are up to 0.039mm oversize.
40 microns, not much really?
I guess they used a 1.82 ish drill and these are what you get.
I assume that this is fairly normal variation?
Out of curiosity I popped them on an optical CMM...
They measure 1.864, 1.856, 1.862, 1.852 So are up to 0.039mm oversize.
40 microns, not much really?
I guess they used a 1.82 ish drill and these are what you get.
I assume that this is fairly normal variation?
I don't have those drill bits to hand... but the CMM is a good one in the lab at work, calibrated, serviced etc.
They aren't original dellorto parts. Have worked with brass orifices used in v.accurate pressure regulators before and understand some variation due to tool wear, jigging etc is not surprising.
Just wondered if jets usually had a big tolerance so when the book says 180, it may well be more so the system is sort of accounts for it.
They aren't original dellorto parts. Have worked with brass orifices used in v.accurate pressure regulators before and understand some variation due to tool wear, jigging etc is not surprising.
Just wondered if jets usually had a big tolerance so when the book says 180, it may well be more so the system is sort of accounts for it.
Over the last few years we have had many, many instances of replacement jets, needles and carb components not measuring what they are said to be. Worst case was emulsion tubes in a pair of brand new webers too short and wouldnt pick up fuel, four old tubes and we were away. I always check the jests are near enough what they say before I change anything. It is not unusual to have a range of too small to too large! I suspect it is the source of manufacture of the parts
Peter
Peter
Hi Mick, I trust you are well?
When jets are too large we solder them then re drill to the size we want to try. Some folk have called this in the past saying it is inaccurate, but, when the car leaves it is with jets suited to the application. Some folk rush out and buy new jets but it is an eye opener to those folk when they measure the 'new' 'proper' jets and find them different sizes to each other and from the size stamped
Peter
When jets are too large we solder them then re drill to the size we want to try. Some folk have called this in the past saying it is inaccurate, but, when the car leaves it is with jets suited to the application. Some folk rush out and buy new jets but it is an eye opener to those folk when they measure the 'new' 'proper' jets and find them different sizes to each other and from the size stamped
Peter
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