ok so ive been back alittle while, and stuck home sick as a dog
loadin the hatch
took my gtech pro/comp so we could play with the braking distance & G-force meter/logging. unfortunately the new fsae car wasn't close to running or driving <rollseyes> so didn't get to play with it. did learn some fun things about some of the personal SCCA cars the guys had. loaded down stock STD hatches fall down hills faster! (reads about 52-58whp unloaded)
elite parking job. got some monstor flex one night by driving half way up it till the frame hit, then let it slide abit longer on the concrete lol (lost that pic
)
last two running fsae cars, much of the welded aluminum on them had long since cracked. reason? welder was shoveling in large amounts of filler to close gaps and concentrating on making his ripples look nice. instead of buying the right size filler, having proper gaps, running the correct arc temp (he was too cold) and shoving too much filler into it at a time (like tossing ice into boiling water - weld cracks WHILE welding because it cools too fast)
keep note of all that because its reoccuring themes LoL!
it had been awhile since i welded aluminum so i spent a good hour and a half playing with thin scrap pieces trying to get the machine (lincon Precision Tig 185) work area and general stuff in order how i wanted it. still, its like a bike. few minutes of practice and you're ready to go! or so i thought!
while i was dicking around for an hour and a half i had virtually EVERY piece of the intake manifold re-cut, re-ground or worked in some way to have a correct fitment! nothing fit! this is 1/16"/16-gauge material and yet almost nothing was in even a 1/16" tolerance at any more than one point! (engineers are engineers. not professional fitters - which is a profession in its own right!)
it wa COMMON to have 1/8-3/16" gaps in the material! 1/8" gaps were the order of the IM (minus the machined pieces) after re-fitting.
bridging 1/8-3/16" gaps on 1/16" material is hard, which brings us to another fun point. 1/16" filler is TOO SMALL for anything but a FLUSH FIT (which is what the spec should be on all of this, oh how i wish engineers were fitters LoL!) better yet! the filler was bought in 2002 for their 2004 car build. what does that mean? it means that a solid 25% of all the 1/16" filler rod i pulled from the box simply balled up and ran away because even with a scotch brite pad & acetone - you can't scrape the ton of oxide off of it.
makes me sad looking at it
oh... the collector i fit together, which is why the damn thing isn't bulky like the rest of the IM
from having to feed 6-9" worth of wire to make 1" of weld![/u]
frame, i didn't weld it beyond to welds trying to show their leader/only DIY competent tig welder how to weld & tacking in the steering column/rack supports. (no tolerances so i did it)
so while waiting for a half dozen machines (CNC machines, drill presses, bandsaws, two plasma cutters - we'll get back too in a min) for people to finish parts i need made to finish the thing. they need someone to do an ALU fuel tank. well... first mistake. you're not setup for me to weld 1/32" alumiunm, nor did I want to play with it! second mistake, couldn't cut out 1/32" aluminum to a flush fit - so it wasn't going to happen regardless.
so we made one out of 3/16" aluminum plate LoL! maybe 6" of perfect weld on the whole tank where the (non MSU) shop we went after hours to another non college shop that had a 3/32" filler rod yay! yes, ONE 3/32" filler rod LoL! rest was done with gaudy 3/16" rod :\
so we get to the plasma cutters! the whole thing was done in no time flat until we got to the filler neck. i wasn't ABOUT to listen to a grinder for two god damned hours trying to cut that out. i ruled out using the wood hole saw on the basis of that's stupid and dangerous. so we try to use a plasma cutter. all it did was rough cut it with the HF start. never would light the plasma arc :\ come back to that problem a day later after finding out the engineering shop we were working in has a nice 80 amp plasma cutter the shop teacher wasn't telling about.
first red flag: plasma cutter is fed by a bottle of 99.999% oxygen because the shop air is too dirty/wet
second red flag: plasma arc lights fine but goes out - hair trigger
so i get alot closer rough cut out for the pipe, i round the last bend! maybe an inch left to go! the torch explosed into a ball of fire, burns both medium thickness MIG gloves (one almost burned through to my hand!) and gets hot enough to turn both my hands red and blister a thumb and finger...
apparantly the trigger "had been fixed" by lincon twice before. ya well... fuck you! it was leaking o2 around the trigger, the trigger was fucked up and arced. the massive o2 content turned the plastic torch into... holding a can of gasoline. btw was running at 65psi. :\
at that point i was done fucking with it. let someone else finish grinding it & just made giant weave passes to welded the gaps on the bitch with the 3/16" rods around 125-130amps.(no pulse) HOT for an aircooled torch!
back to the IM
the first iteration of the flange, they wanted a 1/16" flange welded inside a lip on the cast intake manifold that stands up. yet there was only about 3/16" worth of material before hitting the cast piece. (which is the exact size of that welds profile grrrr) ya well fuck that shit. belt sanded the fucking lip off, cut the runners off & cut out some 1/8" thick flanges in giant squares (which they still took the time to ground down into the approx cast shape??? id rather have the extra surface area for the gasket & bolts to grab myslef)
finishing the chamber caps
must admit i made a mistake on the first one. they had lathed & taped some nice fittings, i melted through the first one tacking it. looked great from my point of view but as soon as i turned it around i saw that nice shimmer on the outside. yup! got full pen all the way through the threads. :\ obviously from there on out i found a brass hose clamp to run into the aluminum fittings to heat sink them hah!
use to be a good drummer, hadn't played in maybe 5 years. always wanted to try it so
broke the pedal :\ fixed it by using thick CA on the plastic, scuffing it, then using a router to trace it in 1/4" santos mohagony. abit of epoxy & laquer and it was better than new!
manifold basically finished. looks like complete ass but it wont have a cracking problem like the others they've made.
27" to the inside runners 31" to the outside pair. here's what they were going for.
supposidely, someone on australia's fsae team wrote some paper on how the split plenum creates a vortex and helps charge the runners. yup, that's what you base a part on; a paper another student wrote LoL!
anyway... arc on time was maybe two and a half hours took probably 5 days just to get them that far <sigh>. everything was hand & eyeball. unfortunately no jigs, nothing level and the workspace quickly went from a large table to the table the fsae car was mounted to. about 1'1/2 of space without hitting the car. wound up trying to balance everything on the car just to hold it together (the moly frame has tons of scratches in it from holding pipe against it LoL!)
all in all... had a lot of fun hanging out. manifold looks like ass. lincon precision tig 185's are fucking stupid, you can't use seven year old aluminum filler unless its large enough to steel brush. you need jigs. engineering students are good on lathes, mills & CNC equipment but can't fab pipe to actually fit anything.
that's what typical aluminum welding from me should look like.
the first welds made (merge piece) are the best looking welds on the manifold
so the question remains is why did the rest of it go downhill! lawlz
oh! and we wrecked a scca street prepaired honda accord into a curb at maybe 45-50mph. (entry had to be at a ballzy 60mph+!) which i welded back together, but alias the subframe was bent a good inch away from its starting location so it had to go to the frame stretcher
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Topic: My trip to make an fsae intake manifold (and gas tank) (Read 14189 times)