rebuilder86

look at that i was rihgt at a guess http://www.club-k.co.nz/Forums/viewthread.php?tid=27396 Check the jet sizes should be 123 primary and 159-162 secondary from memory make sure the air.... just get a 1.5mm hss bit and work it around a bit.

I like that your first idea of the problem is the jets, and i would agree with you. I drilled mine (just the secondary throat main jet) with a fucking cordless drill and a 1.5mm drill bit because I'm running a stock carb whose secondary jet didnt match the specs for whatever reason. My dodgy drill thing worked and i have cured a bog down when climbing over the hills, so it can be done DIY in my opinion. Start by pulling out ur secondary and seeing if a 1.5mm bit will fit though it. If not, i guarantee its too small for a 5k. the largest size for any 4k is 1.68mm and that is on the secondary for the 4k flat top piston with the flappy controlled carby (the one without the crazy number of tubes, and the hot idle compensator inside the coverplate on the side) so if its smaller than that, it can't be right. someone on answers has posted that the stock jets are 1.3 and 1.6 http://www.answers.com/Q/What_is_the_stock_jet_size_of_a_Toyota_5k_engine_carburetor?#slide=3 Now i know the carby throat size is different, but only marginally, you will have to trial and error it, without making an error haha start at 1.5 and see if there is improvement don't go past 1.6 unless u can get some spares.

I think my problem is the extent at which i wish to increase the running viscosity, pushing it up there to the extremes to solve a simple loose bearing issue. Ive looked at the bearings, they seem perfect, i can't see any wear. I cannot remove the crankshaft to have it machined, no one has the capability of doing that here. I simply don't trust them. Commiting lubrication fraud is a more sensible idea. If youd like an idea as to whjy i think they arent capable... I visited the most respected engineering and engine rebuilding workshop in cebu, and asked them to lightly hone out a motorcylce cylinder for me. I left it with them. They had a large expensive automated machine with feed speed and pressure settings, a serious piece of equpiment. Came back and got it, and the bores were smooth as glass. I was a bit upset, but in a panic, anda bit of anger, i quickyl paid them and left thinking i would go find a cylinder hone for my drill at a mechanic. Spent the better half of a day runnign around the entire city, unabel to find a cylinder hone, other than one where the stones were worn down so much i wondered how someone would think it was sensible to use it to get to that point. I ended up going back to the workshop i had it honed at, looked at the hone, and saw 2400 grit silicone carbide sandpaper wrapped around the hone. And asked hem what they thought the purpose of honing was... TO MAKE NICE AND SMOOTH SIR I explained to them how wrong they were, and his response was, NO SIR IN PHILIPPINES THIS HOW WE LIKE IT. fucking idiots.

yeh ive been pondering over that too, but then i think, well the engine wasnt designed to be this loose, its just its age. however not everything will be this loose, the mains are probably fine, the big one is the conrod bearings. This engine has an insanely loose conrod clearance figure, some docs state 0.1mm and some state 0.3!! look at this! that would be enough for me to wiggle it around with my hand in the sump and clearly feel it. I suspect that is where my pressure is going, but they do this for a reason, they want oil to exit and spray out the side of the journal to the piston squirters to keep cylinder wall temps down. It also allows for this is why 4ks go forever. note that our conrod journal is smaller than our main journal, so you would think the clearances would be smaller, but no, toyota are up to sumthing with this engine. Normaly, as arule of thumb you add clearance for every increase in size of journal. I guess rules of thumb shouldn't come in to play with engineering. theres obviously some reason for it. I jstu want some god damn oil to run up the conrod and out to the piston skirts through the wrist pin like its supposed to. when hot it seems to be relying on oil being sprayed from the conrod cutout piston sprayers. so i get knock and slap all at once.

speaking of all this, has anyone got an original 4k piston laying around, i would like to know how many oil return holes there are perpendicular to the wrist pin holes, ensuring not to count the 2 pressure supply holes FROM the wrist pin.

id love to be able to get some of this over here smuggled through the airport: http://www.penriteoil.com.au/products/baseoils/mineral/hpr-50-40-70-mineral At that viscosity, cold starting wouldn't be an issue, id imagine its so thick the oil would happily just hang in the bearings all day with the engine shut down, and when started up, it would be like permanent assembly lube and flow wouldn't be needed haha. These are all my potentials, and you can see why i want HPR50. The nulon stuff is an SAE lie so id steer clear. But i just can't get it, so I'm doing what i can to lower temps instead.

what do u mean an oil cooler wont help. I'm sure thats not right. colder oil means more viscosity. yes the oil stays at 50 grade, so when cooler it is thicker. At 100 degrees it has a cSt of 18.09 at 40 degrees it has a cSt of 159.1 Just a generic thing i found on the net, but lets imagine that 20-50 purple line is my catrol GTX. if i can bring the temp down form 120 (off the chart) to 80, then ive gained some viscosity. Probably not much tho. but somewhere around 34 is better than the current ~17 cSt i guess?? maybe your point is that i wont notice the change, but i think i will, as there is no ticking until the 8th minute of driving down the dirt road. Id imagine the engien wouldve come pretty close to equilibrium for dissipating oil heat by then, so even a few degrees cooler should help. Ill be stoked if a cooler can bring it down to 90 degrees.

well thick all the time wouldnt help, that would either blow a seal or exit the relief valve at startup and starve the engine of oil. but maybe there is maddness to ur theory... maybe a straight sae 30 will stay thicker when hot than a 20-50... nahhh don't wanna risk it. need to find the cheapest nastiest oil cooler to test my theory.

hah fuck i need to find this old picture, you will loose your shit over it. we had a volvo 240gl bush basher on the farm, well 2 of them. we were quite young. For an unkown reason, i replaced the pressurise coolant reservoir with PVC pipe, which went out the quarter panel, and INTO THE CABIN for topping up ON THE GO! This was because the car ran on OILANT! the same liquid wen tin the cooling system as in the lubrication system! Thats how we designed it, and it worked. kinda.

how does that help? that would be as thin as water when hot. bigger number is better, higher viscsity. do u mean straight sae50?

stick it into the cabin to remind you to go easy on the throttle. :P One day you will understand the science behind my joke. Hats off to anyone who understands actually.

hey parrot i had a good read. perhaps i didnt think about the other issues apart from viscosity, that cooler oil might introduce. I have no idea what temp my engine currently runs at, i just know that 20-50 is the thickest oil i can get here so my only option is to cool the oil., unless i smuggle some penrite HPR40 25-70 in my suitcase http://www.penriteoil.com.au/products/baseoils/mineral/hpr-40-25w-70-mineral Perhaps if i do go an oil cooler route, i will have to control it with a thermostat as well. I'm sorry i refuse to use the pansy marketing term OILSTAT. haha

thanks taz, i think that answers my question perfectly. it has quite a significant effect. Dave, this is true, but what if your engine kind of needed warm moderately runny oil instead of fucking hot thinned out oil which slips through the loose bearings like water. Thats the issue I'm facing. Oil likes to be hot yes, but only so that it can perform at its intended viscosity, and that intended viscosity is designed for an engine in nice tight working order and fresh. Mine is old and worn and the crank shaft is unable to be machined. (no one here can do it)

Has anyone on here, ever installed an oil cooler to their car? any car? If so, did you have an oil temp gauge before with any idea how much of an impact it made to oil temps? I cannot find any information on the net about just how much cooler engine oil is when a cooler is used. liek ball park even 1 or 2 degrees, 10 degrees, 20-50, 80?? Anyone know anything about the subject? I ask because id like to consider cooling my oil to keep the viscosity up there for this old engine. when me 4K is hot, it clicks n slaps n knocks at idle.. these old motors don't have much oil pressure at idle when the oil gets hot. Factory specs say 28.4 psi at 300rpm, i get as low as 5-10 at hot 650rpm idle. :( Please don't tell me to rebuild. Id like to avoid that. It runs fine and silent for the first 10 minutes, but once the oils hot, it just can't stay thick enough running 20-50 mineral (castrol GTX)

hey wings, if ur sure ur vacuum advance is working, a good temporary test to see if vacuum leak is still an issue after u have capped the other hoses is to remove the idle (slow) jet from inside the carb and also disable the choke from doing anything to the throttle, then see if it idles. You undo all the screws from the top of the carb, remove the pivot bolt for the accelerator pump arm, remove the top cover being carefull not to tilt it or the float assembly will fall apart, then put it aside. then u will see a little hole on the top next to the accelerator pump with a brass piece with a hole in it and a flathead screwdriver slot. undo it and use a pin on an angle to pull out the jet, its a long tube. remove it and reassemble the carb temporarily. turn choke fully off and ensure "base idle screw" is completely unwound. then turn it in until it just starts to move the throttle activator. turn the 'idle mix screw' gently all the way in and then back out only 1.5 turns. then try to start it after giving the acel pump 2 squirts. u may have to crank multiple times first to fill the fuel bowl with the mechanical pump before squirting with the accel pump. if it starts then dies, turn the 'idle mixture screw' out another half turn, if it starts and runs, let it warm up for 5 minutes then turn the mixture screw back in until it idles at something u consider reasonable and smooth. if this can be achieved, (a smooth idle with no choke) then its likely there is an internal vaccum leak at idle, (internal meaning not a hose) which greatly affects the ability of the manifold suction to pull fuel through the slow jet. the sources of internal vacuum leak are. leaking hot idle compensator rubber washer (simply plug up the hot idle compensator, u don't really need it) worn power valve piston located inside top cover, vacuum supplied from hole in the bolt through the carb(put carb in bin) leaking gasket between throttle assemblies and carby body, (rebuild kit) leaking throttle plate shafts. (put carb in the bin) the other possibilities if u get a good idle is what id reffer to as idle air bleed leaks, where unwanted air leaks in to the idle circuit and reduces the suction caused my manifold vacuum. these sourcea of leak are: the seal on the idle solenoid. (make one out of gasket paper.) the idle mix screw thread (if worn out from an obsessed user like me, grease up a new one from the rebuild kit) the top gasket where the idle air bleed hole sits over the slow jet the t slot, the transition slot itself is a source of idle air bleed during low idle. however, sometimes the t slot can be fed extra air backwards into the fuek stream if there is too much air allready in the idle circuit. a but like cappiliary action, just with airy fuel mixture. so the t slot makes it worse. nothing u can do about that but fix the air bleeding in to the slow circuit. try removing the jet, if no change, then id be looking at the float level. some people muck witg it to make it richer, then a lazy mechanic sets it back but goes to far to lean. naybe while uve got the carby cover off hang the float assembly directly vertical, carefull not to let the pivot pin fall out. if the float hangs exactly parrallel to the fasket face, its all good.

sweet jeesus its amazing.

yeh I enjoy the finicky carburetor. id never trade it for EFI, not on this engine.

cheeky bugger. megasquirt sounds like a dirty porno. does this megasquirt tech deliver spark too? (or is it all just fuel injection. anyway ive made a mistake, its 25 degrees not 35 degrees. i thought the biggeat number on the timing cover was 30 but its 20, and I'm over that at idle.

bugger disnt see that pic, stick it back in ans forget it. judging bybthe rust scale, id say the bowl cover (or air horn as the pros call it) needs to come off and get some elbow grease into the primary circuit, specifically the slow jet tube. banjo, ive got mine purring at 650 now haha. frikn stoked. and i didnt wanna be completely honest because whenever i bring this up people argue with me, but i have a shit idle unless the advanced idle (with vac advance plugged in) shows a timing of 35 degrees with the light. This is how i run both the 4 k motors in my life.. a 4k c in australia with points dizy with one advance tube and a dished piston 4k (4kU i think) in philippines with bosch electric 2 tube. Both run the stock flappy type carbs with only 2 vacuum ports and hot idle compensater molded into the carb shell. Perhaps its not the same for everyone else running webbers, holleys or super sized jetted stock aisans in which case the idle mix is rich enough to take care of itself at 20 degrees advance. I would be interested to see if OP can test mucking with timing and see if it gives him any joy. PLEASE NOT WITHOUT A TIMING LIGHT. I have a video on my other phone of my timing light showing the 35 degrees advance at idle and showing the timing dropping back to static as soon as load is applied and accelerator opened. it was filmed in the engine bay driving through mud just to prove a point in another forum. ill try post it here tomorow.

hey guys. Firstly be careful how u interpret altezzas mention of adjusting idle. u can so very easily be mistaken and think uve solved it when all uve done is opened the butterfly valve enough for the primary jet to engage and start dripping and it hits the butterfly valve and gets vaporized and burns. this is not ideal and is too rich. i actually bought the stock carb and it came with a bolt in the place of the solenoid for the cheap asian market to keep costs down. really don't need it here. if youd like to have it running now, u can just go to supercheap, take the solenoid with u, get a bolt with same thread from the turning stand bolts rack thing, and stick it in. or else, grind tge entire end off the solenoid and screw it in. while ur waiting for the new solenoid. no need to have a solenoid unless u get dieseling or want to invent some crazy engine management system like i did. (see my post about solenoid) further. With a lean idle condition on these motors, i have found requires full manifold vacuum advance to the dizzy ao that with the advance plugged in and idle at 700, the timing should be very advanced, like over 30 degrees. if it isnt this advanced at idle this greatly lowers the power at idle and it dies. I wish i was there to help u. i have so much experience (good and bad) with this carb now, its like its part of my body.

hey guys. Firstly be careful how u interpret altezzas mention of adjusting idle. u can so very easily be mistaken and think uve solved it when all uve done is opened the butterfly valve enough for the primary jet to engage and start dripping and it hits the butterfly valve and gets vaporized and burns. this is not ideal and is too rich. i actually bought the stock carb and it came with a bolt in the place of the solenoid for the cheap asian market to keep costs down. really don't need it here. if youd like to have it running now, u can just go to supercheap, take the solenoid with u, get a bolt with same thread from the turning stand bolts rack thing, and stick it in. or else, grind tge entire end off the solenoid and screw it in. while ur waiting for the new solenoid. no need to have a solenoid unless u get dieseling or want to invent some crazy engine management system like i did. (see my post about solenoid)

i already replied to a topic about the hunjy dollar aisan china ebay carby. it works, but the accelerator pump died very quickly as it was not kept wet with fuel. thr leather just broke apart. the screws on the top have all rusted and all were destroyed even when using an impact screwdriver :( so getting to said accel pump plunger was a cunt of a job. and finally, the air horn gasket it comes with fell apart completely upon opening so fuel squirts everywhere when the bowl sloshes around. however, when it ran, it ran fine. i purchased the non diaphragm operated one, the simple looking one with no hoses.

interesting about sulphamic acid, never heard of it, and ill probably be shit outa luck ever getting it on my carb. No hardware stores here in philippines would even know what anything about the subject other than the word acid and would have no idea there are different types. Toilets here are cleaned with chlorine., so everyone's toilets smell like a public swimming pool haah And I'm sure airlines would be super happy about seeing it in my baggage, so flying it over is out of the question. for all those out there with the idle problem, my experience shows thus. The kp61 and KM20 series carb by asian, that is the one with a vacuum diaphragm operated secondary throat, and all the complicated vacuum hoses everywhere, come with a 0.45 or 0.48 mm slow idle jet. this is simply too small and is a cock up and no engine with a functioning stock PCV valve will idle in this configuration at anything less than 900 rpm, by opeing the base idle screw. The other carb, as illustrated in your scan, of the one where the secondary throat is governed (allowed to be operated) by a mass air flow valve inside the throat, comes in slow jet sizes: 0.45, 0.47, 0.5 and 0.53 mm with the latter being the jet size for the 4K-C. This 0.53mm is getting close, but to idle at 800 rpm the pcv will need to be almost blocked and your hot idle compensator valve must be in pristine working order and not leaking at all. For me it had to be ground open to about 0.6mm and then regulated by the mixture screw. To repair the hot idle compensator, just take the cover off, pull the valve assembly out, and spin the little rubber seal block around and it should be good for another life. interesting also to note that the factory manual states, for this mass air flow valve carby, as illustrated in your pic, the mixture screw setting ranges from: 1-1.5 turns from seat \ (4k-C) 2-2.5 turns from seat \ (2k and 4k) 3 turns from seat \ 3k-c and 3k-H The 3 turns is because of the smaller displacement of the 3k motor, which at idle, is not enough suction to suck out the fuel from a 0.47mm jet. But then again, the larger 4k motors require more total fuel at idle, hence the larger slow jet and smaller mix screw opening. This setup is the best, as more fuel is allowed to the point of atomisation where it is restricted only for the purpose of atomisation. The smaller jets restrict the flow with no benefits of aiding in atomisation. they in fact decrease the atomisation because less fuel is allowed to flow through the opening. In short, reveres the idle circuit setup, because the engineers cocked up. the biggest restriction should be at the exit point, the idle port.

so altezza what they needed to invent with su carbs, was a diaphragm with atmospheric pressure being sucked out of it at a predetermined force to vary the preasure based on altitude, instead of a spring which is a fixed total force. this is how the pitot-static system works. these su carbs are absolutely shit for me here where I'm driving over the 1500 ft hills every week. i had problems finding a diaphragm for my old Variable venturi carb so ended up throwing it in the bin. i like the concept but i think it has been commonly proven to be a massive fail. who is pete? another pilot on here? i was taught to slowly increase the mixture from cutoff while cranking when starting the r44 raven 2 which is EFI but not sure about carby, we were taught to always start carby full rich, however we have no airfields of an altitude greater that a 900ft over in WA so ive never seen that issue. bloody flat and boring place it is, geograpgically.

in the chopper, piston powered robinson, we have a mixture control which sort of does the same thing, but to the entire fuel circuit of the carby. same with nearly all light GA aircraft with carbies. this mixture control is to be in the fully rich condition for cold starts regardless of altitude. aviation engineers had more brains than automotibe ones. the closest we came to this with carbies in cars, is the feedback carburettor by mikuni, which automatically adjusts the entire primary circuit, (slow and main jets on barrel one) by letting air into the fuel circuit to decrease suction applied to that circuit effectively by venting it through a solenoid to atmosphere which ticks open and closed very fast. any other carby is stuck in a single fuel metering setting, but sometimes these are adjustable through adjustable air bleeds. wasnt good enough for me anyway haha.