Steelies Posted November 29, 2012 Share Posted November 29, 2012 i wonder if 5k carb is any different to 4k Quote Link to comment Share on other sites More sharing options...
Spencer Posted November 30, 2012 Share Posted November 30, 2012 There is nothing wrong with those Aisin carbs on old Toyotas, they will run mint and return decent fuel economy with a mildly worked engine with abit of fucking around. I don't know how big your cam is but Ill blurt out what I would try to do if I wanted to get it running well for cheap. First you should be able to get a rebuild kit for fuck all (check the throttle shaft for wear, it probably needs to be bushed), and get some spare jets to drill (may be able to find some from a carb shop). With a decent size cam one thing that really stuffs drive-ability is how much air and fuel the carb can deliver with your new low vacuum idle. Cracking the throttle plates is a shit way to do this, you usually loose your ported vacuum spot and the car wont roll off idle nicely. It shouldn't be hard to mod the idle air bypass circuit and possibly open up the hole on the idle fuel adjustment needle, I'd have to look at a 4k one to be sure. Next if you have a stumble on throttle stabs you need more accelerator pump, pretty sure on some of the old Aisin's I have opened up it looked pretty easy to open up the nozzle a fraction, you need a decimal drill set. Wide band oxy senders and controllers are pretty cheap these days, if you can borrow one it will be pretty easy to get the jetting sorted. I'd put money down you could get it running on the stock carb pretty well up to a point depending on the cam size. Of course the factory manifold is real shit and bike carbs etc would be real nice if you can afford it. Naturally you change to a intake with a nicer straight run to the intake port and can tune the intake length Quote Link to comment Share on other sites More sharing options...
phatt20 Posted November 30, 2012 Share Posted November 30, 2012 i wonder if 5k carb is any different to 4k yep they have bigger venturis, and most are auto choke. lot of people sell 4k carbs as '5k' items tho so pays to know what your looking at. Quote Link to comment Share on other sites More sharing options...
Steelies Posted November 30, 2012 Share Posted November 30, 2012 ah. i see a 5k starlet for sale (tardme) with a a 4k carb on it heh. highly recommend you do what spencer says, in most cases. Quote Link to comment Share on other sites More sharing options...
waylowkp Posted November 30, 2012 Author Share Posted November 30, 2012 cheers for the info guys, all taken on board, the $150-$200 budget was for the carbs alone, entire build is a slow one as im "doing it once and doing it right" Quote Link to comment Share on other sites More sharing options...
Dell'orto Posted November 30, 2012 Share Posted November 30, 2012 If your cam has a lot of overlap, you'll want an individual throttle per cylinder, it'll lessen/eliminate intake reversion which will make it less choppy. Thats either going sidies or bike carbs, both of which will be minimum triple your budget. A set of Coby extractors will help it breathe a little better if you're still running the stock exhaust manifold, though the stock 4-2-1 isn't actually that bad. 1 Quote Link to comment Share on other sites More sharing options...
Gothicteo Posted December 8, 2012 Share Posted December 8, 2012 Interesting reading. I'll put together a 4K engine this winter. But what size should I have on the nozzles on my Dellorto 40is. (vented and flattened top and 290 camshaft) Speaking of bikecarbs .... in my race car, I have Mikuni CV 40 from yamaha r1. The only thing I have done is that I drilled nozzles and bygt an intake of exhaust parts .... Gor as a spear over 3000 rpm .... Quote Link to comment Share on other sites More sharing options...
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