snot35

Cool, I've been searching for this sort of info lately. I don't suppose anyone knows intake and exhaust valve sizes?

For the money you're thinking about spending on machining, cams and twins, I'd probably just say bugger it and do the conversion! At the end of the day you modifying an old motor that is quite small in capacity. If you can do some of the work yourself you'll be better off with something that has cams in the right spot, more of them, more valves and probably EFI. Of course this all depends on state laws on modifications, but you did mention you were going to do a conversion eventually anyway. Make sure you check the regs of the classes you plan to race in though. If it's just for a bit of fun then it doesn't matter. If you actually want to be competitive then you have to give it more thought.

I guess the pertinent question is, what do you hope to achieve from changing to new carbs? What do you want the car for? And no, it's highly likely it won't be as thirsty as your RX7! :lolcry:

That's probably even too big for most K motors. 1.5 inch is probably the go for most, you could probably even get away with 1.25. I've yet to experiment with SU's, but I have a manifold on the way now. They did pretty well on an old SSS Datsun I had years ago :hmm: Manifolds are hard to find though, as they've stopped production. There has been quite a few around in the Car Parts section of this website lately though.

I think what they're referring to, is please keep the text speak to a minimum and make an effort with punctuation and spelling. We're all rolla fans here, and we are all really keen to help you. If you come in and start asking "wots gonna make max OMG powa i wont a ful sik rolla" we might be a bit less enthusiastic. A lot of your questions are addressed quite well in the FAQ. Please make an effort and so will everyone else.

I guess the first thing to know is that it isn't going to be cheap! There is a set for K motors on ebay at the moment with an asking price of around $1000! Realistically you can probably find a set of Webers or Dellortos for $300 or so second hand, and the manifold can be found for around $250 ish. Then budget money for decent filters. One thing to realise is that there isn't a whole lot of space off the side of a K engine, so you need low profile filters. Also, don't go larger than 40mm. Webers seem to be good for finding parts. Dellortors are supposedly superior but harder to find parts for. Solex I'd forget about. Parts will be hard to find. Make sure you get a matched pair that are the same model number of carb, otherwise they won't play together nicely, and you'll have half the motor running differently to the other half. It's highly likely you'll need some dyno time to tune them, unless you can by a setup already tuned for a 4k with a 2 inch exhaust. Jets and tubes aren't overly cheap, so you'd want to budget a reasonable amount. Also factor in that you're probably going to use a hell of a lot more fuel. Twins sound great, and you'll be flooring it all the time! :) If the car is a daily driver, I don't think I'd do twins. It just isn't practical, try and find a Weber DCD. If it's for weekend track work and the like, then I'd consider it. Once you cover everything, you'll probably spend at least $700. Oh, and for it to work properly you'll at least want to port match your head. Better still, get it ported to take full advantage!

I reckon that 270 degree probably isn't too bad an idea in a 4k. Certainly seems reasonably popular in the FAQ. I'm thinking about this one for my next motor. Keep some cash aside for getting the carb jetted reasonably as well. Should be fairly drivable. It won't be really smooth to drive, but should be pretty good.

Well you've probably finally found the right place for doing things on the cheap! Lower the better as far as gearing goes for your setup. I'm not sure what the standard diff ratio in a KE55 is. The might be lower in the auto's? I'm sure someone will pipe up. Last 5 speed cost me about $70 from a u pull it. :D A bit more for a diff centre I think. Two choices for compression. Head shaving, or 3k head. A 3k head might send you backwards with smaller ports, so I'd probably want to check that out before swapping. If you shave you also have to adjust the rocker towers. Check out "How to build a tough K motor" in the FAQ. It will tell you a lot. I'm with felix, I'm not sure the DGV was the best choice, despite your mechanic.

That grind is a big cam, with a lot of lift. Basically you've modified the characteristics so that you'll have to rev it all the time. You'd want to run quite high compression with that cam. You'd also want a very good port job, and probably twin carbs or quite a good EFI setup. That cam is really too big for a street car, it's probably more of a tarmac rally sort of cam. If you want something drive-able, I'd say you want the 621, or 609 TOPS. If you go the 609, you'd still want a pretty well tuned car so it will drive OK. I'd say it's probably a little too much, especially if it's a daily driver. I think you'll have trouble fixing your problems with this cam. It really depends on what you've done so far to the motor.

Really? How much larger? I'm supposed to have a 3K-H in mine, but I think the ports are still pretty small. What cars are 3K-H's in generally?

Check the FAQ. If you mean with standard springs then from memory it's about 0.4". If you have aftermarket springs then that depends on the spring. There are also other considerations depending on your motor. Shaving, pistons, cam timing, etc.

It's not even nearly that simple. Define better flow.

Considering the valve is probably 38mm at the most then it probably is too big. All the texts that I can find on porting, and any work I've done seem to indicate around 30-32mm wide. Are you talking width or height? 3K gasket should be around 25mm. 4K would probably be larger, but still possibly around 27mm. Different manufacturers appear to have different sizes. If you want to use that head, you're probably going to have to trim the gasket yourself and match it to your manifold and ports.

Why on earth do you have 38mm ports??

What do U Pull it charge for diffs? They've always got a heap of KE3's and KE5's. Not a big job.

Probably none! They're so rare they're museum pieces. I saw one in Toyota megaweb, Tokyo a few months ago. Very nice bit of kit.

You do need a bracket like the one you've pictured. It's designed to have a vertical shaft clipped onto the ball. Otherwise you might be able to modify the cable wheel off an old carb. It will take a bit of messing around, but you could probably mount it on the end of either carb so you don't have to muck with that centre linkage.

You also need a pretty good surface finish on a cam. If you don't get these surfaces and treatments right the motor will be junk pretty quickly. You'd want a lot of spares, and would want to love changing over heads! Usually cams are ground using a grinding wheel that follows an eccentric blank that moves the wheel as it's rotated. Ramp rates and lift are also quite important. If you're interested, hunt down a copy of a book like Four stroke performance tuning, by A. Graham Bell. You could go OK lightening the pistons a little, but I don't think I'd get too carried away. 3K pistons would be a better start. You could also lighten rockers and definitely look into porting if you haven't already. Balancing is always good as well. I don't know where to start with the launch control. It would be a pretty harsh way to do it, cutting ignition at a particular revs. One thing you could explore is some of the kits available from jaycar.com.au. They have high energy kits and one that I can recall had a box so that you could program advance. You could possibly play with the advance as a form of launch control? That's definitely a big project though. If you're on a budget and have heaps of spares, I'd be playing with porting and lightening both fixed and rotating components. Have fun!

As said, only really done to fit sidey's. Personally, it would be a similar amount of pain (maybe less), and more gain to fit EFI. I know which I'd do :fuzz:

Hey, I don't suppose any of you guys have the same diagrams for a KE30? I'm just trying to fix the top and bottom of an A pillar and those diagrams are great! Mike

I didn't find Tig welding mild steel was actually that hard. Having said that, that was on a decent quality Kemppi unit. I'm not sure how well the cheaper units go. I thought about getting a Tig when I was shopping around, but realistically to get a quality brand name unit it was going to cost twice as much as a Mig. You can get lift start inverter units for around $400 or so, but I think you really want a bit more control than that. Tig is more of an art, but probably not as much of an art as welding panels with fencing wire and gas! Distortion here we come! I admire the guys that can do that. Tig aluminium on the hand, is very hard! For panel work a small Mig is really the way to go. Like I said, see if you can get a 150 or 165 and you'll be able to do engine mounts and similar as well.

I did the tafe course, and it's definitely a good place to start. I recently bought a CIGWELD Transmig 135. Not a bad little unit so far. I got it second hand for about $400, but had to replace some parts to bring it up to snuff. It's not as high a quality as the WIA unit, but I can't quite justify that sort of cash. The advantage of the cigweld stuff is that you can get spare contact tips and parts from Bunnings. So if you need wire and tips on a weekend it's easy! Other stuff has to be ordered though. It seems to do good welds though. If you're doing panel work you want a MIG that will go down to 30 amps or so. If you want to do engine mounts then you want to go up fairly high as well. I'd probably save and get something like the cigweld 165, or a WIA 150. That's as big as you can go before you need a 15amp plug. That should cover you up to around the 5mm plate mark. The cig stuff usually comes with a regulator, which does OK but isn't great. Also factor in some cash for a decent helmet. The auto ones make life a lot easier. And money for the bottle!

Great Felix, thanks. So this is the "Tuning the A-series" book?? Thanks again. Michael

Excellent debate! As a slight detour off topic, as the Vizard book seems to deal with A series engines do they delve into selecting single side draft carbs? I've got a single weber setup that's going on the k powered rolla, and if there is some tasty info about selection and tuning I may have to grab a copy of this book. Cheers

The linkage setup might be a bit of a nightmare? I'm not sure how they work on the 32/36's, I think there are different types. I'd probably stick with the single and get some twin dellorto's if I really wanted to up the ante. Do the head work and cam, get it tuned properly and see how it treats you.