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Originally Posted by War Eagle' post='884142' date='Oct 4 2007, 11:12 AM
Okay, as a guy who's spent way too much on a 20B conversion, let me chime in.
A used 20B will go for around $3,500 - $4,500 depending on the series and condition. Japan2La on the "other" forum is selling a C or D series (can't remember which) for $4,500. What's the difference in series? All 20B engines come marked. The irons are marked as well as the housings (this is how you can tell if the engine has all matching numbers - then you know it's not made of mixed parts). The easiest place to look is on the rotor housings, right next to where it's stamped with a "20B" The original 20B engines ran 001 - 999, without a letter prefix. Then Mazda switched to using a letter in front of the numbers and produced A,B,C, and D series engines. The A series had a different rotor housing design that was prone to cracking. Not good. This was fixed somewhere in the early B series engines. The eccentric shaft was also redesigned somewhere in the early series, buit I think even before they made it to the A series. So, the most desirable series are the C and D engines as they had all of the modifications made by Mazda. Bs are probably good to go also but the As most likely have the weaker rotor housings and these should be replaced if you want to make big power (isn't this what it's all about?). A lot of A series engines showed up in the states first, but now you can find C and D series. You can use 13B FD rotor housings (don't let anyone talk you into 13B non-FD housings) and these will work very well. They actually have advantages in cooling passages over the 20B housings. So, it's much easier just to buy a complete 20B used engine and rebuild it. If you try to make one out of 13B housings, you'll need also a thick center plate, the front iron, and an eccentric shaft. The thick center plate is impossible to find and Mazda doesn't make them anymore (rumor has it they'll start again) and they're crazy expensive. I've seen them go for over $3,000 if you can find one (I'm fortunate to have a brand new one in my engine:)). The eccentric shaft is also a bitch to find. I bought a new OEM one from japan2la for $1,800. Used ones can be found for about $1,000 but you need to make sure the shafts are not bent. Because of the nature of the 3 rotor, the e shaft is prone to flexing in the middle, thus the bent shafts. Not to be a sales *****, but I have a e shft I was going to use in my engine until I bought the new one. I'll probably sell it soon for $1,000 if anyone is interested. It's been dynamically balanced by Roger Mandeville and it came from the Pettit Racing GT series inventory. As to the cost, $30,000 - $35,000 is a good figure to use. You'll need to used engine and an EMS to drive it. You'll also need to rebuild the engine and depending on how you rebuild it, it can be quite expensive. At a minimum, I'd use the Xtreme Rotaries stud kit on the engine as this will solve the flex issue for the shaft. I'd also pay the extra $1,000 to dynamically balance the center rotating assembly. Throw in a new intercooler and piping, the subframe for the engine, and then a turbo (go with the GT42R), you can see the $$ will add up. Anyway, off the soapbox now. Hope this info helps. ive been doing a converstion also and from what i can gather its not so much the housings being weaker but the rear iron being weaker(unless this is what your on about). didnt know about the fd housing being beter for cooling tho(some good info) . As for the e-shaft and the centre iron , there are replacement shafts guru make them and priscion engineering over here(nz) do them, they also modify 13b irons so you can run it as a 20b...very expensive but there is that option if your that way enclined. I dont think that the stud kit will fix the shaft flex as much as it is designed to hold the irons and housings in place, but shaft flex shouldnt be too much of a problem unless your looking for high rpm, the gt42r is a good turbo but if your looking for something that is smaller(in actual size) and lighter (more expensive) then hks t51r is a great wee number on this engine |
Originally Posted by hsmidy' post='884434' date='Oct 4 2007, 07:55 PM
ive been doing a converstion also and from what i can gather its not so much the housings being weaker but the rear iron being weaker(unless this is what your on about). didnt know about the fd housing being beter for cooling tho(some good info) .
I've heard it's the thick center plate, the rear plate, and/or the housings that were weaker. C and D series are good to go and the way to prevent issues on newer series engines it to stud the engine with the Xtreme Rotaries kit. The info about the FD housings came from the mechanics at Gotham Racing. As for the e-shaft and the centre iron , there are replacement shafts guru make them and priscion engineering over here(nz) do them, they also modify 13b irons so you can run it as a 20b...very expensive but there is that option if your that way enclined. Very expensive indeed, from $2,000 - $3,000. Very nice looking and well-engineered shafts. The Kiwi shaft modifies the center gear assembly. You can buy a complete crank kit from www.kiwi-re.com for about $4,200. This includes an eccentric shaft, center plate, and stationary gears, which is actually a pretty good deal. Would have to add in over $500 for shipping to the US though. I dont think that the stud kit will fix the shaft flex as much as it is designed to hold the irons and housings in place, but shaft flex shouldnt be too much of a problem unless your looking for high rpm, Let me clarify. The stud kit eliminates iron and housing flex, not shaft flex. As I understand it, this is the biggest problem for the 3 rotor and the Xtreme kit eliminates this. The cost is about $500 for the kit and then about $500-700 for the machining needed for the studs. You have to find someone that is very good at machining as this needs to be precise or you'll ruin all the irons and housings and this would suck. My work is being performed by the shop that does the drag racing machining for RX7.com's racing car. To me, this is a must for the 3 rotor. Not so much for the 13B because it doesn't suffer from the flex issues. I agree with you flex is not an issue for the shaft unless you are going to run above 8,500 RPMs which most of us will not do. This is why I went with a new, dynamically balanced e shaft and center assembly instead of the Guru or Kiwi unit. The Guru or Kiwi shafts would be great for anything above 8,500 RPMs. the gt42r is a good turbo but if your looking for something that is smaller(in actual size) and lighter (more expensive) then hks t51r is a great wee number on this engine I really like the GT42R but curiously, I run the T51R from ASE turbos (www.aseturbo.com). It's rated to 1,000 HP so it should work for me:) |
I am looking for 20b any1 have 1 for sale
thanx |
Is the red 20b a semi p port?????????????????????????????????????????????? ???????????????????????????????????????? https://www.nopistons.com/forums/pub...IR#>/smile.gif
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Originally Posted by tony94s4' post='896231' date='Mar 10 2008, 02:32 AM
I am looking for 20b any1 have 1 for sale
thanx |
Originally Posted by To_slow' post='896257' date='Mar 10 2008, 09:39 AM
I have one. For sale. Pm me.
Hi sent u pm but just realised I bought the a arm bushings, and the t56 adapter kit from you, can't wait to get them https://www.nopistons.com/forums/pub...DIR#>/wink.gif I realy like ur engine but not sure yet if I will be able to fit it in my budgett, but will let u know soon, do you have the intake manifold, alternator, ps pump, ac compressor brackets by any chance? thanx again |
To_slow,
U r great, Just recived ur T56 adapter kit, looks like a work of art, I am very happy, I am thinking of building a similar kit for my lotus with 20b to un1 renault box, is there any way you can pm me the part #s for the items used I will need the same twin disk, I hope they have it in un1 spline and also for future rebuild wont hurt to have spare clutch and bearing layin around thanx again tony |
Originally Posted by tony94s4' post='896499' date='Mar 13 2008, 09:59 PM
To_slow,
U r great, Just recived ur T56 adapter kit, looks like a work of art, I am very happy, I am thinking of building a similar kit for my lotus with 20b to un1 renault box, is there any way you can pm me the part #s for the items used I will need the same twin disk, I hope they have it in un1 spline and also for future rebuild wont hurt to have spare clutch and bearing layin around thanx again tony Glad you like the t56 kit. I will have to look fo the part nr.. for you. You are welcome. |
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