My VW baja - potential rotary project
12-10-07, 11:41 PM
#51
Thanks Karis.
I decided to put the KEP adaptor up for sale since I'd rather use the 13B posted above. It's already built and ready to go - the 12A isn't. $100 Check out my ad in the for sale section. https://www.rx7club.com/forum/showthread.php?t=711951
I decided to put the KEP adaptor up for sale since I'd rather use the 13B posted above. It's already built and ready to go - the 12A isn't. $100 Check out my ad in the for sale section. https://www.rx7club.com/forum/showthread.php?t=711951
12-11-07, 06:29 AM
#52
Adolf Hitler Verfechter
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Anytime Jeff!
Using the 13B engine sounds like a good idea to me too.Will have boatloads of torque.
Speaking of Torque,have you ever considered running a Gen 4 13B Turbo engine without the turbo in the Baja?
My Capella had loads of low down torque back in the day.Ports were standard,with short duration.Even used a Nikki.(allthough modded)
Karis
Using the 13B engine sounds like a good idea to me too.Will have boatloads of torque.
Speaking of Torque,have you ever considered running a Gen 4 13B Turbo engine without the turbo in the Baja?
My Capella had loads of low down torque back in the day.Ports were standard,with short duration.Even used a Nikki.(allthough modded)
Karis
12-11-07, 12:41 PM
#54
Karis, that 13B I built and posted earlier in this thread that has a matching paint scheme to the baja 
is the one with stock port timing but smoothed flow. I removed all the casting flash and rounded/smoothed all the harsh 90° edges. The exhaust ports perfectly matched a GSL-SE where they open late and close late (whether that's good or bad for this particular engine remains to be seen). I'm also seriously considering running a Nikki as well. Modded of course. Another item I'm running is a Cosmo reversed runner manifold for better primaries at only a small cost to the secondaries. Since 90% of most driving is done on primaries, it's ok. If I don't like it I've got a normal runner manifiold to try. I'll also hook up DLIDFIS because I've found it to improve starting and low end power - both important in a VW conversion.
is the one with stock port timing but smoothed flow. I removed all the casting flash and rounded/smoothed all the harsh 90° edges. The exhaust ports perfectly matched a GSL-SE where they open late and close late (whether that's good or bad for this particular engine remains to be seen). I'm also seriously considering running a Nikki as well. Modded of course. Another item I'm running is a Cosmo reversed runner manifold for better primaries at only a small cost to the secondaries. Since 90% of most driving is done on primaries, it's ok. If I don't like it I've got a normal runner manifiold to try. I'll also hook up DLIDFIS because I've found it to improve starting and low end power - both important in a VW conversion.
12-11-07, 12:46 PM
#55
Now that I think about it, it may have been a better choice to at least port this engine out to '74 spec, considering the low gearing of a typical 3 rib of 5.3 or so. I'd prefer the taller gearing of a 5 rib but there weren't any available. Well there was one that came out of my friend's baja, but it has a welded spider gear so that would need to be changed. I'll just try the 3 rib and see how it goes.
12-12-07, 02:01 AM
#56
Adolf Hitler Verfechter
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I just went back,and reread everything you wrote.
I think your porting combination will be excellent!The reverse runner Cosmo manifold will be LOADS better than the Rx7.(I believe on of the biggest problems on a stock Nikki manifold,is the primary runners)When i made a custom naifold for my Capellla way back,it performed 200% better than the stock one.I turned the carb around,so the primary runners could be longer,but retained the stock size of the runner.
Iam going to go check the port timing of the factory Gen 4 13B Turbo engines.Might be some clues to torque monster engines.
Karis
I think your porting combination will be excellent!The reverse runner Cosmo manifold will be LOADS better than the Rx7.(I believe on of the biggest problems on a stock Nikki manifold,is the primary runners)When i made a custom naifold for my Capellla way back,it performed 200% better than the stock one.I turned the carb around,so the primary runners could be longer,but retained the stock size of the runner.
Iam going to go check the port timing of the factory Gen 4 13B Turbo engines.Might be some clues to torque monster engines.
Karis
12-12-07, 12:42 PM
#57
Yeah, the earlier the intake ports close, the better the bottom end torque. It's really as simple as that.
I have a feeling with a Nikki carb and a restudded Cosmo manifold, this 13B will be a torque monster with decent high end. If I was to use my nice Hitachi, it would just be a torque monster.
I have a feeling with a Nikki carb and a restudded Cosmo manifold, this 13B will be a torque monster with decent high end. If I was to use my nice Hitachi, it would just be a torque monster.
12-18-07, 03:00 PM
#63
Jeff the thing I like about you is that you don't just build every engine with the largest ports you can get. That's a huge mistake that people make too often. You have a need and understand that larger doesn't always fit the bill. By now you probably have a very nice understanding of what combos make good power and where they do it which is great knowledge to have. Keep up the good work!
Last edited by rotarygod; 12-18-07 at 03:14 PM.
12-18-07, 03:31 PM
#64
Thanks for the kind words. Yeah I learned that bigger is not better and have concentrated more on '74 spec ports and now I'm going to try stock 12A '76-'85 ports on the 13B I built for this baja. Well, stock timing, but reduced restrictions.
That 12A I built for PercentSevenC's white '83 GSL last year (that you commented positively on the exhaust ports) has as much get up and go as my friend's supercharged 4 port 13B in his '83 GSL, or at least that's what it feels like when you drive it. So I built a 4 port 13B for my rotarded MG Midget project with '74 spec ports (I ported a set of 12A Y castings). As for the baja, I wanted to maximize my low end so I kept the port timing stock but worked elsewhere in the engine to improve things such as tight side seals (.001"), later opening exhaust ports, longer runner stock manifold (from a CD Cosmo) and now I'm comtemplating running an '81-'85 Nikki with a '79-'80 carb spacer because I know the Nikkis work well at low RPM but also better than Hitachis at high RPM. Therefore my baja engine will run great up to possibly 7k instead of my previous estimate of runnng out of breath by 5.5-6k if I use the Hitachi.
To simplify things, I might start out with the Hitachi just because it's available and the engine needs probably about 1000 miles to break in. During that time I'll observe the pressure plate's ability to hold the power - it never slipped with the 1600 but because I'm doubling the power, we'll see. I'd rather not get a Kennedy stage 1 if I don't need it. I like how the stock Sachs presure plate drove. Call me old fashioned. I don't need a street strip RB pressure plate in my MG either. Heh.
That 12A I built for PercentSevenC's white '83 GSL last year (that you commented positively on the exhaust ports) has as much get up and go as my friend's supercharged 4 port 13B in his '83 GSL, or at least that's what it feels like when you drive it.
So I built a 4 port 13B for my rotarded MG Midget project with '74 spec ports (I ported a set of 12A Y castings). As for the baja, I wanted to maximize my low end so I kept the port timing stock but worked elsewhere in the engine to improve things such as tight side seals (.001"), later opening exhaust ports, longer runner stock manifold (from a CD Cosmo) and now I'm comtemplating running an '81-'85 Nikki with a '79-'80 carb spacer because I know the Nikkis work well at low RPM but also better than Hitachis at high RPM. Therefore my baja engine will run great up to possibly 7k instead of my previous estimate of runnng out of breath by 5.5-6k if I use the Hitachi.To simplify things, I might start out with the Hitachi just because it's available and the engine needs probably about 1000 miles to break in. During that time I'll observe the pressure plate's ability to hold the power - it never slipped with the 1600 but because I'm doubling the power, we'll see. I'd rather not get a Kennedy stage 1 if I don't need it. I like how the stock Sachs presure plate drove. Call me old fashioned. I don't need a street strip RB pressure plate in my MG either. Heh.
11-22-08, 01:00 AM
#71
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Wow, that's going to sound wicked. I'm glad your getting there.
I've been too busy with my aircooled bug lately, (not running either
) but the end is in sight. I'm ashamed to say that sometimes I am tempted to give up on the rotary. I had better just make things easy and get a sidedraft/dizzy. That would eliminate the fuel plumbing, air intake plumbing (fitting the AFM is going to suck) and a bunch of wiring. I think that would be worth the $$$. Also, I think I'll take your advice and just run the stock water pump. I wanted the cleaner bay, better weight distribution and to avoid cutting the apron, but if I keep that attitude it will never be finished! Hmm, I feel better already; time to place some ads for the stuff I won't be using...
I'm glad your getting there.I've been too busy with my aircooled bug lately, (not running either
) but the end is in sight. I'm ashamed to say that sometimes I am tempted to give up on the rotary. I had better just make things easy and get a sidedraft/dizzy. That would eliminate the fuel plumbing, air intake plumbing (fitting the AFM is going to suck) and a bunch of wiring. I think that would be worth the $$$. Also, I think I'll take your advice and just run the stock water pump. I wanted the cleaner bay, better weight distribution and to avoid cutting the apron, but if I keep that attitude it will never be finished! Hmm, I feel better already; time to place some ads for the stuff I won't be using...
11-23-08, 09:02 PM
#72
As a temporary solution to get my baja running next week or so, I'm swapping in the same engine as yours. It's an FC 6 port. Turns out the new engine I built for it is too tight for the high torque VW starter and needs to break in before it can be used. That's fine bcause I have another project that needs an engine right now. When it's done it will go back in the baja.
As for the FC engine, I have a modded 12A manifold that fits a 6 port 13B. This will get me up and running in no time. Also a dizzy of course, and a waterpump.
Do you think you might be interested in the manifold and dizzy when I'm done with them? It should only take a few months while the baja's engine is breaking in.
I actually have two modded 6 port manifolds. I'm going to try them both and see which I like better (one was a regular '79 12A and other was a rare 6 port 12A and was rigged to flow high CFM - perhaps better suited to a street bug? hint hint). I'll have to keep one for a friend who's doing an FC engine in a rotary truck and needs a way to get it running carbed before upgrading the entire fuel system to EFI. His setup will also be temporary so either manifold could be used. I'll refer to them as the high RPM manifold and the low RPM manifold, or something like that.
As for the FC engine, I have a modded 12A manifold that fits a 6 port 13B. This will get me up and running in no time. Also a dizzy of course, and a waterpump.
Do you think you might be interested in the manifold and dizzy when I'm done with them? It should only take a few months while the baja's engine is breaking in.
I actually have two modded 6 port manifolds. I'm going to try them both and see which I like better (one was a regular '79 12A and other was a rare 6 port 12A and was rigged to flow high CFM - perhaps better suited to a street bug? hint hint). I'll have to keep one for a friend who's doing an FC engine in a rotary truck and needs a way to get it running carbed before upgrading the entire fuel system to EFI. His setup will also be temporary so either manifold could be used. I'll refer to them as the high RPM manifold and the low RPM manifold, or something like that.
11-23-08, 09:25 PM
#73
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You only have to slightly notch the rear apron. It is more to install the engine than for clearance once installed.
You also might have to put stand offs on your deck lid. Mine hits the alternator fan if not installed.
I can post picks if you want, but I didn't want to hijack 20b's thread.
You also might have to put stand offs on your deck lid. Mine hits the alternator fan if not installed.
I can post picks if you want, but I didn't want to hijack 20b's thread.
11-23-08, 09:49 PM
#74
If you use an alt from '84-'85 it has a small body and internal fan. It should fit better. That's what I used on mine even though I don't have to worry about clearance. Also try a 1st gen waterpump because the pulley is shorter. I used one to have as much clearance between the radiator and engine as possible. It's tight there.
11-23-08, 10:10 PM
#75
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I'm running a 74 4 port 13b so I'm pretty sure I have a short water pump.
Also I'm running a ford alternator for more amps to run the torus electric fan. So stand offs it is not really a problem though.
Also I'm running a ford alternator for more amps to run the torus electric fan. So stand offs it is not really a problem though.