My SC Wagon project I've been hiding
10-25-06, 12:03 PM
#1
My SC Wagon project I've been hiding
I haven't said much to you guys about this project, which I have been working off and on for about 14 months now. It's about time I share this with you guys.
'78 RX-4 Wagon
streetported 19 bolt R5 side plates
ported GSL-SE rotor housings
hardened stationary gears
hardened oil pump
.150" shims in pressure reg (over 100psi when cold)
GSL-SE rotating assembly
all new seals and springs
GSL-SE flywheel
SS pressure plate and HD disc
'81-'83 trans (with the big gears; ask peejay)
modified RX-4 shifter to FB trans (shorter throws)
Probably a lot more mods I forgot. A bit over 500 miles on rebuilt engine
recently added a 5" Camden SC
Edelbrock 750 carb (might be too big)
tach, air/fuel mixture, boost/vacuum, volts, oil pressure and water temp guages
Carter 72gph fuel pump
Holley pressure reg
Some older pictures to get you started. This is what it looked like last July.
'78 RX-4 Wagon
streetported 19 bolt R5 side plates
ported GSL-SE rotor housings
hardened stationary gears
hardened oil pump
.150" shims in pressure reg (over 100psi when cold)
GSL-SE rotating assembly
all new seals and springs
GSL-SE flywheel
SS pressure plate and HD disc
'81-'83 trans (with the big gears; ask peejay)
modified RX-4 shifter to FB trans (shorter throws)
Probably a lot more mods I forgot. A bit over 500 miles on rebuilt engine
recently added a 5" Camden SC
Edelbrock 750 carb (might be too big)
tach, air/fuel mixture, boost/vacuum, volts, oil pressure and water temp guages
Carter 72gph fuel pump
Holley pressure reg
Some older pictures to get you started. This is what it looked like last July.
10-25-06, 12:18 PM
#3
More recent pictures from a BBQ (I didn't shoot these).
http://i60.photobucket.com/albums/h1...6/DSCN9948.jpg
http://i60.photobucket.com/albums/h1...6/DSCN9947.jpg
http://i60.photobucket.com/albums/h1...6/DSCN9946.jpg
http://i60.photobucket.com/albums/h1...6/DSCN9945.jpg
http://i78.photobucket.com/albums/j9...6/SSA50815.jpg
Banzai, they're coming up next.
http://i60.photobucket.com/albums/h1...6/DSCN9948.jpg
http://i60.photobucket.com/albums/h1...6/DSCN9947.jpg
http://i60.photobucket.com/albums/h1...6/DSCN9946.jpg
http://i60.photobucket.com/albums/h1...6/DSCN9945.jpg
http://i78.photobucket.com/albums/j9...6/SSA50815.jpg
Banzai, they're coming up next.
Last edited by Jeff20B; 10-25-06 at 12:38 PM.
10-26-06, 12:35 AM
#6
The General RE
Nice Sleeper!!!
I had an edelbrock/carter on my car for a while. Those things don't like to be mounted sideways. Dies on left turns. Since you have a supercharger you should take advantage and put it on straight. You know since it doesn't have to be mounted sidways to feed the correct ports anymore.
Also, a word of caution...Watch for broken metering rods and ovaling jets. Rod jet issue is less severe the smoother the engine runs. The rods tend to rattle around in the jets and mess things up.
I had an edelbrock/carter on my car for a while. Those things don't like to be mounted sideways. Dies on left turns. Since you have a supercharger you should take advantage and put it on straight. You know since it doesn't have to be mounted sidways to feed the correct ports anymore.
Also, a word of caution...Watch for broken metering rods and ovaling jets. Rod jet issue is less severe the smoother the engine runs. The rods tend to rattle around in the jets and mess things up.
10-26-06, 01:29 AM
#7
Rx-hippie
iTrader: (1)
Join Date: Sep 2003
Location: Torrance CA
Posts: 2,076
Likes: 0
Received 0 Likes
on
0 Posts
Very nice work Jeff20B..
Alittle off topic.. but I remember you building a car with a 20b and Megasquirt.... was this for the wagon? Or something different? If so what?
hehe, keep up the good work.. you should make the road trip to seven stock 9. :-)
Alittle off topic.. but I remember you building a car with a 20b and Megasquirt.... was this for the wagon? Or something different? If so what?
hehe, keep up the good work.. you should make the road trip to seven stock 9. :-)
Trending Topics
10-26-06, 10:54 AM
#9
Stock alt. The pulley kit comes with the supercharger.
13BT_RX3, thanks for the info. The 750 is way too big, and it sometimes dies on right or left turns. Idle is rather smooth though; surprising for how big the carb is. It'll be going up for sale soon so if you know anyone who needs a 750 manual choke model...
Should we go with a Holley? My friend has both Edelbrock and Holley in 600CFM and each one performs ok. The Edelbrock on a 5" and the Holley on a 7". The Edelbrock setup is quick in a 1st gen with FC rotors and an aluminum flywheel. The Holley is slow in a '77 REPU with an S5 T2 engine and light steel flywheel. There are several factors comparing appels to oranges, but if what you say is true and plauges all Edelbrocks, I think we should try a Holley.
trainwreck517, something different. I think I'll put it into a 1st gen or something.
13BT_RX3, thanks for the info. The 750 is way too big, and it sometimes dies on right or left turns. Idle is rather smooth though; surprising for how big the carb is. It'll be going up for sale soon so if you know anyone who needs a 750 manual choke model...
Should we go with a Holley? My friend has both Edelbrock and Holley in 600CFM and each one performs ok. The Edelbrock on a 5" and the Holley on a 7". The Edelbrock setup is quick in a 1st gen with FC rotors and an aluminum flywheel. The Holley is slow in a '77 REPU with an S5 T2 engine and light steel flywheel. There are several factors comparing appels to oranges, but if what you say is true and plauges all Edelbrocks, I think we should try a Holley.
trainwreck517, something different. I think I'll put it into a 1st gen or something.
10-26-06, 11:07 AM
#10
The General RE
I liked my holley 650 double pumper pretty well. It can take a turn. The only real bad thing about them is the full float load of fuel dumped every time you change jets. You get used to smelling of gas though. Also power enrichment is fixed. You can drill the hole bigger or put some wire in it, but no jet.
10-26-06, 11:46 PM
#12
I wired up the air/fuel guage today. We added a bung to the header and installed a stock FC oxygen sensor. I know it's not accurate like a wideband, but it is usefull. During transition from idle circuit to primaries, it bogs sometimes, and the guage reads lean. It's some great useable feedback. 
During non-boosted acceleration (near 0 on the boost guage, heh), it shows mostly stoich with some lean tendencies. I'd prefer it to have rich tendencies like my friend's Holley 600 on his 7". I haven't boosted it much yet, and not at all since wiring the guage. so I
m not sure where it's at during boost .
Yesterday the carb exhibited symptoms of being too large during an uphill run. I'd floor it and as I lifted the pedal, the power would increase. I ran into similar problems with stock carbs (Nikki/Hitachi) set to open the secondaries either mechanically, or if by vacuum, to kick open sooner than stock. Basically on those carbs, if the RPM was too low for the secondaries, it was like driving a Dellorto/Weber or other big 2 barrel carb and flooring it too soon. In other words, an educated foot is a necessity with those types of carbs, and it is less so with a 4 barrel.
So then how does this pertain to an unmodified 750 CFM 4 barrel whose secondaries shouldn't open until the appropriate load/RPM range is reached? Well it shouldn't bog like that at such a high RPM. we're talking like 4k at least. I didn't take it past 5k, and yet it behaved like it didn't want the secondaries open even up there. Interesting, no? I won't take it any higher as the engine was rebuilt recently and barely has 600 miles on it.
It's my semi-educated guess that a smaller carb will perform better here. I think my recent experiences will bear this out. Let me know what you think.
Now the next question is Holley or Edlebrock? The bracket, fuel line, throttle cable, return spring, heck even the PCV valve are all set up for an Edelbrock. By the way the lung mustard capuccino mix up under the oil filler cap all up and disappeared after I added a simple Fram PCV valve from my local auto parts store. Totally worth it (although it might be installed backwards. I compared its direction of flow vs blockage and it was opposite of a stock Mazda PCV valve. I hooked it inline in a direction that looks backwards, but it mimics the function of the stocker. In other words, the nipple points at the carb and the threaded end is toward the oil filler tube. Seems backwards. There were no instructions or flow direction arrows anywhere to be seen. Maybe it's causing the lean part-throttle condition? I can't remember if it got worse after installing the PCV valve. I guess I could try reversing it).
During non-boosted acceleration (near 0 on the boost guage, heh), it shows mostly stoich with some lean tendencies. I'd prefer it to have rich tendencies like my friend's Holley 600 on his 7". I haven't boosted it much yet, and not at all since wiring the guage. so I
m not sure where it's at during boost .
Yesterday the carb exhibited symptoms of being too large during an uphill run. I'd floor it and as I lifted the pedal, the power would increase. I ran into similar problems with stock carbs (Nikki/Hitachi) set to open the secondaries either mechanically, or if by vacuum, to kick open sooner than stock. Basically on those carbs, if the RPM was too low for the secondaries, it was like driving a Dellorto/Weber or other big 2 barrel carb and flooring it too soon. In other words, an educated foot is a necessity with those types of carbs, and it is less so with a 4 barrel.
So then how does this pertain to an unmodified 750 CFM 4 barrel whose secondaries shouldn't open until the appropriate load/RPM range is reached? Well it shouldn't bog like that at such a high RPM. we're talking like 4k at least. I didn't take it past 5k, and yet it behaved like it didn't want the secondaries open even up there. Interesting, no? I won't take it any higher as the engine was rebuilt recently and barely has 600 miles on it.
It's my semi-educated guess that a smaller carb will perform better here. I think my recent experiences will bear this out. Let me know what you think.
Now the next question is Holley or Edlebrock? The bracket, fuel line, throttle cable, return spring, heck even the PCV valve are all set up for an Edelbrock. By the way the lung mustard capuccino mix up under the oil filler cap all up and disappeared after I added a simple Fram PCV valve from my local auto parts store. Totally worth it (although it might be installed backwards. I compared its direction of flow vs blockage and it was opposite of a stock Mazda PCV valve. I hooked it inline in a direction that looks backwards, but it mimics the function of the stocker. In other words, the nipple points at the carb and the threaded end is toward the oil filler tube. Seems backwards. There were no instructions or flow direction arrows anywhere to be seen. Maybe it's causing the lean part-throttle condition? I can't remember if it got worse after installing the PCV valve. I guess I could try reversing it).
10-27-06, 08:19 AM
#13
The General RE
Power valve opens a port for extra fuel at a specific vacuum level. Carters raise the metering rods in the jets to a narrower section based on which spring you installed under its actuator.
Tuning with narrowband will let you know which way to correct when the car stumbles. Useful, but not as useful as a wideband. It would be a lot easyer if you got a wideband.
Play with cruise/power and accelerator pump first. You may need to change the linkage setting or even play with different size accelerator pump nozzles. Change nozzles after jetting though.
I didn't like buying lots of jets and rods. I picked up a few jets that were smaller than I needed and used a numbered drill set to change the oriface size. If you over drill you can solder the hole up and redrill. Buy the correct jets + or - 1 size when you are done.
To set cruise. Put no spring or the lightest spring in under the metering rod acruator. This will force or semi force a cruise setting. Adjust leaner and leaner til it runs wrong then richen up til it's good again.
As for setting primary power without changing metering rods yet. Put in the stiffest springs first. This will force the power setting on. Don't activate secondaries yet. Set it richer and richer until it feels like it is drowning and back off til it feels good.If you are not sure put the softest ones in and fix cruise later. You can increase jet sizes and let the cruise run rich until you get a combination that works.
Play for a while... Then pull out your calculator and get the effective areas of the cruise jet rod set that worked and the power jet rod set that worked. Pi/4*(Djet²-Drod²) Small tip of rod is power and the next step larger is cruise. Then select a combo of jet and rod that will give you the sizes that worked.
Now you set the springs that actuate the metering rod. A vacuum gauge can help. get a good transition going.
Now you can do WOT testing the fun part. You may want to retard your timing for this.
As for the big carb problem... Driving style may fix for now. You may have to wait until you get closer to the powerband before you nail it. I drilled the weights in the donkey door with (3 or 4) 1/4" holes each side evenly spaced. The number of hole will be up to you. I had a spare door that I drilled and tapped a bunch of holes in. This allowed me to tune the weight of the door with set screws and set opening characteristics. Just don't tap all the way through. You will need some meat to hold the setscrews from falling into your engine.
PCV should be set so you can't blow into the oil fill tube, but can blow the other way.
If you keep what you have or get a smaller edelbrock you will really want to rotate it 90° so the primaries point forward. This will allow it to work as well as it did on any V8 car. This along with careful float adjustment should make it so you can turn and stop without the car dying. Fuel slosh under acceleration may richen up the secondaries and effect the donkey door. Holleys don't have a problem with being sideways, but may also work better with primaries forward.
Tuning with narrowband will let you know which way to correct when the car stumbles. Useful, but not as useful as a wideband. It would be a lot easyer if you got a wideband.
Play with cruise/power and accelerator pump first. You may need to change the linkage setting or even play with different size accelerator pump nozzles. Change nozzles after jetting though.
I didn't like buying lots of jets and rods. I picked up a few jets that were smaller than I needed and used a numbered drill set to change the oriface size. If you over drill you can solder the hole up and redrill. Buy the correct jets + or - 1 size when you are done.
To set cruise. Put no spring or the lightest spring in under the metering rod acruator. This will force or semi force a cruise setting. Adjust leaner and leaner til it runs wrong then richen up til it's good again.
As for setting primary power without changing metering rods yet. Put in the stiffest springs first. This will force the power setting on. Don't activate secondaries yet. Set it richer and richer until it feels like it is drowning and back off til it feels good.If you are not sure put the softest ones in and fix cruise later. You can increase jet sizes and let the cruise run rich until you get a combination that works.
Play for a while... Then pull out your calculator and get the effective areas of the cruise jet rod set that worked and the power jet rod set that worked. Pi/4*(Djet²-Drod²) Small tip of rod is power and the next step larger is cruise. Then select a combo of jet and rod that will give you the sizes that worked.
Now you set the springs that actuate the metering rod. A vacuum gauge can help. get a good transition going.
Now you can do WOT testing the fun part. You may want to retard your timing for this.
As for the big carb problem... Driving style may fix for now. You may have to wait until you get closer to the powerband before you nail it. I drilled the weights in the donkey door with (3 or 4) 1/4" holes each side evenly spaced. The number of hole will be up to you. I had a spare door that I drilled and tapped a bunch of holes in. This allowed me to tune the weight of the door with set screws and set opening characteristics. Just don't tap all the way through. You will need some meat to hold the setscrews from falling into your engine.
PCV should be set so you can't blow into the oil fill tube, but can blow the other way.
If you keep what you have or get a smaller edelbrock you will really want to rotate it 90° so the primaries point forward. This will allow it to work as well as it did on any V8 car. This along with careful float adjustment should make it so you can turn and stop without the car dying. Fuel slosh under acceleration may richen up the secondaries and effect the donkey door. Holleys don't have a problem with being sideways, but may also work better with primaries forward.
10-28-06, 12:14 PM
#14
Wow, thankyou for the great information. My bro got a 600CFM yesterday and it came with a booklet. Inside it shows what you're talking about. Your info will come in handy when we start tuning it. So far, it is more driveable and bogs way less than the 750. Light throttle cruise at around 10 (inches of mercury?) vacuum is the only place where it goes lean. Idle is ok, as is running at 0. The few times he actually boosted it, it seems to go into stoich and stay there.
The first time I read through your post above, it went completely over my head. However now I'm starting to see how the adjustment techniques you mentioned could take care of the remaining bogs and keep it closer to stoich. Very cool. Thanks.
By the way, it's still mounted 90° off but only gave him stalling trouble once or twice. In turns where I thought for sure it would die, it didn't because he was able to keep it running no problem. All the throttle brackets, cable, PCV valve, power brake vacuum and fuel lines etc lined up perfectly. We'll keep it 90° off for now. I think he prefers the sideways look anyway, lol. Thanks for the heads up though.
I seem to recall one time when I was over at Atkins, Dave said the reason why they rotated the carb 90° was so both primaries would get equal amounts of fuel. The problem with mounting it like a V8 was that the front rotor would tend to get more fuel while on primaries only. Made sense to me.
The first time I read through your post above, it went completely over my head. However now I'm starting to see how the adjustment techniques you mentioned could take care of the remaining bogs and keep it closer to stoich. Very cool. Thanks.
By the way, it's still mounted 90° off but only gave him stalling trouble once or twice. In turns where I thought for sure it would die, it didn't because he was able to keep it running no problem. All the throttle brackets, cable, PCV valve, power brake vacuum and fuel lines etc lined up perfectly. We'll keep it 90° off for now. I think he prefers the sideways look anyway, lol. Thanks for the heads up though.
I seem to recall one time when I was over at Atkins, Dave said the reason why they rotated the carb 90° was so both primaries would get equal amounts of fuel. The problem with mounting it like a V8 was that the front rotor would tend to get more fuel while on primaries only. Made sense to me.
10-28-06, 01:08 PM
#15
The General RE
Thanks, I was afraid I may how overstepped my bounds a bit. If it only went lean under vacuum you may want to try a heaver springset. As for the 90° thing... Front rotor problem sounds more important than turning issues. I have a SC kit photo from Camdon back in '95 and it had the carter on straight. Theory vs. practice. Anyway...with carful float adjustment and installing some baffles to compartmentalize the fuel around the jets it can get under control. I believe higher float adjustment worked better. Well, I suppose the wagon isn't going to be your first choise for taking to track events. The Carters run well for the most part and should stay in tune for a while so long as your engine isn't ported.
10-28-06, 01:20 PM
#16
It's streetported. 
The baffles sounds like a very good idea. The RX-4 certainly doesn't corner like it's on rails, but the only time it had bogs during cornering was at parking lot speeds. Well, maybe a little faster, but freeway cornering felt like the rear end was going to let lose before the carb would even get close to bogging. In other words, no problem.
He took it to work today. The choke isn't set yet and it stalled a few times while cold, but it only took about a minute and then it smoothed out. We'll play with the choke and find a good setting over the next few days.
I'll let him know that the lean condition under vacuum can certainly be tuned out. Where would I find the parts to tune it?
The baffles sounds like a very good idea. The RX-4 certainly doesn't corner like it's on rails, but the only time it had bogs during cornering was at parking lot speeds. Well, maybe a little faster, but freeway cornering felt like the rear end was going to let lose before the carb would even get close to bogging. In other words, no problem.
He took it to work today. The choke isn't set yet and it stalled a few times while cold, but it only took about a minute and then it smoothed out. We'll play with the choke and find a good setting over the next few days.
I'll let him know that the lean condition under vacuum can certainly be tuned out. Where would I find the parts to tune it?
10-28-06, 01:34 PM
#17
Is your edelbrock a thurnder series?? The edelbrock gave the smoothest performance of all the carbs I have (4 in total ranging from 600 to 850) on my s/c. I've had a lot of tuning experience with the edelbrock and you can get rid of the off cruise transuition issue easily. Which pulley are you using?? Does your car fall flat at about 6500??
10-28-06, 09:34 PM
#20
First of all, tuning the carb. I had my metering rods custom tapered by a jeweler, great results! I think it's gonna fall flat because of the air filter you are running, it just wont et enough air. Stuff your foot in it and hold it up there, see if you drop off over 6500 rpm. I assume by "7 lb" you mean you are running the #7 pulley. If so, that is the ideal choice, I have run smaller looking for more boost but you build more heat as well. My snow performance water methanol kit was a great addition. Check this link to learn more about supercharging, it's on the weiand (holley) blower which is the same as the camden. http://www.holley.com/data/TechService/Technical/Supercharger%20Tech%20Info.pdf#search='weiandblowe r'
10-29-06, 04:28 PM
#23
Boost guage yes, I hold steady at 10lbs boost with the #7 pulley and starts dropping off a little after 7000rpm. The #8 pulley can hit 12 lbs but I need the holley 850 to sustain boost in higher rpm. The #8 pulley heats the charger up more though. The number 10 pulley can hit 15lbs boost by 3000rpm but quickly falls off due to heat and belt slippage (damn small pulley). The #7 is by far the best pulley! I suggest every camden user add premix to help lubricate the seals in the charger. Watch fuel and timing, detonation and lean out is quick with the charger. Proper vaccuum advance plumbing is very important.
10-29-06, 05:25 PM
#24
Eats, Sleeps, Dreams Rotary
Join Date: Jul 2004
Location: Allentown, PA - Paterson, NJ
Posts: 3,247
Likes: 0
Received 2 Likes
on
2 Posts
Has anyone tried a Demon carb yet? I'm wondering if they are easier to tune as everyone says they are. Lots of good info I never read before in this thread!
10-29-06, 07:23 PM
#25
I have a 650 demon. I have issues with sticky primary throttle plates and no support from the supplier. Other than that issue (which I will resolve) it is a very nice carb. Little difference from a Holley however Holley has much much better quality control. Some speed shops have quit dealing in Deomons here. In total I have 4 carbs, a holley 600 vac sec, 850 double pukper, edelbrock thunder series 650 and a demon supercharger series 650. I had big hopes followed by disappointment with the demon. The edelbrock by far runs the smoothest and the holley sustains more upper rpm boost because of it's size, but low rpm driveability is compromised. My next carb to find is gonna be an old carter 850 spreadbore or holley 850 spreadbore.