Update on Project Gus
03-09-11, 11:53 AM
#27
Hey, a couple of those look very familier.
On a couple Camden installs with an Edelbrock carb, I use the FV333 because it has a 3/8" nipple on one end and an NPT 27 pipe thread on the engine end. This is because the carb's PCV nipple is 3/8". Ironically, the 3/8" pointed toward the oil fill tube, lol. Kinda made it awkward to go from 3/8" down to 5/16" (the size of the nipple on the oil fill tube). I'm thinking next time I'll just go with a different PCV valve.
FV333
On some old school '70s manifolds with busted stock PCV valves (the plastic end gets brittle with age), I've used the FV266 and shove its hex body inside a piece of 5/8" heater hose and hold it all with a couple of decent sized zip ties or a hose clamps (the PCV valve nipple happens to be 5/8", just kinda short so use a narrow hose clamp or fairly beefy zip tie, not the tiny ones). Of course I check air flow direction first before shoving it into the hose. Then whichever end sticks out pointing toward the oil fill tube, I route a 5/16" hose from it to the oil fill tube nipple. The nipple end is 5/16" and the threaded end is BSP 28 which is a little msaller than NPT 27, so I beleive a 5/16" hose will fit on it, but you might need to "thread" it on, like a righty-tighty because you can't just push it on as the threads grip too much.
FV266
On a couple Camden installs with an Edelbrock carb, I use the FV333 because it has a 3/8" nipple on one end and an NPT 27 pipe thread on the engine end. This is because the carb's PCV nipple is 3/8". Ironically, the 3/8" pointed toward the oil fill tube, lol. Kinda made it awkward to go from 3/8" down to 5/16" (the size of the nipple on the oil fill tube). I'm thinking next time I'll just go with a different PCV valve.
FV333
On some old school '70s manifolds with busted stock PCV valves (the plastic end gets brittle with age), I've used the FV266 and shove its hex body inside a piece of 5/8" heater hose and hold it all with a couple of decent sized zip ties or a hose clamps (the PCV valve nipple happens to be 5/8", just kinda short so use a narrow hose clamp or fairly beefy zip tie, not the tiny ones). Of course I check air flow direction first before shoving it into the hose. Then whichever end sticks out pointing toward the oil fill tube, I route a 5/16" hose from it to the oil fill tube nipple. The nipple end is 5/16" and the threaded end is BSP 28 which is a little msaller than NPT 27, so I beleive a 5/16" hose will fit on it, but you might need to "thread" it on, like a righty-tighty because you can't just push it on as the threads grip too much.
FV266
03-09-11, 02:43 PM
#28
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Hmm, depending on the dizzy, it should mechanically advance either 20 degrees or 25 degrees. I believe the 12A units go 20 and the GSL-SE goes 25 (Ask j9fd3s as he ought to know). What yaw is recommending in reality is an idle at 5° advanced. Is that a good idea? Not exactly sure.
the curves are in the FSM.
and in a performance situation, its best practice to actually check the real advance on the real car as its running. there is enough slop in the pulley to be about 1-2 degrees by itself, and then i'm sure the distributors vary a little after 25 years.
the goal in playing with timing is not to turn the distributor to someones spec, its to make more power. you also have to understand paul yaw is talking about a stock port engine that is NEW rotor housing, rotors, fresh irons, cold air intake, his header, maybe cold plugs too.
for example the P port pings @18btdc, lightly, it would not like 24
03-09-11, 06:49 PM
#29
Lives on the Forum
Coming along nicely man!
You are going to have to come up sometime this summer. 80sOldSchool will be coming up for a 2 day autocross on the 4th of July weekend. That would be a good time, if not sooner. We have to let the twins meet each other.
.
You are going to have to come up sometime this summer. 80sOldSchool will be coming up for a 2 day autocross on the 4th of July weekend. That would be a good time, if not sooner. We have to let the twins meet each other.
.
03-10-11, 09:37 PM
#32
Lives on the Forum
That would be awesome! I've got a huge privat yard that is like a private park, great for camping and we have some great bonfire parties before and after races.
03-20-11, 08:30 PM
#34
Spent the last 3 hours working on the Rx-3 manifold. I've been increasing the channel sizes at the top of the manifold, where the carburetor mounts. I've been attempting to copy the shape that Rx7carl arrived at several years ago. I posted a picture of the manifold he did on Page 1 if you want to see it. I got one side of the manifold finished tonight. Spent about 3 hours on it. Grinding, cutting, smoothing. It was tedious, and nerve wracking but it's going great so far.
I made the channel wider, and rounded off the hard edges that lead into the runners. Check out the pictures. This is the only reshaping that will be required on the manifold. I'm not sure if I smoothed out the manifold too much. Don't want fuel sticking to the walls of the manifold. I think it will be okay though since it's just the inlet to the runners, not in the actual runners themselves. Thoughts others?
Jamie
I made the channel wider, and rounded off the hard edges that lead into the runners. Check out the pictures. This is the only reshaping that will be required on the manifold. I'm not sure if I smoothed out the manifold too much. Don't want fuel sticking to the walls of the manifold. I think it will be okay though since it's just the inlet to the runners, not in the actual runners themselves. Thoughts others?
Jamie
03-21-11, 01:30 PM
#35
Is that how Carl did his? You see on the side where you added a bit of a beveled edge? As if you went too wide? I probably would have kept it straight there and just only go as wide as the runners themselves. In a slight trapazoid shape because the primary runners are a smaller diameter.
When I opened up this area of my RX-3 manifold, I didn't go as wide as you. It performed like a beast. Since yours is based more on what Carl did, I bet it will flow really well too. Just not sure which approach is better. Thinking about it a little, Carl's approach is probably better, since he's the flowmeister.
By the way, I went with a PH266 PCV valve on the old school manifold in my half BP thread.
When I opened up this area of my RX-3 manifold, I didn't go as wide as you. It performed like a beast. Since yours is based more on what Carl did, I bet it will flow really well too. Just not sure which approach is better. Thinking about it a little, Carl's approach is probably better, since he's the flowmeister.
By the way, I went with a PH266 PCV valve on the old school manifold in my half BP thread.
03-21-11, 02:14 PM
#37
Yes but you left a strange edge at the transition point from channel to runner which is not present on Carl's manifold. It appears he enlarged his runners a bit.
What I'd do is I'd funnel and blend the strange edge until it is a smooth transition into the runner. That's actually sort of what I did on my RX-3 manifold. Only difference is I didn't widen my channels as much as you or Carl. That's why I'm not sure if widened channels works well, but Carl knows what he's doing, or rather he must have done what he did based on his flow bench findings.
Notice Carl's channels are more straight across from left to right than yours. Yours are still kind of in the shape of the original channels with more of a brick wall for the incoming AF mixture to run into and loose velocity. Again I can't advise you how to mod the channels because I've never gone this deep before on any of mine (I've only cut a channel to mimic stock on an FB manifold, or created channels in a 13B manifold to mimic stock channels in an RX-3 manifold). Plus Carl started with a 79-80 manifold, which requires a lot more love to get it to flow well compared to the RX-3 manifold.
What I'd do is I'd funnel and blend the strange edge until it is a smooth transition into the runner. That's actually sort of what I did on my RX-3 manifold. Only difference is I didn't widen my channels as much as you or Carl. That's why I'm not sure if widened channels works well, but Carl knows what he's doing, or rather he must have done what he did based on his flow bench findings.
Notice Carl's channels are more straight across from left to right than yours. Yours are still kind of in the shape of the original channels with more of a brick wall for the incoming AF mixture to run into and loose velocity. Again I can't advise you how to mod the channels because I've never gone this deep before on any of mine (I've only cut a channel to mimic stock on an FB manifold, or created channels in a 13B manifold to mimic stock channels in an RX-3 manifold). Plus Carl started with a 79-80 manifold, which requires a lot more love to get it to flow well compared to the RX-3 manifold.
03-21-11, 04:13 PM
#39
Yes! I wasn't able to explain it very well but you got it.
I once came across a modded 79-80 manifold where the flat area between runners was narrowed down a lot and the runners were enlarged a bit up under where the carb sits. They also unfortunately enlarged the primaries all the way through where they meet the engine (to match a tall runner Y plate). This was on a GT1 car and the ports were opened sooner than stock and closed far later than stock. I never measured the closing timing as I didn't have a degree wheel, but if RB streetports close at 60 degrees, these may have closed at 65. The engine had carbon apex seals and 83-85 rotors so I assume it was seeing 9k fairly often and not much action at lower RPMs.
I wasn't able to explain it very well but you got it.I once came across a modded 79-80 manifold where the flat area between runners was narrowed down a lot and the runners were enlarged a bit up under where the carb sits. They also unfortunately enlarged the primaries all the way through where they meet the engine (to match a tall runner Y plate). This was on a GT1 car and the ports were opened sooner than stock and closed far later than stock. I never measured the closing timing as I didn't have a degree wheel, but if RB streetports close at 60 degrees, these may have closed at 65. The engine had carbon apex seals and 83-85 rotors so I assume it was seeing 9k fairly often and not much action at lower RPMs.
.can you hook me up with the part # for the rx3 floats..from autozone..
03-30-11, 09:26 PM
#43
Here are some updated pictures of the Rx3 manifold. I think I have the smoothing and porting where I want it now. I smoothed out the hard edges quite a bit compared to what I posted a couple of days ago. I also funneled the sides of the opening and made the middle a little bit lower. Sort of a compound curve that leads into each of the runners. I used 80 grit for the final smoothing. I didn't want to get it too smooth. Need some turbulence to promote a good air/fuel mixture. I didn't polish the runners all the way through either. It's just too hard to get down in there I only polished the area that I ported.
I am still working to find a source for ported vacuum for my timing. I think I can get a ported vacuum source from the carb, but I'm waiting to get my throttle body back from Sterling. So that's on hold for the moment. I'm fairly certain that there is a ported vacuum nipple on the carb base, as well as a manifold vacuum nipple. All that's left for the manifold is to clean and paint the outside, and then make some gaskets for it. I think I'm going to try making some reusable gaskets out of teflon.
I am still working to find a source for ported vacuum for my timing. I think I can get a ported vacuum source from the carb, but I'm waiting to get my throttle body back from Sterling. So that's on hold for the moment. I'm fairly certain that there is a ported vacuum nipple on the carb base, as well as a manifold vacuum nipple. All that's left for the manifold is to clean and paint the outside, and then make some gaskets for it. I think I'm going to try making some reusable gaskets out of teflon.
03-30-11, 11:14 PM
#46
Thanks for urging me to clean those edges up better. I'm glad I did. It turned out a lot better. It's really nice and smooth now. I think it's going to work great. You can see a definite difference between the pictures I originally posted, and the new ones from tonight. It looks a lot cleaner, and generally more finished.
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