Rotary Engineering Dual Weber 36DCD Carbs
 

My dual webers appeared in the post last week and I figured I'd show off what I've done to them since. A forum member is also sending me some pictures of the original installation manual so when I get that I'll toss it up online for future reference.

Out of the box:
http://foxed.ca/rx-7/sept09/small/DSC_1865.jpg

Not too dirty:
http://foxed.ca/rx-7/sept09/small/DSC_1880.jpg

Velocity stacks:
http://foxed.ca/rx-7/sept09/small/DSC_1883.jpg


Cleaned:
http://foxed.ca/rx-7/sept09/small/DSC_1917.jpg

http://foxed.ca/rx-7/sept09/small/DSC_1919.jpg

http://foxed.ca/rx-7/sept09/small/DSC_1922.jpg

Little 36DCD's:
http://foxed.ca/rx-7/sept09/small/DSC_1927.jpg

Back together:
http://foxed.ca/rx-7/sept09/small/DSC_1934.jpg
http://foxed.ca/rx-7/sept09/small/DSC_1939.jpg

http://foxed.ca/rx-7/sept09/small/DSC_1936.jpg


If anyone has any other information or whatnot, I'd love to hear it.

It was YOU who beat me to them! :) Jk Hope you enjoy them!

very nice setup. I'm running a side draft weber

When I bought my first set for the widebody, I did 2 things, rebuilt the carbs and powdercoated the intake and linkage. If you can get your hands on a wideband, it will make tuning sooo much easier. Fwiw, Holley air corrector jets will work for the main jets at the bottom outer side of the carb. Since RE ground off the jet #s I had no idea where to start and don't have a jet guage.

Don't recall for sure but I think I ended up in the mid to upper 70s, but don't quote me. I may still lean it out a bit since I keep fouling plugs during start up. Once you get it timed, I think you'll be very happy with it. Leep in mind that many of them were set up for thier street ported engine. When You get a chance, post the diameter of the venturis. The number is cat on the top part of the lip. The 12A and 13B had different venturi.

I'll be looking forward to seeing the manual as all I have is a couple exploded diagrams.

uummm pretty!

Lookin' good!

I am hoping they are jetted for a stock port. I believe that they came off a stock port engine.

Here are some pictures of the RE Weber 36DCD Manual

Courtesy of forum member Serzy. Thanks a lot man. He sent these pictures to me a while ago but I lost the file until recently. Sorry it took me so long to post them.

Attachment 710636

Attachment 710637

http://i11.photobucket.com/albums/a1...DSCN1339-1.jpg

Attachment 710638

Attachment 710639

Attachment 710640

Sgt Fox, What did you use to clean the carbs? Did you just spray with carb cleaner or dip them in a carb cleaning can?

I currently have these on a stockport 12a but I'm having some ignition issues at the moment so i have yet to see how the really perform.

i bought a set of these a few years back off of eBay hoping to run them on my 13b 4 port but someone modified the manifold by cutting and welding on a plate to fit a six port i think ....so i never ran them and since sold the car so i am selling them .
had them listed on eBay but i listed it wrong so it didn't show up .

im gonna list them in a day or two again so if you want a set you should check them out

ill post a link when i do

Very nice work, I picked up a identical setup a few months ago, can't wait to try them out, just haven't had the time.

I'm a sucker for old manuals and I wish I had that when I had the setup!

What can a stock 12A dyno with that carb setup?

Never had mine dyno'd....
The original RE advertisement said with a header it was 150hp....I'm assuming at the flywheel. Also it didn't specify if it was a stock port or not.

Got some more info:

http://foxed.ca/rx7manual/dual36dcd_cover.png
RE's Dual Weber Installation Guide

http://foxed.ca/rx7manual/36dcd%20manual_cover.png
Haynes Weber 28/36 DCD Book

I just swapped a motor with the same setup into my '85 and I appreciate the info. I will need to retune the setup on mine and the manuals will help a lot. The vacuum advance on the distributor wasn't hooked up on the other car and I didn't see anything in the manuals about it. Is it just ignored or is there someplace to hook the vacuum line to?

Heres the original catalogue entry for it:

https://www.rx7club.com/attachment.p...2&d=1253019355

Be sure to set the floats correctly. When I had DCDs they liked to flood when I parked nose down on steep hills.

just found same duel weber carbs and intake at yard sale this weekend... got it for $100!! cant wait to put it on my rx3

I know this is a super old thread but anyone have any leads on any of these things floating around?
I was going to give up on my fb project until i heard about them...

There's one on ebay for $1000 that's been up for few months.

Waaaay overpriced......... Even if it is a kickass setup.

I was walking through a junkyard about four years back and saw a set of those lying in the mud. I couldn't believe it, I almost grabbed them.

They changed that article because of me. I called up RE and talked to Joe. They had the duals making 152 HP and the single making 154 hp. After I brought that to his attention they changed it. They were selling more of the singles because everyone wanted more hp. They had the numbers backwards.

Couple of pics from when I had these carbs.

Attachment 693358
Attachment 693359


Loved the look and they performed well too.

Those look like my carbs... Maybe I bought them off you?

28/36 DCD twin Webers on bridge port, engine
 

I have a set of these twin Weber on 12A bridge ported engine. Only the outer two intakes are bridge ported. The engine timing is about 24 BTC. The engine is very hard starting and fouls out spark plugs quickly. It will not idle below 2000RPM. I have reduced the main jets from 135 to 110. the air bleed jet is already 260, largest available. I thinking of reducing the idle jets, but there is only one step down from the current 45. The reduction of the Main Jets brought a slight improvement. The fuel pressure is 3 psi. The floats are at factory spec. This carb uses gross jets above the floats. I need suggestions as to how to the get the engine to idle . And of course start more easily. Does anyone have experience with this set up. These same carbs worked fine on a stock engine,

I just bought a set of these 36 dcd webers off of ebay. Paid too much considering the shaft is wearing through the throttle body. Anyways!

My question is.. where does the pcv go on this setup? Can I run it into my brake booster vacuum hose? The diagram of the rotary eng. Install is good but doesn't show exactly where it needs to go. I can't pick out that note in red writing. Please help. Thanks!!

Also, can someone write out the process word for word from the manual on setting the timing? It's very hard to pick out.

Rotary Engineering Dual Weber 28/36 DCD Carbs
 

We obtained one of the Rotary Engineering Weber 28/36 DCD carburetor sets from the company back in the late 80’s. It was a 12A stock configuration to start with and then was reworked (by R.E.) for use on a 13B street port.

One set is currently running on a Rx3 open track car w/ a 13B street port and another on a daily driver 85’ FB w/ a 12A street port.

Over the years we have compiled jetting information on fourteen of these dual carburetor sets, both stock and street ported, 12A and 13B. Several of these sets are also in storage. If anyone would like setup information regarding these units, feel free to contact me.

~ M

Rotary Engineering Dual Weber 28/36 DCD Carbs
 

Pics

Mine is running off the booster nipple.

Roaster
 

Thanks oschool_3 for the setup info.

I had a set on a REPU engine many years ago, and I liked it. I just dragged an'84 out of a 20 year hibernation, and I bought a 12A RE setup from a forum member a few months ago to replace the Nikki, which had a badly rusted linkage and butterfly mechanism.

It was in generally good shape, but the air cleaners were damaged.

I looked around craigslist and came up with a Magnalite aluminum roaster that was about the right size. I fabbed up a base plate and added studs to the center of the air horns. My plan is to mount a conical air filter in front of the radiator, then duct the air back to an inlet tube that I'll weld to the roaster. I have a similar cold air setup on my turbo '84, and it seems to work well.

Weber 28/36 DCD Cold Air Intake
 

Great looking adaptation.
I have found that a lot of people end up fitting K&N filters that are shorter than the original RE units, which encroach on the top of the air horns.
Your cold air idea is similar to one that I have mocked up for the FB, except I was going to move the overflow bottle, cut the air inlet into the passenger side of the radiator support and fab a box for the cone filter up front within the engine bay. The box would have drain holes for wet condition separation. Any which way, it is a great improvement.

Yes, I also relocated the overflow bottle and plan to draw air through the right hand rad support. The difference is that I plan to mount the filter up front, instead of in-line.

I like your idea. There are a few off-the-shelf setups for that, which I considered years ago. Here's one from Spectre: 9831

Cold Air Intake
 

After looking at my conical air filter and a few of the aftermarket cold air setups, I decided to make my own. I made closeouts from aluminum and added a bulb seal. I cut a large opening in the RH rad support to supply the cold air box. The trickiest part was getting the contour of the underside of the hood. I used a combination of carpenter's contour gauges taped to cardboard mockups and clay. It seals against the hood very well.

very cool indeed!!!!

Hey. Can anyone tell me why the 36DCD webers for the rx7 have no secondary progression circuit in the secondary barrels? There are for the Primary but not for the secondary. I noticed I get a slight starvation/hiccup when WOT is applied under 4500 RPM. I ordered some pump jet nozzles to see if that will help, But I am doubtful.

Let me know if you peoples have the secondary progression circuit or not. Thanks for any info :)

Secondary progression of the type described was not part of the DCD design.
Without knowing other details for your situation, it is difficult to know (and only speculate) on what the shortcoming may be caused by.
12A or 13B ? Stock or ported (& what degree) ? Have you documented the venturi and jetting values ? What fuel pump and pressure ? Engine ignition condition and timing ? There are many things that could contribute to such a condition.
Many of these carb kits are third or fourth hand and the jetting may be changed. If you need original jetting values as Rotary Engineering supplied them, please forward a request with details of your engine and expected duty.

hey i have 28/36dcds
 

Hey M, I'm Justin from Regina, I ha e a set of dual 28/36 dcds on my 12a stock engine. Its an 83. I was wondering if you knew the best fuel must setup how many turns out as well as timing. Idle timing in the destributor and the vaccuum timing while idling at 4000rpm you can text me 13069992081 or email justinsane_00outlook.com . thanks for any help you can give me again everythings stock I adjusted the carbs a bit she will idle but I can only drive a few blocks then she wants to die.

looking for stockport 12a jetting info for these guys

Gonna drop oschool_3 a pm, but figured a post would be good as well. just scored a set of these for $600 (w/ 12a mani)

Here's some info if you didn't find it already:

https://www.rx7club.com/1st-generati...etting-917923/


I'm still messing with my Timing. Kinda worries me now haha. I'm going to set it back to 3 degree on Leading and 15 ATDC on Trailing at Idle.

i got the info, waiting to get the jets right now :) thanks

Hey ! Does anyone know the exact Timing for these weber carbs? Do you have to adjust the timing by synchronizing the leading and trailing. for example, If I advance 1 degree on the leading I have to advance 1 degree on the trailing.

Racing beat suggests otherwise with the timing and says to keep stock timing. I'm confused!

Thanks for any insight :)

i havent ordered the jets for mine yet but id imagine go off stock timing... then slightly adjust and play with timing as needed. usually slightly advanced

There is no exact timing for an engine or a carb for that matter. Start at stock and advance until
power drops then back it off a degree or so.

ordered my jets yesterday. went with 135 main, 45 idle, and my current set up should still have the 100f1 tubes in it. hopefully it'll fire up with the current air correctors that are in it. I got it to fire up with the bridgeport jets in it now (dk the size, the jets were blank when i pulled them last night -_____- ) but under 1800 it would die.
Just to confirm, going off the diagram on pierce manifolds, the idle jet is located inside of the bowl, correct? the diagram makes it look like it unscrews from under the bowl, which is clearly incorrect.

NEVER MIND nvm nvm! man i feel stupid. i guess it was dark and i didnt see the idle screw above the main... sigh

put the new jets in, fired right up after a few pumps of the throttle. idled fine, but at 1800... just need to adjust that today, hook up choke and throttle cables and should be good to go

I've been using my stock port 12A as a daily driver for about a month, and it's awesome! Special thanks to oschool 3 for helping with setup info. Couldn't be happier with the overall performance.

Good deal ! Given a bit of attention, these carbs can be adjusted to give great overall performance and at the same time idle at 700 rpm, even with a rather large street port.
I much prefer a normally aspirated engine that will last forever than a high strung turbo motor that may lunch out under the wrong conditions.

Does anyone know of a online store as to where you can get parts for the weber 36 DCD? I've found gasket kits on ebay, but I'd like to get the other parts like accelerator springs, throttle shaft springs, etc etc.