Project DCOE

carl

carl

True Classic
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OK, let's get started. As I posted in the discussion forum last week, I'm removing my single 34 DATR and installing a pair of 40 DCOEs. Basically just a project to try since I have been the caretaker of the DCOEs for years and they were just sitting in my attic. My 86 X is just a test bed for goofy things to do and if I need to go on a nice Fiat drive I have my 80 spider which is now in good shape.

The 34 and stock manifold came off easy, the previous owner of this motor had plugged the intake manifold coolant ports so no dealing with draining the block.

The other picture shows the DCOE manifold temp. installed. First problem noted, the thickness of the DCOE manifold lower stud seats are not as thick as the stock manifold. Since the motor has headers, I had to make half circle spacers on the header flange to mount the stock intake manifold. The DCOE manifold lower stud mounts are the same thickness as the header flange so I have to cut off those nice half circle spacer I welded on (crap). For test fitting right now I'll just use the upper intake manifold studs. Minor headache, the clearance for the nuts to mount the upper portion of the manifold has limited clearance and while I can use the standard 13mm nuts (wrench size), I would be better off getting some of those flanged nuts that take a 12mm wrench.
Ah, now for the biggy, tried to slip on a carb but it won't fit, hits the upper brace....the problem we all know about. If I removed the carb mounting studs on the manifold I might be able to slip the carbs into place to see how much brace material I have to remove but the studs were locktighted into the manifold and have no desire to come out. I'll make a first cut, taking one inch off the bottom of the brace. When I get the right amount of material removed, I'll box it up. Have to go get some blades for my sawzall, more later.
 
I cut up the brace so the carbs will fit (barely). Everything looks good and the next step is to do the linkage....which may be a big headache as I discovered the throttle shafts rotate 180 degrees from the way stock carbs and DCNFs do, the linkage will have to PUSH on the throttle shaft lever arm, not PULL it. If I had known that I would have worked on this problem on the work bench with a spare head I have laying around. The carbs came with a valve cover with some custom linkage but I have not figured it out yet.

More pics later, apparently my phone does not talk to my Google photos (supposed to be automatically done) and I have to load the pics to an email, mail them to my wife, then go to my sent emails and load the photos into my PC photo collection one at a time....a terrible work around but it's the only way to get it done at the moment....maybe I'll go back to my old digital camera!
 
not to sidetrack but I have found that I can plug my phone into the computer (though the USB) and the computer can see the pictures to upload straight from the phone)
 
Rod, that's what my son in law told me and I tried it but nothing came of it, I can't see the pics. Have to get the son in law to come over and show me.
Erwin, this is all your fault so don't give me any crap!
 
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Here are the carbs on the manifold, on the car. First cut of the cross brace made install of the carbs fiddly. Took another 1/2 inch off and they slide on much easier. Next step is bracing the cut and working on the linkage.
 
You need to make the cut large enough so you can get the tops off the carbs and make jetting changes and set the float etc... otherwise it's carbs off the motor to do anything! (so I'm thinking the cut needs to be 'taller')

SteveC
 
Those sharp squared cut out apexes on the top cross member cut out are a stress crack festival waiting to happen. This is precisely what I'm often harping about when folks do part fab and modifications to parts and structures. The better way to have done this would have been to drill a good size hole (in this case no less than 0.50") at the apex of the cut out then cut the line to meet the edge of the hole drilled. Then smooth out all sharp edges.

Figure out a way to put a large radius into the cut out's corners.

The cut out as is now will produce significant cracks on the top cross member that can result in a serious major failure of the entire cross member.


Bernice


carl said:
View attachment 5493 Here are the carbs on the manifold, on the car. First cut of the cross brace made install of the carbs fiddly. Took another 1/2 inch off and they slide on much easier. Next step is bracing the cut and working on the linkage.
Click to expand...
 
This was a rough cut since I didn't know how much to take off. Now I can go make it all pretty and structurally sound.
 
Next step was throttle linkage which threw me for a loop as the DCOEs rotate the opposite of stock carb or DCNF. The kit came with a custom setup mounted to a modified cam cover and it works wonderful. All the linkages I saw on-line included a second rotating shaft to transfer the throttle motion and I didn't want to go that route. Ordered some threaded rod ends (5X0.8) from Mcmaster-Carr and hooked it all up. I seem to get full motion but now need to figure out a retu
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rn spring which should not be all that hard. I need to box in the cut away section of the cross beam and plan to use two L-sections, one on each side and double lapped on the bottom. Need to get over to my buddy who has a bending brake to make the L-sections.
 
I'm not doing this to max horsepower, I'm doing this because I'm stubborn, I have the parts, I like the way it looks and I know I'll like the way it sounds. The car ran perfectly fine with the single 34 DATR.
 
I had 45 DCOE's on my race car... I got it to work quite nicely on a PBS Big valve head with a B3 cam (IIRC). PBS port matched intake manifold, and PBS header.

It was mighty quick and sounded amazing!
 
Linkage now appears to work and I figured out a return spring so today I'll check the float levels, find some gaskets and mount them for a trial start.
 
I'll be damned, it fired up and runs.....sounds like the hounds of hell, much louder than DCNFs. Now it's time to see how it drives after I balance them better.
 
Hi Carl,

Like a pair of carbs, we are... sync.

While rebuilding my engine, I choosed to replaced my DCNF's with a programmable fuel injection and Individual Throttle bodies. But then, after I bought everything needed, I looked at the SCCA solo2 rules, and decided that I was really more a carb guy and I wanted to compete in HCR in Solo 2. So I went the DCOE's route. As of today, the carbs are on the car, the rebuild engine is running and the carb are OK, just needing a little fine tuning. Instead of cutting a large opening or cutting completely the firewall, like most others did, I just used a hole saw to do 4 round openings. I have long air horns with air socks. (I tried fit them but not on the car yet until fine tuning is done).
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I still have to do some work on the linkage, I'm missing a little travel on the the cam cover mechanism. I will probably put some header wrap around the left exhaust tube because it is really close to the carb.
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Car is not on the road yet, Need to finish installation of new master cylinders and probably need to rebuild the brake calipers since the car is "in the works" for 18 years now!

BTW, we are on the same boat. I'm not looking for ultimate performance. I'm just liking the look of the DCOE's and mechanical parts and linkages are fascinating me. Sharing our progress may help each other... but I don't have much time, so progress is slow (did I tell you I started this 18 years ago...)

Daniel
1980 black HCR X1/9... in progress
1987 white X19... daily driver
Montréal, Canada
 
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The intake manifold came with stud mounts for the carbs, pretty normal for any carb mount. I think if I had removed the studs and used bolts to attach the carbs I could have slid the carbs up into place and hardly had to do any trimming of the engine compartment brace.
 
That's what I did for the carbs to intake flanges. Even to fit the air horn, I kept the bottom stud (it helps locating the air horn) but I'm using bolt for the top hole. You can see it on the left one in my first pic. Stud at the bottom, nothing at the top.

But the removal of the left carb is a pain in the ass if I don't remove the right one first. But that's the price to paid. Access on top to change jets or even complete removal of the top isn't that bad, and I don't expect to remove carbs on a regular basis.
 
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