dean7

Ok So to start off, My project is pretty much done as of tax returns (dual mid pipes and prima from racing beat).

I purchased the carb from someone on the site here, along with a couple other items. This last thanksgiving, I had my new engine,alu fly,clutch, tranny and carb hooked up running headers off to see if I put everything together right. (including the small block to a "big block", and 485847 gaskets).

Well I am happy to tell everyone that the car started up after 3 or 4 turns or so... I did the TDC thing good!!! (last minute doubts). Anywho thats where the fun ended... Leaks developed from brake system, waterpump, fuel pump, and the Dellorto.

Some how my brake booster or master is leaking... I have parts, will do.
The only leak on my engine was coolant from the waterpump, thought that it wasnt sealed correctly, so after taking the pump off puting it back on the engine it leaked again... The waterpump went bad somehow while the engine was dead? My luck! Got a new one put it on. The fuel pump leaked and I learned not to be dumb and will not use that white thread tape on fuel products from now on lol.


Dellorto Woes

OK first thing, the little screw in chokes that are right next to the accelerator pump jets, are those on our version of the dellorto, cause mine just has threads and nothing screwed into them. But the alluminum looks new and its the only place on the carb that looks like new metal, so I was thinking these were taken out, and I havent seen any info about them for rotarys. Ohh and when I say right next to the accelerator pump jets, there the fartherst to the right if your looking at the carb on your passenger side of your car.

I love my Dellorto, even though I haven't been able to experiance it.... I got the webber dellorto book reccomended by gruntled... read it alot front to back.... and heres my once problem, now confusion. That tragic day that I noticed the other leaks, I noticed the carb first, gas all over the LIM. When I started the engine for the first time, if I tried to step on the gas it would die, but it felt strong for a bit before it died. Well I found the leak pretty fast, it was comming from the accelerator pump on the bottom of the carb.

I bought a rebuild kit, and book, and expecting the diaphram to be broken was going to do a rebuild. I read the book for 8 hours yesterday, some today, with about 4 hours internet research and then I went to have a look at my supposed broken diaphram. Well there were only 3 screws, out of 4, on that accelerator pump housing and the diaphram looks to be fine, but I realize that looks can be deceiving. But im guessing most of you reading this would say that if one screw was missing, with the force of the pump arm, it would deffinetly leak because of that right?

Anywho, my other concern is it looks like the carb has been rebuilt roughly before many times. And I might want to see if I can get another screw on the housing and stop the leak, and save doing the rebuild untill there are drivability problems, as I dont know how much more the poor carb case can take. I was gonna inspect some parts and a couple I didn't even get to look at, guy before must of put an impact wrench to it LOL.

dean7

Ohh a little misinformation on my part. On my screw in choke question, when I said that they were to the right of the accelerator pump jet/holder looking from the passenger side, I lied. There to the right of them when you look at the carb from the front of the car (hard to do for most lol) so if your looking at the carb from the passenger side they are on the drivers side of the accelerator pump jets... about 1/2" away.

broke7

iTrader: (1)

The dellorto and weber are very simple carbs. I have had plenty of both. I have played with ida, idf webers, and dhla, drla dellortos. As long as the throttle shafts are tight you are ok. I use to think you had to rebuild a carb when it sits for awhile but from past experince I have learned this isn't ture. Sounds like you need to replace the missing screw and go. I will normally take a used carb take it apart check the float height, find out the jet sizes and put some gas in the bowl and see if the accel pump works and if it passes these test I bolt it on go. It would be a good idea to buy a rebuild kit because most local shops don't stock them. It does sound like you may want to check the carb out compared to the parts break down in your dell manual to see what else is missing. good luck

dean7

Thanks for the help. I think Im going to take your advise. I already have the kit, after 8 years of Rx-7's I learned to look ahead lol.

One of my problems was that the accelerator pump jet holders (flat screw head) were stuck tight and a little rounded already. But I took the plastic choke breather off and took out the jets/tubes and inspected those, Ill double check that they are up to spec and replace that gasket. Im also going to fabricate that rubber spacer/gasket that racing beat used to give the accelerator pump a little more ooomph, as it is dry rotted pretty good. Ive also read hear I believe, that Racing Beat used the # 80 and 90 accelerator pump jets for the 13b kits, depending on the year, so Im not to worried about that. Ive learned so much in the last couple weeks and I think that by next winter I will be alot more efficient tuning/rebuilding/inspecting the carb.

BTW I was wandering earlier, whats the best way to hook up your carb and test it for function... I figured since im testing the accelerator pump, If I get gas into the float bowl I don't need any pressure to test the accelerator pump, I would just have to move the arm and if its gonna leak it will, correct.

dean7

Well I have decided that after all of my reasearch, it would be a waste not to rebuild it right now... If I can get the screws out, and I guess Ill get new screw heads from Euro carb for next winter. Any Idea where I could get the missing screw from, thinking about going to a hardware store.

Also still wandering about the little screw in chokes, saw some pictures on the forum and one persons car had the chokes screwed in. I understand most of the function of all of the carbs parts. But do these even matter if I plan on not running the choke cable anyways, or is It an air choke that limits air all of the time? Need to buy the other book that go's into the funtion of the carb a little deeper.

dean7

I know their supposed to be a 80 or 90 but I cant see either number on them... I see a 7 on one and a 35 on the other, size is the exact same so I know these arent the size markings.... Anyone seen how they are marked, all of the other jets are right, just wanted to know which one I had.

dean7

OK done with tear down. Got everything off that I need to clean carb and parts, thanks to the "safe" use of an impact screwdriver (hit with hammer and it turns, not sure of technical name). One of the covers for the sliding ***** was stripped soo bad, so was one of the progression cover, both covers were tight. The biggest pain? That was the well cover, I was convinced it was welded on lol.

Im pretty sure that the accel jets are right, as all of the other jets/tubes matched up.

So I am missing 1 screw and washer for the accel pump case and apparently 2 small screw in chokes. Well now I found something out, I may have been calling them something wrong.. at Gowler and Lee there called Air bleed screws and later in my carb book they are refered to as a choke and also as a bypass screw (3 names fun lol). Unfortunatley the euro carb site is down for me and I cant see if there are different ones, anyone els have these air bleed screws... Its part number 54 in the powertune webber and dellorto book. Also its number 56 at http://www.gowerlee.dircon.co.uk/Dellorto.html

I have seen it on 1 carb so far on this site, anybody else?

dean7

LOL more stuff, the needle and set is a 200 and the one in my kit is a 225 gonna see what all I can buy on the euro carb site, as it appears to work now. And nope 225 is the largest they carry... oh well.

t_g_farrell

iTrader: (1)

Thats interesting. I think I was told the same thing when I ordered EuroCarbs rebuild. It came with 350 needle/seat which tho which I went ahead and used. That was a few years ago. The original from RB was a 300.

dean7

Yup yup, I found the 350 needle/seat, ordered it with another rebuild kit, plus alot more crud (screws,idle mixture, ect) prolly gonna be a total of 130 or so bucks with the exchange rates .

What kind of fuel pump/regulator did you use? I'm wondering if my holley blue and pr 4-9 might be to much for a bigger orface. Would using the holley pressure regulator 1-4 psi work for my holley blue that pumps at 13 or so psi? Im thinking that if it does, Ill get that regulator.

DriveFast7

iTrader: (1)

350 is big, it's gonna run richer since more fuel can enter quicker into the float bowl.

might want to lower the fuel pressure to compensate. I use 2.25psi, try 2.00. The holley 1-4 regulator is fine withthat pump.

those little air bleed screws never wanna come out.

dean7

are you talking about the ones closest to the air filter part of the carb (the ones i dont have) or the air bleed next to the progression screw? I have those 2 but the other ones are the missing ones, I ordered a pair from euro carb, just incase.

dean7

still haven't found out why my accel pump jets say 7 and 35 there is a 35 size but not a 7 lol, maybee alot got rubbed off? They only have the 90's at eurocarb and It looks like the 13b used 80's im looking and looking to no avail... My powertune book doesent show it... but wait, found an enlarged pic on eurocarbs, yup the numbers on my jets are in the same place as the pic. Reguardless the hole size is the exact same...

dean7

Ok figured out what you meant about puting fuel in the bowl (main cover off) duhh. I started another thread during my stripdown, so I guess post over there so I don't have thread all over the place. https://www.rx7club.com/showthread.php?t=729494

DriveFast7

iTrader: (1)

By the progression screws.

I think the ones by accelerator pump jets are the uber special oil metering fittings that RB threaded into the carb. In a spot usually plugged with a lead plug. Pretty cool idea. You can see in my sig where the omp lines go.

dean7

DOOH, I didn't even think of that. Well I ordered the bleed screws alread for it, and Im running pre mix, so I guess when I get them in, Ill just put a bit of jb weld in the screw and screw it on. THANKS SO MUCH!!!

broke7

iTrader: (1)

I normally buy my rebuild kits from cb performance and while you are at it buy their dellorto handbook. It covers the down draft carbs but it is a well written book and a lot of the information you can use. The book has some pretty good trouble shooting and setup tips which you can apply towards your side draft

dean7

Thanks. I got one kit from cb, getting the "official" dellorto one from europe now also. When you mention the dellorto book, are you talking about the powertune webber and dellorto book? I have that, but Ive seen a white covered book with the dellorto print on it... I read somewhere that there was one that went more into the functions of everything in the carb(thinking that might be it). I understand most of the happenings going on, but I am an obsessive compulsive learner with ADD. LOL.

BTW, my friend has dual Webber40's, has anyone tried to modify dellorto 40's to work together on our engines? I see the double banjo for sale, and besides some attaching hardware, the only hard part would be to figure out all of the jettings ect. I also figure that you could copy most of what is on the dual webbers compair that to a single Webber, then compair that to a single dellorto, and buy alot of sizes.

broke7

iTrader: (1)

I am talking about the cb dellorto book and currently their is guy sell carb rebuild kits on thesamba.com on the high performance engine section he does have dell kits but not sure if he has side draft kits you will have to ask him

dean7

my bad

dean7

Ok I got ya, Ill have to give it an order, next paycheck lol. I have 2 unused kits so Im good in that department.

Heres my "work bench". I hate winter, so yes im working downstairs in the storage/furnace room. For some reason Im not allowed to clean the carb downstairs, let alone bring in the air compressor lol. I hear it may warm up above 25 degrees someday, and that might get me in the garage. Got to wait for parts from Europe anyways.. To bad they cant do overnight lol. Heres the RB 13b 4 port exaust, put my own O2 bung on it (didn't want the tube for 6 ports).

dean7

Well Im rebuilding the carb now, got all of the parts cleaned and my Euro carb order came, unlike cb, they didn't include the gasket for the air filter and the ones for the manifold, but had a throttle return spring, fuel filter, and diaphram spring in their kit. The needle and set is a 350 and it is cross drilled , compaired to my 200 that was in the carb and the 225 in the cb kit, this thing is godzilla. I just need to find out the float settings, my book gives me one, but I thought I saw the setting online somewhere, not sure if there the same.


From Drivefast7's post
From Will Claypoole's excerpt on www.gruntled.com:
"Racing Beat recommends float levels of 15mm from the gasket in the closed position and 28mm in the wide-open position. It’s important to realize that the 15mm measurement is taken BEFORE the needle spring is compressed. These measurements provide a good compromise between the right hand turn stumbling and flooding the carb by over filling the float bowls. After a lot of experimenting and testing, I've found that a 14mm float height provides improved response and less stumbling than the RB recommended 15mm height and zero flooding.

Ok that looks right!!!

t_g_farrell

iTrader: (1)

I have my floats set at ~13mm. RB recommends 14 and the tune book recommends even larger gap. I used 13 to get rid of the right hand turn bog or at least minimize it to large extent. Seems to be working for me and I don't run too rich with it.

dean7

Thanks, sounds like a winner to me. I had 2 dial measures but cant find either. Went to auto part store, they didn't have them. The guy gave me a tape measure that had mm on it, I think they are LOL.

dean7

Ok checking out the float levels, it hits at 13.5 when the needle is just seating, but only 20 mm when its all the way down. The little tab on the back of the floats isn't touching the set. The pin is good, and the floats are moving fine on the pin. Everything looks good except for the 350 needle and set, it seems to not want to come down, if I pull on the floats at the base, until the tab hits the set, it is at 26mm. But I have to pull down to get it there, gravity alone wont do it, any ideas, thoughts?