Fretty84

Hello all, fairly new here, hoping for some help.

**Sorry for the wall of text, but I wanted to be thorough with all the things I've done to the car and what's happened. I'm a fairly novice mechanic so it's easy for me to overlook something. I'm trying to learn though!!**

Just to give some background on me and my 84 GSL... I bought it earlier this year from a guy who j-ported it and ran it with a stock Nikki and a straight pipe. It ran fine, pulled hard, and sounded terrible. Bought it at a decent price as a project for me to learn with. Also, I should mention, the guy had it idling at 2500-3000 when I bought it...

Since I got the car, I've replaced the fuel pump with a holley red and holley FPR and removed the rat's nest. Drove it some, everything ran fine, reduced idle to about 2300 with the warmer weather. It sometimes struggled to idle and really didn't feel too reliable.

A month later I decided the carb just wasn't adequate enough for the jport. Purchased a weber 48 ida off a member and felt the pipe wasn't enough for it to breathe, so I bought the RB full exhaust.

Made the swaps, used the recommended jets on the RB website for 48 ida's on a bridgeport. Also, removed the OMP and blocked off, started premixing.

I ran it a few weeks ago but noticed a fuel drip so I shut it off to go through it and figure out why. Found I hadn't tightened a few things enough...

Yesterday, I cranked it probably 20-30 times before realizing I didn't have the break booster on the intake causing a a major vacuum leak...

After realizing that, voila, it started right up. I messed with the idle (had it around 800-900) and took it for the spin around the block. It was rough, I'm guessing it was kinda lean. It really wouldn't give me much if I floored it, but if I cruised on up past the idle circuit it was pretty smooth. It would cruise easily at 3-4k.

I turned around though because it didn't feel right. Got it home and it stalled pulling into the driveway, lifted the hood and it smelled like something was burning and I could see white smoke coming from the carbs. I had seen this before but really light while I was trying to start it before...

What is this smoke? Is it bad news bears for me?

Also, any ideas on how I can go about getting this weber tuned right? It felt lean, but being new to this, I'm really guessing...

Thanks for the help guys,
Fretty

rwatson5651

iTrader: (5)

Describe in more detail where exactly the smoke was coming from.

The running issues you are describing sound normal for an unturned carb and the smoke could be coming from your new exhaust, which is directly underneath the carb and will smoke for a while till all the residue burns off, the rotary exhaust gets really hot, especially if you are running rich. Did you notice the color of the header when you stalled it in the driveway?

If its really hot it gets red.

Fretty84

Smoke coming right out of the intake. It kinda seeps past the butterfly valve on the carb and then when I open it, a lot will come up right from the carb barrels, but it's really slow moving.

It didn't really smell like gas which is why it concerned me most, but I read somewhere this could just be fuel vapors?

I didn't specifically make a point to look at the exhaust, but I did walk over to that side of the car with the hood up. I feel like I would have noticed if it was red, at the time I was looking around for fire because I smelled a some kind of burning smell.

rwatson5651

iTrader: (5)

My best guess is that the white smoke is in fact gas vapors and the burning smell is normal new exhaust burning off residue and that your only problem is fine tuning the carb. The jetting suggestions from Racing Beat will only be a starting point, every engine is different and requires to be fine tuned. Learning how to go about this is one of the most rewarding endeavors a rotorhead can do, imho.

Rather than attempt to coach you on how to go about tuning the carb I suggest you get a good webber tuning manual , they are cheap and plentiful on ebay:

webber tuning manual | eBay

A good manual will start with theory and walk you through the tuning process, starting with fuel pressure, float level adjustment and then the idle circuit, then main circuit and then fine tuning the transition from idle to main. There are no reliable short cuts, it is a process.

a wideband O2 sensor will make the process easier as both lean and rich conditions can at times mimic each other leaving you chasing red herrings, however if you are patient it can be done the old fashioned way.

There is nothing more pleasing than a rotary running on a well tuned webber, I don't care what the Fuel injection guys say.

A good source for jets and information is Pierce Manifolds.com.

t_g_farrell

iTrader: (1)

Plus that J port may be letting a lot of exhaust backup into the intake at idle. So it could be exhaust vapors
you see when you turn it off. Big ports have notoriously poor vacuum at idle and a lot more overlap
which lets exhaust into the intake, especially at idle.

The fact that you got it running with the IDA better and idling at 800-900 rpm means you are pretty close.
Do what Robert said above and get jets and learn how to tune that weber.

Siraniko

iTrader: (13)

sounds like your float is not set correctly so fuel is overflowing/flooding. are you running a return or deadhead? also, many years ago, ive experienced same issue with fuel seeping into the carb even with the engine off so i added a return line on the IDa carb using a fuel inlet from a RX-2/3 carb. the fuel tank icould be over pressurising due to clogged vent lines during hot days (dead head/returnless carb)

imho opinion, after using a bridge and now half bridge semi-pp, these motors require lots of gas so its best to run a fuel injection fuel pump such as msd (cheapest i found) along with a mallory regulator (ie 4309) and upgrading the fuel return line to 3/8. 45 venturies is recommended but you can get away with 43. exhaust wise, the full rb exhaust will be too restrictive (primaflow muffler to be exact) for a ported motor. yes it will be quiet but the motor cant breath...rotaries are meant to be loud

Fretty84

Thanks for the advice guys. I will pick up the weber guide and start to learn how to tune it... I did read a lengthy online weber post from a Weber enthusiast that went in pretty good detail of the different circuits and how to tune each. I still find it difficult to translate that to rotary at times.

It's possible the float isn't set correctly as I didn't set it, I just used what the guy was using before me. It's not deadheaded though. I have a return lone set up from the FPR. Haven't noticed any flooding issues in the carb, but that's not to say they aren't there. Most of my initial leak issues came from only had 1 washer on the banjo bolt and fitting...

I'm regards to the exhaust, I went from single 2" straight pipe to s fuel dual 2", I feel like that's got to be quite an increase letting the engine breathe, right?

One thing I failed to mention. I was able to idle it at that range but given 3-4 minutes of idling, it would begin to stutter and almost stall unless I revved it. Then it would repeat for another 3-4.

TheRX7Project

iTrader: (3)

Definitely sounds like it's loading up with fuel. Maybe your fuel pressure is a tad too high, or maybe your float level is a tad too high.

I agree with the statement above about getting an AFR guage. It makes tuning 10x easier, and they're not hard to install. If you're running a true dual exhaust (each rotor on it's own pipe front to back) you'll probably want to spring for 2 complete setups, one for each rotor, or invest in a crossover/ balancer pipe and put the single one in that spot.

Fretty84

I played with it this weekend and got it idling without issue. I bumped the idle to about 900, after all bridgeports are supposed to idle higher. Then I slowly screw in each idle mix screw until that cylinder began to chug, once it did, I went out one turn. This put both at about 2 full turns out.

I then drove it and it never had trouble with idle, but seemed to lack some top end. If i ever just floored it, it would chug and struggle, but I read that can be due to the lost of vacuum under acceleration. This might require larger acceleration pumps to get me through?

Other than acceleration, it seemed to cruise just fine. I'm having a hard time deciphering if it could be lean or rich, if it matters at this point? After getting back and shutting the car off, the pipes were not red.

Also, would love an afr gauge, but they are kinda pricey and out of my budget at the moment. Long term, I think I'll definitely get one.