Carb swap, and all the adjustments with it.

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JR

JR

Pissed off senior member.
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I took off the Eddy carb on my 73 so I could rebuild it and I replaced it with a rebuilt (with a stock BG rebuild kit) 625 BG road demon. I am trying to fine tune this thing the best I can for daily driveability until I get the eddy back on.
It is a 76 360 block bored 40 over I used a Summit rebuild kit (page 118 of the new summit catalog) Sealed Power/ Fel-Pro kit with hypereutectic 8.66:1 pistons. The crank and rods were the stock 76 units, the heads were picked up at the Portland, OR swapmeet and were rebuilt later (nonmagnum) heads with 2.02s and real nice port job. ARP bolts and studs hold all the gutts togeather.
The cam is from Delta cams in Tacoma, WA www.deltacam.com and set at 4* advanced on the keyway.

Specs. INT EXH

Dur Deg@ .050 210 220
Valve Lift .429 .444

Ignition is a stock electric dist, MSD blaster 2 coil, and a chevy 4 pin HEI unit (don't give me crap, It's worked fine for 3 motors, I did it before that guy started selling the kits and I don't have to worry about my ballast going tits up. Hell Im also running a chevy alternator). Intake is a Eddy performer.

For the 4 corner screws the fronts are 3/4 of a turn out and the rears are 1/2 a turn out. Float lev. is 1/2 way up the sight glass.


At idle with the dist. vacume plugged and a vac. guage hooked up to constant vac at the carb baseplate.

DSC04107.jpg


Temp is 180* and at idle.

DSC04110.jpg


Cam is set at 4* advanced on the keyway. This pic is at idle. (center of the black line is 0*)
DSC04109.jpg



At idle.
DSC04110.jpg


Im also running into a clearance issue with the vacume advance on the dist and the rear of the intake.
DSC04112.jpg



When I hold it at 2000 RPM timming is at 31*

These carbs are a ***** to tune on a street car and I will admit I don't know that much about Holley type carbs. The main problems Im having right now is when I come to a stop it kinda sputters like Im getting some fuel slosh, can I just adjust the float lev a little higher? I know that too much is bad on these carbs.
Im not getting anymore blue or black smoke with these settings and it seems to run fine. After a good cleanning and a few high speed test runs down the freeway my plugs are right where they should be with no fouling but my exhaust smells more like gas than with the Eddy carb.

Anyone else having a clearance issue with the vacume advance on the dis. and the rear of the intake or am I stupid and have something adjusted wrong?
 
if the float setting is like holleys, yours is too high. you should be able to take the sight plugs out and it is just below the lip and will sometimes spill out if your motor moves around. what is the timing at 2500, 3000? you need to make sure you find TOTAL timing and at what rpm it is at.
 
redfastback is correct. floats are set to high. should just wet threads at bottom of sight plug. good place to start.
 
And for that vacuum pod hitting the back, take out the distributor and move it one or two teeth to rotate the canister away.
 
I lowered the fuel level and it got rid of the sloshing. If I take out the distributer and the oil drive gear and move it a few teeth wont that take the aim off of the #1 cylinder when at TDC and screw up all the timming or will only one or 2 teeth still be ok, at the maximum how may teeth would be with in the "safe" range?
 
Barry Grant carbs have a non-removable site plug. The nominal setting is in the middle of site glass.

The position of the distributor is not relevent. As long as when you are at top dead center on #1 the rotor is pointing to where the number one wire is on the cap and the rest of the wires are in the correct order you are fine.

Instead of pulling the distributor and oil pump drive just move all the wires on the cap over one and rotate the distributor so it's pointing to #1 and you will accomplish the same thing.
 
dave, very interesting about bg carb float levels and sight glass. i thought they might be just like holleys in that respect.

360scamp, what is the timing at when you hold it at 2500rpm?3000rpm? is that pic showing 21* advanced at 901rpm?
 
All those pics are at idle. At 2000 RPM it is at 30*I will check 2500 and 3000 when I get home from work today and repost.
I had the base settings so the fuel level was at 1/2 way on the sights and it didn't work for crap. I lowered it to where redfastback said and it improved a whole lot. These BG carbs are kinda sorta like holleys they make great racing carbs but for the street I would keep my Eddy!
 
If you drop the primary jets down one or 2 sizes and lean out the idle mixture you can put the float level back up to BG recomendations. Personally the Holley is a better carb than the BG...they are similar but they are very different. What PV do you have installed? The PV should be 1.5" less the in gear idle vaccum.
 
The only differences in the BG carb is it was designed to generally run better leaner rather than richer. They are very good carbs. So good in fact, I dont like them. They are a pain to keep in tune if you live where days are 50° and nights are 30. The floats, Dave is right. Tehy should be center of the glass, but there is a little lee-way, and if it is splashign around or stalling due to excess fuel on stopping, you can lower the floats a little. There are lines cast in the bowl next to the sight plug. Go one line lower than dead center, see if that cures it. Now, being that Holleys and BGs are basically the same, the same settings need to be addressed if it's not what your engine likes. So basic tuning comes in to play. First, you have to get your timing set. If your distributor is indeed stock, including the vaccum pod and advance weight springs, you have some improving you can do. For now, a stock distributor will not let you run more than about 12° initial without giving you fits at higher rpms. So with the vaccum hose disconnected at the pod and plugged, set your initial timing at 10 or so, and clamp the dist down. Then move to the carb. First, set float level. Get yourself a vaccum gage and plug it on the port below the float bowl. That's manifold vacum. Then, fire the engine and set the idle speed to 700 by your timing light or tach. Now you can set the idle mix be the fastest rpm and highest vaccum reading (should happen simultaneously) you get by turning the screws in very small amounts in or out as required. Then while keeping the vaccum gage in view, hold the brakes, and drop it in gear. Get the reading off the vaccum gage. If it's below 8" in gear at hot idle, then you will want to pull the front bowl and verify the power valve is correct. If not, replace it with the right one, and start with the idle speed and mix adjustment again. When that's set, you can start with the drving and jetting part, and the secondary spring and squitor routine.

It might be easier to rebuild the Edelbrock ;)
 
I rebuilt the Eddy lastnite as soon as I got home and it's going on today after work! The BG is a neat carb but not for a daily driver in Seattle, WA (it's snowed the last 2 days).
Im going to reset the dist drive gear a few teeth over to get the vacume pot away from the back of the intake and reset the timming as well.

So far the BG has run the best on my car with the fuel lev just below the sight glass, front screws 3/4 turns out and the rear screws 1/2 turn out.
 
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