SickLD28 Posted September 10, 2013 Report Share Posted September 10, 2013 I have a L28 crate engine with a V07 Diesel Crankshaft. Drag Cam I would say (4000-6000RPM) l24 8mm rods ka24 cast pistons stainless steel valves Triple Dellorto Carbs (40 DHLA Non- Emission) Does this model have a air bypass screw used to adjust for timining along with the fuel mixture screw?? My carbs have been tuned strictly with the fuel mixture screws. I have not adjusted anything else except for the linkages.* LOOK at the PIC BELOW** I have used a Holley Black fuel pump with a holley regulator running at 3-4PSI, and I was running SUPER RICH. I changed the fuel pump out and put a carter pump without a fuel regulator. I ran it with a return though, with a needle valve connected to adjust psi.( I was only able to do slight increases in psi) Even with this change I was still running super rich. However, a hair length decrease of smoke... FYI: the timing, tuning of carbs, and even at the leanest condition of fuel mixture for the carbs I am still blowing out black smoke. Mechanics have suggested that my cam is a drag cam, and therefore the engine loves the richness of the fuel, which is why I cannot get rid of the black smoke... Another mechanic suggested that my idle jets are off... I have even adjusted my float levels on all carbs, and they are all at good levels. Not to mention redoing the timing multiple times. Also adjusted all the lashes. ( does anyone have recommendations on the measurement of lashes?) exhaust and intake.. Can anyone point me in the right direction to cause this richness in fuel? I am literally smoking black smoke every where I go. Here are some pics: http://i567.photobucket.com/albums/ss115/squannn/81f82232-04e8-4246-b5f5-175626817d48.jpg http://i567.photobucket.com/albums/ss115/squannn/photo3.jpg Quote Link to comment
Farmer Joe Posted September 10, 2013 Report Share Posted September 10, 2013 it comes down to the jetting of the carbs... were they setup for this engine? if its rich, then youll have to find out how many jet sizes to go down. theres more to it than just the jets too. side drafts will have different venturi sizes that have to be sized according to how much air the engine will take. there are others on the board that know more about weber jetting than i do. Quote Link to comment
SickLD28 Posted September 10, 2013 Author Report Share Posted September 10, 2013 I agree with you. And to answer your question, no they have not been jetted for this engine. I actually bought the carbs used and supposedly "rebuilt", however I can assume the engine I have now is more powerful than what the previous owner was running... Any advise for the correct jetting for my engine? it comes down to the jetting of the carbs... were they setup for this engine? if its rich, then youll have to find out how many jet sizes to go down. theres more to it than just the jets too. side drafts will have different venturi sizes that have to be sized according to how much air the engine will take. there are others on the board that know more about weber jetting than i do. Quote Link to comment
Farmer Joe Posted September 10, 2013 Report Share Posted September 10, 2013 honestly, i dont know... youll have to get it hooked up to an air/fuel mixture gauge, and youll need a few sets of jets to play around with. where are you at? might be worth your time to get it tuned by a professional? Quote Link to comment
72240z Posted September 10, 2013 Report Share Posted September 10, 2013 You jet to the CC, google it and youll find how to do it. Searching will also show other people with similar or the same set up and what they are running. Quote Link to comment
flyfish Posted September 10, 2013 Report Share Posted September 10, 2013 Advice.. Know your jets; find out what you have in each of the carburretors so you can relay that to the professional you seek advice from.. There would be a basic starting point (sizes of all jets, emulsion tubes, etc.) where you need to be. Once you have that info, post it here. There's no use guessing where to go. Quote Link to comment
SickLD28 Posted September 11, 2013 Author Report Share Posted September 11, 2013 Advice.. Know your jets; find out what you have in each of the carburretors so you can relay that to the professional you seek advice from.. There would be a basic starting point (sizes of all jets, emulsion tubes, etc.) where you need to be. Once you have that info, post it here. There's no use guessing where to go. I agree with you. Anyone have any idea about the air bypass screws?? Does my dellorto 40 DHLA require the screws? I do not see any threads in the holes. Quote Link to comment
EricJB Posted September 12, 2013 Report Share Posted September 12, 2013 Some carbs don't come with an air bypass. I think your over thinking this. It's not the cam. ( I run a sizable cam with 48 dcoe's and it doesn't smoke.) Where are the air fuels at? If you turn one down till it's shut, does that cylinder die? If not, you have fuel getting in elsewhere, or your idle speed screws are in too far. If so, turn each one in, one at a time till it starts to die out. Then out slowly till it comes back, +1/4 turn. My guess is still fuel pressure or float levels. Quote Link to comment
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