jon521 Posted July 6, 2011 Report Share Posted July 6, 2011 hey i have a 71 521 with an L16. i am getting very bad mpg with. the two times i have checked it, it was 14 and 12. im not driving it super hard either. i think it may be my weber. i got this weber dfav in a trade awhile back, and (i know i should have pulled it apart and checked everythings size) put it on my truck. it runs just fine, just poor mpg. the guy i traded with is a friend of mine, who said it came off a 1.8 vw bug. i pulled my plugs and they are black as night, so im burning rich. could my poor mpg be due to the carb possibly being over jetted for my L16? thanks ps i do plan to take my carb apart and measure everything, but there are some other things i need to take care of first. Quote Link to comment
Skib Posted July 6, 2011 Report Share Posted July 6, 2011 ya its deff to rich. Iv got an L16 with closed chamber head, SU's, EI dizzy, cam, ect. and I still get 25-30MPG Quote Link to comment
jon521 Posted July 6, 2011 Author Report Share Posted July 6, 2011 Iv got an L16 with closed chamber head, SU's, EI dizzy, cam, ect. and I still get 25-30MPG damn that would be great to get atleast that much. so its probably over jetted? Quote Link to comment
Skib Posted July 6, 2011 Report Share Posted July 6, 2011 damn that would be great to get atleast that much. so its probably over jetted? prob, I dont do webers tho so I cant say %100 on the jetting part. its deff too rich tho. Quote Link to comment
jon521 Posted July 6, 2011 Author Report Share Posted July 6, 2011 alright thanks man Quote Link to comment
ggzilla Posted July 6, 2011 Report Share Posted July 6, 2011 Yes, the carb is too rich. L18 can run leaner mixture than L16 generally so it probably was too rich on the L18. You only need to change the primary main jet & air jet to start with. I'd try the "baseline" primary jetting which is #140 main with #165 air jet. Quote Link to comment
Wide14u Posted July 6, 2011 Report Share Posted July 6, 2011 i drive mine hard and i get 17 or 18 on bad days Quote Link to comment
jon521 Posted July 6, 2011 Author Report Share Posted July 6, 2011 Yes, the carb is too rich. L18 can run leaner mixture than L16 generally so it probably was too rich on the L18. You only need to change the primary main jet & air jet to start with. I'd try the "baseline" primary jetting which is #140 main with #165 air jet. sweet i will look into doin that. and dont i need to adjust jets to elevation too? i mean i will still probably start with the baseline, but i would like to get the correct jets for the correct elevation. also, should i buy a carb kit for when i take it apart? something like this http://cgi.ebay.com/ebaymotors/Weber-Carburetor-32-36-DGV-DGAV-DGEV-Rebuild-Repair-Kit-_W0QQcmdZViewItemQQhashZitem53e5e161d2QQitemZ360339038674QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories? Quote Link to comment
ggzilla Posted July 6, 2011 Report Share Posted July 6, 2011 DGV almost never need a carb kit. The gaskets are reusable. What altitude are you at? For mile-high, use even smaller jets... Quote Link to comment
jon521 Posted July 6, 2011 Author Report Share Posted July 6, 2011 DGV almost never need a carb kit. The gaskets are reusable. What altitude are you at? For mile-high, use even smaller jets... im between 135 and 150 above sea level Quote Link to comment
datzenmike Posted July 6, 2011 Report Share Posted July 6, 2011 Even if that was yards above sea level, it's nothing. You would have to be thousands of feet up. Quote Link to comment
jon521 Posted July 6, 2011 Author Report Share Posted July 6, 2011 Good to know, thank you! Quote Link to comment
banzai510(hainz) Posted July 6, 2011 Report Share Posted July 6, 2011 521s dont get the best milage due to the gear ratio I get about 19/20 the DGFV is a reversed throttle carb meaning the main barrel is on the outside on the manifold. ON reg carbs the main barrel is next to the valve cover . the manifold has different hole sizes so they dont match up. I dont know why people get the DGFV versions. I think they came on french cars just so the French say they are different. also time the motor with a timming light. I dont know if the jetting can be that far off to get 12mpg. I run a 38/38 and I get better. By chance you have a electric fuel pump over pressure??????? or stock maual. if stock manual then your OK. If electric you need a reg it down to like 3 pounds Quote Link to comment
jon521 Posted July 6, 2011 Author Report Share Posted July 6, 2011 521s dont get the best milage due to the gear ratio I get about 19/20 the DGFV is a reversed throttle carb meaning the main barrel is on the outside on the manifold. ON reg carbs the main barrel is next to the valve cover . the manifold has different hole sizes so they dont match up. I dont know why people get the DGFV versions. I think they came on french cars just so the French say they are different. also time the motor with a timming light. I dont know if the jetting can be that far off to get 12mpg. I run a 38/38 and I get better. By chance you have a electric fuel pump over pressure??????? or stock maual. if stock manual then your OK. If electric you need a reg it down to like 3 pounds i was thinking about switching out the diff gears to a 720 gearing. i havent researched it yet, but i was told by someone that it was alot easier than a 5 speed swap, that it just bolts right up, but that for another thread..... i got the dfv because i got it in a good trade (good for me) and i didnt have the money to buy a new one so i kept it, stupid French dont do anything right.... i believe my brother has a timing light i can borrow, i will check it but i wanna know what my jets are so im going to pull the carb apart too. im running stock manual fuel pump. Quote Link to comment
banzai510(hainz) Posted July 6, 2011 Report Share Posted July 6, 2011 be honest do the timming light first.cost nothing unless you buy one. The jetting is going to be close enough believe me unless it was fucked with. Quote Link to comment
datzenmike Posted July 6, 2011 Report Share Posted July 6, 2011 Dirty air filter Brake dragging Chokeon/stuck Quote Link to comment
jon521 Posted July 7, 2011 Author Report Share Posted July 7, 2011 Dirty air filter Brake dragging Chokeon/stuck air filter is practically brand new, only few hundred miles on it. i will check the brakes. they should be adjusted so you can hear them just brushing right? it idles at about 800. i am not sure if the plates are opening all the way, but that wouldnt have do to with richer/leaner right? just air flow? maybe im wrong.... i still have yet to check my jets...... as far as setting my timing, i looked at my crank pulley, and i saw nearly 7 notches in it, and i couldnt find the marker on the block. i havent set the timing on anything before, ive only seen it been done. Quote Link to comment
ggzilla Posted July 7, 2011 Report Share Posted July 7, 2011 To check the brakes, jack up a wheel, and see if you can spin the tire with your pinky. If not, something is dragging (brakes, probably). Quote Link to comment
ggzilla Posted July 7, 2011 Report Share Posted July 7, 2011 it idles at about 800 yes that will cause a B210 to diesel for sure. Set it to 600 RPM and it might help. Quote Link to comment
datzenmike Posted July 7, 2011 Report Share Posted July 7, 2011 hey i have a 71 521 with an L16. i am getting very bad mpg with. Also a jet may have come loose and unscrewed? Have to ask what the plugs look like? Black dry, black wet? Gas tank leak? Quote Link to comment
jon521 Posted July 7, 2011 Author Report Share Posted July 7, 2011 yes that will cause a B210 to diesel for sure. Set it to 600 RPM and it might help. i have a 521, but i guess if they are both L16s its the same. isnt 600 a little low? under the hood on the little info decal it say set to 700 or 750. DM i will pull the carb apart as soon i locate a float seal, just in case something goes bad with the seal, i want to put it back together and drive it (its may daily). they are black and dry i believe but will pull again to make sure and will check the gas tank plug. i do not leave any puddles any where i sit for awhile so im guessing its not a tank leak, but i will check any ways. Quote Link to comment
banzai510(hainz) Posted July 7, 2011 Report Share Posted July 7, 2011 as far as setting my timing, i looked at my crank pulley, and i saw nearly 7 notches in it, and i couldnt find the marker on the block. i havent set the timing on anything before, ive only seen it been done. Start there first!!!!!!!!!!This will help choke plate. If its a electric choke and you dont have 12volts on it the choke plate will always be closed and get bad gas milage and possible no high end as the palte is blocking. Only you know if its electric choke or manual. Quote Link to comment
LenRobertson Posted July 7, 2011 Report Share Posted July 7, 2011 If vacuum advance diaphragm is bad, what does it do to mileage? How about running hotter? Or does it just lower power? I tested about 8 dizzys I have around here, and only found 1 or 2 that passed the suck test. Makes me wonder how many Datsuns on the road have no vacuum advance. But maybe it doesn't matter that much. I've never known for sure. Len Quote Link to comment
jon521 Posted July 7, 2011 Author Report Share Posted July 7, 2011 as far as setting my timing, i looked at my crank pulley, and i saw nearly 7 notches in it, and i couldnt find the marker on the block. i havent set the timing on anything before, ive only seen it been done. Start there first!!!!!!!!!!This will help choke plate. If its a electric choke and you dont have 12volts on it the choke plate will always be closed and get bad gas milage and possible no high end as the palte is blocking. Only you know if its electric choke or manual. well i know you line up a notch on the pulley to the marker on the block, but i dont know where the maker on the block is, and i dont know what notch to set it to if i knew where my marker on the block was. i have an electric choke and i have 12v to it Quote Link to comment
banzai510(hainz) Posted July 7, 2011 Report Share Posted July 7, 2011 usually if a L16 its just a pointer that is atthached with a 10mm head bolt. on left side of the front cover. I cant post a PHOTO BUT SOEMONE HAS IT. Quote Link to comment
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