pl521sss Posted September 24, 2008 Report Share Posted September 24, 2008 I swapped my Weber to Hitachi DCH328. Opted for a smoother engine and suffer on the performance. Removed the diaphragm assembly (#9 on the drawing) that connects to the secondaries. It got in the way of the throttle cable (long story) but can explain if needed to be. Question Now that this diaphragm removed, what issues will I expect at WOT or at least when the secondaries starts to open? Quote Link to comment
datzenmike Posted September 24, 2008 Report Share Posted September 24, 2008 :lol: The diaphragm is what opens the secondaries. .... (I hate when that happens!) Quote Link to comment
ppeters914 Posted September 24, 2008 Report Share Posted September 24, 2008 I swapped my Weber to Hitachi DCH328.Opted for a smoother engine and suffer on the performance. Removed the diaphragm assembly (#9 on the drawing) that connects to the secondaries. It got in the way of the throttle cable (long story) but can explain if needed to be. Question Now that this diaphragm removed, what issues will I expect at WOT or at least when the secondaries starts to open? :lol: The diaphragm is what opens the secondaries. .... (I hate when that happens!) Ummmm, does that mean suffer performance -AND- mpg? :eek: Quote Link to comment
pl521sss Posted September 24, 2008 Author Report Share Posted September 24, 2008 :lol: The diaphragm is what opens the secondaries. .... (I hate when that happens!) Well, the secondary butterfly is free to move as soon as it passes certain throttle position. At that point I would think the force of the air going in will make the butterfly just open up. Ummmm, does that mean suffer performance -AND- mpg? :eek: Weber is quicker off the line and any speed. MPG is hard to tell cause it's not noticeable yet. Still goes with no problem even in the highway. Can reach 80MPH with no problem. If that diaphragm is really what opens it then have to figure out how to get it in there to work with the throttle cable. Will take picture during the day to show what I mean. Quote Link to comment
datzenmike Posted September 24, 2008 Report Share Posted September 24, 2008 Big thing is to be sure it will close when you let off on the gas. If it jams full open the primary interlock may not reach it to close it. Quote Link to comment
dat521gatherer Posted September 24, 2008 Report Share Posted September 24, 2008 according to this the hitachi gets better mileage and runs smoother than the weber 32/36. not trying to start the old war back up but i have heard this from other people also. http://wiki.datsun1200.com/index.php/Hitachi_DCH340 somewhere a few years ago there was a real good comprehensive write up on the hitachi vs weber but i cant find it. i'll keep looking. so both sides still say that each is smoother, more power and better mileage. personally i have webers on my l16 and l20b but i had a dch340 once that would smoke the pants off a weber and was smooth with good mileage. i wish they weren't so temperamental. i'm planning on checking out my hitachi's to see if i can get better mileage. i have a couple 328's. the 340 is the one to get. sorry i have no answers for you. i haven't ran a hitachi for many years. Quote Link to comment
pl521sss Posted September 24, 2008 Author Report Share Posted September 24, 2008 Big thing is to be sure it will close when you let off on the gas. If it jams full open the primary interlock may not reach it to close it. It closes when you release the throttle. That diaphragm then is what resist the secondary butterfly from just opening up right away. I'm intrigue on Hitachi DCH340 and how it can be made to work better than Weber 3236. Anyone have one for sale? Quote Link to comment
pl521sss Posted September 24, 2008 Author Report Share Posted September 24, 2008 Big thing is to be sure it will close when you let off on the gas. If it jams full open the primary interlock may not reach it to close it. according to this the hitachi gets better mileage and runs smoother than the weber 32/36. not trying to start the old war back up but i have heard this from other people also.http://wiki.datsun1200.com/index.php/Hitachi_DCH340 somewhere a few years ago there was a real good comprehensive write up on the hitachi vs weber but i cant find it. i'll keep looking. so both sides still say that each is smoother, more power and better mileage. personally i have webers on my l16 and l20b but i had a dch340 once that would smoke the pants off a weber and was smooth with good mileage. i wish they weren't so temperamental. i'm planning on checking out my hitachi's to see if i can get better mileage. i have a couple 328's. the 340 is the one to get. sorry i have no answers for you. i haven't ran a hitachi for many years. Other reason why I switched back to entertain the idea of better Hitachi carb. http://dimequarterly.tierranet.com/articles/tech_carb_tuning_guide.html Quote Link to comment
dat521gatherer Posted September 24, 2008 Report Share Posted September 24, 2008 i hear ya. found it, now to find the follow up custom tuning artical. if anyone finds it please post it. http://dimequarterly.tierranet.com/articles/tech_carb_tuning_guide.html Quote Link to comment
lynchfourtwenty Posted September 24, 2008 Report Share Posted September 24, 2008 i'll stick with my weber :P or go dual's of some kind Quote Link to comment
ppeters914 Posted September 26, 2008 Report Share Posted September 26, 2008 Interesting. Keep us informed. A Weber came on my L20b, so I'll stick with that for now. Quote Link to comment
pl521sss Posted September 26, 2008 Author Report Share Posted September 26, 2008 Interesting. Keep us informed. A Weber came on my L20b, so I'll stick with that for now. it's already been done and proven. Read this article on DQ. http://dimequarterly.tierranet.com/articles/tech_carb_tuning_guide.html Still looking for a DCH340 Quote Link to comment
ppeters914 Posted September 26, 2008 Report Share Posted September 26, 2008 Yes, I've reviewed it, however, that's the only time I've heard anything good about the Hitachi carbs. OTOH, few people were successful with the stock Rochester QuadraJet (fondly known as the QuadraJunk) on Chevy's although there were a few folks successfully racing with them. Quote Link to comment
bonvo Posted September 27, 2008 Report Share Posted September 27, 2008 take it from me someone who cant change carbs due to smog junk the hitachi there such crap i have had to do so much work on mine just to keep the damn thing together i dont know if you will have the same problem because you are runnining s cable but the action of the linkage causes the carb to seperate :eek: thus giving you a huge leak Quote Link to comment
pl521sss Posted September 27, 2008 Author Report Share Posted September 27, 2008 Yes, I've reviewed it, however, that's the only time I've heard anything good about the Hitachi carbs. OTOH, few people were successful with the stock Rochester QuadraJet (fondly known as the QuadraJunk) on Chevy's although there were a few folks successfully racing with them. Good point I won't use Hitachi carbs for racing either Didn't like them for a long time cause don't want that air filter housing and other hoses that goes with it. Solution, run it without the housing. Hands down, Hitachi is a lot smoother and works well in cold mornings. take it from me someone who cant change carbs due to smog junk the hitachi there such crap i have had to do so much work on mine just to keep the damn thing together i dont know if you will have the same problem because you are runnining s cable but the action of the linkage causes the carb to seperate :eek: thus giving you a huge leak Hitachi carbs are complicated If not overhauled right, won't run right. That's where the issue your having. I say this cause I have a properly overhauled Hitachi carb (like new condition) and it's perfect. This is not to convince folks to switch over. Stay with what works for you. Hitachi carbs are not junk They would be if their old and worn out hence it will work like crap. Quote Link to comment
sdsurf Posted October 6, 2008 Report Share Posted October 6, 2008 Does anyone have a pic of the stock throttle cable as it attaches to the carb? I get how the end hooks on but there is a "stop" I believe is missing... Quote Link to comment
pl521sss Posted October 6, 2008 Author Report Share Posted October 6, 2008 Does anyone have a pic of the stock throttle cable as it attaches to the carb? I get how the end hooks on but there is a "stop" I believe is missing... Not sure what your looking for but this is what mine looks like. Carb is out of a 510 and it's slightly different. Removed the secondary diaphragm and swapped the throttle mechanism from my old 521 Hitachi carb to work with the cable rather than the linkage. Quote Link to comment
sdsurf Posted October 6, 2008 Report Share Posted October 6, 2008 perfect! the bracket mounted to the intake mani... I hope I have it somewhere Quote Link to comment
pl521sss Posted October 6, 2008 Author Report Share Posted October 6, 2008 perfect! the bracket mounted to the intake mani... I hope I have it somewhere hmmm what carb did you have before this? Are you switching back to the OEM carb? Quote Link to comment
bonvo Posted October 6, 2008 Report Share Posted October 6, 2008 Hitachi carbs are complicated If not overhauled right, won't run right. That's where the issue your having. I say this cause I have a properly overhauled Hitachi carb (like new condition) and it's perfect. This is not to convince folks to switch over. Stay with what works for you. Hitachi carbs are not junk They would be if their old and worn out hence it will work like crap. it was rebuilt by an ase certified master tech (my dad he even has the papers to proove it) it works just fine just i find the car kinda starves for fuel in the higher rpm ranges (i like to beat on it once in a while) that and finding a good rebuild kit (all the diaphrams for the secondaries and so on) is really really hard and there a pain in the ass to tune Quote Link to comment
pl521sss Posted October 6, 2008 Author Report Share Posted October 6, 2008 it was rebuilt by an ase certified master tech (my dad he even has the papers to proove it) it works just fine just i find the car kinda starves for fuel in the higher rpm ranges (i like to beat on it once in a while) that and finding a good rebuild kit (all the diaphrams for the secondaries and so on) is really really hard and there a pain in the ass to tune hmm ok exactly what do you mean by hard to tune? There's only fuel mixture and idle speed to work with it for you standard motor. So your saying Hitachi's are junk? Like I said, Hitachi's are not for everybody specially if you don't like it to begin with. I LOVE IT Quote Link to comment
SickDrift Posted October 6, 2008 Report Share Posted October 6, 2008 I learned recently that those idle and mixture screws are only for idle (mostly), idle I knew, a/f I didn't. To tune these properly a person would have to do tons of runs with different jets to figure out what works best on any engine. Bleh. Gimmie fuel injection any day. Quote Link to comment
sdsurf Posted October 6, 2008 Report Share Posted October 6, 2008 hmmmwhat carb did you have before this? Are you switching back to the OEM carb? I was Taking different pieces from a couple of places (2 trucks) to get where I am at. The truck it is in didn't have the throttle cable so it came from somewhere else. Quote Link to comment
bonvo Posted October 6, 2008 Report Share Posted October 6, 2008 Not sure what your looking for but this is what mine looks like.Carb is out of a 510 and it's slightly different. Removed the secondary diaphragm and swapped the throttle mechanism from my old 521 Hitachi carb to work with the cable rather than the linkage. how is the trottle responce over the linkage? and i guess junk is to strong a word but there not my favorite if i could i would rather run a weber Quote Link to comment
sdsurf Posted October 7, 2008 Report Share Posted October 7, 2008 I need the bracket pictured. anyone? Quote Link to comment
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