Hitachi Carb Upgrade?

[Datsui]

My carb just bit the dust, a pre-fire sent the primary venturi up into the choke flap and jammed it shut. After a long tow home and some very frozen fingers I got the carb off and reseated the venturi. Now the carb is dumping fuel into the engine and fouling the sparkplugs with just 10 minutes of idling. I'm guessing the idle adjusting screw was also damaged since turning it does nothing to affect idling. Ok so now for my question.

 

I'm assuming I need a new carb and since this is my daily driver I'm thinking of another hitachi (webers sound great but I'm not doing much racing in my four door wagon :). Oem-surplus.com has a newer (1980+) hitachi carb for $125 (#16010-H8760) and my Sunny B310 is a 1979 A14, would this be a direct bolt on or should I expect some problems?

[Jester]

The Weber is a good carb.I wouldn't call it a RACE carb. But, for $125, an oem is a good deal.

[Datsui]

The Weber is a good carb.I wouldn't call it a RACE carb. But, for $125, an oem is a good deal.

 

From what I've read the weber seems to be overkill, lessing mileage and only really good for 5K+ rpms? Do you have any idea if the carb mount on the 1980's 210 was different from earlier A-series engines?

[josh_t]

From what I've read the weber seems to be overkill, lessing mileage and only really good for 5K+ rpms? Do you have any idea if the carb mount on the 1980's 210 was different from earlier A-series engines?

 

 

i've had both an 81 and an 82 210 carb on my 76 b210. the bolt pattern for the carbs are the same. the only major difference would be the vacuum hoses. on mine, the emissions parts have been removed so that wasnt an issue for me.

[Datsui]

Mine's already had the emission delete, so it should be good to go? Awesome! Anything to look out for when installing the new one?

[ggzilla]

1981 & 1982 are different from 1980. But similar. Some have high-altitude fittings, some do not. CAN may be the same.

 

But 1971-1982 all will interchange. The fittings and such are different almost every single year, as are the jetting. Also different FED, CAN, CAL. It will work fine.

 

the weber seems to be overkill, lessing mileage and only really good for 5K+ rpms

For an A12 yes or for a 65HP A14. For an 80HP A14 the A14 stock carb is already larger, so maybe 4500 RPM.

 

Careful jetting can achieve close mpg to the stock Hitachi. But almost no one carefully tunes their 32/36.

[josh_t]

1981 & 1982 are different from 1980. But similar. Some have high-altitude fittings, some do not. CAN may be the same.

 

But 1971-1982 all will interchange. The fittings and such are different almost every single year, as are the jetting. Also different FED, CAN, CAL. It will work fine.

 

 

For an A12 yes or for a 65HP A14. For an 80HP A14 the A14 stock carb is already larger, so maybe 4500 RPM.

 

Careful jetting can achieve close mpg to the stock Hitachi. But almost no one carefully tunes their 32/36.

 

i have a holley 5200. you know, the weber copy. i like the water heated choke on it. it is the motorcraft holley. luckily mine is fully adjustable and doesnt have any of the fixed jets like some fomoco holley's. i'm all about careful tuning, so i'll be all over the jetting. too bad i dont have a real weber or i could make a how-to specifically for the 80hp A14. if i can afford it, i might even get a some dyno pulls for some evidence of the best jetting since there is a performance shop down the road from me that i think has a dyno.

[ggzilla]

Motorcraft was the Ford brand. I haven't seen any with fixed jets, but the jets are different from Weber.

 

Check the venture sizes of the Holley, as they vary. Mine is 26/27, same as the Weber DGV, but some 5200/5210 are smaller.

 

Is your A14 stock? Stock exhaust, cam, etc? If so here is the basic jetting that works well:

Venturis: 26/27

Auxiliary venturis: 3.5/3.5

Main jets: 140/140

Emulsion tubes: F50/F50

Air correction jets: 170/160

Idle jets: 60/50

Jump jet: 50

Needle valve: 2.00

 

As I understand those DGV size correspond to millimeters somehow. So maybe you can find the Holley 5200 jets that match. Although if your venturi sizes differ, you will need different jetting.

[josh_t]

Motorcraft was the Ford brand. I haven't seen any with fixed jets, but the jets are different from Weber.

 

Check the venture sizes of the Holley, as they vary. Mine is 26/27, same as the Weber DGV, but some 5200/5210 are smaller.

 

Is your A14 stock? Stock exhaust, cam, etc? If so here is the basic jetting that works well:

Venturis: 26/27

Auxiliary venturis: 3.5/3.5

Main jets: 140/140

Emulsion tubes: F50/F50

Air correction jets: 170/160

Idle jets: 60/50

Jump jet: 50

Needle valve: 2.00

 

As I understand those DGV size correspond to millimeters somehow. So maybe you can find the Holley 5200 jets that match. Although if your venturi sizes differ, you will need different jetting.

everything is stock on mine except the down pipe is 1.75" until half way down the exhaust it steps up to 2 1/4" before the glasspack and last section of exhaust. and timing is 15 deg. BTDC

[ggzilla]

The stock jetting should work fine.

 

You may want to dial the timing back, because that is 3 to 10 degrees more than the design specs. It will work fine for idle/midrange but could over-advance the engine at high RPM.

 

Spec for A-series engine is 30 to 38 degrees at 4100-4350 RPM. Your timing will put it at 36-40 degrees, possibly dangerous if on the 40 side of the distributor tolerance.

 

The best way is to put marks on the crank pulley, and set it for 36 degrees at 4200 RPM using an actual timing light. Then let your idle timing fall where it may (which differs by 7 degrees depending on which distributor you have). The dyno will tell you if 38 is better than 36. It all depends on the cam and the head (high swirl heads, like the round-port or the 1981-1982 swirl-port heads, need less timing to make more power).

[josh_t]

The stock jetting should work fine.

 

You may want to dial the timing back, because that is 3 to 10 degrees more than the design specs. It will work fine for idle/midrange but could over-advance the engine at high RPM.

 

Spec for A-series engine is 30 to 38 degrees at 4100-4350 RPM. Your timing will put it at 36-40 degrees, possibly dangerous if on the 40 side of the distributor tolerance.

 

The best way is to put marks on the crank pulley, and set it for 36 degrees at 4200 RPM using an actual timing light. Then let your idle timing fall where it may (which differs by 7 degrees depending on which distributor you have). The dyno will tell you if 38 is better than 36. It all depends on the cam and the head (high swirl heads, like the round-port or the 1981-1982 swirl-port heads, need less timing to make more power).

 

sweet. i didnt know it was that easy. i had one guy tell me it would be too difficult to do all that and i should leave it alone. but i have tested it as far as 20 deg. BTDC and 15 pulled the hardest and it hasnt pinged once. i'll have a look at datsun1200's tech wiki and see what they say about the timing curve. i really want to check that out.

[ggzilla]

It is really hard to hear pinging at 4,000 RPM full-throttle unless you have a stock exhaust ...

[josh_t]

i've done several WOT uphill pulls till 5k and checked the plugs and there is no "pepper" on them. its all gray-tan and no signs of overheating them. and at 10 deg. it feels like it cant even get up the hill. i have swapped the 1.75" muffler back on temporarily and i havent heard anything either. its an OEM style muffler. anything else i can check?

[ggzilla]

Sounds like it's OK then. More power to ya.

 

Datsun distributors have a tolerance of 2 cam degrees (4 crank degrees), so it can still be within spec, if your distributor is on the low side of the tolerance.

[josh_t]

Sounds like it's OK then. More power to ya.

 

Datsun distributors have a tolerance of 2 cam degrees (4 crank degrees), so it can still be within spec, if your distributor is on the low side of the tolerance.

 

haha literally more power to me. there is a little play on the dizzy gear. not anything ridiculous. but it is noticeable. i need to check what my max advance is after i get my stuck temperature sensor sorted out.

[ggzilla]

Play in the dizzy gear will not change the total advance. Just make it vary a little while running.

 

Datsui, the new Hitachi for $125 sounds good. You can't get a new Weber 32/36 for twice that. A new Weber will work well too, but at more than $300.

 

But what I do is look for good used carburetors. I paid $20 for my 1980 carburetor off eBay and it ran great on my 1971.

[Datsui]

Play in the dizzy gear will not change the total advance. Just make it vary a little while running.

 

Datsui, the new Hitachi for $125 sounds good. You can't get a new Weber 32/36 for twice that. A new Weber will work well too, but at more than $300.

 

But what I do is look for good used carburetors. I paid $20 for my 1980 carburetor off eBay and it ran great on my 1971.

 

The carb just arrived, and it has at least 7 extra connections compared to my old one. Anyone have a guide on how to hook/block these extra connectors up?

[josh_t]

the fitting on the base of the carb pointing towards the valve cover goes to the distributor vacuum advance. The two above it are blocked with vacuum caps on mine. i assume one goes to the egr valve, but i dont have an egr system anymore. I have the hoses going to the choke pulloff and the power valve actuator hooked up still, with the y shaped hose. The rest are all plugged up and the big fitting coming off the top of the carb for the vapor canister is left open as a vent. Mine runs great that way. Since yours has no emissions equipment either, then it should be the same for you.

[Datsui]

thanks for the help! I just got it installed :D except now it's got a bit of a stutter, or surging sound. Any idea what might be causing it? the carb is brand-new, just out of the bag<_<

[josh_t]

maybe a vacuum leak at the base gasket or maybe the idle mixture isnt adjusted right. it still is from a different engine. I had to adjust mine coming straight off of an 82 A15 going on my 76 A14. Chances are, its probably too lean. You can use your ear or a vacuum gauge to get it right. The gauge is better tho. lol

[ggzilla]

Brand new carb will need a tune-up. First verify the fuel level, then warm the engine fully, set the idle speeed and idle mixture. Don't set it with a vacuum gauge, use the procedure in the factory manual instead.

 

RE: the many connections, Plug all the vacuum connections except the lowest one (for the distributor). Keep the choke pull off vacuum line connected for best performance.

 

The "power valve actuator" is probably the vacuum secondaries, as the power valve is all internal. And if it has vacuum secondary that would make it a 1981-1982 carburetor which is very different from a 1980 carburetor.