0-60

[datzenmike]

You buy fuel pumps by their rated output don't you? The 720 is 2.7-3.4 PSI

[captain720]

1 minute ago, datzenmike said:

You buy fuel pumps by their rated output don't you? The 720 is 2.7-3.4 PSI

Yes I do, but this 720 has had some weird stuff done to it

[datzenmike]

On 9/30/2021 at 6:47 AM, captain720 said:

He has no fuel pressure regulator, his carbs detuned to run with no choke, plug wires mis match. Seems to be overflowing the float bowl sometimes

 

 

 

 

9 hours ago, That Ol 720 said:

My timing is factory spec 3 BTDC and u replaced the fuel filter about 2 weeks ago. My carb is brand new and was put on when my engine was rebuilt about a year ago. Haven't checked the valves tho. 

 

 

He says carburetor is new, no mention of it being a Weber so I assume Hitachi. If it's a Weber it should have been stated long before now. If it's an Hitachi you can't buy new just Chinese knockoffs or 're-conditioned' which is just as bad. Usually a new Weber is fine with 3 PSI. 

[captain720]

He has a Weber 32/36 

[datzenmike]

Turn the key on and look down the carburetor. If it's going to flood it will do it when not taking gas out of the carb to idle. Even less likely when driving.

[Veraciousreasoning]

10 hours ago, datzenmike said:

 Timing is 5 degrees +- 2 degrees so you are on the low side.

 

 

Backfire out the exhaust or the carburetor?  Spark plug wires have no real expiry date. If they look old then they are and need to be replaced. Check the distributor cap insides and the rotor. Under load the spark has a much harder time jumping the plug gap and will look for an easier path to ground. Like a crack in the cap or insulation on the boots or wires. 

 

 

 

 

The 720 is perfectly capable of above highway speeds. It sounds way worse than it is. It's not really revving that much

 

Yea, I haven't done a timing chain or valve tune up yet. I usually shift around 3-4,000 rpms and it just sounds so loud. I also have a non existent muffler system so I do believe a lot of that sound is coming from the muffler system. 

[datzenmike]

Timing chain replacement is not indicated yet. Valves are easy to check and should be part of a tune up right away. Get a muffler on there, you can't hear your truck taking to you. It will tell you what's wrong if you listen to it.

[Madkaw]

I actually was thinking of starting a 0-60 thread . It is actually a ballpark indicator of how the truck runs . Not for bragging rights , but for some real world perspective . Folks have commented that my 3.90 gear on a 4WD drive would be soggy , but it really isn’t . How would I compare to another truck that was tuned ? 
I did this with my Z . How do most production cars get compared ? 0-60 times. You think you 

Does the 38/38 really give you added hp? Or just a grunt of torque for a second but gulping the fuel 

[bottomwatcher]

4 hours ago, Madkaw said:

I actually was thinking of starting a 0-60 thread . It is actually a ballpark indicator of how the truck runs . Not for bragging rights , but for some real world perspective . Folks have commented that my 3.90 gear on a 4WD drive would be soggy , but it really isn’t . How would I compare to another truck that was tuned ? 
I did this with my Z . How do most production cars get compared ? 0-60 times. You think you 

Does the 38/38 really give you added hp? Or just a grunt of torque for a second but gulping the fuel 

Instead of from a dead stop for a time which would have a bunch of variables. Shift points, temperature ect. Start timing at 4th gear at 40 and see how long it takes to reach 70 without any shifting. This makes for great repeatability when tuning a car and you are not flogging your vehicle. Now if I can find a flat spot in Maine I can give a KAE time. This may take a while.

[captain720]

Finding a flat spot where you can do 70 is not really possible hear either 😂

[Veraciousreasoning]

5 hours ago, datzenmike said:

Timing chain replacement is not indicated yet. Valves are easy to check and should be part of a tune up right away. Get a muffler on there, you can't hear your truck taking to you. It will tell you what's wrong if you listen to it.

 

Yea, the muffler system is royally fucked. I am just finding the parts that would work with the 80 720 and seeing how much it cost. I basically need an entire new system. All of the piping is rusty and got a bunch of holes and shakes. 

[captain720]

I have tried a bunch of mufflers and stuff, a magnaflow does a good job of taking out some of the "4cylinder" raspyness but if you don't care about the tone anything works

[A guy named Rick]

my best 0-60 was 10.2, about 17.5 1/4 mile @ 76 mph. All stock, weber 32/36, 2wd, 2.4 napz. 5-speed. I launched it too (idk how many rpm), and let off the gas a fraction of a second after clutching in to gaim some rpm before shifting up to help it lurch forward on the next gear.

 

But yes these are not performance vehicles lol. i just wanted to see what it was capable of.

[None_zero]

I have about 18" with a slight downward turn at the end after the muffler (not by design mind you its just what was still there when the section i added bailed going down the interstate) I decided to leave as is because people always make a point to mention that the truck sounds "bigger" than it is. And for some reason I enjoy that

Edited October 2, 2021 by None_zero

[Madkaw]

58 minutes ago, A guy named Rick said:

my best 0-60 was 10.2, about 17.5 1/4 mile @ 76 mph. All stock, weber 32/36, 2wd, 2.4 napz. 5-speed. I launched it too (idk how many rpm), and let off the gas a fraction of a second after clutching in to gaim some rpm before shifting up to help it lurch forward on the next gear.

 

But yes these are not performance vehicles lol. i just wanted to see what it was capable of.

That’s actually not too bad for these turds

[datzenmike]

6 hours ago, Madkaw said:

I actually was thinking of starting a 0-60 thread . It is actually a ballpark indicator of how the truck runs . Not for bragging rights , but for some real world perspective . Folks have commented that my 3.90 gear on a 4WD drive would be soggy , but it really isn’t . How would I compare to another truck that was tuned ? 
I did this with my Z . How do most production cars get compared ? 0-60 times. You think you 

Does the 38/38 really give you added hp? Or just a grunt of torque for a second but gulping the fuel 

 

For tuning purposes, 30-70 is better as launches are not really repeatable and certainly not comparable between vehicles. Traction, weather, temperatures, tires, gearing, clutch and hand/eye coordination all affect the results. 

 

The 38/38 would benefit the top end grunt. However at 30, suddenly opening up this style carburetor might cause a loss of grunt till it clears out. It would be ok for tuning comparing the same vehicle but not comparable to other vehicles with different carburetors.

[datzenmike]

1 hour ago, Veraciousreasoning said:

 

Yea, the muffler system is royally fucked. I am just finding the parts that would work with the 80 720 and seeing how much it cost. I basically need an entire new system. All of the piping is rusty and got a bunch of holes and shakes. 

 

Unless the pipes are crushed the condition of the exhaust won't affect the running much. It's much easier to hear the engine and drive train 'talk to you' with a quieter exhaust.

[datzenmike]

1 hour ago, A guy named Rick said:

my best 0-60 was 10.2, about 17.5 1/4 mile @ 76 mph. All stock, weber 32/36, 2wd, 2.4 napz. 5-speed. I launched it too (idk how many rpm), and let off the gas a fraction of a second after clutching in to gaim some rpm before shifting up to help it lurch forward on the next gear.

 

But yes these are not performance vehicles lol. i just wanted to see what it was capable of.

 

17.5 sound about right.

 

 

7 minutes ago, None_zero said:

I have about 18" with a slight downward turn at the end after the muffler (not by design mind you its just what was still there when the section i added bailed going down the interstate) I decided to leave as is because people always make a point to mention that the truck sounds "bigger" than it is. And for some reason I enjoy that

 

I have stock resonator and a 1/4" expander to a 2" or 2 1/8 " size, then a larger than stock generic muffler and a 45 degree down turn outlet in front of the axle on my 710. Yes, exiting the muffler under the vehicle seems to lower the tone.  Maybe the sound bounces off the ground and the body becomes a sounding board

[A guy named Rick]

2 hours ago, Madkaw said:

That’s actually not too bad for these turds

Especially for mine not being 100%. Would have been a little stoked if it was in the 9's on 0-60. Hell, i think I was only running mechanical advance at that time before realizing I had the outer hard vacuum lines crossed, so there was no vacuum to the distributor advance. May have worked in my benefit or balanced out because I was running higher timing at idle. I noticed more torque at lower rpms after fixing the vacuum advance.
 

[A guy named Rick]

2 hours ago, datzenmike said:

I have stock resonator and a 1/4" expander to a 2" or 2 1/8 " size, then a larger than stock generic muffler and a 45 degree down turn outlet in front of the axle on my 710. Yes, exiting the muffler under the vehicle seems to lower the tone.  Maybe the sound bounces off the ground and the body becomes a sounding board

All my piping is stock including original cat, which passed smog so it should be in good shape. The only thing is the muffler was replaced. I had hacked the exhaust off when doing the clutch because I couldn't unbolt and remove to get the transmission out. It was my understanding, and looked that way too, that the exhaust is in the way of removing the transmission (though I got it out alright the second time i removed the transmission when the retaining clip came loose for the throwout bearing 🤔) I had it welded back and told them "give me a muffler with some sound to it". well, idk what they gave me, but it doesn't give it much sound over stock. I would say it is also a larger than stock muffler.

[That Ol 720]

3 hours ago, A guy named Rick said:

my best 0-60 was 10.2, about 17.5 1/4 mile @ 76 mph. All stock, weber 32/36, 2wd, 2.4 napz. 5-speed. I launched it too (idk how many rpm), and let off the gas a fraction of a second after clutching in to gaim some rpm before shifting up to help it lurch forward on the next gear.

 

But yes these are not performance vehicles lol. i just wanted to see what it was capable of.

10 seconds?? That's pretty insane! You have a Z24 in there??

[A guy named Rick]

2 minutes ago, That Ol 720 said:

10 seconds?? That's pretty insane! You have a Z24 in there??

Yup. Probably a little down on compression too, or at least a little leakage past the rings for sure. Only 130,000 miles, but I think the previous owners (most likely original owner) didn't treat it right. I don't think 10 seconds is insane. Gearing plays a factor. I have no clue what my rear ratio is. I wouldn't be surprised if it were 3.90ish. I also have i believe 205/55/R16's or 215/55/R16's.

[datzenmike]

Find the engine tag mounted on the passenger side inner fender below the hood hinge.

 

 

Bottom line. TRANS/AXLE...... FS5W71B.... HF38

 

41 is 4.11

38 is 3.889

37 is 3.71

35 is 3.545 and so on

[A guy named Rick]

25 minutes ago, datzenmike said:

Find the engine tag mounted on the passenger side inner fender below the hood hinge.

 

 

Bottom line. TRANS/AXLE...... FS5W71B.... HF38

 

41 is 4.11

38 is 3.889

37 is 3.71

35 is 3.545 and so on

Yup I keep forgetting to do that. I'll look after work in a bit. I think it's 38

[datzenmike]

Is your build date between Jan '83 and June '83??? My info shows 3.889 but then switching to 4.11 from then on.  Almost looks like Nissan started out with too low a gear and switched to the 4.11.