atkinson40 Posted July 19, 2011 Report Share Posted July 19, 2011 My 4 speed is grinding down shifting into second and sometimes even when going from first to second. I'm going to use this truck for hauling short distances only. I'll be climbing up into the mountains into Mexico. I don't mind cruising at 55 while the motor sounds like its wound up. I want the power to haul a load into the mountains. Any reason I should put in a 5 speed? Or just get the syncros replaced on the tranny that's in it. Its also got a sloppy shifter but seems to make it into all the gears OK except the grinding going into second. Thanks -K Quote Link to comment
datzenmike Posted July 19, 2011 Report Share Posted July 19, 2011 Check the clutch master cylinder fluid level. Probably low and air is in the hydraulic system and the clutch isn't disengaging. Bleed the slave cylinder and that should fix it. Check the tranny oil level and top up if needed. A five speed won't climb mountains any better that what you have. Depending on which 5 speed you get it could be worse. A lot of work and bother to swap it too. Quote Link to comment
ZackTheImpaler Posted July 19, 2011 Report Share Posted July 19, 2011 Sounds like you need some more power. My answer to everything is just bigger intakes :D That helped me in my mountain driving woes Quote Link to comment
Z-train Posted July 19, 2011 Report Share Posted July 19, 2011 If it is a driver,the LAST thing you want is a bigger intake. Quote Link to comment
atkinson40 Posted July 19, 2011 Author Report Share Posted July 19, 2011 Check the clutch master cylinder fluid level. Probably low and air is in the hydraulic system and the clutch isn't disengaging. Bleed the slave cylinder and that should fix it. Check the tranny oil level and top up if needed. A five speed won't climb mountains any better that what you have. Depending on which 5 speed you get it could be worse. A lot of work and bother to swap it too. Thanks DM. I'm happy with the 4 speed. Twin son Dat Rats are trying to get me to swap to 5 speed because they think its winding up too much on the freeway. When I swapped the clutch slave, the push rod wasn't long enough and I had to go JY shopping to find a longer one. Maybe I need to revisit that along with the issues you mentioned. -K Quote Link to comment
banzai510(hainz) Posted July 19, 2011 Report Share Posted July 19, 2011 When I swapped the clutch slave, the push rod wasn't long enough I usually use the same push rod. if a different size was used could have been a different T/O bearing collar was installed? alwasy match the old parts to see if correct. Quote Link to comment
datzenmike Posted July 19, 2011 Report Share Posted July 19, 2011 Twin son Dat Rats are trying to get me to swap to 5 speed because they think its winding up too much on the freeway. They can take he revs all day no worries. Sounds worse than it is, just keep lots of oil and water in them. A five speed may give you a bit more mileage on the flats. Quote Link to comment
Stupid_fast Posted July 20, 2011 Report Share Posted July 20, 2011 My opinion is more gears is better! I learned to drive manual on 6 speed transmissions and I love them. If your doing a lot of pulling, then extra gears would be even better. The reasoning is you will have a good OD cruising gear for flat parts or downhill where you don't need the power, then you will have more gear options for pulling uphill. If you don't mind shifting more, you can improve your fuel efficiency while towing quite a bit depending on your driving style. Swap first, ask questions later. Right? If it is a driver,the LAST thing you want is a bigger intake. I don't understand why? Bigger intake is less starved engine, Especially in thinner mountain air? Maybe would burn more fuel, but being more soft on the throttle could compensate for that. Quote Link to comment
datsunaholic Posted July 20, 2011 Report Share Posted July 20, 2011 Bigger intake generally causes lower low-end torque. It's best for high-RPM. Forced induction can compensate for that, but in a N/A engine big ports are meant for high-RPM applications. At low RPMs you end up with almost no intake velocity, which really screws up the fuel delivery. The end result is that off-the-line power is pretty bad. You have to rev the engine up to "launch" from a stop or risk a stall, which in turn adds a ton of wear on the drivetrain. It's a pain to drive a car like that in city driving, or in stop-and-go traffic. Sure, you get great top end, but how often you you run the engine over 5K in everyday driving? Quote Link to comment
datzenmike Posted July 21, 2011 Report Share Posted July 21, 2011 I'll be climbing up into the mountains into Mexico. I don't mind cruising at 55 while the motor sounds like its wound up. I want the power to haul a load into the mountains. Any reason I should put in a 5 speed? A five speed won't climb mountains any better that what you have. Depending on which 5 speed you get it could be worse. A lot of work and bother to swap it too. My opinion is more gears is better! I learned to drive manual on 6 speed transmissions and I love them. If your doing a lot of pulling, then extra gears would be even better. The reasoning is you will have a good OD cruising gear for flat parts or downhill where you don't need the power, then you will have more gear options for pulling uphill. If you don't mind shifting more, you can improve your fuel efficiency while towing quite a bit depending on your driving style. I disagree, and here's why. Throw away 5th gear. It doesn't even enter into the argument of having more gears to climb hills as it is above 4th and is an overdrive. So this leaves us with 4 lower speeds with 4th being straight through 1 to 1 (same as the 5 speed) as our upper limit. Now we have only three gears to work with for take off and climbing hills. Since we are talking a 521 or early 620 4 speed we know that the gear ratios are 1st.... 3.592 2nd... 2.117 3rd.... 1.419 4th.... 1 to 1 Now there are really only two 5 speeds that will fit with reasonable mods... the 200sx dogleg and the later 620 and 280z and zx. 200sx 1st..... 3.382 2nd.... 2.013 3rd.... 1.312 4th..... 1 to 1 5th ... 0.854 Later 620 5 speed (the later zx 5 speeds were even worse) 1st.... 3.321 2nd... 2.077 3rd.... 1.308 4th.... 1 to 1 5th.... 0.864 As you can see at the same vehicle speed the original 4 speed will be lower geared and the engine revving higher which is good for climbing hills. The later ('79) 620 is the only transmission with these lower ratios... 1st.... 3.592 2nd... 2.246 3rd.... 1.415 4th.... 1 to 1 5th.... 0.882 So the only advantage with this 5 speed is the overdrive and pretty much has the same bottom 4 gears as the 4 speed. Swap first, ask questions later. Right? Quote Link to comment
Z-train Posted July 21, 2011 Report Share Posted July 21, 2011 Bigger intake generally causes lower low-end torque. It's best for high-RPM. Forced induction can compensate for that, but in a N/A engine big ports are meant for high-RPM applications. At low RPMs you end up with almost no intake velocity, which really screws up the fuel delivery. The end result is that off-the-line power is pretty bad. You have to rev the engine up to "launch" from a stop or risk a stall, which in turn adds a ton of wear on the drivetrain. It's a pain to drive a car like that in city driving, or in stop-and-go traffic. Sure, you get great top end, but how often you you run the engine over 5K in everyday driving? At least someone here understands port velocity. Quote Link to comment
Stupid_fast Posted July 21, 2011 Report Share Posted July 21, 2011 Bigger intake generally causes lower low-end torque. It's best for high-RPM. Forced induction can compensate for that, but in a N/A engine big ports are meant for high-RPM applications. At low RPMs you end up with almost no intake velocity, which really screws up the fuel delivery. The end result is that off-the-line power is pretty bad. You have to rev the engine up to "launch" from a stop or risk a stall, which in turn adds a ton of wear on the drivetrain. It's a pain to drive a car like that in city driving, or in stop-and-go traffic. Sure, you get great top end, but how often you you run the engine over 5K in everyday driving? Makes sense, thanks for the explanation. I It was a sarcastic take on noobs that dive into projects they will never finish... I've been here long enough to know to ask questions first. :P Quote Link to comment
datzenmike Posted July 21, 2011 Report Share Posted July 21, 2011 It was a sarcastic take on noobs that dive into projects they will never finish... I've been here long enough to know to ask questions first. :P .... and I like posting videos. :lol: Quote Link to comment
ZackTheImpaler Posted July 22, 2011 Report Share Posted July 22, 2011 Haha I won't argue that with you! I knew before swapping my carb to the 38/38 I was going to have off the line issues, which I do. I consulted long enough, I just wanted a lot of power out of my engine. That's why I had to get another wagon for my daily! However today I went deep into the olympic mountains, and I cruised a steady 80-85 up and down. My engine is stock except for the carb, and I have a stock 5 speed. Listen to these guys though, I'm just a punk kid... Bigger intake generally causes lower low-end torque. It's best for high-RPM. Forced induction can compensate for that, but in a N/A engine big ports are meant for high-RPM applications. At low RPMs you end up with almost no intake velocity, which really screws up the fuel delivery. The end result is that off-the-line power is pretty bad. You have to rev the engine up to "launch" from a stop or risk a stall, which in turn adds a ton of wear on the drivetrain. It's a pain to drive a car like that in city driving, or in stop-and-go traffic. Sure, you get great top end, but how often you you run the engine over 5K in everyday driving? Quote Link to comment
datsunaholic Posted July 22, 2011 Report Share Posted July 22, 2011 I have no problem with a Weber 38 on an L20B in my '74 beater 620, but the cam is a little different. Dunno how much, it's an aftermarket grind that was in it when I got it. Super lumpy idle but great power through the range. You can't stomp on it off idle, but I never do. Nice easy starts, then hit the reheat in 3rd. Enough power to send a dogleg to its grave... HOWEVER... I have stock ports and an unmodified intake. Gas mileage isn't bad either, mid to high 20s. Quote Link to comment
Z-train Posted July 22, 2011 Report Share Posted July 22, 2011 Haha I won't argue that with you! I knew before swapping my carb to the 38/38 I was going to have off the line issues, which I do. I consulted long enough, I just wanted a lot of power out of my engine. That's why I had to get another wagon for my daily! However today I went deep into the olympic mountains, and I cruised a steady 80-85 up and down. My engine is stock except for the carb, and I have a stock 5 speed. Listen to these guys though, I'm just a punk kid... If your Weber is jetted correctly,you should not only have no issues,it will be slightly better than the Hitachi(or a lot better,depending on how FUBAR the Hitachi was). Quote Link to comment
ZackTheImpaler Posted July 23, 2011 Report Share Posted July 23, 2011 I'm not going to hi-jack this thread, but my weber does run great! My hitachi was fine, fixed a fuel line leak the next day so I wouldn't have noticed. mileage stayed the same for me. If your Weber is jetted correctly,you should not only have no issues,it will be slightly better than the Hitachi(or a lot better,depending on how FUBAR the Hitachi was). Quote Link to comment
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