l16 mated to 280z 4 speed problem.

[Zfighter76]

so i recently bought another datsun 620, a '74 with an l18, the motor in it was leaking pretty bad from just about everywhere, i think the previous owner used the old gaskets when he put it together, anyways, because of this and that the 3rd gear slips out i decided to pull it and drop in my l16 and my 280z 4 speed. the trans worked perfect when i pulled it out of the z car and after some research i decided that it was the same length, and it actually appears to be the same tranny as my factory '74 620. the l16 is from a 510 and the clutch and pressure plate are also.  i bolted it all together and had no issues, motor runs great, ect, but, after bleeding the clutch and ensuring that the fork was going through its full range of motion, i still cant put it in gear when running.? is there a specific combo i need to use to make things work? i have on hand a 280z clutch, flywheel, and my l18 throwout bearing and fork. i used the stock 510 clutch and pressure plate but did not disassemble to make sure they werent rusted. any ideas? the clutch feels normal, how it did before, and the fork seems to be moving the entire distance, but it will not disengage. also any info on the gearing differences between the z car 4 speed and the 74 truck 4 speed? i figured the z car would have longer gears or something. thanks!

[DanielC]

"i used the stock 510 clutch and pressure plate but did not disassemble to make sure they werent rusted. any ideas?"

 

First guess, the pressure plate is stuck to the flywheel. 

I think I understand you just bolted the L-16, with flywheel, and pressure plate to the Z transmission. 

If the L-16 sat for a while, it is possible that the flywheel rusted, from moisture.

 

You might try putting the transmission in fourth gear, and pushing in on clutch pedal.  Set the hand brake hard.

Try to crank the engine VERY BRIEFLY!  That might be enough to break the pressure plate free from the flywheel, and pressure plate.

 

There is a good possibility doing the above procedure could cause a chunk of the clutch disk lining to break free of the clutch disk.  If this happens, you will need to replace the pressure plate.

 

A safer way is to remove whatever you feel comfortable doing, to get to the pressure plate, and unbolt it from the flywheel, and and inspect the flywheel face, the clutch disk, and the pressure plate.

[datzenmike]

If the L16 motor and z 4 speed were swapped as a unit with nothing else added or taken away it should work. Yes it's very possible the disc is perhaps stuck to the flywheel and or the pressure plate.

 

Do this is a safe place:

 

Start it in first gear. Push the clutch pedal down and floor it and let off suddenly. Repeat several times in a jerking motion. This will put the maximum torque on the stuck surfaces with (presumably the pressure plate in the release position. This may not work so be prepared to drive it home this way. Stalling the motor is the only way to stop.

[datzenmike]

Daniel's way is good too. Yes there is a risk but right now you would have to remove it anyway.

[Zfighter76]

i mated the z car tranny to the l16 myself and checking the clutch for some reason didnt occur to me, but yes the motor has been outside for a couple months. i dont have any problem with taking it out i just wanted to get some ideas beforehand in case i mis matched parts that are not compatible.  thanks for chiming in so quickly, i am just alittle frustrated because i ran into some snags with electrical and after finally firing it i cant drive :( anyways, it sounds like if all my parts are compatible than it is most likely a rusted clutch. once again just for clarification i am using a 280z 4 speed, and throw out bearing / clutch fork, 510 clutch, pressure plate, and flywheel, and stock 1974 slave cylinder and rod. i will most likely remove the engine and trans wednesday to fix the problem. also, any word on the gearing differences between the 280z 4 speed and the truck? 

[datzenmike]

As long as you kept everything together fron the L16?. For example did you keep the truck's original L18/4 speed release bearing collar and use on the L16?? This would cause the problem .

 

As long as you kept and used the L16 collar it should work.

[DanielC]

I do not know exactly what transmission you have but if you take a few pictures of it Datzenmike can probably tell you what the gear rations in it are, the date of manufacture, the shift it was made in the Datsun factory, the name of the person who put it together, and possibly the weather in Japan that day. 

My experience with 521 trucks is they have a lower first gear, and possibly a lower second gear.  The trucks have a wide ration transmission, to get a heavy load moving.  A car has a closer gear ratio set, because it is not expected to carry a heavy load sometimes.  even more so, with a Z-car, little car, bigger engine.

If you do load your truck down, no problem.  But if you do this,

you may miss the lower first gear.  That is a ton of wood pellets.   I have done that three times so far, since August.

[Zfighter76]

the l16 was originally an auto but the person who sold me the engine put the flywheel, clutch, and pressure plate from another l16 in, which was possibly from a 73 620 now that i think about it.  other than that i put the throw out from the z car on, it seemed to fit perfectly and the clutch feels exactly how it did before which makes me believe that the pressure plate is correct. sounds like i have a stuck clutch disc. ill take some pics when i pull the motor back out, i hardly ever carry a load in my truck, besides my bicycle or car parts, my main purpose is just to drive around with good gas mileage and have fun in it.  i think if i re-gear the diff to how the z car was it would be pretty cool, i got the z to 120 with the 4 speed and i probably wont ever go that fast again lol, i was a stupid 16 year old at the time. by collar do you mean the T/O bearing datzenmike? 

[Zfighter76]

i didnt use any parts from the l18 besides the master and slave.  the 74 and up 4 speed looks identical to the z car 4 speed, mounted up perfectly with no driveshaft mods, just had to switch the z car male trans mount to the female l18 4 speed female mount

[Zfighter76]

turns out it was a stuck clutch disc, i dont have pictures because i used DanielC method of putting it in 4th with the e brake locked and bumping it, worked like a charm! will start a build thread soon, need to invest in a camera first, thanks for the help!