clutch break in

[doomdatsun]

just installed a new valeo clutch and pressure plate, would like to know how to do proper break in and what is the max rpm I can rev my engine to (engine L20a six), I did drive a couple of miles about 2000 rpm, and at the end of the trip I sorta got into stupid mode and shifted at 4.5K or 5K for the rest of the trip, is that bad.

[Trophy24]

No break in period that I have ever heard of.

[datzenmike]

Just drive as you normally would.

 

On a good solid well maintained L20B full of oil and water...

The L20B redline is 6,500 -7,000 but will rev safely higher although in stock condition there is no need or sense in doing so. It has little usable torque above 5,000-5,500 anyway. Unless carrying a heavy load

 

L20A I have no idea, we didn't get them. Look up info for L24/L26/L28 engines probably similar.

[Ratwagon1600]

No break in required (unlike an engine).

 

Drive it hard and enjoy !

[doomdatsun]

thanks guys, I sorta got board from slow driving, since I don't go out too much using my car it seemed like a nightmare not being able to get its guts out.....

datzunmike the l20a engine is the same as l6 you have in US l24 l26 l28, to be more precise the block is the same as RB20 block with a datsun OHC head, the RPM gauge in my car ends at 8K, the red line starts at 6K, so is it ok to rev until 6K or til 8K...

 

one side note I forgot to ask, when depressing the clutch I feel a strong metal noise from the car, I fixed the U joint and checked the differential, changed the old prssure plate and resurfaced the flywheel, is it the car or my driving style?

with the new pressure plate the clutch pedal is like a soft cushion, the old one was stiffer ?

DATZUNMIKE I used the 1006 sleeve as you told me and I have checked it as well with a vernier calibar as well because the clutch is 225 mm

[datzenmike]

The start of the red is the red line. (in this case 6,000) It's a suggested maximum rev limit.

 

You did replace the release bearing right??

[doomdatsun]

yep, new koyo release bearing, I installed it using a c clamp with wood so no hammering ,

I always get this strong scary sound like I destroyed something when depressing the clutch for shifting and when releasing it, sometimes I depress and release fast and others slow, but all the same? I fixed and replaced u joints at machine shop and changed rear wheel bearings and made sure the diff is in good cond (by the way its a live axle (whole unit H190 diff) with 3.89 ratio, when I got my hands on the car and started messing around with it, once I decided to take the trans down I noticed that the trans mount is dead ( no rubber at all) and the trans was hanging from the engine ( top 2 bolts were unscrewd all the way and the trans is leaning on an angle form the engine. is there something I'm not noticing ?

[banzai510(hainz)]

On the 6cylinders 225mm, I would be going with the Daiken Stage 1 kits.

 

importrp.com sells them.

However Im not a expert on interchangeablilty on 6 cyl. so ck the diapram height. This will determine the T/O collar length

[Sealik]

..... and the trans was hanging from the engine ( top 2 bolts were unscrewd all the way and the trans is leaning on an angle form the engine. is there something I'm not noticing ?

 

Well...depending on the severity of that angle....the input shaft on the trannie could be somewhat compromised.

Also.....was the pilot bushing in good condition???

[datzenmike]

Doug the input shaft is HARD!!! stuff. Don't know if it will bend or just snap.

[Sealik]

Doug the input shaft is HARD!!! stuff. Don't know if it will bend or just snap.

 

Correct....I cut one off with a zip cut for an aligning tool.... but... a trannie should never be hanging at the back of the motor like that.

Trannie weighs what??? and at 31 inches long....puts a lot of stress on the short input shaft????

Maybe..............................?..................... :)

As Gilda would say.............never mind

[doomdatsun]

in this clutch replacement I did replace the pilot bushing as well, put some little grease inside of it as well(wheel bearing caramel like grease), I asked an OLD datsun man bout trans, he laughed about the input shaft and said that thing would either be straight or broken nothing in between. possible soft pedal is the fluid so I'm going to check if I can find some good dot3 maybe dot4 fluid to use, still that doesn't change the fact of that distracting noise...

 

by the way the trans is the 26" fs5w71b aka stubby.... :)

it was >< to lift (spent whole week meddling with it until it surrendered) used a 10mm deep socket with tape for alignment and it was perfect

[doomdatsun]

men, I changed the clutch fluid with dot4 caltex clutch fluid and the pedal seemed to harden a bit, while driving today I to go in reverse from a stop and my leg was on the clutch all the way (flooring it), still the shifter resisted going to the reverse and when it did I heard a grinding sound loud and clear... , so I'm asking how far should the slave cylinder push the arm fork from rest ?

also at a traffic light other cars wanted to race :) and while shifting to third I missed it (actully couldn't find it or it was stuck), what causes such problem ?

[datzenmike]

Clutch slave travel is usually 1.18 inch. Again the L20A is not common to me. I know of it, but nothing much particular. Where are you located?

[banzai510(hainz)]

also at a traffic light other cars wanted to race and while shifting to third I missed it (actully couldn't find it or it was stuck), what causes such problem ?

 

17 posts?

NOOB!!!!!!!!!!

 

Bleead ther clutch and ck the slave cylinder.

 

was the orginal t/o bearing sleeve used???????

[doomdatsun]

hainz, yes I did bled the clutch and it travels a distance, but I think that my slave cylinder(not the original) might be the cause.rod is the same, as for the depth of the piston I think 1/8" of difference from the original, still I did adjust under the clutch pedal where the look nut is, perhaps I should recheck the adjustment, Mike don't worry much about the engine think of it as L24 or L28, its the same as them. finally, yes I'm a noob in mechanics, but I was around ratsun for more than 2 years I think, and your vids hainz are very informative thanx for them, as for the car it was with me since childhood so I'm familiar with it, I did overhaul the engine (not perfect due to financial issues) and not the first time I took gearbox out.

[Sealik]

Even if the clutch is not adjusted correctly....you shouldn't ..."always get this strong scary sound like I destroyed something when depressing the clutch for shifting and when releasing it"....

Can't remember if it's possible to install the throw out bearing backwards...?????...but

[72240z]

Even if the clutch is not adjusted correctly....you shouldn't ..."always get this strong scary sound like I destroyed something when depressing the clutch for shifting and when releasing it"....

Can't remember if it's possible to install the throw out bearing backwards...?????...but

 

Ya agreed.

It is possible I think but Idk if it would cause that issue.

 

Is the sound continuous while the clutch is depressed or for a moment then goes away?

[doomdatsun]

it happens when you depress the clutch or release it either lightly (slow) or fast, as well as when you release it.

no leak in the lines and the clutch master is full. the release bearing is fitted to the slave with the round pointy side facing the pressure plate as in the pic

 

 

I can't down shift even if I floor the clutch pedal unless the speed falls way down to say 16 miles in all gears, IMO the gearbox should shift to any gear regardless of the speed the car is when the clutch is fully depressed, that is unless its somehow slipping in between making it difficult to shift up or down ?

[72240z]

Have you DEFINITELY bled the system properly? The slave rod too? It sounds to me like its not fully disengaging. That or the syncros are going/gone.

 

You were driving the car fine before the clutch change?

[doomdatsun]

nope, it wasn't fine before (I drove it after my first overhaul with new daikin clutch (used old pressure plate and didn't resurface FW)), as for bleeding I did bleed it and it moves, I think its as you said not fully disengaging, I'll try tomorrow to readjust and bleed the system again to get the furthest distance from the clutch, one question is bugging me, should the release bearing be riding the pressure plate when the clutch release or should there be some free play distance before engagement? why, becos I think the more I push the rod to the fork (adjustment) I assume it might hit the PP? just assuming

[banzai510(hainz)]

Thats T/O bearing lokks like a 200mm type to me.

 

 

the slave cylinder themselves are pretty much the same.

Just use the same rod or make sure the rod is the same that goes in the slave cylinder.

 

what I would do is loosen up the slave and see if there is tension on the t/o bearing(see if it moves more fwd if the slave is removed)

Im fortunate as I use the old 510 style Fork arm that has a pass thru hole to adjust the slave cylinder ball end on the threaded rod. The newer style the fork arm just has a cup and the slave rod fits in to it. So if eveything is correct it should work.

Maybe the rod is too short or long. But you said it was the orginal. So maybe soemthing changed.

 

Only thing I can think of is the T/O bearing collar length. But now I see the T/O bearing looks like a 200mm.

 

I know the early 240z 225mm clutch had the same T/O bearing size as the diaphrame height was the same. But only the early cars. Later it all changed . My How to race Nissan book had the specs. I barely caught the diffence in them as I get also confused on the Z car 6 cylinder stuff.

[doomdatsun]

well when I went to buy a bearing there was a bigger bearing than what I have now that was supposed to be for the 720 truck, it was way bigger than the one in the pic, here are some pics of the old PP and bearing (same one in above post)

 

 

 

 

 

the current slave is not the orig(the one when I took the car DK if been replaced or something), but it mounts the same the only difference I found is the depth of the groove in the piston on the current one is deeper by say 1/8", my guess is that the rod might need changing, but need to figure out where the fork should travel to to fully disengage the clutch?

[banzai510(hainz)]

I looked at Rockauto.com and it looks like you got the right Bearing.

[datsunaholic]

OK, I think I know some of your problems. One thing I've noticed is you haven't said what kind of car you have or where you are. You say you have an L20A, which is really rare in the US but a little more common outside, then you say you have a shorttail 71B transmission in another thread... which NEVER matched to the L20A, and since the short 71B only ever came in a NAPS-Z 720, I really don't know what you have. I'm guessing you have a Fairlady Z with some mods?

 

1) You mentioned the mount doesn't line up. No kidding- that's why you shouldn't ever use a NAPS-Z transmission front case on a L-series engine. You have your front mounts (engine mounts) fighting the rear (transmission) mounts for a 15 degree difference in angle. Eventually one of the rubber mounts is going to tear in half or de-bond from the metal plates it's attached to. It's fixable, by using an L-series 280ZX 5-speed front case with the back half and guts of the truck trans, though I don't know why you'd want to go that route. I thought all Z cars used the long trans to begin with. But maybe the Fairlady was different.

 

2) The throwout bearing and bearing collar MUST match the PRESSURE PLATE, not the transmission. The NAPS-Z 720s had a 240mm pressure plate and a larger release bearing. An L20A had a 225mm pressure plate. The 2 are incompatible unless you switch flywheels.