How to measure/identify flywheel size

[TheBirdistheWord]

Bought a flywheel at a swap meet recently and realized after I brought it home that I dont know how to figure out what size clutch and pressure plate I need. 

 

Can anyone lend a hand on where to measure to figure it out?

[banzai510(hainz)]

https://zcardepot.com/products/aluminum-flywheel-l16#&gid=1&pid=1

 

here is a aluminum flywheel but in the center is the friction disc of steel measure across for the far end of the friction disc to the other side of far end

a 200mm will be  7 7/8 or 7.87 inches

a 225mm will be 8 56/64  or 8.85inch

 

next I believe is a 240mm

[datzenmike]

200mm 5 bolt are L16/L18 truck and car. There was a one year only '74 620 truck 5 bolt L18 that was 225mm.

 

200mm six bolt* are for cars

 

225mm six bolt* are for trucks and Z car/810 Maxima six cylinders. Also used on Z22 powered S110 200sx cars.

 

240mm six bolt* are for Z20 (mileage option) Z24 and KA truck applications. Has 9 mounting bolts for the pressure plate instead of 6.

 

* all six bolt are interchangeable with any six bolt crankshaft engine. 

 

Generally there were two different weights of approximately 21 and 29 pounds +-. As a rule heavier ones were for trucks, lighter for cars or larger displacement four or six cylinder. Twenty-nine pound wheels are solid and flat on the engine side, lighter ones are scalloped to reduce weight.   

 

When you select the correct pressure plate it must be matched to the correct release bearing collar. Some universal 'one size fits all' supply the correct collar with the clutch kit which is handy.

[TheBirdistheWord]

Okay great, thank you everyone for the help.   So my next question is if I'm taking a 4 speed that's mated to an l16 that presumably has a 200mm flywheel. Can I use all of the associated hardware other than the pressure plate and clutch disk (Fork, T/O bearing, slave, master) with a 200mm flywheel on an l20b?

[datzenmike]

Yes. Again the release bearing collar must match the L20B pressure plate. Pressure plates come in a variety of heights but the clutch slave and clutch are must remain basically in the same position and travel through the same movement. This is kept by varying the release collar length. A 'tall' PP would use a shorter collar, a thinner PP would use a longer collar.

 

I would never use an old release bearing. Most release bearings are the same. The '71 1200 sedan with A12 engine uses the same release bearing as the '89 300zx turbo.

[banzai510(hainz)]

so your saying you have a 200mm 6 bolt crank flywheel?????

 

 

I always like the 510 clutch fork with that slave set up as its more adjustable.with the rod going thru the clutch fork with half moon nut and lock nut.

 

https://datsun-roadster-parts.com/product/dt-279/   581

This will work with the datsun 510/521 set up. the t/O bearing matches the stock Collar ect.  fits the 200mm 5 or 6 bolt on crank.

 

maybe you can find it cheaper but make sure its the 600kg one by Exedy. the Nissan ones were 650KG.

 

 

if this is a stock car and you want it to last a long time then stock 510 is what you want.  Less were on the hydralics

 

Edited July 14, 2023 by banzai510(hainz)

[banzai510(hainz)]

https://www.ebay.com/itm/233202857642

here is cheaper free shipping

NSC581 is the Roadster clone 200mm  

 

this ia actually cheap if anybody needs spares but reading carefully its only the pressure plate

 

try this

 

https://www.ebay.com/itm/233202857988?hash=item364bf93804:g:BWsAAOSwBpBiVbjb&amdata=enc%3AAQAIAAAA4IPQ%2BCxleecdE6K2Mtulvp9pKq5bVBindM99NP4CVf2UuBORdtQO96sEzSG7uNSBsw4weE4pqzNg2KCtGeVAABofqphGOL8IUnk1iVQPXs9flZZOS%2FSh6dIsEmXw4PnPjxcEHHT7ogc3LrCnmcp0nr9LIaHyV%2BOHhuP3KemzOloJDTI%2Fg%2FttfORL7h96miiqxqXWtkf3MJ0GsB96uTDWqG%2BITT9%2Bvaflv2cGbsxXH4hQYTvKgiSsy%2Bwtwd9rqAqxJRKFyhc%2FQ2x1J5BgB%2BGarQJuQZXt67suw7DlxOR0FVfv|tkp%3ABk9SR4bcldeqYg

Edited July 14, 2023 by banzai510(hainz)

[datzenmike]

The L20B powered 710 and 610 200mm are 450Kg. The 200mm S10200sx are 400Kg. The PL510 about 350Kg.

[TheBirdistheWord]

3 hours ago, datzenmike said:

Yes. Again the release bearing collar must match the L20B pressure plate. Pressure plates come in a variety of heights but the clutch slave and clutch are must remain basically in the same position and travel through the same movement. This is kept by varying the release collar length. A 'tall' PP would use a shorter collar, a thinner PP would use a longer collar.

 

I would never use an old release bearing. Most release bearings are the same. The '71 1200 sedan with A12 engine uses the same release bearing as the '89 300zx turbo.

 

3 hours ago, banzai510(hainz) said:

so your saying you have a 200mm 6 bolt crank flywheel?????

 

 

I always like the 510 clutch fork with that slave set up as its more adjustable.with the rod going thru the clutch fork with half moon nut and lock nut.

 

https://datsun-roadster-parts.com/product/dt-279/   581

This will work with the datsun 510/521 set up. the t/O bearing matches the stock Collar ect.  fits the 200mm 5 or 6 bolt on crank.

 

maybe you can find it cheaper but make sure its the 600kg one by Exedy. the Nissan ones were 650KG.

 

 

if this is a stock car and you want it to last a long time then stock 510 is what you want.  Less were on the hydralics

 

 

Let me explain better what I'm doing and what I have.  

 

I have a running l20b with a working 5 speed and 200mm hardware in one car

 

I also have a running L16 with a working 4 speed and hardware in another car. (This is presumed to be 200mm but I have not opened it up yet)

 

I'd like to swap the transmissions so if I'm understanding correctly the T/O bearing and fork should go with the respective clutch and pressure plate.

 

However if they are both 200mm it doesn't matter if they're 5 or 6 bolt flywheels the hardware I have on both transmissions should be interchangeable with one another?

 

[datzenmike]

If you swap the transmission keep the throw out bearing collar with the pressure plate it's being used on.

 

For example if wanting to put the four speed onto the L20B use the L20B release bearing collar. If putting the 5 speed on the L16 keep the L16 release bearing. Clutch arms are the same.

[TheBirdistheWord]

7 hours ago, datzenmike said:

If you swap the transmission keep the throw out bearing collar with the pressure plate it's being used on.

 

For example if wanting to put the four speed onto the L20B use the L20B release bearing collar. If putting the 5 speed on the L16 keep the L16 release bearing. Clutch arms are the same.

Copy that thank you for the clarification. 

 

I will eventually confirm this when I do the job and compare and measure the L16/4speed release bearing collar, but I think I just had a dopey "ah-ha" moment. just for kicks let's say I have an L16, L18, and L20B all of my clutch hardware is fitted properly to 200mm flywheels on each respective engine with various non matching manual transmissions. Theoretically all 3 collars should measure the same size, correct?

 

Edit: I understand there is a discussion about successfully mismatching parts, but I'm asking for clarification about interchangeability between 200mm clutch parts as it relates to swapping transmissions between an LZ2.X, L16, and L20B.  

 

Edited July 15, 2023 by TheBirdistheWord

[datzenmike]

No, there are several applications where different collar sizes are used and the clutches are all 200mm. An L20B 200mm clutch is probably slightly taller than the L16 200mm. Don't take the chance. It's a lot of work to pull the transmission out and back in to correct this.

[TheBirdistheWord]

Ahh I see thank you again for the clarification.

 

  I don't plan on taking a chance, I know what I need to do with this project.  I'm asking because I plan on selling the L20b/4speed combo car and that would mean even though I have another 6 bolt 200mm flywheel I cannot use the L16 200mm collar and will need to find a new one and they seem to be a bit hard to find.  The ones I have seen for sale are ambiguously marketed... If I can't find one when I have finished my LZ build I will have to shelf the 200mm 6 bolt and use a 225 setup as parts seem to be easier to aquire. 

[datzenmike]

An LZ build? The 200mm is a bit light for that I think.

 

The collar is matched to the clutch and pressure plate and are a set. Just keep that in mind. What ever 225mm clutch you buy the collar must match it. If you tell me what 225mm pressure plate you have selected was used on I can get you the correct collar part number. Nissan may still sell them on line.

 

Again, some after market clutches are a 'one size fits many applications' and they come with the correct collar.

[TheBirdistheWord]

Well, I also have a lightly modded L20b as well and was hoping for an easy clutch solution between all of them.  What if I don't have any info on donor car for flywheel? Is it just a crap shoot until I find a collar that works?

[datzenmike]

The flywheel has nothing to do with the collar size. They are drilled for 200mm, 225mm and 240mm pressure plates and that's it. It's the pressure plate thickness that determines the collar length. There are at least 4 different collar lengths used on at least four different 200mm PPs. No single 200mm PP is going to serve the wide variety of engines used.

 

With clutch installed if you measure from a diaphragm finger down to the flywheel clutch disc surface and then measure the collar from where the clutch arm touches it to the front of the release bearing... they should add up to 89.4mm. The 510 Realm says 92mm so close enough. If the collar is too long, when the clutch is released, the bearing will still be rubbing and compressing the diaphragm fingers and the clutch may slip, not to mention the release bearing will soon wear out. If the collar is too short the clutch arm will run out of travel and the clutch will not fully disengage.

 

I measured the 89.4mm myself on my 710 because I know it works just fine. 92mm is barely over 2mm difference. 

[banzai510(hainz)]

if you use the Exedy kit  581 600kg with a 200mm flywheel wheither 5 bolt or 6 bolt

the parts from a 510 will all work with this kit. collar and t/o bearing

I say also use the 510 clutch fork also.

PERIOD!!!!!!!!!!!!!!!

 

if you have a 225 mm flywheel

14 hours ago, TheBirdistheWord said:

though I have another 6 bolt 200mm flywheel I cannot use the L16 200mm collar

why not.?????????? it goes by the pressure plate diaphram height. the stock 510/521 L16 is the same as the Roadster and this Exedy kit NSC581

[datzenmike]

 

Top is 710 but same as 510 I'm sure. Bottom is from truck 71B transmission may even be from 720. I measured it 10 different ways couldn't find any difference other than those two fold lines.

[banzai510(hainz)]

a 510 521 has a hole thru it for the slave threaded rod to go thru.  more adjustable or Moroinc mistakes

 

the none hole fork you better be sure you have the right size collar

Edited July 16, 2023 by banzai510(hainz)

[TheBirdistheWord]

I'm definitely responsible for my own misunderstanding since I have been jumping in and out of hypotheticals. 

 

However, if I'm not mistaken I'm getting conflicting info.  But I think I found the disconnect with the emphasis on the adjustable threaded rod on the slave/fork connection making up for potential differences in collar lengths.

 

The last time I did this I did not use the pressure plate measurement, I just put one collar in and when it didn't work I used a shorter one with the exedy kit hainz linked already. Obviously the measurement is a less labor intensive way to figure it out.

 

So with that said, I will be selling a collar PP combo that I know works with an L20B and 6 bolt 200mm flywheel. Best I can do is measure it before it goes and compare it to what I'm keeping? so I know if I need to look for a different collar and PP for this freshly machined 200mm 6 bolt flywheel I have. 

 

I could possibly have matching collars and PPs between the vehicles.  I'll be removing and swaping everything this upcoming week so I'll report back what I find. 

Edited July 17, 2023 by TheBirdistheWord