Best Flywheel & Clutch - last one you will buy!

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Re: Best Flywheel & Clutch - last one you will buy!

Post by DatsunRoadster2000 » Thu May 05, 2016 3:31 pm

JT, will there ever be more of these for purchase?
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Thu May 05, 2016 9:22 pm

Yes, I'll prob do at least one more run of them. I have one that I kept for an engine build here, but possibly could let it go.

J
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Re: Best Flywheel & Clutch - last one you will buy!

Post by SLOroadster » Wed May 18, 2016 2:33 pm

I'm still scratching my head with this. The U20 clutch was the highest pressure clutch up to the VG30DETT clutch. The L series clutch has less clamping power than the U20. Its also larger so more rotational weight. Buy an AASCO U20 10 lb flywheel, U20 clutch and call it good. I have yet to kill a U20 clutch, and I'm pushing 90K miles since I bought my car. Lots of high rpm shifts, lots of clutch drops, and hard driving. Still going strong.

Yes, the 510 and R16 clutch does not last, but there is a reason for that. It was never intended to be used on a U20. Why Nissan made the thing is beyond me. Perhaps because the R16 came first and they found that it was inadequate for the U20. The U20 clutch has been the upgrade for the 510s since they were new.

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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Wed May 18, 2016 3:27 pm

It's not really confusing, Its all about math, economics and engineering.

The Z plate is just a better option all around for anyone except one looking for absolute minimum weight. If you want minimal weight, I'd suggest a purpose built racing clutch.

Clearly your results are not exactly typical since just about every originally made 2L expired its clutch way before 100k - they just did. Even 1600's did. They were lucky to make 75k on the original clutch.

Most roadster owners HAVE had to change a clutch - I'm going on 20 years on a Solex Z clutch equipped 2L, never babied (Venolia's)- thrashed hard.

The cost difference between the Z equipped AL FW and an AL FW for standard clutch is negligible.

It's not all about the plate, you can buy much better clutches for Z for much less money, but a standard, plain jane Dakin 240 disc will handle about 35-40% more torque than the little roadster disc.

That's why all the higher powered next generation Nissan's got larger discs..KA's SR's VG's? They don't run 200mm discs because the 200 was marginal at best for a healthy 2L.

The weight difference with the upgraded Z clutch is exactly 1 lb. and that weight is inboard of the outer perimeter of the FW, so the increase in moment of inertia is an absolute non-issue. Basically the same as a 11-12 lb FW rather than 10. Besides the 10 lb with a standard clutch is rather light for street, and annoying for most people, so a little extra is not a bad thing.

For pressure plates and discs, there is no simply substitute for square inches. The 6-cylinder clutch will simply last longer all things being equal. The weight penalty is a non-issue for a street car.

Everyone who would rather pay more than $300 for a clutch instead of $100, raise your hand??

Makes no sense unless you really do think that 1 lb is going to slow you down....
Last edited by JT68 on Wed May 18, 2016 9:54 pm, edited 2 times in total.
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Wed May 18, 2016 3:41 pm

Oh, and yes, for those who have inquired about the next run, yes I'll do some more with the 225mm Z clutch, and a few for the guys who would rather run the little disc.
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Thu May 19, 2016 6:33 am

A few more thoughts, The common opinion is that the 1600 or 510 clutch is too wimpy for use in a roadster, but the fact is that the 2000 clutch is only a moderate improvement over that unit.

There is no increase in surface area of the wearing parts for the various Nissan 200mm clutches. Surface area directly determines torque capacity and wear characteristics if everything else is the same.

The better L20B 510 clutches are 600kg, so the original U20 plate provides a whopping 8% increase in clamping load.

From a design/manufacturing perspective, increasing from 600 to 650 was a very cheap and easy fix compared to complete retooling for a more substantial clutch. All Nissan did was bump up the spring rate - no other improvement. It is adequate, but that is about it. Still very wimpy compared to more current designs.

Truth be told a good 600 kg L20B clutch will usually work fine on the stock U20. It typically will not slip, but cheap versions may. There are countless roadsters out there using 510 clutches. The problem is there's very little safety margin so it's very easy to tear them up if you are hard on them.

If you buy a budget 510 clutch, that is an even bigger gamble. It will have a very limited life unless you are very gentle.

The 650 kg unit is only an 8% increase so just a marginal improvement at best- nothing to write home about.

Of course since changing the clutch involves removing the engine, I suggest using the best clutch you can. JMHO
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Re: Best Flywheel & Clutch - last one you will buy!

Post by SLOroadster » Sat May 21, 2016 9:18 pm

From someone who knows more than me. The 650 kg -20111 pressure plate is good for 250 hp plus 200 ft/lbs. the 240z style pressure plate is prone to self destruction like the Excedy versions because of the straps going on a tangent to the pressure ring.


Based on that, and who made the statement (A guy from the land down under who builds some impressive engines) I'll stick with my findings in that the -20111 pressure plate is just fine for 99% of the roadsters out there that run a U20 or R16. Pulling 250 hp out of a U20 might be possible with a turbo, but I only know of 1 in the US. In NA form, its only happening on a full blown race engine with a 9000 rpm redline, and very limited lifespan. I know that I have one of the healthiest U20s that can be driven on the street, and its well under 250 hp. Heck, getting an L24 to that sort of power takes some work. The biggest killer of clutches in roadsters is either a leaking rear main seal, or a poorly adjusted slave cylinder, or both.

I'm not trying to bash your product, but it seems to be addressing a non issue. For those people who want this setup, have at it, but the -20111 clutch with a light flywheel is really hard to beat.

Will
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Re: Best Flywheel & Clutch - last one you will buy!

Post by fj20spl311 » Sat May 21, 2016 11:05 pm

SLOroadster wrote: The biggest killer of clutches in roadsters is either a leaking rear main seal, or a poorly adjusted slave cylinder, or both.
Will
And I always thought it was my fault.......... :lol:
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Sun May 22, 2016 12:55 am

Slave cylinder yes,

Engine oil get blamed a lot, but that is actually quite rare. All rotational force is throwing engine oil away from the clutch. ( The rear main is on the other side of the FW btw...) if you look at the geometry and physics, there isn't an easy path for oil to get to the disc since it can't go thru the crankshaft. A really bad leak, throwing oil all over could do it, but again, fairly rare.

If you have lube on you're disc, check your trans input shaft seal, that is the more common offender.

Clutches also simply wear out because the friction surfaces have a finite life. If the clutch is marginal in the first place, it's life will be shorter than a better clutch.

There is a lot of variation in clutch durability across Auto makers, some cars have pretty wimpy clutch packs that won't take much abuse, others have robust designs and some degree of overkill. I prefer the latter.

If you are trying to say that it is always the owners fault that a clutch wears out, that is just nonsense. The friction surface IS a wearing surface. EVERY clutch will eventually wear out even if it is adjusted properly, but it will certainly will last longer if that is done.

Brake pads wear out
Fan belts wear out
Timing belts/chains wear out
Bearings wear out
Clutches wear out

All Automotive Engineers design these things to have a reasonable service life- NOT to last forever.

In fact, auto dealerships make A LOT of money replacing "wearing parts" .....of which a clutch is absolutely.
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Sun May 22, 2016 1:48 am

SLOroadster wrote:
I'm not trying to bash your product, but it seems to be addressing a non issue. For those people who want this setup, have at it, but the -20111 clutch with a light flywheel is really hard to beat.

Will
Will, You may see it as a non-issue, but there are a lot of other bright people who do see a more durable, less expensive clutch option as a major advantage. It isn't all about max horsepower capacity, it is about service life as well.

Regardless of yours or others opinions of the 2L clutch, with all things being equal, the 225mm will simply out last the 200mm if the same quality components are used, and it is far less expensive. That is why I did this, simple as that.

A brake pad with 30% more surface area will significantly out last a smaller pad all things being equal. I'm sorry you don't like the math, but it's just reality.

The 650KG unit is adequate. Why run a heavier duty clutch?
Stock pistons are adequate, why use forged?
Stock rods are adequate, why use alloy?
SUs are adequate, why run Mikuni?

The answer is the same - improved durability, reliability, safety margin, power capacity, etc.

You get all this at less cost with this clutch. For most roadster owners, - those who would prefer the extra life of the clutch- this is a great option, with NO significant downside.

The 650KG unit is acceptable, we agree on that, but as noted is only a slight improvement over the 600kg. If you drive your engine as hard as you say, you will ultimately be pulling it out to do a clutch at some point.

If you would rather pay $350 for a stock clutch, and that is fine. To each their own. Personally I think a lot more folks will find a 10lb FW and stock plate TOO light and pretty annoying for street. I don't mind an the extra pound or so, and used light steel FW's for years. This is a nice compromise, like it or not.

Another issue is obsolescence. At some point the 20111 plate will go OOP. You may reconsider if you are looking at 750-1000$ for a pressure plate? All the folks that bought these will be glad they did - they never have to give it another thought, or worry about that nonsense.

And I think you are forgetting also that many owners have to pay someone labor to swap a clutch. It may not be a big deal to you to pull the engine, but it costs others well over $1000/1500+ in parts and labor. From my perspective the longer a clutch lasts, the better.

Personally, I'd rather buy a $125 clutch that I know will out last the one for 350+....that math makes sense to me and many others.

Will, If you don't want to buy one, that is cool, I've been an engineer for over 30 years now, and have worked on roadsters for longer. Worn out clutches are a common occurrence, and if you prefer the stock setup, that is totally cool too. But there really is no reason to criticize this setup or try to convince others that it is somehow bad ???? For what reason?

This is just a heavier duty, higher capacity, more cost effective setup than the expensive stock clutch any way you slice it.

jt
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Sun May 22, 2016 7:29 am

Whoops....looks like the U20 plate is already discontinued again from Nissan....

Jt
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Re: Best Flywheel & Clutch - last one you will buy!

Post by Linda » Sun May 22, 2016 10:10 am

I would defend anyone's right to question a product, or even just state a preference. It serves to sharpen and clarify your arguments anyway which if you have confidence in them, should be welcome.
I think the points made make sense. One point Will made was that the 240z clutch comes apart because of the way it is made....this was not addressed.
My question would be is it harder to operate this clutch than the U20? I can push the U20 just fine, but wondered about any difference.
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Sun May 22, 2016 12:53 pm

I'm not sure how great it is to fill the announcement thread with a bunch of personal opinions....long debate about clutch lore could have be done in a separate thread ;-).

If you are talking about a specific manufacturers pressure plate, of course there are variations in quality. I said that all things being equal, a 225 will out last the 200, hands down, with almost NO weight penalty.

Nissan used the 225mm on tons of cars and trucks. If the 225mm clutch had major issues, I doubt the 240z would have the reputation as a great car that it does. Everyone would have blown them up at 50k with the 6-cylinder. Just like the 510.

Clearly the 510 clutch was a mis-step and we all know about that. HAD NISSAN PUT A 225mm in the 510, like with later cars, the 510 owners would never have had a problem. This is now possible for the U20.

Sure, you can blow up a 225mm with a 6cylinder - bored? stroked? Mikunis?.. but you'd have to abuse it to do that with a U20. With an R16 a good quality 225mm will like outlast your rebuild.

That is exactly the case with my U20, 20 years since the rebuild and a ton of miles later, the lower end is fine, the clutch is fine, but it's time to freshen the head again.

Your question is a good one Linda. The pedal effort is slightly less with the 225 because the plate has longer release levers. The U20 clutch is the worst combination for that - highest spring rate and shortest release levers. That is also the reason throw-out bearings fail with the U-clutch. (highest spring rate) Time to pull the engine. The 240 release bearing is used with the 240 plate, so they are designed for each other.

Oh, and buy the way, if anyone prefers to spend 3-$500 on a clutch, don't let me stop you, buy the best quality 225mm you can find- it will last a long, long time on a U20 - way longer that the stock setup.

I have trouble seeing why anyone would object to increased clutch capacity and life at a lower cost...

Again I'll make the point, if the U20 clutch were so amazing good, no one would ever have to change them, but instead, almost everyone has. It's 8% higher capacity than the cheaper clutches out there and costs 3 times more. I'd expect them to increase in price as they get used up. Enjoy the ride.
Last edited by JT68 on Sun May 22, 2016 1:15 pm, edited 1 time in total.
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Re: Best Flywheel & Clutch - last one you will buy!

Post by Linda » Sun May 22, 2016 1:06 pm

That's a good selling point about pedal effort. I remember a few people thought I might prefer the 1600 clutch set up since it is less effort. No way, I always prefer durability, plus I knew pedal effort would not be a problem for me. But some guys would prefer an easier pedal effort clutch for their wives, so this set up could benefit.
Useful discussion I think overall, IMHO
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Re: Best Flywheel & Clutch - last one you will buy!

Post by JT68 » Sun May 22, 2016 6:43 pm

So to sum it up, If we assume only non-inferiority on the pressure plate and disk, and only assume equivalent useful life - (My experience says it is actually much better) and empirically conclude that since the 225mm worked fine with thousands of L-24 and KA's, it will work fine with less applied power, with the 225mm unit you get:


Increased torque capacity,
Increased HP capacity,
MUCH better availability/sourcing of the pressure plate (The 30210-20111 is NLA),
All kinds of performance options on the disk,
Lower cost for good quality street parts, equal cost for the expensive stuff,
Slightly reduced pedal effort,
A heavier duty throw-out bearing,
A heavier duty disc which provides a larger friction surface to help with novice drivers or starting on hills, or hard launches.
Most likely improved resale if you explain show you installed this package &AL FW.


The downside is one pound or so in rotational weight vs. the stock unit.


Despite the admitted risk of adding some degree of "unnecessary/extra capacity" to the clutch, I think the PROS outweigh the CONS by a good margin.

jt
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