Topic: 1200 lb vs 1600 lb clutch

[Brazos Bill]

Which is best replacement clutch for 87 22R 5 speed - 1600 or 1200 and why?

[blackdiamond]

Pretty sure I have the 1200 lb clutch and there's no need that I can see for more.

[Gnarly4X]

Which is best replacement clutch for 87 22R 5 speed - 1600 or 1200 and why?

Unless you are drag racing a 200+ HP 22R, a stock pressure plate and clutch disc should work fine.  In 20+ years of wheeling I don’t recall anyone saying.. “Oh crap, my clutch is slipping”.  I’ve witnessed one smoked clutch failure and that was a high mileage truck in the sand dunes.   I do know guys that have installed heavy pressure plates and Centre Force discs and had issues when crawling – clutch disc is too sticky, and the pressure plate caused premature master clutch cylinder, clutch slave cylinder, and throw out bearing failures.

I’ve run Toyota stock, Beck Arnley, LUK, and M-Pact, they all worked fine.

Marlin offers a very high quality clutch kit for both 1200 and 1600 lbs versions.  $219 and $239.

For my daily driver, and my frugal budget this was my choice:

https://www.rockauto.com/en/moreinfo.php?pk=6083505&cc=1277502&jsn=438

That’s just my opinion.

Gnarls.

[emsvitil]

You want to use .026" as the step on the flywheel for a little more grip

[Gnarly4X]

You want to use .026" as the step on the flywheel for a little more grip

What is the Toyota stock flywheel step?

EDIT:  One internet source stated that the 22R flywheel stock step is .0197" or 5mm.

The difference between .026" and .0197" is .0063" or about the thickness of 2 sheets of 20# printer paper.

I don't see how I'm going measure, calculate, or even "feel" the difference between a flywheel with .0063" taller step?

I'm having a hard time understanding why anyone would want to pay for a custom flywheel with a step of .026"

I'm open to any enlightenment.

.026" is about the thickness of 7 sheets of 20# printer paper.

I assume this .026" decreases the distance between the face of the clutch disc to the mating face of the flywheel thereby increases the clamping force?

How much more pressure per square inch does this add to the contact surface?

What is the distance that the clutch slave cylinder moves the clutch release fork?

Does the .026" step change the air gap?

Can you please explain how this increased step increases the "grip"?

How would you get a .026” step on a flywheel without ordering a custom machined one?

Gnarls.

[emsvitil]

Remember grip lessens as clutch disc wears (there's less spring pressure).    The slightly different step size just gives you a bit more spring compression.     Search this site for 'clutch step' 'flywheel step'...…….

You don't bother with new flywheel.

When you get your old flywheel surfaced, it's 2 passes.   

First pass is the surface that contacts the clutch plate.  They take off minimum amount that will surface the contact area.

Second pass is to get the step the correct height.     You just tell the machine shop you want .026 rather than whatever the stock step height is.


Also measure the before and after thickness of flywheel.     Then add washer/shim under fork pivot bolt that's the same thickness as what you lost on flywheel.    This puts the fork in the same relative position it was before you machined the flywheel.

[Gnarly4X]

Remember grip lessens as clutch disc wears (there's less spring pressure).    The slightly different step size just gives you a bit more spring compression.     Search this site for 'clutch step' 'flywheel step'...…….

You don't bother with new flywheel.

When you get your old flywheel surfaced, it's 2 passes.   

First pass is the surface that contacts the clutch plate.  They take off minimum amount that will surface the contact area.

Second pass is to get the step the correct height.     You just tell the machine shop you want .026 rather than whatever the stock step height is.


Also measure the before and after thickness of flywheel.     Then add washer/shim under fork pivot bolt that's the same thickness as what you lost on flywheel.    This puts the fork in the same relative position it was before you machined the flywheel.

I’m still having trouble.

Perhaps I’m missing something, or my old brain cells just are not firing on all 4 cylinders. 

Hypothetically - on my 22RE flywheel with 100,000 miles on it -- If the measurement between the surface of the bolt hub that bolts to the end of the crankshaft, and the surface where the clutch disc will contact is 1.00”

I take it in to a machine shop that has a sander for resurfacing flywheels and they clean and resurface the .020” step.  They sand it down .010” to get it correctly flat and resurfaced (Pass #1).

Now the step is lowered by .010” and the measurement from end of the crankshaft to the step face is .990”

If I want the step to measure .026” - How does the machine shop add back (.036”) to the thickness of the flywheel from the surface of the bolt hub that bolts to the end of the crankshaft to the surface of the step where it contacts the clutch face? (Pass #2).

I understand why the clamping pressure of the pressure plate could possibly become less over time.  Although insufficient clamping pressure is not a common failure.

How thick is an OEM replacement disc from Aisin, Beck Arnley, M-Pact,  Exedy, LUK, Centerforce, etc? 

Why does Centerforce spec their 22RE flywheel step at .018”? 

How much “Marcel” is built into each of those manuafacturer’s disc? 

If you add too much, or increase a step incorrectly you run the risk of minimizing the air gap then a potential issue with the clutch disc not fully disengaging from the flywheel. 

Who came up with the .026” number? 

Gnarls. 

[emsvitil]

Initial conditions:

Thickness clutch surface 1.00"  Thickness at step .98"

Surface clutch surface .99",   Thickness at step is still .98" for step of .01"

Surface step to .97" for stock, or .964"  using .026"


Bunch of threads here mentioning .026"

[Gnarly4X]

Hey e...

Ok…. I did more research on the dimensions of the flywheel.

Oddly, I had trouble finding descriptions.  I finally found a description!!

NOW… I understand how the step value, the .020” or .026” is determined and machined!

I understand what you meant by Pass #1 and Pass #2.

Wow… that was a real mind-boggler for me.  I was trying to figure out where Pass #2 was located on the flywheel.  Got it!

Pass #1 resurfaces the area where the clutch disc contacts.

Pass #2 grinds the area AROUND the raised area where the clutch disc contacts.

I thought the “step” was the area where the clutch disc contacts. 

The area on the flywheel called the “step” is the area around the raised area.  Totally not intuitive to my thinking.  The “step is referred to as the area where the pressure plate bolts to.  It is odd that the “step” measurement is actually the dimension and surface of the raised area where the clutch disc contacts.

This is the best description I could find so far....

https://artsautomotive.com/publications/8-automotive/60-repair-clutch-job/

Look at the photo with this statement….

“This is the flywheel after grinding. The friction surface has been ground perfectly flat and the “step” (the area the pressure plate bolts to has also been ground to maintain the original flywheel dimensions.”

After hours of internet research, I was very surprised that a simple description of the repair or resurfacing process of a flywheel was no where to be found until this morning!

I’m still curious about who came up with a step value of .026”, which is plus .006” more than factory stock of .020”.


Gnarls.

[T-Revv]

If you are running over 40" tires, the 1600 lbs clutch is good, or if you are towing a lot with this truck the 1600 lbs is good.  Anything other than that the 1200 is more than sufficient.  There is going to be little to no pedal feel difference between a factory clutch and a the 1200 lbs clutch.  The 1600 lbs clutch you will see a small increase in pedal feel, but nothing extreme.  However unlike the clutches that Gnarly4X is talking about, they are not too sticky.  Many of those companies use a ceramic disc and extreme lbs on the pressure plate, Marlin Crawlers clutch does not.  Its still the original organic style material on the disc, with stronger springs and the upgraded pressure plate.  This just allows the clutch to last longer without altering the driving feel of the clutch too much.

[T-Revv]

Also, I would not suggest the extra step in the clutch.  The clutch works much better with the factory step.  The increased step does have its benifits, but you lose most of your clutch pedal when you do that.  Instead of the clutch starting disengage early on or midway in the stroke of the pedal, the clutch releases almost at the top of the pedal. I personally like having the full range of motion in my clutch.

[OVRAROK]

Also, I would not suggest the extra step in the clutch.  The clutch works much better with the factory step.  The increased step does have its benifits, but you lose most of your clutch pedal when you do that.  Instead of the clutch starting disengage early on or midway in the stroke of the pedal, the clutch releases almost at the top of the pedal. I personally like having the full range of motion in my clutch.

I thought marlin recommended the .026 step ?

[T-Revv]

Marlin himself still runs the .026 in his truck, but that's just his personal preference.  The .026 step provides a better stronger pinch on the disc. however it takes most of the travel out of your pedal and it doesn't release until the top of your stroke. We had our new guy move marlins truck yesterday and he came back in and asked what was wrong with marlins clutch, because it was weird to him that it released all the way at the top of the pedal. I move marlins truck around with no problem, its easy to get used to, but my choice on my truck (and most other guys here at the shop) was to keep the factory step.

[emsvitil]

I don't see how the step would have any effect on the cluch pedal.

Once the disk has worn .006", you should be back to "stock" measurements.    The self-adjusting slave cylinders should keep everything the same.


I can see a self-adjusting vs the older manual adjusting slave cylinders having an effect on the pedal (the self adjusting slave would tend to keep everything constant.  The manual adjusting would vary with your adjustment and as the disc wears), and the free-play adjustment on the pedal having an effect...………...

[jimbo74]

I ran a 1600 in my 2wd. Had the .026 step as well. It was awesome.

[Gnarly4X]

I don't see how the step would have any effect on the cluch pedal.

Once the disk has worn .006", you should be back to "stock" measurements.    The self-adjusting slave cylinders should keep everything the same.


I can see a self-adjusting vs the older manual adjusting slave cylinders having an effect on the pedal (the self adjusting slave would tend to keep everything constant.  The manual adjusting would vary with your adjustment and as the disc wears), and the free-play adjustment on the pedal having an effect...………...

Marlin obviously knows something about his choice of a .006” deeper step.

The wear factor on the flywheel is probably negligible.   The wear on the clutch is probably few thousandths of an inch.

Adding .006” to the step to increase clamping pressure AND to gradually compensate for the wear factors on the clutch fork where it holds the throwout bearing, pivot ball, the clutch disc, and the flywheel seems reasonable, but I would like to see any historical data on mileage and clutch longevity.  100,000 to 150,000 miles on a clutch seems common on most early Toyota pickups and 4Runners.  That’s 5 to 7 years for typical daily driver.  For a 4-wheeler only or non-daily driver that could be many years.  Of course for a tow vehicle, the mileage numbers can be very different.

My concern would be the air gap and making sure the throwout bearing does not ride constantly on the pressure plate fingers. More importantly that the very short movement of the clutch fork is adequate to completely release the pressure from the pressure plate to clutch disc during shifting.  AND, the clutch pedal throw feels proper during release and engagement.

The pivot ball on the bell housing is adjustable and can affect the leverage and length of movement when the slave cylinder pushes the rod to move the clutch fork via the clutch pedal and master clutch cylinder.

Toyota engineers could have designed the flywheel and clutch system any way they wanted, but they spec’d the step at .020” for a reason.

Can the additional clamping pressure with a .026” step be measured?

If your application requires more clamping pressure for your engine torque numbers just buy the right pressure plate and clutch disc.

For my 5-speeds, a factory clutch, pressure plate, flywheel replacement - whether I use a .026” step or a factory stock .020” - I don’t think I’ll be able to tell the difference, but it would be an interesting long term test.

Gnarls. 

[T-Revv]

Toyota engineers could have designed the flywheel and clutch system any way they wanted, but they spec’d the step at .020” for a reason.

Gnarls. 

Exactly why I leave mine at .020 , its set there by toyota for a a reason and the clutch is designed to work with that number.  The .026 does give more clamping pressure, but because where the teeth now sit in comparison to the throw out, it does not grab until right at the top of the pedal.  Marlin did say machining it to .030 will cause the teeth to hit and make noise when the clutch is depressed, so he keeps it under that at .026 . To me the gained clamping force is not worth the pedal loss, so I stick at .020 , and if you want more, go to a turbo clutch set up with a 9 5/16" flywheel and clutch rather than 8 7/8".  Yes its a 1200lbs, but thats 1200 Lbs spread out over a greater surface area resulting ultimately in more grab.

[blackdiamond]

Toyota engineers could have designed the flywheel and clutch system any way they wanted, but they spec’d the step at .020” for a reason.

Toyota engineers were not designing with oversize tires and dual ultimate gearing in mind.  The closer you are to stock the more likely it is that the Toyota engineers got it right for you.  The farther you are away from stock the more reasonable it is that modification could prove beneficial compared to OEM.  Just my $0.04.  It may be twice as worthless as $0.02.

[Gnarly4X]

Toyota engineers were not designing with oversize tires and dual ultimate gearing in mind.

Everyone has different experiences.

I agree that it makes sense to modify and change hardware to enhance strength, drivability, and safety.

HOWEVER….it’s well-known that the early Toyota pickup and 4Runners are considered - by most automotive enthusiasts – that Toyota’s engineering and design is “over-built” for longevity.

I 4-wheeled a basically stock 1985 Standard Cab, 22R, 5-speed for 10 years on the most difficult trails and terrain in California, Utah, Arizona, New Mexico, and Sonora Mexico.

Many times I started and finished the trail in front of, or behind, vehicles that were modified and tricked out with 10’s of thousands of dollars.  My $5,000 Toyota truck with 33” tires did the same trail as the $50,000 blinged-out-terrain-thrasher with 40” tires with that heavy-duty-rooty-tooty-super-clamping-no-slip clutch!

I had one (1) drive train failure in that truck on Pritchett Canyon and it was my careless move that broke the factory stock J-arm.   Was I lucky?  Was I just a very good driver? Or… was it that the Toyota engineers designed and built it right?

As I said, in 20+ years of serious and active 4-wheeling, I don’t recall an issue with clutch discs prematurely failing due to lack of friction and insufficient pressure plate clamping… on any 4x4 vehicle.  I have never experienced a premature clutch disc failure on my stock or stock replacement clutch, pressure plate, and flywheels.

Gnarls …. My 4 cents worth. 

[blackdiamond]

Everyone has different experiences.

I agree that it makes sense to modify and change hardware to enhance strength, drivability, and safety.

HOWEVER….it’s well-known that the early Toyota pickup and 4Runners are considered - by most automotive enthusiasts – that Toyota’s engineering and design is “over-built” for longevity.

I 4-wheeled a basically stock 1985 Standard Cab, 22R, 5-speed for 10 years on the most difficult trails and terrain in California, Utah, Arizona, New Mexico, and Sonora Mexico.

Many times I started and finished the trail in front of, or behind, vehicles that were modified and tricked out with 10’s of thousands of dollars.  My $5,000 Toyota truck with 33” tires did the same trail as the $50,000 blinged-out-terrain-thrasher with 40” tires with that heavy-duty-rooty-tooty-super-clamping-no-slip clutch!

I had one (1) drive train failure in that truck on Pritchett Canyon and it was my careless move that broke the factory stock J-arm.   Was I lucky?  Was I just a very good driver? Or… was it that the Toyota engineers designed and built it right?

As I said, in 20+ years of serious and active 4-wheeling, I don’t recall an issue with clutch discs prematurely failing due to lack of friction and insufficient pressure plate clamping… on any 4x4 vehicle.  I have never experienced a premature clutch disc failure on my stock or stock replacement clutch, pressure plate, and flywheels.

Gnarls …. My 4 cents worth. 

Again, you were running 33s and Marlin is running 38s. You're experience driving has been done in closer to stock vehicles that what Marlin has.  I think you're likely a skilled and careful driver that got a lot of your rigs that most couldn't have done without a lot more breakage and damage.