Clutch - Scew Blown FC

Thanks Justin. All good points.

In my case the driveline is dead square. I have presently a raw .500" rear motor plate which I am going to have to machine for rear clutch over hang (if ordering a new clutch I might even be able to specify the rear over hang). I can either machine the motor plate for defined clearance between the back of the clutch & plate, OR, I can machine and press in a hardened insert into the pocket in the plate against which I could run clutch buttons at say .030-.040" air gap. My thinking is that if the clutch was to wobble, then at least I could limit the wobble via the buttons, like the TF guys do. Due to the nature of our motor, we will be often well beyond 10K, and we are looking at a triple disc unit to harness the gross power.

Sounding more & more like all Ti is the way to go?.......

 

I didn't say you weren't telling the truth. Of course it's stiffer, it's structural pieces are thicker and it has 1 more stand than most conventional clutches.

I'm also not arguing that the Crower and AFT lockups aren't really old technology, what I am arguing is that just because something is realitively new, doesn't make it the best choice either. Ask most any TAFC driver/crew chief what they thought of the AFT lockup unit after they bought one and re-sold it within a season or two.

I don't believe for a second that the Leanders clutch isn't more prevalent here in the States because it isn't American made. Thats like calling someone that disagrees with the president a racist. Racers want the fastest and best their money can buy, doesn't matter where it comes from, unless maybe it's China we're talking about.

 

If you choose not to go with the Leanders, then yes, I would definitely recommend all Ti. The Leanders is made of a really wicked Aluminum alloy that is incredibly strong, so there is no Ti option.

In a lot of cases you can specify how deep you would like the crank flange to be to a certain point. If you go too deep, you can weaken the material and it could spin the crank mount out of the flywheel. If you are going to place some sort of stop on the motorplate, I would recommend using a soild piece of aluminum that can surround the entire outer diameter of the flywheel. This way there are not flat edges the flywheel/ring gear can snag. Pucks work when they are mounted to the moving piece and hitting a smooth surface, but I'm weary of mounting them to the motorplate and letting the flywheel hit them. It could cause some severe damage.

 

Agreed and i know its damn hard to change from something that works for something that maybe dont work and the AFT/Crower stuff is prevalent here too
buying a clutch is a big investment someone sometime has to try something new but no one wants take the chance with their money...dont matter what side of the atlantic you live we all want the best and fastest for me personaly i liked what i saw and was willing to take a chance
are you interested in seeing the latest design??? if you want a look ill post if your not bothered i wont

PS i have a regular 12 stand 2 disc AFT and a 2 disc all Ti 10.7 crower so im not adverse to US made stuff ........ onward and upward

 

Thanks.

Yes, what I had in mind was rub buttons or pucks affixed to the back side of the clutch. If I order a new clutch, I can specify the rear over hang of the assembly, to an extent. I could machine the motor plate to accommodate a hardened plate insert, smooth for the entire clutch diameter swing. The buttons on the clutch would swing near/by a smooth hardened plane about 030-.040 inches away static. I don't trust aluminum as a hard smooth plane.

If I can custom order an all Ti clutch, and get the rear nearer the block, then do you think the button idea is worthwhile or over kill?

 

they have american made machines so dont feel too bad about buying from them
http://www.leandersbros.se/Images/press/new2007_02.jpg

another pic of the clutch: http://www.leandersbros.se/Images/press/new2007_04.jpg

 

Leander homepage

Her is a link to a more updated page.
http://www.leandersclutch.com/

 

the last link has a pic of the modern clutch check out the reinforcing round the spring housing then read the text and reviews from pro us racers

 

The Leanders alloy (being aluminum & beefy) would still be subject to heat soak issues over time, much like any other aluminum clutch would ?....

 

This may sound cruel but what super secret alloy would they have that is not a available over here, not that many alum alloys anyway

 

Not stepping on toes here but here is an answer to how many aluminum alloys: 1284

http://www.matweb.com/Search/MaterialGroupSearch.aspx?GroupID=178

Sure you can't just get them from metalmart but they are out there. However, unless they have some boron fibers impregnated in there somewhere to create a composite super material, it will most likely be a 7xxx series material with a special heat treating that slowly annels over time due to the temperature cycles. However, this clutch's design negates that issue because the doughnut isn't being subjected to the same things a traditional clutch would be.

Like:
-Interchangable surfaces on flywheel and pressure plate which should be surfaced each run would improve consistancy from run to run.

-Also, having 2 different materials that expand and contract at different rates bolted together as is the case with conventional clutches causes some serious deflection. I see it when I try to grind my pressure plate without coolant, very hard to get flat. (Hmm... Maybe I should plug off the breather and fill my clutch can with coolant...)

-Alumimum is lighter than TI.

-No holes in the adjusters for the floaters to catch, or pull material over.

Dislike:
-7 stands, odd #, non-semetrical, meaning you can't cross load it and remain in perfect balance. With 6 you can have every other lever the same then adjust in small increments by adding 3 washers etc.

-Special floaters, adjusters, etc. so I can't borrow anything to get me by if I have a problem.

-It is still simply a variation of the crower small stand. A really cool looking version but still the same basic design. I would like to see the lock up version to compare with my AFT "combo" clutch. If all the fingers are attached to the doughnut you can change the finger's weight, shape, height, etc. and it simply alters the amount of nuts and bolts required to get the plate load to where the discs stop slipping IMHO.

Flash

 

dislike 7 stands
this is something i asked about and in the opinion of the manufacturers who are sucesfull racers
the distance between stands with a 6 stand is too much to be fully ridgid remember these guys have a clutch dyno so they can realy see whats going on not just guess work,
B in their opinion the practice of loading fingers unevenly is a bad one that leads to uneven hat loadings and this causes distortion the fact that this can run 035 air gap without rolling the beams attest to the ridigity of this clutch,

The lock up version is no different to the non lock up in any way exept finger design and can quickly and easily be changed from one to the other,

the lock up does exactly what any other lock up does, and introduces more weight to the dounut than is available during normal operation as do any others, with staged release bearing actuation, But it is applied to ALL fingers not just two

if your being a pioneer and running something different you need to carry your own spares floaters arnt expensive discs are US made and they have US based service centres

it may look like a glorified crower at a quick glance but then crower is a good proven clutch,
it dosnt realy have any features in common with a regular crower,

speaking to Sean Brown at Acceleration Enterprises who has seen this first hand, His opinion is that it has taken clutches to the next level,

 

who said super secret
the sfi inspectrs just said it was the best alloy they had ever encountered being used in a clutch

we can sit here and argue the pros amd cons all we like,
when someone who uses it comes on and rubbishes it their opinion will be worth a lot of concideration,

when it comes to trying new stuff Brad Personett is prety brave and obviously knows his stuff,
remember this is the clutch behind the fastest legal pro mod in the world,

and a 3 sec car using dot tyres....but what do i know

 

isnt this stuff about alloy clutches annealing over time being carried too far look how many aft 12 stand clutches are in use all over the world id be interested to know what the failure rate for softening is,
shure things Break/wear out the clutch can is a prety hostile enviroment,

if everyone gets so paranoid about alloy clutches AFT may as well shut up shop,

 

suprised no one has mentioned the 8 stand east west clutch i switch to one from small stand crower and i feel its the best clutch i,ve ever used it is one bad arse unit and the guys there are great to deal with.

 

I mentioned East/West. Bob and Randy are great to work with and really know their stuff!

 

All clutches are subject to the annealing and tempering of the heat cycles. Figure every time you make a run, you're bringing that clutch from ambient air temp to over 1500 degrees F in 5 seconds or less in a blown alcohol application. Lots of guys out there still run Aluminum flywheels, but they will replace them every year or so, or about every 40-50 passes. Titanium just affords you the chance to extend that time frame out a little longer. My biggest problem with aluminum in high horsepower/extreme abuse applications is the growth rate with heat. Aluminum grows a lot in comparision to any Titanium alloy. Not saying that the aluminum Leanders is using wouldn't be different, it seems to be different in most other regards.

Badbird, you need to understand how the SFI process works. You send your clutch assembly to an independent engineering lab to have it destroyed. The engineering lab then posts and certifies the results. SFI then views the results and makes a decision based on posted and certified results. SFI at almost no point in time actually views and inspects the clutch. It is also a pretty rare occurance that an aluminum flywheel actually breaks because of the annealing alone. Usually the first sign of something wacky is hammering the rear mains. When the main gets bad enough you're spinning it, it creates a TON of vibration, expecially at 10,000 RPM. That vibration can actually crack/shatter the aluminum flywheel if exposed for a long period of time because it is causing the entire rotating mass of the clutch to get out of whack. You've got a polar moment of intertia well over 1,100lbs/cu. in. of material, that's a lot of mass to get out of whack.

I would differ in opinion on the Personett being the fastest Pro Mod. He runs turbos, so he's not subject to the same blower RPM limitations, and therefore boost limitations. The fastest blown Pro Mod IMO is Jason Scruggs. 3.666 @ 207 to the 1/8th is hauling the mail, and not just for a Pro Mod, most TAFC's would kill for those kinds of front half numbers. Don't give me that running to the 1/8th is different crap either, you better believe he could back those numbers up to the 1/4. My biggest thing is consistency and winning. Granted there are A LOT of other factors than the clutch involved, but it is a pretty big part of getting down the track. Tutterow is #12 in win percentage in ADRL and has been to the finals once this season, which was Houston when he won.

Maybe I'm wrong for looking at new technology and expecting to see some results. I'm glad you are satisfied with your purchase of your new clutch. Please realize that I'm not dogging the Leanders clutch either, it works for people and thats great, I am dogging the hype you are putting around it as a revolutionary piece of equipment. It hasn't conclusively served anyone any differently than any other clutch out there.

 

I have at no time said its revolutionary in its operation as a clutch, Because as you said a while back a clutch is just a clutch what i have said and stand by it that it has several revolutionary features that seem as of the time of writing to have caused no problems for being revolutionary, and seem to have some bennifits
one place where this will beat a crower / AFT hands down is the way the ring gear is manufactured and fitted, but thats just one of many design inprovements
at the end its the tuner who makes it work or not, all the manufacturer can do is make his job easy or hard

i started this by merely sugesting that TOL take a look befour he spends his money,
and since have answered questions as honestly as i can knowing the manufacturers/the special features of the clutch/ and the results of those using them/
sorry as far as NHRA racing is concerned Brad Personette is the worlds fastest legal pro mod and im cirtainly not getting involved with your 1/8 mile v 1/4 mile drag racing debates,
and what does or dosnt constitute a pro mod, for me a pro mod is a legal car an outlaw pro mod is exactly that..outlaw but thats just my personal opinion

on another subject anyone know how the brad 7 heads compare to the 6's
i heard they have a different chamber volume and need a different piston anyone using them??

 

Thanks Will, all good advice.

Our motor is purpose built to scream. It is in no way a standard deal and the stroke is only 4.00"

We will be running a mix of 1/4 and 1/8 th mile racing. Not a lot of runs in total, maybe 40-50 per year.

Yes our intention is to run the clutch as a lockup unit via the cross shaft, and we had wondered about the 10" for that reason

Had wondered about running a converter drive (Lencodrive) at one point but after thinking about it a lot we decided that we really need to have a direct coupling of the engine to the drivetrain (ie: no coverter viscous shear), to fit with some of the other automated dynamic schemes we will have going on during a run.

Thanks to all for the various inputs. It has been a great learning experience and a wealth of information to ponder. Glad there is a place like ITA on the WWW !.........