Clutch Pressure Plate Styles

[housejoe]

Hi Everyone,
I am currently in the process of prepping my new to me citation 98V for driver’s school at Roebling at the end of Feb. Part of that process is swapping out the short box in favor of the long box. While I’m there I thought I would refresh the clutch (seems like a good idea since the car has not run in 10+ years).. The current pressure plate is the old 3 finger type (top picture) and I see that current replacements that are available are the full diaphragm type. Is there an advantage to either? The current pressure plate is damaged. It looks like something came loose inside the bellhousing at some point in the car’s life causing dents and damage to the “spring holders” on the backside of the pressure plate. Therefore a replacement seems to be necessary. Any advice would be appreciated.

Thanks,
Joe

[Dietmar]

Biggest difference is the price. There are some German three fingers available but most are Amortex ( Sachs) from Brazil. The diaphragm seems to be better balanced and is bit cheaper. Stay away from anything Chinese!

The three finger plate that you have pictured is missing the center disc that runs on the throw out bearing in the trans.

Hope that helps.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

[housejoe]

Thanks!!

[veeten]

Off Topic but why are you putting in Long Box?
Most folks run short box and use 4th all the way around.
If you plan on going to Daytona you will need it then
Good luck, several folks from Driverz Cup will be there

[housejoe]

Off Topic but why are you putting in Long Box?
Most folks run short box and use 4th all the way around.
If you plan on going to Daytona you will need it then
Good luck, several folks from Driverz Cup will be there

Thanks for letting me know. Being a complete newbies to FV, I assumed that due to the long straight at Roebling we would need the long box to avoid extreme RPM’s at the end of the straight. We actually have 2 cars, one for me and one for my daughter. I have experience at Roebling in a Champcar (endurance series not the former Pro series), but she has only karting experience and a couple of track days. So I figured it would be lower risk to run the long box, since we are not out to “Win” the driver’s school. Our first race in competition will be at Road Atlanta, so we can have a bit of a shakedown with the long boxes at Roebling. Also, during the teardown I found that the input bearing on my shortbox is toast, so I guess I am forced to run the long box (at least in my car), as I have too many other items to finish that will not afford me the time to fix it before the event.

I glad to hear that some other Vee folks will be there, I look forward to meeting them and learning what I can!

[Dietmar]

Might I ask what you mean by ...input bearing?
The input SHAFT does not have a bearing until it reaches the main shaft .

If you are referring to the "loose" input shaft and the seal at the end where it enters the transmission, that is a "normal" wiggle

Dietmar
www.quixoteracing.com
fvraceri@cox.net

[housejoe]

Thanks for the tip Dietmar. I was looking at the exploded drawings trying to figure that out. Nevertheless I think I still may have an issue, as the front seal is completely torn up, and the amount of “wiggle” is significantly greater than the long box which is going in. Maybe it’s just the difference between a good seal vs. a destroyed one, but I’ll only know once I have a chance to analyze it a bit more thoroughly..

Joe

[Dietmar]

The seal is easy to remove, more difficult to press in. Helps if you use a tube the size of the seal.

If the seal is destroyed, it will allow for more "wiggle" giving the impression that something is not right.
Dietmar
www.quixoteracing.com
fvraceri@cox.net

[housejoe]

[housejoe]

So do all FV flywheels end up looking like this? I am thinking I should have it machined before going back together with the new clutch, as I have concerns about the ability of the clutch to not slip on such an irregular surface.
Also, while pulling the flywheel I noted (but did not measure) quite a bit of crankshaft end play. The manual says 0.15mm max, what is the max for a race engine and should I even bother to adjust it considering that the engine runs fine? I welcome any thoughts you all might have. Thanks, Joe

[Dietmar]

First, I HOPE that you marked the location of the flywheel to the crank. It needs to go back in the same location ( most of the time).
Second, the end play, just like the input shaft (mentioned earlier) can be deceiving unless you actually measure it. VW stock specs do not apply to FV. I have seen as much as 0.013" on engines. I prefer 0.006-0.008"(inches). Be sure to reuse the metal shim between the crank and flywheel - if one was there as a new one might be a different thickness than what you have. Unless you have access to shims of different thicknesses, I would leave the end play alone.
The flywheel looks nasty. Beyond what would clean up with some emery paper. I would suggest a resurface- but be careful as too much MIGHT get the weight below legal ( 12#). You will then also have to adjust your slave -free play on the throw out bearing . I would also suggest a new clutch disc.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

[housejoe]

First, I HOPE that you marked the location of the flywheel to the crank. It needs to go back in the same location ( most of the time).
Second, the end play, just like the input shaft (mentioned earlier) can be deceiving unless you actually measure it. VW stock specs do not apply to FV. I have seen as much as 0.013" on engines. I prefer 0.006-0.008"(inches). Be sure to reuse the metal shim between the crank and flywheel - if one was there as a new one might be a different thickness than what you have. Unless you have access to shims of different thicknesses, I would leave the end play alone.
The flywheel looks nasty. Beyond what would clean up with some emery paper. I would suggest a resurface- but be careful as too much MIGHT get the weight below legal ( 12#). You will then also have to adjust your slave -free play on the throw out bearing . I would also suggest a new clutch disc.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

Thanks for the reply Dietmar, yes I marked it. I was quite surprised that it could go on more than one way. I think it is beyond saving. The flywheel is marked 12.1# and I think to clean this thing up would take me below or dangerously close to the limit. Are these flywheels typically balanced to the specific engine, or can I buy a new one, lighten and balance it and be good to go? On second thought, I guess if I needed to mark the flywheel, that kind of answers the question…

[Dietmar]

You are welcome. Glad I could answer your question.

I would go ahead and surface it, knowing that it is underweight ( or not) and when the engine is rebuilt, get a legal flywheel. I have seen some that have been welded on to add weight and that might be an option depending on how much has to be added, and of course it would then have to be balanced.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

[nhJohn]

You are welcome. Glad I could answer your question.

I would go ahead and surface it, knowing that it is underweight ( or not) and when the engine is rebuilt, get a legal flywheel. I have seen some that have been welded on to add weight and that might be an option depending on how much has to be added, and of course it would then have to be balanced.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

Dietmar, regarding 'balance'.
If one has to replace both the disc and the clutch assembly, can it just be put on, or does the whole moter need to go back to the builder for a rebalance?

[Dietmar]

John:
Need a bit more info.
As I understand it, as explained to me by the shop that does my balancing...if the individual components are balance separately and then as a unit, any part can be replaced if it is first balanced.
If all the parts are just assembled and then balanced as one unit, then the replacement COULD cause an imbalance.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

[housejoe]

You are welcome. Glad I could answer your question.

I would go ahead and surface it, knowing that it is underweight ( or not) and when the engine is rebuilt, get a legal flywheel. I have seen some that have been welded on to add weight and that might be an option depending on how much has to be added, and of course it would then have to be balanced.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

Good news! It cleaned up with just .004” removed (I thought it would be at least double that) and it still meets minimum weight.

[DannyPip]

Is it necessary to remove the same amount from the clutch cover mounting surface when refurbishing a flywheel?

[Dietmar]

VW has a spec for the distance from the pressure plate mating surface to the bottom of the flywheel. If that distance is "exceeded"- too little, then the face of the flywheel has to be surfaced.

Dietmar
www.quixoteracing.com
fvraceri@cox.net

[Bob Posner]

Is it necessary to remove the same amount from the clutch cover mounting surface when refurbishing a flywheel?

Not exactly on point but when I blew up a disc and pressure plate my engine man said to replace and he’d rebalance on next rebuild. Never noticed an imbalance and he saw no evidence that the new disc/cover was an issue unbalanced

[housejoe]

Not exactly on point but when I blew up a disc and pressure plate my engine man said to replace and he’d rebalance on next rebuild. Never noticed an imbalance and he saw no evidence that the new disc/cover was an issue unbalanced

I’m hoping for the same. I purchased a new Sachs clutch kit with diaphragm type pressure plate (Brazil) and it has some big honkin’ balance weights welded to it, so at least that shows they tried..

[Bob Posner]

I’m hoping for the same. I purchased a new Sachs clutch kit with diaphragm type pressure plate (Brazil) and it has some big honkin’ balance weights welded to it, so at least that shows they tried..

Try to get a German disc. My explosion was a non-German disc. I had to search and pay up for a German disc but it’ll be in there for many years.

[Hardingfv32]

I built my own dynamic spin balancer. Just finished balancing my first assemble and was surprised to find that the disc pressure plate was only a few grams out of balance. The weight of one of the washers you might use under one of the pressure plate mounting bolts.

An interesting note: While researching on how dynamic spin balancers are used I found that you do not need high rpm's to balance accurately. I spin up with a variable speed drill to about 3000 rpm. The formula used to calculate the balance weight does not have an input for RPM. The best $10-20K balancers all spin at about 3500 rpm no matter what type of engine rpm might be seen.

Brian

[housejoe]

Try to get a German disc. My explosion was a non-German disc. I had to search and pay up for a German disc but it’ll be in there for many years.

Thanks, I’ll take a look around, but In the meantime I’ll have to use the Brazil disc, since time for driver’s school is almost here..

[DannyPip]

An interesting note: While researching on how dynamic spin balancers are used I found that you do not need high rpm's to balance accurately. I spin up with a variable speed drill to about 3000 rpm. The formula used to calculate the balance weight does not have an input for RPM. The best $10-20K balancers all spin at about 3500 rpm no matter what type of engine rpm might be seen.

Brian

This is certainly true. I bought an old Snap-On electronic/dynamic wheel balancer years ago on Craigslist. It has no motor, it has a handle that YOU spin the wheel up with. The balancer beeps at you when you've reached a sufficient speed, then it calculates the balance.

It also runs on a small 12v DC adapter, and could easily be used at the track.

[Rich_G_SC]

I assumed that due to the long straight at Roebling we would need the long box to avoid extreme RPM’s at the end of the straight. We actually have 2 cars, one for me and one for my daughter.... Our first race in competition will be at Road Atlanta, so we can have a bit of a shakedown with the long boxes at Roebling.

Just FYI, both Roebling and Road Atlanta are short box tracks. Road Atlanta apparently used to be a long box track before they added turns 10A & B - at least that's what I've heard.

We only use 3rd on the start at Roebling then 4th all the way - my top speed at the end of the straight is <110 which is well within safe RPM. Most drivers I know use 3rd 2 to 4 times per lap at Road Atlanta depending on how you want to do T3 & T5. Top speed here is a bit less than Roebling for me.

Long box certainly isn't going to keep you from doing a school at Roebling but it will slow you down.

Hope this helps a bit,
Rich

[housejoe]

Just FYI, both Roebling and Road Atlanta are short box tracks. Road Atlanta apparently used to be a long box track before they added turns 10A & B - at least that's what I've heard.

We only use 3rd on the start at Roebling then 4th all the way - my top speed at the end of the straight is <110 which is well within safe RPM. Most drivers I know use 3rd 2 to 4 times per lap at Road Atlanta depending on how you want to do T3 & T5. Top speed here is a bit less than Roebling for me.

Long box certainly isn't going to keep you from doing a school at Roebling but it will slow you down.

Hope this helps a bit,
Rich

Wow. Thanks for that info Rich. I never would have guessed that Road Atlanta would be a short box track! Guess I have to give my short box the attention it needs before Roebling. Good Stuff Everybody! Thanks!!!

[Hardingfv32]

Having raced at most the fast tracks in N America, I would say Daytona might be the only track you need a long box.

The correct way to think of gearing in a FV is to consider what rpm range your engine spends the most time in. A bar chart is the best way to evaluate this data. You want the engine performance optimized for the greatest time period not the fastest part of the track (end of straight?). If you happen to max out rpm's somewhere just feather back a little. This usually is only for 5-10 sec. This is what happens at Road America. The short box is perfect for everywhere but the last few seconds at the entry into Canada corner.

The other part of this discussion is the quality of the driver and engine. If you are not a great driver, then the short box is better for recovering from driving errors. If you are not in the lead pack (drafting?) there is no chance that you are going to over rev in 4th. It takes a top of the line engine to get into over revving situations. A subpar engine (or car) is simply not going to have the pull to get you into 4th gear redline territory.

Brian

[housejoe]

Having raced at most the fast tracks in N America, I would say Daytona might be the only track you need a long box.

The correct way to think of gearing in a FV is to consider what rpm range your engine spends the most time in. A bar chart is the best way to evaluate this data. You want the engine performance optimized for the greatest time period not the fastest part of the track (end of straight?). If you happen to max out rpm's somewhere just feather back a little. This usually is only for 5-10 sec. This is what happens at Road America. The short box is perfect for everywhere but the last few seconds at the entry into Canada corner.

The other part of this discussion is the quality of the driver and engine. If you are not a great driver, then the short box is better for recovering from driving errors. If you are not in the lead pack (drafting?) there is no chance that you are going to over rev in 4th. It takes a top of the line engine to get into over revving situations. A subpar engine (or car) is simply not going to have the pull to get you into 4th gear redline territory.

Brian

Thanks for the info Brian!