Fidanza flywheel, ACT clutch install and pedal mods

[rejracer]

Hey there Hybrid,

I never created a post on my flywheel and clutch install. I did this about 2 years ago. I searched for many options available and I decided the best bang for the buck is the Fidanza aluminum flywheel with ACT clutch. By "best" I mean that it is:

1. Improvement over the stock flywheel.

2. Reliable.

3. Serviceable

4. In an emergency off the shelf parts can get me up and running

 

Concerning why I chose the above, I started a rev-happy-flywheel-clutch-choices-for-street-use thread. Had I to do this again, I might have chosen different parts, regardless, lots of info in the other thread.

 

Just an FYI, if I were to scratch requirement 4 off the list, I would have went with the clutch masters setup like monzter is running. If I were to scratch 3 off the list, I would have went with a kamari or similar steel flywheel. It all depends on what your priorities are.

 

Now back to the topic! To start off with I wanted maximum thread engagement for the clutch/pressure plate mounting. Some have reported that these strip out upon fastening them down because the holes in the flywheel are blind, and this forces us to use shorter bolts. To get around this I decided it was best to use a stud. The hardware I chose for this is:

Class 14.9 M8.1.25x25mm socket hex screws (used Class 14.9 because 10.9 was not available from McMaster Carr)

Class 10.9 M8 washers

Class 10.9 M8 1.25 nuts

 

A visual of the problem, because the holes in the flywheel are blind, it's not possible to use longer bolts. When tightening the bolts down some have reported the aluminum threads are pulling out. To get around this I thought a stud would be better for this application.

 

It all assembled:

For the final assembly, I used locktight green for the setting the dowels and studs in the flywheel.

 

I measured the depth of the hole, and threads in the crank, the thickness of the flywheel where it mates with the crank, and the thickness of the ring I was planning on using for installation.

 

I then called up ARP and purchased longer 12 point bolts. These bolts were a 1 off design that ARP custom made for another customer, who did not buy them all. I ended up picking them up for a really good rate, but I had to buy a set of 7 as part of the deal. I cannot remember the specifics of the length, but I had a very helpful sales rep that did the research and was able to find these. As I recall they have 20mm of thread engagement. I want to say stock was 10-12 mm when you consider the increased flywheel thickness and spacer

I had read of someone milling the top of the bolts to gain clearance when you run the spacer, and these bolts have a shorter head on them, so this will not be necessary.

 

Here is the crank side of the flywheel, I did not have the spacer at the time the picture was taken, so they are protruding 3mm's or so more than they are installed.

 

When I installed it I thoroughly cleaned the mating surface, and thread bores on the crank. Then ran a thread chaser down them to ensure the threads are in good shape. Finally cleaned everything with brake clean and compressed air. The flywheel bolts were installed using blue locktight. The pressure plate nuts were installed using locktight blue. I then measured and confirmed I was using the right collar and after I was confident, I installed the new throwout bearing, greased the shift fork, and installed it.

 

My clutch pedal was worn quite badly, so I opted to fix it! I increased the clevis pin to 10mm instead of 8mm. I also wanted to give the clutch pedal a bit more throw, so I wanted to bias the hole further away from the clutch pedal pivot point. I would say I lowered it perhaps 1mm. I also wanted to use a hardened steel sleeve, which I had handy. I took the outside diameter of the sleeve and drilled a hole the same size in the clutch pedal. To drill the larger hole in the right spot, I used a thick washer(approx 3/8" thick) to guide the drill bit. I had predrilled the hole to the right diameter in the washer before hand. I then tack welded the washer to the clutch pedal where I wanted to hole to be.

 

As you can see I positioned the washer with an 8mm bolt. The bolt was in the original hole. This enabled me to bias the hole down and forward as I wanted to do. When I got the washer in the right place, I tightened up the bolt, then tack welded it.

 

Using the washer as a guide, I was able to drill the hole off the center line of the old hole.

 

With the hole drilled I ground off the tack welds and inserted the steel bushing, and tack welded it in place The bushing I used was a bit longer than the width of the clutch pedal lever, which gave a bit wider (better) contact area and would hopefully be more durable. Not that a 40 year service life is bad, but why not go for 100? I was able to drill the clutch adjustment clevis to the right diameter for connecting to the clutch pedal. For a clevis pin a Class 10.9 10mm bolt was used. It was necessary to cut it to length and drill a small hole in it for a cotter pin. Due to the additional width of the bushing, it was a tight fit. With a hardened steel bushing and the class 10.9 bolt, I don't see it wearing out anytime soon. I should probably take it apart and inspect for wear to satisfy my curiosity.

 

Lastly, the clevis did not seem to have enough thread engagement, maybe 2 full threads when adjusted. So I removed it again, and welded a nut to the end of it to add another 5mm's worth of threads. It solved the problem, although I really want to make a new clevis, I have stainless steel stock to make it from.

 

For final adjustment I followed Atlantic Z's Clutch Free Play guide.

 

I finished the install in the summer of 09, and it's been a big improvement. WRCBONK drove the car in the spring of 2010, and he liked the feel of the clutch. I can't believe how much of a difference the clutch pedal mod made. No more squeaks, rattles or play, just quiet and smooth. The clutch drives well on the street, and I noticed a big difference in the way the engine responds. In the rev happy flywheel thread, someone pointed out that they can feel every pulse of the engine, an that is certainly true at lower RPM's.

 

So far no problems! I will give it a good inspection when I do my trans swap. I will be putting in a FS5W71C, hope to do that swap soon.

 

happy wrenching

[cygnusx1]

The Fidanza flywheels may have a QC or MFG issue. All of the tap holes are tapped only about 1/2 way down. It seems that Fidanza does not use a "bottom tap". I ran into the issue on mine. As soon as the bolt hits the ends of the threads, it rips the four or five existing threads out of the aluminum. The bolts feel like they are bottoming but they are probably not. Run a bottom tap with a fluid, into all the holes and you'll get much better results. I just ground the tapered section off of one of my taps to make a bottom tap.

Edited May 26, 2011 by cygnusx1

[rejracer]

Good to know, I recall mine were tapped all the way down, I checked fitment in every hole. I never did check into it, but it might be possible to drill the hole all the way, and make it a through hole. It looks like it might interfere with the ring gear:

 

 

it could be done, but would require a good machinist. Im thinking use flathead counter sunk bolts to go through. If it interferes with the ring gear, it will secure the ring gear better, but it would be a pain if you ever had to replace it.

 

Steel is looking better all the time...