Projects rebuilding after the crash

For those that don't know how a real race clutch works here is a quick introduction. It's far from complete. Between the flywheel and the pressure plate there are adjustable stands. There are three clutch discs and two steel floater plates. A long feeler gauge is run into the assembled clutch pack. The stands are adjusted to set a predetermined gap. The more gap the higher the engine revs up before the clutch grabs. For a consistent launch the pack is reset before a run.
On big show nitro cars the packs can weld themselves together. The heat generated from these race clutches is extremely hard on the back of the block and rear bearing. The crank flange can also get destroyed.
Putting one of these clutches into a car can get complicated very fast. The discs are never the same. They all vary on how they grab. Then there's the fingers. The fingers are forced outward as the engine revs engaing the clutch. They have different ramp options. These different ramps can contribute to how the clutch engages. The fingers have a hole drilled into them. This is to allow a bolt to get attached. Short bolts or long bolts add weight to the fingers. More weight a more aggressive clutch. Multiple nuts can be added to these bolts. These clutches are very messy do to the dust. The black haze you see when these cars leave is clutch dust. It's nasty the mess it creates. Running a clutch requires a steel liner in the bellhousing because of all the heavy steel parrs wirling around inside. A good titanium clutch costs around fifteen grand. They do fatigue over time and need to be replaced. The pressure plate begins to flex. This is a good way to ruin a block and crank. I won't get into clutch timers tonight I need to go to bed.

 

In 2018, I ran an adjustable drag racing clutch in my Hemi Coupe for drag week.
The idea is that if a clutch has stiff enough springs to hold a whole bunch of horsepower, it will also lock almost instantly when you dump the clutch and launch the car. And that is hard on parts, and does not allow the suspension and the tires to work as good as if they had a little bit of cushion. So the adjustable racing clutch uses low spring pressure so that it will slip a little bit at launch but has other means for locking it up once the car is off the line.
The clutch I ran is a little simpler than the one Brian is talking about. It is a single sintered iron disc sandwiched between an aluminum flywheel and aluminum pressure plate. ( With bronze friction surfaces riveted on) The pressure plate is clamped onto the disc by 18 springs, six of which are adjustable. Each of the adjustable springs has a screw that I can access with a long Allen wrench through a small hole in the back of the bellhousing. The clamping pressure can be adjusted from about 300 lb up to about 1200 lb. Which is pretty soft compared to the old school 3600 lb racing clutches. There are also three levers with arms sticking out around the outside perimeter of the pressure plate. Weight it is bolted on to the ends of the arms. As the RPM goes up, centrifugal force acts on the weights causing the levers to apply more clamping force to the clutch. The high RPM holding force is adjusted by adding or removing weight from the levers. But you can't use too much weight or it becomes impossible to shift the transmission at 7,000 RPM.
When the sintered iron disk is cold It has a lower coefficient of friction. So when you launch the car, it slips a little bit, that heats up the disc, which increases its coefficient of friction causing it to grab more, while at the same time the RPM is rising and the centrifugal is applying more pressure, locking up the clutch. The initial hit is adjusted by turning the 6 adjusting screws for the springs. My car seemed to be launching best with about 300 lb of base pressure.
But with every engagement of the clutch comes a little bit of wear on the sintered iron disk. In normal drag racing you might have to tighten the screws a half a turn about every 15 passes, which is no big deal.
At the beginning of Drag Week, I had the clutch dialed in pretty well. But after 3 days of street driving, the disc had worn enough that when I hit the track at Bristol, the clutch slipped when I hit third gear. I went back to the pits, tightened it up a little bit, and went out and made another pass but it still slipt when I hit fourth gear.
The clutch made the changeover from street to race, and then from race back to street a huge pain. When we arrived at the track in the morning, with the clutch set at its tightest setting for street driving, I had to remove a floor panel, turn the engine by hand until a mark on the damper lined up, then adjust the screw two turns because the most you can turn one screw without turning all of the others an equal amount is two turns or you could warp it. Then the motor would need to be turned to the next mark, turn that screw two turns, then repeat until all six have been adjusted two turns, then make four full revolutions of the engine, stopping every 6th of a revolution to adjust. And you can't see the screw you're adjusting, you have to reach inside the bell housing through a little hole and feel the wrench engage into the screw. And then people come and start talking to you and you lose track of where you're at. And then go make my couple of passes down the strip, go back to the pit and readjust the clutch the opposite way. It took a good half hour to adjust the clutch. Because we had to turn it so many turns each time. It was way too cumbersome and time consuming for drag week. So I took that clutch out and put in a twin disc, non-adjustable. And then I put a clutch tamer on it, which is a hydraulic cylinder like on a screen door that goes on the clutch pedal that can be adjusted to cushion the hit. That was much simpler.

 

This year on Drag Week there were lots of 55 chevys in the gasser classes. The two that were leading B gas were both running low low tens. They both were using slipper clutches....and they both were making them work, but also they were adjusting them kind of often (I encountered one at the hotel parking lot at Cordova, kind of late at night).

Makes a torque converter look pretty attractive....I had mine rebuilt several years ago, and haven't messed with it since.

 

Squirrel, a slipper clutch is doable on a normal car, but it is a lot of extra work. But when you get into the power level that Brian is at, the complexity goes way up, and the clutch tune becomes much more critical, and a harder target to hit.
With the clutch tamer, I can do the clutch adjusting in 15 seconds by turning a knob under the dash.

 

http://clutchtamer.com/

https://bangshiftbilly.com/ - Made by Bill Armstrong, and longtime D&D event participant

 

I bought a bang shift Billy to test. It's supposed to be more precise than the clutch tamer. It is controlled by an app on the phone. It sounds good, but usually anything electronic hates me.

 

I received the new flywheel as planned. I placed them over each other to see the new design better. There is much more material in the areas the other one cracked.
I took a few pics of the bellhousing liner. Most on this site don't see these kinds of parts so I thought it would be interesting to see them. Clutch cars need the liner. Converter cars don't. I remove mine to save seven pounds. A single bolt holds it in place. These bellhousings are sfi safety rated. They require regular inspections and recertification to be legal to race. It may sound excessive or alot of extra bs but when your strapped into the car and something goes wrong it's all worth it.

 

I've raced for a while in street cars, but had the "it's all worth it" message really sink in during the last month. My FED build is nearing chassis completion, and I got to sit in it with the cage in place. The diff is precariously close to parts of me that I'd rather not lose. The tyres are around my ears. It's a contortionist act to get in and out, even with no harness. Made me realise that SFI ratings on trans blankets, harnesses and fire suits and IHRA chassis inspections are worth every penny.

Cheers,
Harv

 

Looks like they also added more material to the crank flange area by reducing the O.D. of the bronze bushing in the center.

 

Guessing some harmonics get transferred through that piece.

 

Noticing what looks like witness marks on the bronze bushing in the center of the failed flex plate I went back through the thread to find a picture of the front of the converter and how the new smaller bushing would match up with the converter. I would imagine there is supposed to be some clearance there as well even while ballooned.

While looking back I found this photo from March 22 (post 4912). Not trying to be critical cause you certainly had your hands full back then, but looks like it had at least one crack back then.

 

The hole for the bushing is the same size. The new design flips it. The flanged side of the bushing is now on the crank side. The mounts on the converter prevent it from bottoming out onto the bushing. The converter growth moves it back toward the pump in the Bruno unit. The .150 clearance is to prevent pump damage.
Tomcat11 good eye. It looks like it might have been starting to crack at that time.
I just need to put the trans back in this morning and it's a runner again. No trips to the track this weekend. The weather is bad cold and some rain. I don't like to race the car when it's below 55 degrees. It's dangerous. The track can't hold the power.

 

Harv if your having some issues getting in and out of the car put on all your safety gear and try it. You would be surprised how tight it gets. Have someone measure your helmet to cage. There needs to be a few inches of clearance. Check the rule book. Make sure you can reach all of the controls belted in tight. With a helmet on it really reduces what you see.

 

The FED construction has been a real learning exercise for me. The chassis builder is in his 70's (I think... it would be rude to ask), and has built chassis from simple altereds through to jet cars. He is a real gentleman - quiet, patient, and gracefully puts up with the dumb questions I keep asking.

My local track is IHRA sanctioned, so I spent a lot of time trying to work out what rules apply. The IHRA rule book is online, and not too badly organised. IHRA Australia has a few local interpretations, and it has caught me out at times. I thought I needed both a trans blanket and a flex plate shield, but apparently locally there is no need for a shield (I now have a spare SFI-rated flexplate shield as wall art ). Some different local interpretations on SFI recertification periods too. Have had some great experience dealing with Stroud in the states - there should be one of their chutes waiting for me when I get home from work.

As the builder has been making the chassis he has had me in and out of the framework to check clearances. I borrow his helmet for the time being for the checks. I street-car race my avatar using an Aussie-standard helmet, though for the FED will step up to a SA2020 Simpson helmet (sigh... those are a 6-month lead time locally... still waiting on mine to cross the pond).

The caution around the controls is a good one. I opted for a hand brake as it feels more period-correct. The builder was nice enough to point out that with one hand on the brake you only have one hand left to operate the shifter when backing up or staging. The IHRA rules call for a reverse lockout. With some of the period shifters I need two hands to manipulate the reverse lockout... no hand left for the brake. Ended up using a one-hand Precision Shifter (those are 6-months lead too ).

As an aside, thankyou for posting the detail in your thread. Stepping up from street cars to a FED has taught me a lot of stuff that I had heard of but not really understood. Reading the info in your thread is teaching me about a much higher class of racing.

Cheers,
Harv

 

Harv you should look up a guy called roo man. He moved back to Australia. He is very knowledgeable and will be able to help you out.

 

I second that. Keith Burgan is his real name. If you look at the last few cars that Brendan Murray has raced, or the current car that Brian Hall races, they are all Rooman cars.

https://www.facebook.com/keith.burgan.7

 

Many thanks.

Small world... my FED front wheels are ex-Brendan Murray

Cheers,
Harv

 

NHRA rules supersede IHRA, Build your dragster to Nostalgic rules that way you will not have issues @ any sanction track Tec, that way if you ever go 6.0's 1/4 your chassis will be Covered ,
Stay with SFI Bell / trains will free up room for your feet & legs.
Their are a few other shifters that are small & con packed , Percision has there place , For me not in dragster /Fc/Altered, (function )
I prefer a hand brake in a
FI or rear Dragster or Fc No matter what trains & a Hand brake added to door slammer ,
Practice getting in & out with eyes closed with your safety gear , Getting out is more critical , you will be prepared if needed.

 

The Aussie rule setup is a bit funny. I have to meet IHRA rules on my local track. Some Aussie tracks are IHRA, some use the local ANDRA rules.

If I have a street registered car, I can race once a week at my local track. This has been fun in my avatar, but I want something more interesting. I'm building the sedan version of my avatar with a vane-blown McGee injected I6 in it, road registered. It will be a pig to drive on the street, but meets the rules to let me race it once a week. The engineering inspection alone to register as a modified car will be around $US3000. Annual insurance/registration around $US800. If I am lucky, it will run mid-12s. This will be my play toy.

The FED will have another blown, injected I6. These engines have been known to produce 200HP when leaned on heavily. With 200HP and maybe 1300lb it's good for mid-11 quarters. That won't let me run in Modified, which locally has a 10.99 cutoff. Some research shows that sub-11 seconds has not been done with one of these engines in Australia (GMH grey motor, 1948-1963, 138ci, 75BHP factory, 200HP when heavily modified). This will be my research project - how do I get another 1/2 second out of this FED to let me run Modified. I'm trying a lot of tricks - aftermarket crossflow head, injected and blown. Can't run giggle gas and a blower on the same engine because of class rules, and don't want to run just giggle gas. I'm guessing I'm going to have to wind the boost right up (need 220HP) or cut the weight right down (less than 1200lb) or both to meet 10.99. Doing these things and still keeping it relatively period correct (no carbon fibre, few modern components) will keep me entertained. I will learn.

If I want to race a FED, I can play at a test-and-tune once a month. If I can get it below 10.99 and run modified, I can run maybe 4 race meets a year at my local track. Most years only one Nostalgia event... if it's rained out, come back next year. There are some small tracks within 300 miles of me that run once or twice a year, but to get to a major track away from home I need to travel about 800 miles. That's a lot of trailer time.

Cheers,
Harv

 

It's snowing out this morning. The decision has been made to pull the plug on this year. The track won't warm up now. On to taking the car apart for upgrades. Next years season has begun.

 

Yes. The property was sold. Everything needs to be removed by the end of November. The semi trailer has been filled up. When it's moved away we can get at the car. Right now the semi trailer is blocking the garage. It will be be pulled out with a tractor. It will be a very dangerous removal.

 

It's no big deal. There's already 175 pages of clutter. No one will notice.

 

"One mans junk is anothers mans clutter"

 

Well things have changed. The weather looks like 65 on Saturday and mid 70s on Sunday. So I will start prepping the car to race this weekend. I can take a break after that. I really need one more weekend to test a few more things before I go into the off season.

 

Come on it's WI, things can change in 10 minutes.

 

This Winter in yr up grades The data logger will be eye opener of information of what if ,decisions and frustration
But you/ we continue!!

 

I'm all in on the data logger. I will be checking them out at pri. The problem is coming up with at least five grand. I'm also trying to complete my 66 chevelle. It's body is still off the frame. I can only do so much over time to pay for two cars. I'm not 20 anymore.
When I did the cackle show at the Iron invasion it pinched 2,4,8 rings. I'm clearly doing something wrong getting the engine too hot. So after I got out of work today I pulled the head. I'm out of low compression pistons. My higher compression pistons have the same pin location. All I needed to do was take .050 off the top. I put them in the lathe using a six jaw and did the deed. I have extra rings so over the course of this week it will get done. I didn't want the season to end on a sour note. It's alot of work to get it ready. The world hates quiters and I'm no quiter. I think decades of martial arts training has something to do with it. Loosing was one thing and it happens. Quiting was unacceptable and was the biggest dishonor to yourself.

 

Without reading the 175 pages, I don't recall what EFI system you are using for the street mode. Some of them have data logging capability. Can you use your street EFI computer to data log your vitals like converter slip and pressure, suspension movement, boost, etc?

 

I have a fast xfi-2. This has the capability of recording 24 channels. It will data log on the gas side. The problem is the efi is not on during nitro use. If it's on the fuel pump is running. Im not concerned about the efi controlled ignition because the mags timing is way ahead of the efi timing. To make it data log the lap top needs to be plugged in and the space bar hit. That means I need to make a mount to hold the lap top in a area I can reach yet still be able to exit the car in a emergency. That hasty exit might be through the passenger door. I have thought long and hard on this option. I'm most concerned about shock travel; fuel pressure and volume; egts; drive shaft speed; boost pressure; shift rpm. The fast system can do all those things. I have called the fast tech line they can't tell me how to flip it back and forth when the nitro side is on. I have a friend that's local to me and very experienced with fast efi. He is a graduate of msoe with a electrical degree. He has brought up the same scenario using the fast system. He thinks he might be able to pull it off. We will explore this more over the winter.

 

The two best tec guys have stepped away from FAST a few yr ago , the ones that worked in Dyno & development, from my experience, (a stand alone Data logger) Race Pac one of the best.