Technical REV IT UP AND DUMP THE CLUTCH!

That's what I'm working towards, just some mild dirt burnouts so far. What amazes me is the power some of you put out (my flattie might put out 100hp on a good day) and through your chassis; wishbones and/or heim joint links, tie rod ends etc.. I would think that stuff would just get ripped right off the frame. I'm pretty confident my drive train is up for it (T5, 8 inch Ford 4:10 trac lock, 1,500lb. car) but I'm clueless as to what stresses it places on the chassis and where. The rear end tries to rotate itself backwards, right? And the engine tries to flip itself over clockwise? I just have rubber biscuit motor mounts (no through bolts) but I did wrap a cable around the frame and exhaust manifold on the driver's side. How important is preventing frame twist? I have a pretty good front cross member but no x-member at the trans, just a simple cross mount and another out back for shock mounts.

I guess what I am wondering is where the major stress points are that I should be most concerned about.

 

Nothing? No tire burners? I know it's a bit of a vague subject.

 

rear end wants to lift the pinion up.

also are you sure your car is only 1500k? that is very light

 

I use rubber dounut side mounts with a bolt through them with no problem. I don't think I ever saw one without a through bolt.

But I did learn one thing, I don't wind 'er up and dump the clutch! I have a stock 11" Z-28 clutch as the fuse in the system. It will go up in smoke if I speed shift to 2nd. It saves a lot of parts that way. (465 HP, 590 FT/LBs)

 

How is your rear axle set up? HRP

 

The stress on the drive train is dependent on how the rear tires hook to the pavement. That's why "wheely bars" were invented; when you get enough traction, things start lifting and twisting and probably breaking.

 

I busted the bellhousing off my 904 Torqueflite due to chassis twist. It was still hanging on by the half inch of crack-free bell, and the trans pump was whining bad, but it still got me home. The engine was only making 520lbs of torque, but I had a high stall converter and a low first planetary gearset in the trans, and sticky tires on a chassis dyno. So yeah, if you plan for traction and power, try to stiffen things up a bit. -rick

 

Thanks guys, I was about to change the title to 'What color should I paint my truck'. Took a nap instead. .

It does weigh 1,500, maybe 16 now with all the junk I've added American Bantam, puny. Through bolts on the motor mounts, that's the plan next time I go digging down there. Rear end is leaf spring with traction bars.

Would have thought your Torque Flight would just turn in the mount? I only have a single bolt center of my trans rubber mount.

 

T5 won't last long dumping clutch or, power shifting.

 

I think Joel hit the nail on the head. If your just "playing" with it run skinny meats. The one time I tryed my buddys sticky M/H's I hooked hard enough to break a rear shock mount. To me its more fun frying pizza cutter slicks...have fun,haul ass!

 

A suspension built to withstand the rigors of 'normal' driving safely (steering, stopping, potholes, and any 'emergencies' that can pop up at any time) should take a clutch-dump in stride. My experience is the shock loads involved break driveline parts; motor mounts, clutch hubs, tranny shafts/gears, u-joints, differentials, axles. That's why line-locs were invented; to pre-load everything so the 'slop' doesn't shock the parts.

 

Following Crazy Steve's thoughts; I would expect the clutch/flywheel or trans to be the most likely and would want a blanket to cover the clutch at least. I don't know if you can get "blow up proof" bell housings for a FH.

 

I remember the "side step the clutch" days and have shit tons of broken goodies to show for it, but its still fun at 51.

 

The end result of "side stepping the clutch" is things that were at rest instantly no longer are. Everything pays the price and things break. What breaks, and how fast they break will largely depend on how much traction is involved, and how much weight is involved. The more of both, the faster a large pile of broken parts appear.
Without traction, the tires and motor pay the price do to rpm. Traction with a light weight car is not as destructive as traction with a heavy weight car.

The weakest point is going to fail first, what that weak part is on your car is hard to tell, but I suspect the T-5 will be among the first causalities, after that, start at the tires and move upward and forward.
I can tell you that of all the accumulated broken stuff I have had over the years, the twisted chassis are the things that bugged me the most. Were I starting over again, I would spend the time and effort bracing the chassis & body for the abuse ahead. Then, as things break, rebuild them stronger, bigger and better until the next thing breaks. Then repeate the process. Eventually you will modify your driving habits so there is a reduction in breakage. Gene

 

Ya know what bugs me?
3/8 clevis pins in a rear ladder bar set up.

 

I was concerned about breaking shit when i built my coupe too. I knew some day i'd want to take it to the track and see what it would turn, and also know i can be a little aggressive on the street at times....and run 10" cheater slicks all the time.
My weak link, transmission ALL the way!!! I have a t5 in it and broke it twice within the first 3 weeks it was on the road.
Then a week after that i ripped the splines off an aftermarket 31 spline 9" axle...i firmly believe there was an issue with that axle though.
That being said, here's some of what i did to help prevent issues..
I used split bones front and rear, but out back i made them into long ladder bars and rod ends up front instead of hime joints. Both front and rear chassis mount point for the bones are double sheer and all chassis components are bolted using grade 8 hardware.
I built some pretty hefty legs off the stock 32 K member out of 11ga 1x2 rec tubing. And from the K member forward, and from the rear section i built, i boxed the frame.
I also built tabs on the frame for a bolt in 4 pt roll bar to stiffin it up a bit more when i did go racing...which wont happen til i upgrade the transmission.
Im running a sbc, and used the side mounts on the block with high quality mounts that "lock" if the insulators ever break. Most mounts have them honestly.
The rest of the mounts i built from 11ga steel.
Real good wheels studs are a good addition if you ever put sticky tires on too.
Drivetrain...i chose a billit steel flywheel with an 11" centerforce clutch and the all important scattershield.
I had the driveshaft built with hd solid ujoints as well.

Honestly, im a king of overkill, but i didnt want shit to rip apart and kill someone.
With a flatty and lightweight car id say your pretty safe overall when it comes to breaking stuff...especially with skinnier tires that dont bite hard.
I was personally just more concerned with my suspension mounting points..so thats why i went rod ends and double sheer.
Hope some of that made sense man...i think i began rambling. Sorry
Tony

 

Great info. I'm surprised at the T5 weakness, a friend of mine has an old 90s Mustang 5.0 and beats the crap out of his T5, stock widish radials.

 

The world class box's are a bit stronger than non world class too. I too have a good friend with a late 80's Mustang that runs 11.80's with a t5.
GM didnt even offer the t5 in a 350 iroc/ trans am due to its weakness.
Mine is a non W/C and my car is roughly 600hp with 4:10 rear and cheaters....i knew it was going to blow the day i bought it. Lmao
I've found that if im easy on it, it stays together. Just no snapping the clutch from a stop or hard speed shifts....til i can afford a Tremac.

 

I did this once in 1958. I had a 1951 Ford and 3 friends and i were riding around. We ended up walking home 6 miles because of a broken axle. I have had more respect for my possessions since then.

 

Good point on shocking the chassis. All my drag racing has been with automatics, chassis already loaded at the tree with brakes on. I guess with a stick and line lock you can accomplish the same thing, is that the norm?

 

Did a little testing today and unfortunately, or fortunately depending on how you look at it, found the weakest link. Revved it up a bit higher after this launch and wham, then nothing. Drive shaft spinning, nothing at the wheels. No crunching gears, no nothing, just like it went into neutral. Towed it home about 1/4 mile with a rope, no cocked wheels, no nothing. 8" Ford 4:10 two pinion trac lok. Any ideas what broke? Coming apart tomorrow.

 

Pinion gear or an axle.... I sheared the splines off many a 28 spline axle back when....

 

Thanks, hopefully pinion, axles are narrowed. Oh well, only money.. Really thought it would hold up better under 1,500 lbs.

 

I put an Astro Performance gear set in mine. They take about 450 ft. lbs. http://www.astroperformance.com/product_info.php/products_id/207
Still careful about dumping the clutch.

 

I have a 39 Ford truck with 150 horse(estimated) Merc flatmotor with Cosworth vega 5 spd(1st gear is 3:10) with a 2:88 gear in 87 xjs 12 cylinder IRS mounted via Snow White brackets.With approximate 9 to 1 starting gear ratio,I have done many burnouts(left equal lengths of black rubber) with no consequences or tire hopping; passengers are amazed that flattie will "lite em up" easily with the 2:88 gear.I guess I have the perfect set of ratios;70 mph is 2450 rpm and truck will run honest 85-90 mph. Flathead Forever!

 

If you just wanna do burnouts, set your pinion angle 0-2 degrees up with the car parked and fully weighted.
If you want to hook up set pinion angle 2 degrees down. There's more to it but it but it plays a big role.

read up on making a car launch hard then do the reverse so the tires always spin, still stressful but not like a hard launch.

 

Appear to be shortened stock axles. I bought the rear already narrowed. Who's the source for good axles?

 

Mark Williams for axles..... http://markwilliams.com/axles.aspx?gclid=CJ7E04a-vMQCFc9hfgodPokA3A

Yep, just like back in the day...

 

2nd the Mark Williams axles--what we use

 

That looks painfully familiar ! I hate when that happens. Have fun, haul ass!