Projects Two gun guys build a front engine dragster

Tyler,
I'll throw in on advice. Consider what you have in an adjustable ballast in that fuel tank.
At 138" you are going to have the front in the air most of the time. Five gals. of fuel up by the front crossmember may be a good thing.
Most important..have fun with it!

 

Cool build!

 

This is a very cool build. It's erie that the questions you are asking and the flying blind style of build reminds me of my first serious build. You think you have it all sorted out before you start then BAM... you realize you don't know sh#t once you get started... or for that matter... you don't know where to start.

Looking forward to the engine build... I have some plans along the same lines.

 

Tyler,
sorry that I did not get back to you sooner but I was at Indianapolis Raceway Park yesterday working on Tommy Johnson Jr's ride for the US Nats.They were short a crew guy so I ended up pulling the right side head while he made some shakedown runs.
If you could PM me your address I can find out what the shipping cost would be. I will send you the sleeves for the small block with the bar.

Roo

 

Only one picture tonight . . . too many late nights and early mornings.

Big thanks to Rooman who let me borrow his alignment bar. I would be up a creek without his help.

Also a big recommendation to HR Racecar products. Toni is somewhat local to me and is true diehard race car guy. He has started on the rear end and he will be getting it back after Mike and I get the tabs finished on the axle tubes and frame.

Believe it or not, that is the same rear end from all the other pictures!

 

Got the motor plate and rear axle tabs in today. Getting closer . . .

 

Very cool project! Great work!This will be fun to watch!

 

Cool build!! Good luck...

 

Looks good Tyler , Tim Jones

 

Here's a couple of things you might want to consider:

Weld in small several tubes (horizontally) that pass thru your motor plate uprights. You can use these to run your wires and cables thru instead of running them thru the motor plate. It's nice to pull the motor and NOT have to fiddle with too much other things.

I kept the front of the body on the tall side - it's nice to be able to stretch your legs out if need be. Occasionally you might find yourself sittin' in the car a LONG time. Once after siting in staging for a long time I finally got to the bleach box when they shut me down - as someone oiled the track in front of me - I then had to sit there for another seemingly eternity- doesn't sound like a big deal, but at times - having that extra room was really nice.

When you are placing components - do so with ALL YOUR GEAR ON. Getting in and out of the car with your helmet and firesuit on is gonna be more difficult and use MORE ROOM than in your street clothes.

Put in some seat belt hangers - yes I said seat belt hangers. Getting in and out of a tight cockpit is only a bigger pain when you have to fish out the belts from under your behind!!! Also - forget the old style belts - cam lock!!! - only way to fly in a digger IMHO.



I initially wanted to run the heavy duty housing as you are, but found it too uncomfortable - instead I braced a medium duty one - far more comfortable - at least the way I sit in my car it was.
v
Welding on some of the smaller (shorter) tubing sections you might experience problems with the gas expanding - in this case drill a small hole in the tube to vent that gas - it'll save you tons of grief. If you plan these out - you can cover them with the next tube and never see them.

Almost lastly - not to throw rocks - but I see a Strange street duty case - behind a blower - not sure if that's the best idea or not - I'd have to research that one a little further if I was you.

Lastly (wink wink) - you made a comment about tough to build one cheaper!!! Now we're talking the same language!!! I built mine largely out of what was laying around, Ebay and swapmeets. Let's compare notes when you're done!!!! (big grin)

 

good luck on dragster front engine cars rule

 

Cool. I will be watching this one to see how it comes out. Love a good fed build thread.

 

The comment made about using the 5 gallon fuel tank as added weight; it's still going to stand on the rear, just come down harder. With modern slicks you need wheelie bars; especially on a short wheelbase FED. I had 60 pounds of lead on the front of my 120" FED, and it did absolutely nothing in keeping the front end down. The only answer is wheelie bars, preferably, adjustable ones (mine were'nt). Butch/56sedandelivery.

 

I like the tube idea for wiring however the only wiring I plan on running is a mag cut-off switch and I guess the fuel pump cutoff cable/mechanical tach cable are in that category as well. External starter, magneto, mechanical boost/oil pressure gauges right off the back of the motor.

The seat belt hangers sound good to me . . .

I plan on the motor making 750-800hp or so. 355, solid roller, 10:1, aluminum heads, unstripped 6-71, enderle hat on alcohol. I've never built a blown anything on alcohol but I can't imagine the motor making any more. Between that, a powerglide, and a ~1500lbs dragster, I was steered towards the s-series case over the pro-series simply because of the lack of HP combined with the weight.

The strange rep said they rate the s-series case to 800hp in a traditional car before you have problems with gear wear, let alone something with half the weight.

I'll let you know how it turns out

I'll be on radirs (still on backorder )

I won't say NEVER but I might as well . . . I don't want to ever run wheelie bars. I don't think it fits the look of a FED very well . . . seems to go much better with a funny car or RED

 

Plans change. So far I run the mag kill, tach signal, starter, fuel shutoff, throttle, 2 halon lines (I actually threaded those tubes and screw the fittings directly to them), battery disconnect cable,and whatever else I can't think of.I hadn't originally planned on running 1/2 this stuff, much less running it thru the uprights.

 

Congrats on a great start to your build, I appreciate the fact you want it simple, no frills etc. The tires you use and the Track prep today "Mandates" a Wheelie Bar, if an Automatic Tranny is used. Our Car @ 183" With Auto would do a Blowover before the 60' Clocks if we did not use a Wheelie Bar! Not what you want, but it is what you have do deal with.......... A clutch can be slipped to eliminate the need for Wheelie Bar, but the tuning with an Automatic is.... Height of wheelie Bar off track, stall speed of convertor, and launch RPM. I wish you all the best with your FED, and have a Blast! They are the Best!

 

Interesting thread, think i'll subscribe.
The biggest problem i see is that engine will never run well painted ford blue.

 

This is the second car being built on this board with an unsupported bend in the middle of an upper frame rail / transmission bay. Whats up people?

 

Tyler I believe this is what Bruce is talking about, an unsupported bend is considered a weak link, One good wheelstand and the chassis will fold there , here's a pic on fixing this, bear in mind I'm no chassis builder ,but I've had a few of these cars, Don't want to see anyone get hurt, Tim Jones

 

Right . . .

Haven't the slightest clue why its blue . . . its a 80's 305 block. My 350 4-bolt block is currently undergoing cleaning not to mention this setup block has had a plasma cutter touch it before making it easier to move around.

Ah. I like the MS paint diagram. The dreracecar rant didn't make much sense to me.

I'm not an engineer but isn't the fact that two 1 3/8" .065 tubes are running parallel to the ground (and un-bent) with several cross braces and uprights enough? I get the idea behind having a bent tube be a weak point but the fact that a tube is directly below it seems like you have to bend those tubes first before the whole thing would "cave-in".

I would think its akin to saying a traditional car/truck will fold in half based on the cage in the cabin when its sitting on a "normal" boxed/tube frame.

A supporting piece certainly isn't a bad idea but the bent tube isn't the only thing holding it together.

 

Well like I said I'm no chassis builder, But I do know these car flex alot more than a person thinks when they are running, even the short cars, Just easier to change now, Hell, I've been changeing stuff in my car all through my build, But bruce is a chassis builder also , He might come across as a prick but he's got your best interest in mind, check with Rooman , or the guys at king chassis for other opinions Tim Jones

 

Check out the vids on this link, The first one shows how hard these things come down on a good wheelstand, If anything cool footage to watch Tim Jones http://www.jalopyjournal.com/forum/showthread.php?t=737971

 

"I'm not an engineer but......"

For a quick, practical lesson in Engineering, try this:

Take an empty aluminum beer can, place it upright on the ground, stand gently on it with one foot. It can support you.

Empty another beer can, put a slight curve in one side, like your top rail. Attempt to stand on it.

Accept that the unbraced curved member is a serious weakness.

Empty another beer can, (after 3 beers this can be quite funny). Carefully balance on the can on one foot. Slowly reach down and poke the fingers of both your hands into opposite sides of the beer can at the same time.

Here Endeth the Lesson

 

I would never tell anybody HOW to build their cars, but I will RANT to get you and others to look and anilyze very obvious mistakes.
NHRA gives us minimum specs base on basic theory that both tension an compression loads are strongest in a straight line. ANY interuption in that straight line flow degrades load capability and will yeald depending on degree of interuption. There are 2 ways to combat this yeald, one is to support the failure or increase the mass of the flaw itself. To figure out how much mass needs to added would take some higher engineering to establish the minimum needed, so most people without that skill tend to go overboard whereas NHRA specs give us the required mass for support.
In bending the tube using the draw method (which most of us use), by bending in the lower degree range tends to crush the tube before the acctual bend starts to form.Take some calipers and measure the dia of the tube at the bend and you will find another reason for a support tube.
For the shoulder hoop to have been raised properly where it was without pulling it off the jig was to have set up 2 rosebud torches and heat a 5-6" section at the motor plate upright and lift the hoop to the desired hight. This gives you two things 1)A lesser deg of bend because its further away and 2)because you heated up a larger area the deformity of the tube and bend were spread out further. You still wind up with interuption for straight line forces but to a much lesser deg and well within spec tolerances.

 

Got it

I am around enough engineers all day and seen enough stuff fail that I could make quite a slideshow.

I program CNC machines for a living . . . on a easy day its 304/316 stainless, on a rough day its Inconel 625/718. I have an awareness of materials and why things fail you could say, at least on machine guns and silencers.

There's a certain tact with knowing the right thing and translating that to someone else. You came up short. But who knows, inflection doesn't come across well in printed words. Maybe you were trying to be helpful but it came across as being a prick.

My point was this:

For the frame to deform structurally, it will have to bend BOTH the bottom two 1 3/8" tubes AND the 1 3/8" diagonal support tubes running from the rear end uprights to the motor plate upright.

It is undeniable that the frame would be stronger with a support piece there, however your statement leads nicely:

Short of a shear test, no one can say with any certainty how much weaker the frame is because of that bend. The only way to measure this would be to clamp the rear part of the frame and pull or push up on the front until the metal fatigues/deforms/then breaks.

In much the same notion of the "street/strip" 3rd member, we are talking about theoretical limits imposed by educated guesses.

 

The lower rails and diag would remain straight and the deformation would occur at the motor plate upright because where the diag attaches to it would act as a pivot.

Failure can be discribed many ways. By just locking the frame down and applying force might show flexablity because your force is spread out over the entire structure without load ie just squeezing an empty soda can on the bench. Now you place load on the structure by adding the weight of the engine and trans ie standing on the can, and what happens next? you come to the realization that one can not stand on a bent can. Second look is at the can from the begining. Its bent top and bottom, but the deformation is at the very ends but it still supports the weight and will only deform into itself when an extrem amount of force is applied.
Failure in this case will be the inability to hold stucture in the form of alignment. Continue the build and lets see if the coupler goes together or the tranny case breaks, tail shaft bushing burns or over time a crack appears at intersection of the diag to motor plate upright.

I also program my CNC's , I design my own parts using Mastercam and in the beginings of Solidworks. I have also done crash analysis both practical and computer model. My only fault here is that I did not take a Dale Carnige class (and spelling)

 

I think I'll just sit back and leave this to you chassis guys I'll just keep pluging away on my ole beater, Tim Jones , Have fun on the build Tyler

 

"no one can say with any certainty how much weaker the frame is because of that bend".
Actually, that's exactly what Engineers can do!


"The only way to measure this would be to clamp the rear part of the frame and pull or push up on the front until the metal fatigues/deforms/then breaks."
This is what will be happening every time you accelerate/decelerate and particularly when your front wheels touch back down on the deck. You DO NOT EVER want it to fail on the track.

Remember, dreracecar, dragsled & I are trying to help you Succeed, not put you down. The thing I love about the HAMB is that people will spend their valuable time answering questions and giving others the benefit of their experience.
You have a great project and have done a very good job so far. You have also been given some excellent advice, by many people with practical experience.


A Smart man learns from his mistakes, A Wise man learns from the mistakes of others.


cheers, Daryl.

 

October has been busy with work . . . getting to mess with the dragster only 2-3 days this month.



Roll cage is almost done, just the little 1" bar left.

Rear is done and in thanks in large part to Rooman and Tudor.



Not period correct I know . . . at this point the 60s period correct frame is about out the window considering the upper bar in front of the mid plate and the rectangular design of the roll cage.



For the haters =)

 

cool build dude. keep it up