My sfi specs and nhra rule book are in route. I have a few basic question on chassis design. im laying out my componants. what is a ball park demension from back of the engine or motor plate to the center of the rear. Im using a odd trans /rear combo and dont want to much engine set back. I also need a center of rear to rear of chassis measured at the lower frame tube. Basicly how much room behind the rear or how to determin it. Looking at a 115" to 120" chassis. Where is the best place to splice the lower chassis rail ,ahead of the motor plate? or at the intersection of the lower rail and motorplate bulk head tube. My friend has a chassis jig and builds dirt mod chassis for a living so fabrication is not a problem. I read the post by king chassis on fed building and cant wait to get started. Thanks guys
the splices will be spelled out in the sfi specs. I built a 134'' fed and the sfi specs were a big help. The Car certed the first time and the next two times. Are you going to use 4130 ,or mild steel. First determine what your expectations are for the car. Lots of info on the board, and at King Chassis, and Cen -Penn.Good luck.
You need to get the trans and axle you will be using and get dimensions for a "Greek" coupler (replaces u-joint). Once you have those things, place the trans and axle the correct distance apart to fit the coupler and measure bellhousing face to axle centerline. It must be exact, and no one will be able to tell you this if you're not using standard components. The rear axle back should be pretty standard, but you can figure that out too. Set the rear up at ride height (15-16 axle centerline depending on tire). Put a 4 1/2-5" stack of phone books behind the axle and sit on it with your knees centered on the housing. I'm not kidding, this is how it was figured out "back then"... Lean back about 20deg and have someone hold a level against your back. Measure as needed to determine bottom and shoulder distance to axle centerline, and you have a custom fit FED...
WestCoast pretty well spelled it out. If you use a 9" ford you can get a device that bolts to the 3rd member at the pinion support and it has a precise 2" or so piece of heavy tubing that is use to locate the engine, it'll pass right thru the mains. If done right you'll see the engine will run uphill into the rear. On that tube you keep the driveline info, trannylength & location; coupler, male & female location; midplate etc I got mine from Mark Williams, i expect they'll have another or two. I belive they sell plans and kits for nostalga FED's but they are probably those tall necks for fuel, worth a looksee tho. Good luck, oj
OJ, They make the driveline jig bars with a turned down end and threads for other rear ends now. You put in a set of dummy bearing cones and tighten it all up kinda like a brake lathe. Can't remember the mfr though... Sorry explaining how it's done wasn't any help...
As OJ mentioned, Mark Williams has couplers and other parts. I learned a lot just reading through it and looking at the pretty pictures. Order up their catalog and drool over the 15K rear ends!
Wow! What a great article! There is some slick stuff, i really like the locater for the rear end that set frame height. But using an 'i' beam axle to to set kingpin inclination was too cool. Thanks for posting.
thanks guys spoke to mark williams yesterday , they don't make a coupler for my tranny. looks like a ujoint and a sheild. spicer makes a heavy duty yoke and u joint.
went to the nostalgia drags today there were several feds there some motorforward some motor back is there a somewhat standard engine to rear axle measurement . i have the option to place my motor.
Assuming you're going to run an automatic trans, you have two choices, shorty or full length. The shorty will set the engine back several inches and increase the tendency to wheelie. Decide if you want to wheelie, more or less, or if you just prefer the set back look, then set your engine/trans between the rails and locate your motor plates. By the way there are a lot of chassis available for very reasonable prices. By the time you buy all your parts you wont save a lot of $$$ by building one. You will however have a learning experience which i'm personally a glutton for. Good luck!!!
the car is going to have a standard trans. i guess i need to clarify it going to be a vintage dragster. early 60's style im using a quick change style floater rear closed drive to a yoke on the trans so length is not an issue . just looking for a good starting point.
Quickchange will affect the seating position some... I would also seriously recommend a removable sheild over the change gear housing. I have seen the rear covers blow off those things if the rear wheels get off the ground and come down under power... And in an FED what's right behind the rear axle might be pretty important!
If you are going traditional i would scrap the QC/floater and go with a 9" ford. The only QC/flloaters i know of are champ series and they are too big. There is a small hole that the rear has to pass thru to get inside the rails. Reread what 'Afaulk' wrote, he is giving good advice. Get a store bought chassis - you cannot build a better one yourself - it'll have the right tabs and mounts for the engine, trans and rear. You will still have a ton of work doing the detail stuff. Doing the detail stuff is what makes a good car a great car. The other advantage is that when you go to the track and have a problem if your car is set up similiar to other guys' cars they can help you or loan you a spare part (try to find a ring gear tension adjusting screw for that QC for instance). If you have an oddball combo they can even offer advice. One other thing to consider. The actual race takes less than 10 seconds, that is how long your parts have got to work together. The rest of the time you are working on them or talking to competitors about them. It is nice to share common parts so that you will have something to talk about, when everybody is pissing and moaning about junk parts in thier shorty glide and you bring up an old mannual gear box they will look at you as if you fell off a turnip truck. Start your combo off with known and proven true stuff, when you master that and get it running faster than everybody else then is the time to delve into the unknown - the 'bleeding edge'. Right now you just want to have fun and see where it takes you, right? Good luck, oj
OJ, and the others know what they are talking about. I used a shorty glide,and olds/pont r/e in mine. The 9'' is lighter and very strong. The olds r/e is heavier, and lots more expensive. I used the olds because I bought a narrowed r/e with most of the right parts. determine what range you want the car to run in, and go from there .
I mock everything up in 2X4s or 2X1 strapping. I sit I move I measure I cut glue change and adjust till I like it and THEN and only THEN I duplicate it in steel. A mistake in wood can be changed in an instant with glue and nails. A mistake in the finished chassis is a nightmare and often leads to making a bad decision. (aka known "as fudging it")Make your fake, Sit in it. block the engine and trans in it make dragtser noises if no one s around but take the time to sort it out so YOU are happy with it. You wont be sorry. The extra $20 for the wood fake dragster will be the best bargin of your build. Ifyou use 2X4s you can use part of your fake for a jig. I do. Don
Can a Quick Change handle the shock load of modern drag tires on a good track? What motor is going in it? HP? Good luck and I look forward to seeing the build! I just finished one if you need any ideas or parts sources PM me.
This build is stricky for fun in a vintage style. The purpose was to build a car out of what is kicking around the shop.I have a dyno time only 500hp small block engine left over from my dirt mod racing. the rear is already put together narrow housings and double spline axles. floater hubs . im 5'8" tall 265# i spoke to several chassis guys about a frame and they say the cars they build are to small for me . I spoke to a local dirt mod chassis builder about building one that fits well. looked at several cars and they were not what im looking for. Im not new to racing just drag racing. I like the nostalgia events but want to build a safe car. I dont really mind being the odd ball. I do beautiful work this car will be super cool. i would consider using a glide if i could purchase one reasonably. The goal is a 10 sec car. The rear is not a quickchange It has no rear cover or changeable gears so no blowing up between the legs.
Im looking for some basic dragster info. How far from the motor plate to the centr of the rear axle housing. how high is the shoulder hoop on the cage what is a standard chassis width. im building a a car aprox 24-25 inches wide. how is the rear mounted to the rear uprights , single plate two plates with the plate welded to the rear inbetween. how do you guys do it the sfi book is very confusing.
You are on the right track as far as mounting the housing. Usually 1/8 - 3/16 plates welded to the outsides of the vertical tube. 1/4" plates welded to the housing (frame rail centerline width) with aluminum spacers to center the housing in the chassis. 4) 1/2" bolts per side. I think the banjo rear is a much safer choice than a QC...
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