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La Bala Rolling Chassis
sgraber - 4/8/03 at 08:12 PM

This weekend was good. I made a lot of progress on my car. Here is a photo of it. There are still misc braces and brackets missing, but it is close to being ready to move on to the body.... I'm looking forward to that and at the same time NOT looking forward to it!

The wheelbase is 96". Height ground to top of windshield is 39". That's with 5" ride height. Wheel height is 22".

Please let me know what you think. Rescued attachment La-Bala-Aug-4,-2003.jpg
Rescued attachment La-Bala-Aug-4,-2003.jpg


robinbastd - 4/8/03 at 08:15 PM

WELL DONE THAT MAN!!!!!!
Looks great Steve
Ian


Spyderman - 4/8/03 at 10:28 PM

Looking good!

I bet you can't wait to get working on the skin of it now?

Terry


ps. how high is the top of engine from ground?

[Edited on 4/8/03 by Spyderman]


sgraber - 4/8/03 at 11:19 PM

I am really dreading the bodywork. I have a very bad back which can put me in bed for months at a time if I make one wrong move, caution will be the better part of valor in this case.

Engine height: I think it's around 26", Other people are using 4AGE with 5" ride height) but when I get home I'll measure it to the top of the Oil Filler cap and also to the top of the intake and let you know.

I have a lot more photos of the car taken from various angles posted on my website. See them here:
http://www.newtier.com/graber/mid-engine/diarymain.html

[Edited on 8/4/03 by sgraber]


TheGecko - 4/8/03 at 11:34 PM

Steve,

Looking good (although I'm not so sure about the new avatar ). I'll be cutting and welding soon too. My engine and gearbox are sitting in the garage now and I've found a set of front suspension uprights, rack and coulm that another builder has surplus to his requirements.

Terry,

Assuming Steve's 16-valve 4A-GE isn't too much different to my 20-valve, the top of the engine is about 850mm from the ground - say 34" in the old money.


Dominic


TheGecko - 4/8/03 at 11:42 PM

Ha! Steve replied while I was still composing my reply.

My figure of 34" is based on level driveshafts and 24" diameter wheel/tyre combo - ie driveshafts 12" off the ground. Also, by my measurements, the front of the package (eg clearance for the extractors) is ~550mm (22" from the axle line.

Dominic


sgraber - 4/8/03 at 11:51 PM

Hey Dominic! Don't care for my ugly mug eh? My feelings are hurt.... not.

In anycase, my driveshafts are not level when the car is at ride-height. I didn't think that this would be a problem. Is it?! If so, I can simply redo the motor mounts to raise it an inch or two. But I much prefer to keep the engine height lower.


TheGecko - 5/8/03 at 01:39 AM

quote:
Originally posted by sgraber
Don't care for my ugly mug eh?

It's not that Steve - it's just that the image of an apparently naked man standing in his workshop taking a photo of himself is ...... I don't know
quote:
In anycase, my driveshafts are not level when the car is at ride-height. I didn't think that this would be a problem. Is it?!

I don't think it's a problem at all - after all they are CV joints at each end and they're designed to cope with angularity. I suppose I've just mentally been making them level in all of my designs. Hmmm, I could probably save some height which would be A Good Thing. I'd be interested to know the actual installed height of your engine because I'll be amazed if you've saved 6"-8" just with driveshaft angularity Then again, the 20-valve motor does appear to be a bit bigger.

Congrats again on your progress,

Dominic


ProjectLMP - 5/8/03 at 02:17 AM

Looking good. Look forward to hearing reports of it moving under its own steam.

Regarding the drive shafts, I think it is better if they aren't level at normal ride height. You can wear the joints in one place if they aren't oscillating (not sure if this describes the motion correctly) much. In real life driving on bumpy roads this probably isn't much of a problem though. So as long as the joint angles don't get too extreme at the limit of travel you should be OK.


Alan B - 5/8/03 at 02:39 AM

Steve....looking good.....very satisfying isn't it?

Now the body......


ProjectLMP - 5/8/03 at 02:51 AM

Steve, would it be possible to add bracing like the following to your chassis?



It would stiffen the cockpit area quite a lot I think. Are you planning on welding in a steel floor or rivetting in an ali one. If you are going ali maybe it would be worth putting some 3/4" square diagonals in the floor area. At the very least it will stop the ali drumming which is really annoying.

Regarding your rear wheels I would probably go with a 1/8 or 1/4 spacer. It is amazing how much tires can deflect under load. Also I am sure there will be a little bit of deflection in the suspension. Its amazing that even really stiff TransAm chassis deflect under load. I spoke to a criew chief who said they had some really bad handling problems caused by the swaybars locking up in their bushings due to chassis flex. They went with a floating system to avoid this.

What spring rates are you using? Looks like the rocker ratio is 1:1 Have you plotted out the spring compression as you move the wheel vertically? Did you go for a rising rate or static rate setup?


sgraber - 5/8/03 at 05:04 AM

Ok, thanks guys for the kind words. It's nice to know that at least it doesn't 'LOOK' like it's going to suck.

Here are most of the answers to previous questions.

The wheels are Panther 16x7-1/2 with a 5-7/8" backspacing. (feel free to convert to mm. Since I am a back country 'merican, I never was lerned that shyte in school.) They were 'Freebie'. The tires are BFGoodrich EuroRadial T/A 40H. Size 205/40 R16 75H. I am sure that it will be a very harsh ride with this little bit of sidewall rubber. The tires are used and abused, so I will need to get a new set anyways. Khumo or Sumitomo I think.

LMP-man, Your drawing of the additional bracing is almost exactly what I have planned. (it's already cut, but not welded in yet.) I also intend to add triangulation across the main footwell compartments.

I am using 18ga steel floor panels, continuously bonded to the frame with 3M VHB epoxy tape. There will be no welding or rivets for any structural panels. I am going to trust the VHB tape. I will gladly report on it's effectiveness in the future.

The steel paneling will be used to enclose the passenger compartment. Notice the package shelf behind the seats. That will all be 'steeled'.

There will be a removable engine undertray (carbon fiber, or ali?) attached to my engine bay brace that will completely cover the back under-half of the car from the fuel tank back. There will be cutouts for the oilpan and other vents, but essentially the car will be completely flat bottomed with a rear extractor... ground effects hopefully.

The Bellcranks - I am using the Yamaha R6 bellcranks that came with the stock Yamaha R6 shocks I bought off of eBay for $30 each. They are 3-1/2" x 2-11/16" The fronts are definitely rising rate. The rears are.... just stuck on there for now! I intend to refine the spring/bellcrank setup once I get the car rolling. The stock Yamaha springs are #420. The shocks are fully adjustable.

Engine Height:
Ground to oil cap - 27-1/4"
Ground to top of intake - 28-1/2"
Dominic: Distance from axle line to front of engine(extractor you say?) - 28" (Old world)

I hope this info is useful to someone.

Graber

Dominic - how did you know I was naked!? Actually, I was simply adjusting my webcam for a better angle of me with my autoparts.... kinky! uuuuuhhhhh. Just kidding!


TheGecko - 5/8/03 at 05:39 AM

quote:
Originally posted by sgraberEngine Height:
Ground to oil cap - 27-1/4"
Ground to top of intake - 28-1/2"
Dominic: Distance from axle line to front of engine(extractor you say?) - 28" (Old world)
Hmmm, I'll run around my engine with the tape measure tonight when I get home. The height difference is very interesting because I didn't think that the 20-valve was that much taller. With respect to the "extractors" I mentioned - the 20-valve 4A-GE comes from the factory with nice, tubular, 4-into-1 extractors.
quote:
Dominic - how did you know I was naked!? Actually, I was simply adjusting my webcam for a better angle of me with my autoparts.... kinky! uuuuuhhhhh. Just kidding!
OK, now I just feel dirty

Dominic

[Edited on 5/8/2003 by TheGecko]


pbura - 5/8/03 at 11:04 AM

quote:
I am using 18ga steel floor panels, continuously bonded to the frame with 3M VHB epoxy tape. There will be no welding or rivets for any structural panels. I am going to trust the VHB tape. I will gladly report on it's effectiveness in the future.


Somewhere on the 3M site I saw where you can flex a taped joint and it will rebound. Dunno whether there's enough movement to matter in a chassis.

Betcha that 3M would be glad to give you some tech support on your application with regard to degree of flex and shear strength, too, especially when they see what you're building! The car would look great in their 'applications' literature.


quote:
Dominic - how did you know I was naked!?


As it is, my kids think this looks like an M4M site. Can't let them see this stuff!

Way to go, Steve. Your progress is amazing.

Pete

[Edited on 5/8/03 by pbura]


Spyderman - 5/8/03 at 11:18 AM

Steve,

It is looking great and coming on well!

Hope you don't mind me making a few observations?

First is the clutch and brake lines. In the one photo it shows the clutch line radiused around the outside of the passenger box. Although I realise you have the box sill area that can be utilised, I think it would be better that the clutch and brake lines went through the passenger cell and not around it. This ensures there are no corners or sharp edges that a line can be crushed against. What is more worrying is that the lines at the front pass along side the offside wheel and would be prone to stone damage! Extreme I know but I am not aware of any production car that does this. All cars I have worked on have the pipes passing inside the passenger cell.

A bit too late now to change things, but I would have packed the clutch and brake master cylinders forward and extended the push rods instead of cutting away the lower screen mount.

And yes I think you will need spacers with those wheels. As has be stated you can get quite a lot of tyre deflection when cornering. The tyre will roll quite a bit.
Also if you change the tyres there is no guarantee that the next one will fit the same way.

Why are you going for steel floors over Ali as you are going to bondit on?

Dominic,
Is your measurement to the top of the air intake?
Wish I'd remembered to measure mine whilst it was on the ground!

Terry



[Edited on 5/8/03 by Spyderman]


TheGecko - 5/8/03 at 12:53 PM

quote:
Originally posted by Spyderman
Dominic,
Is your measurement to the top of the air intake?
Wish I'd remembered to measure mine whilst it was on the ground!

Terry,

I measured the engine/gearbox a little more carefully tonight and came up with this:

Axle c/l to top of plenum (highest point): 500mm
Ditto to top of oil filler/cam cover: 450mm

Here's what the package looks like at present, sitting on a palette in my garage. Feel free to ask for any other dimensions.

Dominic Rescued attachment 20Valve01.jpg
Rescued attachment 20Valve01.jpg


sgraber - 5/8/03 at 02:39 PM

quote:
Originally posted by Spyderman
First is the clutch and brake lines. ....... I think it would be better that the clutch and brake lines went through the passenger cell and not around it. ..... the lines at the front pass along side the offside wheel and would be prone to stone damage! Extreme I know but I am not aware of any production car that does this. All cars I have worked on have the pipes passing inside the passenger cell.



Hi Spyderman, thank you for the astute observations. The side pods, which are not finished at this time, will actually be more like encased tunnels. Look at the modified photo LMP posted and imagine steel or ali panels creating an encased tunnel. With VHB tape that will be easy to accomplish. Across the front wheelwell you are absolutely right! I thought about that as I was bending them and I am fabricating a rock guard to cover the lines through that area. Since the car is full-bodied, it will also have complete fenderwell covers around the wheels front and back.
Do you think that will be enough? Or should I still re-route the brake and clutch lines through the cabin? I 'CAN' do that...

The lower windshield frame is not a structural member of the chassis and I assumed that it would not be detrimental to hack a piece out of it... Why, do you think this is bad? I thought it looked ok.

Steel floor over ali - after listening to the threads about chassis intrusion I thought steel would be safer. Is that point overblown? I'd certainly like to use the ali and I have a local supplier that can get me 8x12 sheets (14ga) for around $80 usd.

Pete - I will certainly ask the 3M techs. however, I think that all of my loads into the material will be in shear and not in bending. With hundreds of inches of continuous bonding, (Think about all of the square tube surface area facing the bottom of the car having a 3/4" wide strip of this stuff adhered to it!) I think the panels will be more solidly mounted than ANY rivets and probably equal to welding, but without the heat distortion or need to apply sealant.

Dom - Now everytime I look at my avatar I see myself naked frolicking through my parts... Thanks A LOT! gotta change my avatar.


ProjectLMP - 5/8/03 at 03:05 PM

I think I read that the VHB tape has a foam core. Is this correct? If so this may limit the amount of rigidity of the bonded panel. If the foam distorts even a few thousands of an inch rigidity will be effected. The problem with adhesives is they often have poor peel strength. Maybe a few rivets would help avoid this.

A lot of kit cars (Ultima, Westfield etc) use ali floors for at least the part forward of the seat mountings.


Spyderman - 6/8/03 at 12:16 AM

Dominic,

Thanks for the measurements.

Steve,

Please don't take what I say as gospel!
I only say what I think might cause problems, after all you did ask for comments!
I look at your work and Alanb as guidence for my project.

I look at things and sometimes see things that don't quite seem right, not really knowing why. Then I forget about it and come back to it later. Usually the second time looking I can work out what I think is wrong. This does not always work out right, but very often does! Therefore if I think something is amiss then I will say and either get corrected if way out, or ignored if right!
Nobody likes a smart ar*e!

The floor should be fine using Ali as you will be putting in crossbracing anyway.
The only way you might get intrusion was if you tried to jack the car under it.

The clutch and brake lines I think should be protected as much as possible. Putting covers or guards over them just hides any possible problems. Running them through the passenger cell you are more likely to notice any leaks (although less likely) due to soggy carpets, etc.
Worse case scenario; you don't want to loose your brakes after or during a shunt.
Maybe I'm just a pessimist!

Terry


ps, I've got to stay on your good side, cuz as soon as I've finished rewiring the garage and got some steel I'll be drilling you for suspension measurements!

[Edited on 6/8/03 by Spyderman]


sgraber - 6/8/03 at 12:45 AM

quote:
Originally posted by Spyderman
I look at your work and Alanb as guidence for my project.

The floor should be fine using Ali ....

The clutch and brake lines I think should be protected as much as possible. Putting covers or guards over them just hides any possible problems. Running them through the passenger cell you are more likely to notice any leaks (although less likely) due to soggy carpets, etc.
Worse case scenario; you don't want to loose your brakes after or during a shunt....

ps, I've got to stay on your good side, cuz as soon as I've finished rewiring the garage and got some steel I'll be drilling you for suspension measurements!



Well, I look to Alan's project for guidance, so in reality you are just looking at Alan's project for guidance. If he's wrong we're ALL screwed! hahaha

Regarding the flooring. I feel like a transistor. You know - flip-flopping away. Ali is the current material of choice. Now I will have to paint the frame with the VHB tape pre-adhered to the frame side, but leaving the protective sheeting undisturbed. Aluminium will certainly look more sporty.

Re-doing the brake lines won't really be that big of a deal. Just more expense in buying hard lines. I already know where I will run them.

Regarding suspension design: I have susprog3D, but have never even used it! So many parameters to input@! I simply don't have the time to run the numbers and I have already built my suspension. If my suspension design really sucks (don't think so), then I can do a complete re-design. In the meantime. If you want me to analyze something for you and can hand me a spreadsheet full of numbers, I can run it through for you.

Graber


Rorty - 6/8/03 at 03:40 AM

Well done Steve! I like your project a lot, especially the simplicity and functionallity of the whole rear end of your car.


Spyderman - 6/8/03 at 10:13 AM

quote:
Originally posted by sgraber

Well, I look to Alan's project for guidance, so in reality you are just looking at Alan's project for guidance. If he's wrong we're ALL screwed! hahaha

Graber


It's good to have someone to blame if it doesn't work out. I was going to blame you!


Alan B - 6/8/03 at 11:55 AM

Yep...blame me.....

Should be reworking the body very soon.......lots of fun.........NOT

Ah well.....


gsand - 17/11/03 at 07:53 AM

Very sweet looking car!

On the topc, as coincidental as it may be, im in the doing a car with basically idental requirements as ProjectLMP, and i had no idea about his project. Hehe the world is a funny place. Mine will be built around a modified Locost chassis (wider, longer mid-mounted) and probably with a 4AG unless i can figure out how to use a bike motor cheaply
Mind you, me being my lazy self will prbably cut off the back of a MR2 and ust weld it in .
Stealing bodywork from Le Mans cars , that will certaily get the looks cruizing trough town.

(I have a reputation for not finishing things and am currently unemployed!)

[Edited on 17/11/03 by gsand]

[Edited on 17/11/03 by gsand]


kb58 - 18/11/03 at 03:40 AM

quote:
Originally posted by sgraber

I am using 18ga steel floor panels, continuously bonded to the frame with 3M VHB epoxy tape. There will be no welding or rivets for any structural panels. I am going to trust the VHB tape. I will gladly report on it's effectiveness in the future.



Do me a favor then and at least put a few rivets in the leading edge. Or, put a second floor panel directly below your feet. There are dire consequences if that floor starts to peel off. Seriously.

I'm just not convinced anyone can apply the bonding and pressure necessary to have a truly permanent connection that'll last years and years. Ask 3M and I bet they'll run the other way and hide behind lawyer-speak about their liability in this. In fact I bet they'll tell you to not use it at all. Not that it won't work perhaps, but that they don't want to know about it...

As a side story, Gates is a big belt manufacturer here in the states, and when they heard people were using their belts on home-built aircraft they about had heart attacks and "prohibited" their belts be used in that way.

[Edited on 18/11/03 by kb58]


sgraber - 18/11/03 at 02:53 PM

quote:
Originally posted by kb58

Do me a favor then and at least put a few rivets in the leading edge. Or, put a second floor panel directly below your feet. There are dire consequences if that floor starts to peel off. Seriously.



KB - I can do that! I am as concerned about safety as the next guy, maybe more, (notice that my windshield surround is in fact a 2"x.120 rollbar..)
I read your website about the extra floorpan you put in below the feet and I think it's a great idea. I will post photos of how I do that.

Graber