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Duke's '72 510 (Carbed KA Autocross/Hillclimb car)


Duke

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The 280zx ball joint hole is also offset differently than the 510 joint with respect to the strut bolt center line, changing camber and scrub radius slightly. Also, the tie rod mounting surface is at a different pitch than 510, so tie rod articulation/bind should be checked through suspension range.

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Thanks for all the info!  I will look into the pitch of the tie rod, the arms I have have been dropped and that may have been tweaked too.  I have a hunch that the scrub change may be in my favor...  ;)

 

Sorry for the thread jack Duke!

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Thanks for all the info!  I will look into the pitch of the tie rod, the arms I have have been dropped and that may have been tweaked too.  I have a hunch that the scrub change may be in my favor...  ;)

 

Sorry for the thread jack Duke!

 

No worries!  This is a good discussion.  As Matt said they do change scrub.  I had to lengthen my new LCA's another 1/2" compared to the old because of the difference in ball joint mounting hole.  In regards to the difference in angle of the tie rod mounting hole, it isn't a problem.  Because the inner tie rod on a 510 is at a 90* angle compared to the outer, binding is virtually impossible.

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  • 1 year later...

I have been a bit quiet on the updates lately, not because nothing has been happening with the car, but because I have been so damn busy!  Before I get to what has been going on with regards to the Datsun, I'll give you guys a little taste of what else has been occupying my time.

 
For the last few years my dad and I have been kicking around the idea of building a lakester to go land speed racing with.  My dad has been really into the land speed scene for quite a while, attending the Bonneville Speed Week almost yearly for the last 10+ years.  I have gone with him a few times and have always been fascinated and impressed with the innovative and creative approaches people take to building a car to go fast on the salt.  I also love that you will see everything under the sun out there, from Geo Metro's trying to go 120 mph to multi engine streamliners trying to be the first wheel driven car to go 500 mph.
 
Late last year my dad mentioned to me that one of his friends was looking to offload an I class (under 1000cc engine) lakester in preparation for starting a new project.  Apparently the car had a bit of a storied history, and had a lot of potential, but nobody had ever been able to get it to run really fast.  I was immediately interested.  A few weeks later we arranged to go take a look at it to asses if it was something that we would be interested in buying.  Upon first sight of the car I was all in.  Once I strapped in to make sure that I fit (you will see what I mean when you see pictures of the car) I couldn't contain my excitement.  The thought of going 200+ mph on the salt in this thing was firmly planted in my mind.  A week later and we were offloading it from the trailer and into our shop.
 
Plans for modification started brewing on the drive home.  The car is currently torn down and we are in the process of widening the track as well as moving the front axle forward and revising the front suspension.  The next order of business is going to be fabricating a new tail section that will be a bit shorter and more aero than what was originally on the car.  From there we have a few more things to button up but we should be on track to be on the salt this year for Speed Week 2017.  Our goal is to run the car as much as possible to get comfortable with it and iron out any kinks.  If that all goes well we may try for the current IFL class record of 221 mph, but honestly that is more going to be something that will be on the agenda for upcoming years.
 
Picture from a standing mile event the car ran a few years back.  Because of some issues it never made a full pass.
34676657581_e2f56b7799_b.jpgIMG_1179 by Eldukerino, on Flickr
 
And in our shop.  You can see how small it really is!
33999549463_cc677df371_k.jpgIMG_1184 by Eldukerino, on Flickr
 
Here are a few pictures of the car from when it was for sale a while back as well as an interesting article ( http://www.ridelust.com/death-wish-nitrous-huffing-lakester-will-give-you-a-plexiglass-and-salt-facelift/ ) that we stumbled across.  If you want to follow along with the build, my dad has a thread going over on the land racing forum that can be found here: http://www.landracing.com/forum/index.php/topic,16445.0.html
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After much deliberation and planning, I have finally decided to dive down the rabbit hole of installing rack and pinion steering on my car. Like many 510's out there, my steering box was badly worn, and definitely one of the main weak points of the chassis. I have seen many different iterations of rack and pinion installations in 510's, some better than others, and in this research I set a few ground rules for what I wanted.


1. Keep the rear steer setup-I didn't want to have to make new steering arms, a new front sway bar, etc.
2. Keep the oil pan rear sump- With how low my car is, I really like the security of having the crossmember there to guard the oil pan.
3. Use a new rack and pinion- As awesome as the MR-2 rack setups that I have seen are, I don't like the idea of using something that is 30+ years old and can be difficult to find. Also, I didn't like how slow the ratio's are for most stock steering racks.
4. Make it bolt in- I want to use the stock steering mounts on the frame rails to mount the rack, essentially making it a bolt-in affair.
With those guidelines I set about selecting a rack.
I initially was ready to buy a custom built rack. I even went as far as drawing up a print for the necessary dimensions. However, after a few misleads and concluding that it would just be to damn expensive, I stumbled upon a CAD drawing of a MKII Ford Escort steering rack. After taking some measurements, it looked like it would be a good fit. The pivot points were a little wide, but I had plans on how I could correct this. The big plus for me though was the aftermarket support. MkII Escorts are like the Ford Mustang of England. I was able to find steering racks in all types of ratio's, BRAND NEW! I decided to bite the bullet and order one. To my surprise it arrive 3 days later from around the world. Crazy how good international shipping has become.

The rack required a bit of modification to work.  I chucked it up in the lathe and turned the left side mount round (they are normally D shaped like most stock racks) so that I could more easily fabricate a chassis mount for it.  For outer tie rods I got lucky in that the outside to outside width is similar to the stock 510 width.  Because of this I was able to use 14mm female heim joints for outer tie rods.  This allows me to adjust bump steer by using spacers to move the tie rod down with respect to the steering arm.

33886238884_9b0519e467_k.jpgDSC01006 by Eldukerino, on Flickr

To mount the rack to the chassis I used the existing holes in the frame rails for the steering box and idler arm.  I also ran some smaller tubing rearward to some captured nuts just to give it some more support.  I made doubling plates for the wheel well side of the holes to hopefully give me a little more stiffness.  I then positioned the rack as optimally as possible while still having clearance between it, the oil pan, and the front of the transmission.  I would have liked it to be a bit higher, but space constraints didn't allow this.  To be able to get it far enough forward I had to modify my current oil pan for clearance.  Honestly, it was all a game of compromises.  I had a very small space in which to mount it and I knew that the final location wouldn't be completely ideal.  I was confident that would have enough adjustment for bump steer that I could optimize it once everything was in place.  The mounting structure was fabricated from various diameters and thicknesses of mild steel DOM tubing, with an emphasis on making it as stiff as possible to minimize deflection while driving.

34566695302_17077c2fa9_k.jpgDSC01000 by Eldukerino, on Flickr

34566592752_cc4aff56d9_k.jpgDSC01008 by Eldukerino, on Flickr

34566681722_83764720d8_k.jpgDSC01001 by Eldukerino, on Flickr

34688444826_656ea90065_k.jpgDSC01002 by Eldukerino, on Flickr

33919177683_874a699848_k.jpgDSC01007 by Eldukerino, on Flickr

34688357766_d348c6c2fc_k.jpgDSC01009 by Eldukerino, on Flickr

34566570282_3575bb286b_k.jpgDSC01010 by Eldukerino, on Flickr

34566681722_83764720d8_k.jpgDSC01001 by Eldukerino, on Flickr

34566558742_bba134be15_k.jpgDSC01011 by Eldukerino, on Flickr
This guards the pinion on the steering rack.  Just a little extra insurance against damaging the rack.


For various reasons I decided against using the stock 510 steering column.  I wanted to move the steering wheel down and back a significant amount, and doing this with the stock column would have been more work than it was worth.  I made my own shaft support that bolts to the stock mounting point on the dash.  This utilizes 4 tubes in a parallelogram to allow the column to be moves up and down so that I can position it where I want it.  The steering shaft rides in bronze bushings that are pressed into the support.  There are 2 U joints in the shaft, one in the car and one at the rack.  I used Woodward Steering U joints and other components though-out the steering system.

I also had to modify the header to clear the new steering setup.  With where the steering shaft comes though the firewall it left me very little space to snake the exhaust through.  I pretty much had to rebuild the whole header to re position the collector so that I could make it though the small space that was available.  In the end I have about 3/8" clearance all the way around the exhaust.

34597103341_4551c136cd_k.jpgDSC01029 by Eldukerino, on Flickr

34727973225_12963ee35f_k.jpgDSC01040 by Eldukerino, on Flickr

34566355392_3f486af190_k.jpgDSC01032 by Eldukerino, on Flickr



To say that I am happy with the new steering setup would be an understatement.  Because the rack is brand new there is NO steering slop, and the quick ratio is perfectly suited for autocross.  Steering effort is perhaps a bit higher than stock, but honestly I haven't really noticed a huge difference.  Because of the quick ratio, it is a little twitchy at higher speeds.  You have to be careful with your steering inputs as there is now zero play in the wheel, so when you turn the wheel, the car MOVES!  I also really like the new steering wheel position.  By moving the column down about 3" it has given me much more leverage on the steering wheel.  Previously I would find myself hunching forward in my seat in an effort to get closer to the wheel.  With this new position I can comfortably sit back in the seat and still have good control of the wheel.

 

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Another one of my "winter projects" was upgrading the front brake calipers.  The goal here was mainly weight savings, but also the ability to run 13" wheels (which ended up not happening because of the steering, but oh well).  I did a lot of research into what calipers to buy and I wasn't able to find a traditionally mounted caliper that fit my needs that would be simple to adapt to the 280zx struts.  Because of this I decided to go with a radial mount caliper.  I selected the Wilwood Ultralights after reading a long thread on a Miata forum about a kit that Flying Miata offers that uses these calipers.  They seem like a good lightweight caliper that will be well suited to my needs.  I machined a bracket that bolts to the 280zx struts to be able to mount the calipers.  I took care to make sure the calipers were as close to the rotor as possible to maximize wheel clearance.

34566485582_4e538a0d91_k.jpgDSC01020 by Eldukerino, on Flickr

To go along with the weight savings from the calipers I purchased a set of aluminum hubs from Techon Toy Tuning.  With these and the calipers I have saved 9 lbs of unsprung weight per strut!  I was amazed when I weighed the assembled struts side by side.

34728258805_08ae406939_k.jpgDSC01013 by Eldukerino, on Flickr

As you can see, I also had a bunch of stuff electroless nickle plated and anodized.  I'm really happy with the finished look it gives the suspension.

The brakes have a great feel to them.  Piston volume is a bit less than the 280zx calipers so the pedal is a bit firmer than it was previously.  I was a bit concerned about caliper flex as I had heard that this is a common complaint with Willwoods.  From my initial assessment, they seem to be plenty stiff and provide a very good pedal feel.
 

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  • 3 weeks later...
This last weekend I was supposed to be running in the Cascade Lakes Hillclimb, located just outside Ashland, Oregon.  However, as anybody who attended Canby knows, the weather in Oregon over the weekend was a little wet.  Unfortunately, this lead to the cancellation of the event.

 

Luckily, there was a local autocross on Saturday so I was able to get my racing fix in for the weekend!  It was a great flowing course, set up to mimic Sears Point (now called Sonoma Raceway, but it will always be Sears Point to me).  It was run similar to the NASCAR qualifying setup, with a warmup lap and then a timed lap.  With a couple of hard braking points on the course, there were some people complaining of brake fade by the end of their runs, something you rarely hear about on an autocross course!  It wasn't exactly Datsun friendly, a little to fast and wide open to really take advantage of the maneuverability of our small cars, but very fun to drive regardless.   Also, I have finally gotten myself a good setup for in-car filming so I have some good video for reviewing runs, and for your entertainment!  Here is my fastest run of the day, good for 2nd overall and 1st in class.

 


 

35176591651_3407fe5d9a_z.jpg6/10 Autocross by Eldukerino, on Flickr

 

35176591481_75723b4b74_z.jpg6/10 Autocross by Eldukerino, on Flickr

 

35176591281_9f5ed1eaea_z.jpg6/10 Autocross by Eldukerino, on Flickr
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Dude....That is super badass. Nice work!  I have been looking down that same rabbit hole and I am all in.  By chance did you make a jig, or do you have a NAD (Napkin Aided Drawing) drawing to share? :)

 

 

Thanks!  I didn't make a jig of any kind, or do any drawings...it was pretty much all in my head.  I didn't have very much space to fit the rack, so the position was kinda dictated by that.  I just made sure it was centered, level, and in the best position fore and aft that I could achieve.  From there it was just a matter of cutting and fitting tubes to get it solidly mounted.  Bumpsteer was then corrected by spacing the outer tie rods down.

 

Not very scientific, but it works!

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  • 1 month later...
There was another local autocross last weekend, and with no new modifications on the car, I am basically just getting used to the new handling characteristics and really enjoying the feel of the new steering.  After putting a few miles on the rack setup I can feel that is has begun to wear in a little bit and steering effort has decreased some as the gears break in.  

 

The course was another really fast one.  My top speed for the day was just around 70 mph (7000 rpm rev limit in 2nd gear), but the higher HP cars were besting that by a few MPH.  The course featured a few fast transitions, something that is a strong suit of my car.  I was hoping that I would be able to make up for my lack of horse power by carrying more speed though these sections than the larger, faster cars could.

 

This ended up working out for me way better than I expected and I was able to set TTOD for the second time this year.  The gap to second was 1.2 seconds.  To say I was happy with the result would be a bit of an understatement.  Here are a few pictures from the event.  I also have video that I'll hopefully get around to uploading in the next few days.

 

35215603553_426a4cf1f6_z.jpgIMG_9441 by Eldukerino, on Flickr

 

35854822122_ffff11e8e4_z.jpgIMG_9436 by Eldukerino, on Flickr

 

35854822132_9232c839ed_z.jpgIMG_9435 by Eldukerino, on Flickr

 

35854821922_ff80c3db29_z.jpgIMG_9731 by Eldukerino, on Flickr

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Work on the Datsun has slowed as Bonneville draws near.  My dad and I are wrapping things up on the land speed car and are looking pretty good to be totally finished with this round of modifications with a little breathing room before Speedweek starts on Aug. 12th.  We fired it for the first time a few days back and I was able to get it on video.  The sound of this thing is AWESOME.

 


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  • 1 month later...

I finally had a chance to get my car on a set of proper corner scales yesterday.  I'm very pleased with the result.  All it took to get the cross weights to 50/50 was two turns on the front right coilover.  Also pleased at the weight with me out of the car.  It would be cool to loose 50 lbs and get the car under 1900 lbs, but drastic measures might be necessary for that, and I'm not quite sure I'm ready to get that crazy.  Any weight loss measures will be concentrated at the front though, at an attempt to improve the F/R weight distribution.

 

All weights are with 1/4 tank of gas (~3 gallons, which is what I typically run when autocrossing).

 

Total weight without me.

 

36996274272_d60b83cfdf_z.jpgTotal_WO_Driver by Eldukerino, on Flickr

 

Total with me.

 

36331283374_09fc05c443_z.jpgTotal by Eldukerino, on Flickr

 

Rear.

 

36996275272_b51c990ae7_z.jpgPercent_Rear by Eldukerino, on Flickr

 

Front.

 

36331283704_089d289f2f_z.jpgPercent_Front by Eldukerino, on Flickr

 

Right front/left rear cross weight.

 

36996275562_d5d796e3b9_z.jpgCross_RF_LR by Eldukerino, on Flickr

 

Left front/right rear cross weight.

 

36331284034_68f8c96125_z.jpgCross_LF_RR by Eldukerino, on Flickr

 

You may notice that there is a small amount of fluctuation in the weights, I just chalk this up to "noise" in the scales and ignore it.

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  • 4 weeks later...

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