Duke's'72 Carbed KA project

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icehouse
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Re: Duke's'72 Carbed KA project

Postby icehouse » 25 May 2017 10:48

Did you draw the entire front suspension in Solid Works? It's been a while now but I remember the LCA pivots don't match the rack width. The LCA and the tie rod follow different arcs. As the suspension compresses caster is added which moves the outer tie rod down creating a different arc. That might be why you have to space the outer tie rods down so far.
I liked Hainz better...... Can we trade back?

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 25 May 2017 22:43

I didn't model anything. I determined the size of the spacer using a bump steer gauge and trial and error. I was able to get bump steer down to .030 per inch in bump and droop from ride height. I can't feel any bumpsteer while driving so I am going to call it good. The spacer is exactly 1" long, which I though was pretty long until I saw the bump steer spacer on my friend fox body Mustang. It's at least 3"!!
Duke Schimmer

'72 2-Door 510
"Simplify and add lightness."

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icehouse
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Re: Duke's'72 Carbed KA project

Postby icehouse » 25 May 2017 23:09

I'm also curious about the end result in steering speed. Lock to lock i'm sure different between our cars. With the rack and pinion I get more angle than with the box. It's slightly faster, I'm not sure how much faster. I guess at the next shasta autoX we will just have to swap cars for a lap or two! :)
I liked Hainz better...... Can we trade back?

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icehouse
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Re: Duke's'72 Carbed KA project

Postby icehouse » 25 May 2017 23:28

1/2" wider than the MR2 rack. Although the model loaded weird on my machine.
I liked Hainz better...... Can we trade back?

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 30 May 2017 10:01

As well as the rack and pinion steering upgrade I also recently revamped the crank pulley and trigger wheel setup on the engine. KA's are know to vibrate quite a bit due to their long stroke and not fully counter weighted crank. From what I have read they will pretty much die from any sustained running above 7,000 RPM's. I don't plan on ever really winding the engine anywhere close to that tight, but there are some autocross events where it can be faster to bounce the engine off the limiter for a second rather than shift. For instances like this I wanted a little extra insurance. I have read that harmonic dampers can be very effective on these engines so I decided to go that route. As it goes with anything, it required a little modification before installation. First I needed a way to mount the trigger wheel for my Megajolt system. To achieve this I purchased a wheel from trigger-wheels.com (nice product BTW) and machined an adapter to mount it to the front of the pulley. This also required me to make a new sensor mount. The new one is two pieces and adjustable to achieve optimal sensor to wheel distance. I also machined off the ribs for the power steering and AC, as I don't need either of these. I run a single belt that drives the water pump and alternator, which is not typical on a KA, but has become a popular modification as it simplifies the belt setup. The one thing that always was a gripe for me though was that the belt for the water pump is a 3 rib and the pulley on the alternator is a 4 rib. It really is no problem because you can just run the belt on 3 of the ribs on the alternator pulley. However it always annoyed me. I decided to make my own alternator pulley to get rid of that extra rib. Some research gave me the dimensions for the pulley ribs and I was able to grind a lathe tool to this profile. Once I had this it just took a little time on the lathe and I had a custom, 3 rib pulley. Honestly, I don't know how I ever functioned without a lathe.

ImageDSC00995 by Eldukerino, on Flickr

ImageDSC00996 by Eldukerino, on Flickr

ImageDSC00997 by Eldukerino, on Flickr

ImageDSC00998 by Eldukerino, on Flickr

ImageDSC00999 by Eldukerino, on Flickr
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 30 May 2017 10:02

Along with all these modifications, I purchased a set of Hoosier A7's, perhaps the fastest DOT approved radial autocross tire available. At the very first autocross with this setup, I was able to post the fastest time of the day! This was something that I have been working towards for the past few years and I am pretty happy about it. I am signed up for the Cascade Lakes Hillclimb next month and I am really looking forward to seeing how the car performs there! It will be cool to be able to directly compare it to a couple of years ago and see how it has improved.

Clearance is a bit tight, but man are they STICKY!

ImageDSC01041 by Eldukerino, on Flickr
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

Cmac
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Re: Duke's'72 Carbed KA project

Postby Cmac » 01 Jun 2017 06:05

Attention to detail as always ! It's always amazing to see what you can do Duke. Looking forward to the next upgrades and how well you do in this years events.

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 16 Jun 2017 16:59

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.

https://youtu.be/u-rPlvcOfuQ

Image6/10 Autocross by Eldukerino, on Flickr

Image6/10 Autocross by Eldukerino, on Flickr

Image6/10 Autocross by Eldukerino, on Flickr
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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icehouse
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Re: Duke's'72 Carbed KA project

Postby icehouse » 16 Jun 2017 17:18

Your arms looked ripped in the corners!
I liked Hainz better...... Can we trade back?

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 17 Jun 2017 09:19

icehouse wrote:Your arms looked ripped in the corners!


That's the armstrong power steering!

It's one of the side affects of my other hobby.

ImageDrawind of the Three by Eldukerino, on Flickr
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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icehouse
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Re: Duke's'72 Carbed KA project

Postby icehouse » 18 Jun 2017 22:43

Wow! You are one crazy hair cropper!
I liked Hainz better...... Can we trade back?

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 24 Jul 2017 12:55

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.

https://www.youtube.com/watch?v=LQjr3jAduCI&t=12s
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 24 Jul 2017 13:07

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.

ImageIMG_9441 by Eldukerino, on Flickr

ImageIMG_9436 by Eldukerino, on Flickr

ImageIMG_9435 by Eldukerino, on Flickr

ImageIMG_9731 by Eldukerino, on Flickr
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 25 Jul 2017 09:01

As promised, here is the video from the most recent Autocross.

https://www.youtube.com/watch?v=xS2j-kDC-h8
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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Doraemon
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Re: Duke's'72 Carbed KA project

Postby Doraemon » 25 Jul 2017 14:14

Whoa looks like a great thrill to drive ! And amazing bracket you made for the crankshaft sensor.


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