Homebuilt Mid-Engine Sports Racer

Neil

Supporter
I am now fitting my new shift linkage and need to put a few Rivnuts into my firewall to fasten the bearing mounting brackets. I can confirm that Inconel 718 is a bastard to drill holes in.
 

Neil

Supporter
While my wife and I were waiting to get her car serviced at Holmes Tuttle Ford here in Tucson I had a look in their showroom and discovered GT40 P/1061 sitting there. I took a few pictures and looked up its history. I was surprised to find that it was the same car that I had sat in back in 1967 or so at the Ford dealer in Charlottesville where I was living at the time. It was also Bib Stillwell's car that my friend John Horsman had told me about restoring some time ago. I'll have to ask him about it next week. It's for sale... $4.1M.
 

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Hey Neil out of curiosity there is a member in Manta Registry who I am sure that you know Rex Svoboda?
I could not find much info on his car other than it was powered by Buick stage3 V-6 no other info listed ?

Your Mirage is killer by the way, was the door set up you have an option ?? mine are 2 piece
 

Neil

Supporter
Hello Lee.

Yes, I know Rex, he ran his "McLaren M6B" replica at Bonneville a few years ago and did 200 mph. He also competes in the Nevada open road event "Silver State Classic". I did ask him about what rear uprights he used and he said that he had fabricated them. I don't remember much more about his car but I'll post a few photos for you.

No, the doors on my car were not an option. I decided that if I needed to exit the car quickly (on fire, etc) the stock two-piece door arrangement was too complicated so I bonded both upper and lower doors together.
 

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Hello Lee.

Yes, I know Rex, he ran his "McLaren M6B" replica at Bonneville a few years ago and did 200 mph. He also competes in the Nevada open road event "Silver State Classic". I did ask him about what rear uprights he used and he said that he had fabricated them. I don't remember much more about his car but I'll post a few photos for you.

No, the doors on my car were not an option. I decided that if I needed to exit the car quickly (on fire, etc) the stock two-piece door arrangement was too complicated so I bonded both upper and lower doors together.
do you remember if was the engine was mounted longitudinal or transverse?

in case of fire that makes sense!!
 

Neil

Supporter
Lee, Rex mounted his V6 Buick engine in the conventional longitudinal position. I don't remember what transaxle he used. Notice that Rex added some rear fins for stability at high speed.
 

Neil

Supporter
I have put more work into my shift linkage than I should have but I want to get it right. I replaced the mild steel tubing that I used for my shift rod with ground & polished Rockwell 60C and it really improved the back & forth motion- far smoother and easier. I was pleased with those results but the shaft rotation in the Thomson linear ball bearings was not as good as I wanted. Fore & aft motion allowed the ball bearings to roll in their tracks but shaft rotation resulted in the ball bearings skidding across the surface of the shaft instead of rolling. My mistake. I pulled those bearings & housings out and made plain bearings from some UHMW polyethylene and the feel was not bad. However...
Just by accident I found that Thomson also makes Flouroplastic- lined plain bearings in housings that are the same size as their ball bushings. I ordered some and tried them on the G & P shaft- perfecto! Now I'm replacing the ball bushings with the plain bearings. I'm not finished yet but this looks like the best solution so far.
The shaft and bearing ID are very precision so they allow only +/- 0.5 degrees of misalignment. I installed the bearing housings as close to alignment as I could and then loosened the screws holding the bearing housings to allow them to "float" just a little to make the bearings "self- aligning".
 

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Brian Kissel

Lifetime Supporter
Nice job Neil. Have used those lined bearings for years with great success. After the last couple of disappointing outings, I hope this will be the year for you.

Regards Brian
 

Neil

Supporter
Thanks, Brian. I made another small improvement to my shift linkage. The end of the shift rod has a 1/2" 6061-T6 right angle piece that functions to rotate the transaxle shaft and push it in & out. I used an aircraft counterbore to make a 3/4" hole for the 0.750" shift rod. It turned out the hole was bored about 0.020" oversize so I used some 1/4-28 set screws to secure it to the shaft. This worked OK but I thought that I could reduce the chance of rocking back and forth when shifting by adding a second thickness to it. By bolting the two pieces together with a 5/16-24 Ti bolt, the two pieces are held rigidly together. So far so good...
 

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