71K5 - BP71K5's Just for fun build

[bp71k5]

Some pictures of the clutch master cylinder bracket I used to reinforce the firewall from under the dash. It just ties the MC into the brake bracketry with a few bolts.

You can also see I had to bend the pivot arm out to line it up with the MC bore. It took me a few hours to discover I couldn't bend 3/8" steel bar with a hammer. So I used a cutoff wheel to cut halfway through the lever and then bent it to where I needed and welded it back up and welded the splined portion onto the end as well.

I had to use an offset pushrod (I used the one K5MonsterChev sold me) which was bent and welded up from thicker rod stock. It turned out that since I was using parts from his pedal assembly, the pushrod he built is about the right length.

 

[4X4HIGH]

If it were me i would be welding a triangulated gusset on that pushrod otherwise it may decide to bend on you at the bends.

 

[bp71k5]

cross members installed

Here's the dual crossmembers. I gave up trying to get the extra inch of clearance. It was gonna just be too much work and I figure I can do it later.

I mostly used parts from the existing crossmember and a new one I bought. I still need to add some bracketry to support the tranny mounts.

After all this I also need to route my exhaust much differently than before. When ORD recommends a 1" body lift, it makes a lot of sense now. It would have eliminated all the cutting and give me some room to route the exhaust over/around the 205.

I also mounted the tranny cover, but forgot the "measure twice, cut once" rule so the hole is bigger than needed. I'll fix that up later.

 

[bp71k5]

You're right, that part feels kinda hoaky to me too. But you'de be surprised how strong it is. I'm going to keep thinking of a better way to do it. A gusset would work and I may try a trick indirect linkage like the 205 linkage uses for the twinstick. That way I can use a stock straight pushrod.

 

[Greg72]

You're right, that part feels kinda hoaky to me too. But you'de be surprised how strong it is. I'm going to keep thinking of a better way to do it. A gusset would work and I may try a trick indirect linkage like the 205 linkage uses for the twinstick. That way I can use a stock straight pushrod.

This build is looking good....I always like seeing nice shiny parts getting installed. Quite inspirational!

Is there any way to rotate that actuating arm at the top of the pedal assembly? It seems like if you could rotate it 180 degrees you'd have almost a straight shot to the master cylinder and could completely eliminate that whole double-offset linkage bar (which does look like it will flex and eventually bend out of position).

Just a thought. It's hard to tell from the pics if what I'm suggesting is even possible.






ps. Nevermind. Rotating it would create a "pull" instead of a "push", so you'd need some other complex central pivot point to give it the correct motion.....guess I should take a few more sips of coffee before I post up again.

 

[bp71k5]

Yea, I sat with my head under the dash for several days and late nights trying to think of a better way to do it. The gusset is the best idea so far, I'm just not a fan of how it looks.

In addition, the angle of the pivot lever is the ideal position because as it rotates forward, the height of the pushrod is pretty contant. I could rotate the lever forward a bit, but by that point it starts rotating upward so the throw would be really off.

 

[BUDDY]

I found a few options on my idea to single stick the doubler instead of having triple sticks. This hurst shifter looks like it's used for dragracing and uses similar link rods as the doubler. I'm thinking to find one of these and modify it to be able to work the three x-case shift levers.

Anyone used one of these shifters before and know how they work? My big question is whether each shift link moves independantly from the others when you move the lever through the shift pattern.

http://www.hurst-shifters.com/catalogpdf/2-Manual-Shifters/DragRaceshftr.pdfhttp://www.hurst-shifters.com/catalogpdf/2-Manual-Shifters/DragRaceshftr.pdfhttp://www.hurst-shifters.com/catalogpdf/2-Manual-Shifters/DragRaceshftr.pdf

I am a big fan of this in concept for sure!! I even think that you could get that shifter to work quite well. The NP203 rangebox already has the rotating shift rail situation & the other two rails just slide in & out so you would just have to cut the hurst rails to length, thread them for a rod-end, & hook them up to the range rails. All good in theory.

However & I think my biggest concern is how would be able to determine which rail is in which range? You'd have to come up with some kind of indicator to make sure you weren't in High & low at the same time. Either that or just get into the habit of shifting all the ranges each time you get into the truck.

Something to think about!!

Buddy

BTW - the build is looking great!!

 

[bp71k5]

Yes, it could be tricky to know which range everything is from just looking. I have some ideas on making some little indicators near the shift boot to tell me which state everything is in.

For safety, the 205 rails won't allow high and low range at the same time so that is probably safe, but I've heard it's not a good idea to use the 203 in low while the 205 is in high.

 

[BUDDY]

Yes, it could be tricky to know which range everything is from just looking. I have some ideas on making some little indicators near the shift boot to tell me which state everything is in.

For safety, the 205 rails won't allow high and low range at the same time so that is probably safe, but I've heard it's not a good idea to use the 203 in low while the 205 is in high.

If you can figure this out, I'd DEFINITELY be interested in what you do.

I don't think it would matter much to run the 203 in low & the 205 in high. You'd just have 2:1 reduction to either 2wd or 4wd, depending on the range the 205 is in.

Later,
Buddy

 

[bp71k5]

shifter setup

I took a chance and bought a shifter from Jegs. I haven't taken it fully apart yet so I can sell it if it turns out I can't do what I want with it. But from my initial observation, it looks possible to use this kind of shifter to control all three gear rails independantly.

I have some illustrations to help show what the idea is. Although at this point using 3 sticks is looking like the simpler method.

This first picture is the shift pattern on the Hurst shifter in stock form compared to what it needs to be for use with a doubler.

 

[bp71k5]

The basic idea is that the shifter has three moveable levers (at the bottom) which would control each of the three doubler shift rails. Which lever you are controlling depends on which direction you move the shift handle. For example:

Old shifter positions 1-N-2 will be 203 L-N-H
Old shifter positions 3-N-4 will be 205 rear L-N-H
Old shifter positions 5-N-R will be 205 front L-N-H


After looking at the actual shift mechanism and studying this a bit, the challenge with this type of shifter is that it even though it has 3 levers, only one of them can be "in gear" at any one time. This is because when you move the shifter out of one position, you always have to move up or down through "N" first. That won't work well because, for example, the "205 rear" rail needs to stay in the gear I selected when I move the lever over to change the "203" or "205 front" gear selection.

In order for this to work, I need to be able to move the lever out of position without having to shift into "N" first. So I made some illustrations to help visualize what would really need to happen for this to work. The pictures show the shift pattern needed to get into different modes.

 

[bp71k5]

If the pictures make any sense at all (they almost do to me), the idea is that once you shift into a gear by moving the lever up or down, you can disengage it from the x-case rail by moving the shifter horizontally left or right. Once you are in this "in-between" mode, you can move the shifter up/down/left/right to choose other x-case shift positions.

Here's the moves needed to get into 2WD hi starting from the case when all x-case gears are in neutral.

 

[bp71k5]

And here's how to get into 4WD Low

 

[bp71k5]

And here's it shifting into 4WD extra low.

 

[bp71k5]

Even if it doesn't work perfect, I'll have a foolproof way of keeping someone from driving off with my truck. They'll never be able to figure out how to get it in gear.

 

[BUDDY]

I though about that on the way to Cleveland on friday night. I said to myself, "That won't work unless there is a way to keep the range in gear once it is shifted. Dang!!"

I was thinking about some kind of spring-loaded rachet-type mechanism that would "lock-in" the range, but still allow the shifter to move back to neutral like normal. Then you'd just have to release the rachet to go back into neutral on that range.

I know on some shifters, you have to push down to get it into reverse & that was kinda what I was thinking, as the release mechanism, but as far as the actual pieces, I don't know. It would definitely be custom & may take a LOT of trial & error.

Just throwin' it out there,
Buddy

 

[BUDDY]

Here's the dual crossmembers. I gave up trying to get the extra inch of clearance. It was gonna just be too much work and I figure I can do it later.

I mostly used parts from the existing crossmember and a new one I bought. I still need to add some bracketry to support the tranny mounts.

After all this I also need to route my exhaust much differently than before. When ORD recommends a 1" body lift, it makes a lot of sense now. It would have eliminated all the cutting and give me some room to route the exhaust over/around the 205.

I also mounted the tranny cover, but forgot the "measure twice, cut once" rule so the hole is bigger than needed. I'll fix that up later.

BTW - I really like the crossmembers you came up with. Nice & simple & at first glance, looks stock, but then you start looking at it a little closer & see what it's holding up. NIIIIICE.

Regarding the exhaust, could you just crossover to the driver's side instead of the passenger's side? I know that when I redo mine, it'll just be a single 3" out in front of the driver's rear tire. I may even use a supertrapp only for ease of routing the tubing. Nice & simple.

Later,
Buddy

 

[bp71k5]

Yea, you can see how just triple sticking it would be much simpler. I was hoping to drive this thing to blazer bash in a few weeks.

 

[bp71k5]

I called ORD today just on a longshot chance that they might already make a triple stick adaptor for the nv4500. It turns out they do.

I've ordered it in case my goofy hurst shift idea doesn't work in time for blazer bash.

 

[tRustyK5]

FWIW Northwest fab also has the NV4500 triple stick set-up. Mine was the proto-type which works awesome BTW.

Rene