Build Rock Lizard build

[bwillrich]

After a long while of stalling I finally started on my Rock Lizard project. It’s my first time with a project of this magnitude but as I stumble along progress is being made!
Drivetrain is a GM 3900/ 700r4/nwf eco205. 79 hp60/14 bolt rear. Hope to have the engine settled in and mounts built over the weekend. I know it’s going to be a super tight fit.

 

[woody]

very cool....SO many things to think about, especially at this stage

 

[SteerAndStuff]

Love watching a new build thread. Thanks for sharing.

 

[Blase]

Can't wait to see what all you come up with!! I can see you modified the rear of the chassis. Is that to make it a small 4 seater? Looks great!! keep up the good work.

 

[bwillrich]

Can't wait to see what all you come up with!! I can see you modified the rear of the chassis. Is that to make it a small 4 seater? Looks great!! keep up the good work.

I bought it from a guy that did that. He said he liked the wagon look. I agreed and that was a big part of buying it for me. He also had some custom suspension set up by BFR made specifically for it also. Tim does good work so I’m anxious to see how it works. Not enough room for an extra seat but it’ll be nice for a little more storage.

 

[vogelj]

Looks like a great build! Im in for the 3.9 700R4 tech. Did you do anything to refresh the engine?

 

[bwillrich]

Looks like a great build! Im in for the 3.9 700R4 tech. Did you do anything to refresh the engine?

I flipped the intake around and new gaskets for that, and did the oil pickup mod but nothing else. It was a good runner before so I figured it’d be ok.

 

[bwillrich]

Not much progress over the weekend but every little bit helps. Got the engine and trans set down and back. Clearanced the chassis for tcase room. Parts coming for tcase and trans mount.

 

[Dave22]

man when I was looking at chassis this was a serious consideration saw one at KOH 2022 and fell in love with it
looking forward to seeing it come together!

 

[bwillrich]

Got the bridge in for the tcase clearance. Hopefully the mount will be in this week and I can make some more progress. I guess any is better than none!

 

[DirtSquirrel]

Nice. Thanks for sharing.

 

[vogelj]

That ended up fitting pretty well. Nice work.

 

[bwillrich]

Moving forward… Tcase mount arrived. Fit good with very minimal effort. Got the rear links in place and heavily tacked in. Moved on to the front and realized the front pinion wants to be in the same place and my relocated power steering pump. So I guess if someone needs an Eversen Fab aluminum bracket, hit me up. I had plans of flipping the intake around but I guess that’s not going to fly. Planning to spin the intake back around and put the pump in the stock location , just need to find the correct coolant crossover.

 

[Dave22]

man that thing is going to be nice

 

[mustcamp]

Very interested in how you end up liking the np205/EcoBox combo. How often you use double low vs just 2.7 of the EcoBox or 1.9 of the np205. How deep are you going with your ring & pinion's?

 

[bwillrich]

Very interested in how you end up liking the np205/EcoBox combo. How often you use double low vs just 2.7 of the EcoBox or 1.9 of the np205. How deep are you going with your ring & pinion's?

I’ve got 5.38’s in the axles. I have a buddy with the same setup with a Jeep 4.0 in his buggy. He says for crawling technical stuff the low-low is great but it’s too slow for some hill climbs. I guess I’ll find out, but I think it’ll be a good mix. I wish there was more of a difference between the 2.72 and the 1.96. I had this stuff when I had my xj and never got around to putting it in. Otherwise I think an atlas or something smaller would have been a better choice.

 

[mustcamp]

I’ve got 5.38’s in the axles. I have a buddy with the same setup with a Jeep 4.0 in his buggy. He says for crawling technical stuff the low-low is great but it’s too slow for some hill climbs. I guess I’ll find out, but I think it’ll be a good mix. I wish there was more of a difference between the 2.72 and the 1.96. I had this stuff when I had my xj and never got around to putting it in. Otherwise I think an atlas or something smaller would have been a better choice.

Thanks... It seems like most who have this set up that I can find writeup are not disappointed other than the size. I figured between the two ratios and being able to double up in addition to using second gear start you have a lot of options depending on the obstacle. strength, front dig capable and ratio options. It's the direction I was planning to go. for me us coming from dual Toyota cases and manual trans I just feel more comfortable with the options and willing to sacrifice the weight and size.

 

[woody]

Thanks... It seems like most who have this set up that I can find writeup are not disappointed other than the size. I figured between the two ratios and being able to double up in addition to using second gear start you have a lot of options depending on the obstacle. strength, front dig capable and ratio options. It's the direction I was planning to go. for me us coming from dual Toyota cases and manual trans I just feel more comfortable with the options and willing to sacrifice the weight and size.

Create a spreadsheet for your ratios, covering all your t-case options and trans options. I've done that for my next build, very useful info. Notice that for my current 700r setup, the Third L and First H overlap. The C4 ratios are specifically being chosen to NOT overlap.

 

[DirtSquirrel]

Create a spreadsheet for your ratios, covering all your t-case options and trans options. I've done that for my next build, very useful info. Notice that for my current 700r setup, the Third L and First H overlap. The C4 ratios are specifically being chosen to NOT overlap.

View attachment 17650

Whats the theory about not overlapping in a higher ratio? I know im regularly not in Third/Fourth L when doing anything technical. And im only in high on the park roads. I figured 1st/2nd low range are the most important crawl ratios to look at. Just curious.

 

[mustcamp]

I have played with this web site ratio calculator a bunch.

Gear Ratio Calculator

 

[mustcamp]

Create a spreadsheet for your ratios, covering all your t-case options and trans options. I've done that for my next build, very useful info. Notice that for my current 700r setup, the Third L and First H overlap. The C4 ratios are specifically being chosen to NOT overlap.

View attachment 17650

I see you are going much lower with your 1st Low. on your new set up. Do you currently wish for a bit lower crawl in First-Low? The C4 1st, 2nd, 3rd splits look really nice. Will you be able to stop it or just pop neutral?

 

[woody]

I see you are going much lower with your 1st Low. on your new set up. Do you currently wish for a bit lower crawl in First-Low? The C4 1st, 2nd, 3rd splits look really nice. Will you be able to stop it or just pop neutral?

I mostly stop in 2nd now, 75:1 can push thru the brakes

Yes, I'd like to be lower on occasion, but 90% of the time 75:1 is perfect, and use 2nd for throttle bumps. The new ratios would bump in 3rd, normal wheel in 2nd, crawl in 1st. There are also lower 1/2 ratios available for the C4, toying with that option too.

Whats the theory about not overlapping in a higher ratio? I know im regularly not in Third/Fourth L when doing anything technical. And im only in high on the park roads. I figured 1st/2nd low range are the most important crawl ratios to look at. Just curious.

Takes a split second to stop and hit high, not overlapping offers the most options for gearing as needed.