Moving the engine back behind the front axle.

[Charlie Lawhon]

I just got 2 trucks donated for test bed vehicles. 1 is a half ton quad cab the other is a 12v extended. Both are 2wd.

We will be cutting the firewall and moving the engine about 2 feet behind its original location. In the process the engine will drop several inches as the mounts follow the curve of the frame under the cab.

The rear frame rails will be swapped side to side to make the springs inboard for 18 inch wide tires inside a single wheel body line and allow lowering.

The front will get C notched most likely to allow a 4x4 front axle to be installed with ride height at 2 inches above tire rub at lock to lock on the hard bump stops.

Then after the roller is base line satisfactory we're going to begin the journey of R&D for an all wheel drive transfer case.

Basically stock 12v p7100 and NV4500 to get the ball rolling.

 

[mfurrh55]

Wow, hope you keep us posted with pics through the proccess, sounds interesting, Monte

 

[Charlie Lawhon]

Wow, hope you keep us posted with pics through the proccess, sounds interesting, Monte

Oh there will be an abundance of pictures and information. I had intended to cut the firewall today but the shop I'm doing this at was in a really bad mess so I've been getting everything ready to go. Will probably cut it tonight and try to get a mock up engine in l planned l placed so we can see what its gonna be like

 

[Charlie Lawhon]

Has anyone else built a mid engine 2G?

 

[Charlie Lawhon]

Just made the cut. The drop is the full 24 inches behind its original location. Tomorrow I'll try to get a mock up engine placed in the tunnel to see how it looks.

I decided last minute to change my mind on the front drive type to independent front drive rather than straight axle. I want the ability to put caster and camber in as I wish because my driving style is road race, more specifically cornering and safe handling at 150+ mph in the real world. The straight axle would just be too restrictive.

 

[Cummins12V98]

You going to create a console above the engine that doubles as a Burrito warmer?

 

[JR]

Well your committed now! How much ground clearance do you anticipate on the new engine location?

 

[Charlie Lawhon]

Well your committed now! How much ground clearance do you anticipate on the new engine location?

I'll most likely have to dry sump it to stay at a real world ground clearance. The engine is about 8 inches lower than original placement. I'm not worried about that much though because it will get the new high tech suspension we're testing on a race truck now and it doesn't have much travel. Super soft springs and super heavy damping.

I am antsy and threw a common rail long block under it for a general idea of where I am on it . The 12V isn't here at this shop right now.

 

[Charlie Lawhon]

Got the 12V mock up swinging in the frame pretty close to where I want it for center of gravity. With the factory pan it's about 3 inches lower than the factory transmission crossmember right where the cross member is factory. The entire block is tucked up in the frame.

If you look at the shot I drew the line on the center of the engine is at the top of the highest part of the frame in the front.

Tomorrow I'll try to get the rear end hanging in the front to make sure the left axle stub is not outside the left frame rail when it's rigid mounted in the frame and the front driveshaft will clear the block.

 

[Wayne M.]

Tuning in here for sure!
Have you built anything like this before? I do watch a lot of Motorsport, and I don’t ever recall seeing anything like this running around other than maybe a Baja type deal. Will you be in a sanctioning body? Is there a certain series you’ll be with? Will your seat position be original? I’m curious about how you’ll shift the 4500. What plan do have for a front suspension, and are you going to clip the front? Have you ever dry sumped a 6B before?

Many ideas I’ve never seen applied to a vehicle like this before. Very interesting!

 

[Charlie Lawhon]

Tuning in here for sure!
Have you built anything like this before? I do watch a lot of Motorsport, and I don’t ever recall seeing anything like this running around other than maybe a Baja type deal. Will you be in a sanctioning body? Is there a certain series you’ll be with? Will your seat position be original? I’m curious about how you’ll shift the 4500. What plan do have for a front suspension, and are you going to clip the front? Have you ever dry sumped a 6B before?

Many ideas I’ve never seen applied to a vehicle like this before. Very interesting!

Thanks for the interests! This is a combination of a personal street toy that will probably end up a Corvette killer anywhere anytime in the real world.

I have done all kinds of things to the 2nd gen. I cut my teeth on them when they were in production still and my dad was a dealer. We did real good buying them totaled and turning them around on a tote the note basis for guys that needed a truck but couldn't afford a new or even a non salvaged used.

I was a fabricator before I became a mechanic. I used to build compound turbos all the time before kitsch were available.

I agree that I've never seen a mid engine built and I've wanted to do it for a long long time now and finally the cards turned up all aces. I got the truck for free for helping a buddy build another 2G into a short bed drag truck.

The other deal with this one is to be a test bed for an all wheel drive transfer case. For now it will have a Chevy hard mounted rear end in the front and custom arms with another secret project I've got going on racing suspension I put on the front of the drag truck that is lighter than half ton springs and enough damping we did a drop test of the tires 10 inches off the ground and it only squatted the arms about an inch or 2 below ride height and was settled after 1 rebound.

With that this truck will be as low as I can get it on springs alone like maybe 5 inches frame to road and have the nice piston type bags to lift it a couple more for speed bumps and what not.

I'm HIGHLY considering using the Chevy front rear end in the rear along with the knuckles but just have heim joint link to set the steer ahead angle needed to correct contact patch angle caused by negative camber. I want around 20 inches of contact patch low profiles in the rear on both sides and as wide as I can get to allow lock to lock steering at full compression on the suspension.

I have not done a diesel dry sump, never had the need. For what I like I want the C/G as low as possible and as close to center of the wheel base as possible. Where the engine is in the pictures is pretty damn nice.

Funny you asked about seating because I think I'm going to have to move all the controls back at least 15 inches to put the shifter straight up out of the trans landing right in your hand like a sports car does. I like sitting low so it will get a race seat with full gated sides up to the shoulder and sitting in it now I'd say about 4-5 inches off the floorboard. The closer you are to C/G the more you feel what's really going on rather than your whole body swaying with body roll making it seem exaggerated.

I can go on for days. Most of the parts are donated or on hand. I haven't decided on component part list of the engine but I will have a lot of room under the hood for compressors and it'll need a long tube header to relocate the turbo even if I stay HX35WZ.

Getting back to Corvette killing, I'm looking for around a .220 or .240 ring and pinion set. it won't ever pull anything and I have had many vehicles that were over 170mph in real time. This one will be designed for those speeds. I think the math said a .270 with 30 inch tires and 4000 rpm was in the 170mph range. That would make 1st gear a real life gear and 2nd would pull as hard as 3rd and so on.

 

[Wayne M.]

There have been a couple of standout builds here on the TDR so I do hope you keep us in the loop and become one of them.
I don’t have much input on the chassis and body, but I am curious about how the dry sump will turn out since the Cummins B is a very deep skirted block. This lays out a great challenge for pan design and scavenging. You’ll need quite a tank too.

 

[Charlie Lawhon]

There have been a couple of standout builds here on the TDR so I do hope you keep us in the loop and become one of them.
I don’t have much input on the chassis and body, but I am curious about how the dry sump will turn out since the Cummins B is a very deep skirted block. This lays out a great challenge for pan design and scavenging. You’ll need quite a tank too.

I have been thinking about that as well. I think there will be enough room to build a pan that has a couple inches of depth at the flywheel end and potentially get a bit deeper going forward on the passenger side only to gather it up. Since the driver side will be so busy with drive line that's the logical choice as well as the fact that's closer to the front axle to be carried over more elevation change guarded a bit more The only thing I don't like is hard acceleration will pause return flow to the suction hose.

At least being deep skirted that helps avoid windage that would be more pronounced with the crank whipping below the skirt.

 

[Charlie Lawhon]

Just dropped the differential in to look at drive shaft location and I think its gonna be all good. In the pics its being cramped by all the factory crossmember and suspension pickup points that are getting cut off completely.

Its also being held to the passenger side about half an inch and I have room to move the engine over that way to make some more room down the driver side frame rail.

Also when the crossmember is gone the axle center will be about 14 or 15 inches forward of where it is just sitting where I have it now.

All and all I think we have a green light. Now I'm off to try to find a second differential like this one to make the rear decisions of whether or not its going fully independent.

Looking at it here and now I'll most likely use full race style connections using heim joints and multi link rather than A arm's.

 

[Charlie Lawhon]

Please excuse the mess. I've been doing the work on this in my spare time. I'll get it all washed soon so its it's a little easier to tell what's going on.

 

[Charlie Lawhon]

I'm thinking for all the accessories I'm going to get just a gear pump to replace the power steering and vacuum pump. Those are tiny enough it won't get in the way of the driveline. My plan for that is to relocate every single accessory except the water pump and do an electric on that to keep it clean looking. The accessories can be arranged neatly and driven off the hydraulic pump by a small motor and allows me to use smaller components like those nice tiny import power steering pumps.

 

[BigPapa]

If you don’t need the vacuum pump, you could run one of these HD pumps that are on our buses. They’re a little bigger than your fist.

 

[Charlie Lawhon]

If you don’t need the vacuum pump, you could run one of these HD pumps that are on our buses. They’re a little bigger than your fist.

View attachment 118913

That's exactly what I had in mind

 

[Charlie Lawhon]

Cut the parts out of the inside of the frame last night. Still needs to be dressed obviously but I'm trying to share the raw journey. Going to try to scare up a transfer case just to mock up with. I need to know what all the components are going to look like before I attach anything.

Just looking at it here in person I'm pretty sure its worthy of building the independent rear to match the front. I'll have my machine shop make custom knuckles and multi link heim joint all the attachments for full freedom of setup.

I also thought it was a good idea to just physically set the frame on the ground to see that I can have a flat under body. It may well get a full closure plate under it with front splitter and rear diffuser. The ride height will be low enough to create a vacuum to the road at higher speeds.

 

[Mschuman88]

Thanks for the pictures and frequent updates.