Project Madera: A Jimmy GT

[jaros44sr]

Sure helps me, as i hav nt gotten that far yet

Ya gotta downsize that pic way up top, hard to read your thread it s small....
Nevermind were on the next page

[jjzepplin]

AWWW DAMN! I mean
AWWWWW DAAAMN!

[skorpioskorpio]

I don't see how I can not get one, I mean eventually the truck is going to have a stripe of aluminum from radiator to fuel tank, interrupted by a steel rear end. It just doesn't seem right, not when I could have one of those. Already talked to a guy in San Bernardino who can fan up the tubes to use all my Moser parts. Maybe not today, maybe not tomorrow, but soon....

[jaros44sr]

Tried to google that company and part, but couldn t find it, any help....

[watahyahknow]

you know looking at that diff i starting to wonder how difficult it would be to wittle it out of a piece of billet , looks pertty straight forwarth

[skorpioskorpio]

Originally Posted by jaros44sr

Tried to google that company and part, but couldn t find it, any help....

Sure:

http://speedmaster79.com/tds/rear-axle-housings/

There is also a previous versions of it that doesn't have the extended fluid capacity and uses round end axle tubes instead of octogonal end.





Speedmaster only sells the new style with the saggy diaper bottom.

[skorpioskorpio]

Originally Posted by watahyahknow

you know looking at that diff i starting to wonder how difficult it would be to wittle it out of a piece of billet , looks pertty straight forwarth

Considering the kit costs under $600, I seriously doubt you'd be able to wittle one out of billet for anywhere close to that. The block of 6061 itself would probably cost you triple that, easily. The fabricator I talked to was giving me a non-binding quote of a grand (give or take) with ends and mounts installed on the tubes and races for my existing taper bearings.

The description on the kit claims being able to accept 28, 31 and 35 spline axles, and aluminum 3rd members are available from several manufactures (mine is from Moser). If you used a 35 in the rear and a 31 or even a 28 in front it'd make for one stout but somewhat light drive train. I know even a steel housing Ford 9 is lighter and stronger than a 12 bolt and probably half the weight of a 14 bolt or a Dana 60 (both of which are very seriously heavy).

[zammer]

Wow nice work! Subscribed!!

[skorpioskorpio]

Thanks, and I take that as a serious compliment from another building an unnessisarily complicated project . Your project is on my subscribed list as well.

[skorpioskorpio]

It's a small thing but I'm excited about it, I scored 4 original NOS black Marchal covers for my "big" lights. These are almost non existent in any condition,


and I already had matching ones for the fogs.


...and revised my Photoshop rendering to show what they'd look like on the truck.

[watahyahknow]

i think you better only put them on there during cashows or they be gone before you know it
they kindah eazy to get off the lights

[skorpioskorpio]

Yea, I hear ya. The black covers will be the trucks fancy dress outfit. I have other covers as well that I value a lot less. I have white plastic covers (that are actually a ***** to get off) and the vinyl sock type, all of them are actually original Marchal covers. The plastic ones I also have matching fog covers the vinyl I don't. As a daily thing I don't think I'd cover the fogs anyway. The drivers and the spots on the other hand may technically violate laws to run them uncovered.

[skorpioskorpio]

I guess I never posted pics of my crazy under floor hydroboost since it came back from machining. The mount is a Scott's Hotrods assembly but didn't clear the accumulator for the hydroboost so it needed to be machined to tuck the accumulator inside the frame rail. I also had all the holes counterbored for RivNuts so they would sit flush. I still plan on replacing the rodend for the booster with a split fork type and changing the bronze bearing inside the pedal pivot with a needle bearing assembly and also needle bearing thrust washers on the ends of the pivot so that it can operate really smoothly. The pedal also does not have a return spring which I'll also probably add.




I also have to devise a new mount for the apportioning valve and residual check valves, the mount that is on it is too low, I don't want a valve that all the brake fluid runs through to be lower than the frame, that's a bad idea. This thing is going to be interesting to plumb with 3 brake lines, a portioning valve, 3 residual check valves, 2 remote reservoir lines, 3 hydraulic pressure lines, and 2 pressure limiting valves all crammed into a space the size of a load of bread.

[Wasted Income]

Originally Posted by skorpioskorpio

...and revised my Photoshop rendering to show what they'd look like on the truck.
Attachment 1313929

Maybe it's already been covered and I missed it...but it looks like all those lights might severely restrict airflow to the cooling system.

[skorpioskorpio]

Originally Posted by Wasted Income

Maybe it's already been covered and I missed it...but it looks like all those lights might severely restrict airflow to the cooling system.

Which is the reason for the spoiler, cowl hood and Trans Am extractors in the fenders, to direct airflow from below and give it a place to exit up high. Also plan to dimple die the roll pan to increase airflow. As long as there is a non pressure bound path and the general flow is low to high I don't see where the lights will have any real negative effect. Most new vehicles have hardly any frontal airflow at all.

[Possmguts]

Ok.. Im in.. following this to the end. You guys have way too much money!

[watahyahknow]

it was my initial idea to use the atlas as whell , since i live in europe i found an engine that does about the same thing
- makes 245 hp and 289 lb·ft of torque in stock form
- 4 valves per cilinder
- twin overhead cams
- chain camdrive
- coil over plug ignition
- 4 liter
- forced crank
- 7 mainbearings
- normal oilpan with the sump in the back
- fully aluminium with cast iron liners
- comes stock with a 4l80e (in the high performance versions at least )
- is available with a supercharger and intercooler from the factorie making 322 hp and 378 lb·ft in stock form (and there not rare to find)

the donorcars with the engine and the trans can be found for about 500 to 1500 euro
the jaguar AJ6 4.0
http://en.wikipedia.org/wiki/Jaguar_AJ6_engine
nice thing is that the jaguar xj6 4.0 and xjs6 4.0 usually come fully loaded with all kinds of luxury too like fully electric leather seats cruise controll and aircon

[skorpioskorpio]

The Trailblazer engine is really similar dimensionally (bore x stroke, airflow, HP potential) to an old E-Type 4.2 liter, so I absolutely get where you are coming from. My goal is for the end result to have a E-Type sound to it, specifically I'm shooting for the sound of an Eagle E-Type, just a fantastic sounding engine.

[watahyahknow]

i think doing a 6-2-1 collector on the exaust will help with that

[skorpioskorpio]

Interesting, hadn't really considered that to be a contributor. My headers are 6-2-1s but the secondary collector is really short, although it's just a slip fit collector that I could easily extend. Maybe that is a good idea to extend the secondaries a bit before going into the single.

This is the best pic I have of my headers:

[Dagobah]

I'm fascinated by your project. Before reading this thread, I hadn't heard anything about the atlas motor. Not that changing directions at this point in the project would be a good idea, but had you ever considered something like this?

It seems like you're already doing a ton of fabricating, and I'm assuming that 3-d printing is only going to make one-off parts like this more affordable. Anyway, I'm looking forward to seeing more progress in your project.

[watahyahknow]

if you could 3d print it in wax and make a lost mould casting of it , it could be done but you need to take the schrinkage of the aluminium in consideration (make the wax mould a percentage bigger)

[skorpioskorpio]

Originally Posted by Dagobah

I'm fascinated by your project. Before reading this thread, I hadn't heard anything about the atlas motor. Not that changing directions at this point in the project would be a good idea, but had you ever considered something like this?

It seems like you're already doing a ton of fabricating, and I'm assuming that 3-d printing is only going to make one-off parts like this more affordable. Anyway, I'm looking forward to seeing more progress in your project.

Looks a bit like the Ryan Falconer engine:



which is based on the 250/292 bottom end and along with the Atlas was used in GMs Baja and Pikes Peak racers. GM built it with Ryans help and Ryan retained ownership of the design (or bought it out) and now sells them for about $50,000 bare. In this program both of these engines in turbo form were pushing 700-850 HP during that program and dominated both events even against teammate trucks running Chevy V8s. The injection is available as an off the shelf product from Kinsler for the Falconer engine.

All that said I decided on what I did for a few reasons, one I felt it important to use a GM engine in my project, two I didn't want a push rod engine, three the Northstar has issues and in the end still sounds like a typical cross crank V8 (bubba-da-bubba-da...) and four GM never made a production V10 or V12, OK not a modern V12, the GMC V12 is actually a twin V6 and weighs near a ton.

You know putting anything in one of these trucks that isn't a variation on the original theme to what came in them is blasphemy to many so in the end putting a GM truck engine in a GM truck seemed like the way to go. There will always be the occasional, well my sisters cousins husband who works on these things all the time says that those engines are junk and you should have used a small block, garbage. Fact is that among the small community that are swapping these engines in, they consider 100,000 mile engines low milage, and there are others running these at the strip running high boost turbos and 800+HP and spinning them up past 10,000 rpm and I've heard no stories from that crowd about *any* catastrophic failures at all.

[skorpioskorpio]

Originally Posted by watahyahknow

if you could 3d print it in wax and make a lost mould casting of it , it could be done but you need to take the schrinkage of the aluminium in consideration (make the wax mould a percentage bigger)

Shrinkage rate for investment cast is 100.008% or that is the scale you need to compensate for when doing your print. I am 3D printing my intake manifold to have it investment cast. A head or a block is probably too big and too complicated to investment cast as your shrinkage ratios at that scale start to become non-linear, and good luck finding cheap access to a 3D printer that can print it...and it'd probably take weeks to print. Probably not a practical project. Even my manifold will need to be printed in at least 2, and maybe 3 pieces and then glued up (or actually melted together as I am going to print straight to wax).

An engine block and heads has all kinds of internal water jackets, lots of post cast machining, lots of blind passages that are difficult to get the casting medium out of, it's a lot more thought and a lot more complicated, and probably really needs to be done as sand cast, which means cores and all that.

If I was going to do a whole engine it'd probably be a V12, and would probably be a 60 degree so the math worked out, and probably use something like a Harley connecting rod to keep it as short as possible. But having to rely on others for this sort of thing means such a project would take insane amounts of money. Don't get me wrong designing an engine from the ground up is a dream of mine, just not a practical one.

[watahyahknow]

yeah i think even the factorie makes the core with the water passages and stuff seperate from the outside , it would take time and monet allthough the price might go down over the next coupe of years