Bonneville Comanche 4.9 build

[Plechtan]

Is building a stroker just about the engine? I would hope we all have vehicles to go along with the engines. The projects section has seems to be mostly about engine builds, but in my case many other items are coming into play. all the systems on the car to support the engine and going fast. I read a thread today in general tech on rear ends, is this stroker related? I would say yes, because the D35 will not hold up to the power of the stroker. What we are doing on the LSR3 is extreme, i hope that I end up with the most powerful Jeep I6 ever built. But many of the things we are doing have application on street motors or daily drivers. For example, we bored our block to 4". Most people are staying away from this, why? Most of us are getting our blocks bored and to go to 4" probably wouldn't cost that much more. Pistons could be an issue, but if you are going with KB944 pistons, custom pistons don't cost that much more. Maybe go with the Eagle rods and the Ford SB pistons, $500 for the rods and off the shelf pistons.

But let me bring you up to date, the engine build must be one of the longest in history, Things keep changing. The big holdup right now is the 4" offset ground crank. the guy doing it has been jerking me around since February. Should be done this week. The Isky roller lifters are also due in this week, and once we have them and the tie bars, we can clearance the block. Once the block is clearanced we can start the engine assembly. The head is also a major item that is holding up the build. I should have final flow numbers this week, the flow numbers will determine the Cam, the lift on the Cam will work into the piston design. The final combstion chamber size will also work into the piston design. The cam will probably have around a .650-.700 lift If you are a Doantor you can see the Desktop Dyno sheets in the Donators section.

But as I said eariler, the engine is only part of it, the truck cam back from paint thei week and we tool some pictures to send in with the entry. We will photo shop the numbers on the car and put it on the salt by removing the background. The first picture is the car with ny son Scott standing next to it, he will be the driver. You can imagine the conversation with my wif when i told her that he would be driving, it started out somthing like this "Are you trying to kill our only son? " It went downhill from there.

Scott-Comanche.gif

comanche-cage.gif

quarer-front-comanche.gif

[dwg86]

COOL!

[gradon]

Looks good. Are you running the stock steering set-up? What tires are you using? Suspension mods(are you allowed to lower it some?)? Brake mods?

[SilverXJ]

Is that a long bed MJ?

I don't think I would plan brake upgrades.... they will usually add weight.. how long is the roll out area? I agree that tech from racing tends to trickle down into mainstream.

What do the rules allow you to change as far as aerodynamics?

[johnhalabama]

I'm building a stoker to go in my 1936 Dodge Sedan. A little different but I am going for fit, unusual and a go fast motor. I like the torque for pulling a tear drop trailer but mostly going for higher rpms. I'll be keeping up with your build.

Nice looking truck.
John -Chesapeake, VA

[Plechtan]

Looks good. Are you running the stock steering set-up? What tires are you using? Suspension mods(are you allowed to lower it some?)? Brake mods?

The comanche has a little drop on the pitman arm stock, so we will probably put a straight one on. We will use a manual steering box. The car will be lowered at least 4" i will post pictures of the drop axle when we get it done. The rear is getting a 4 link with coil overs. We are adding a dual diapraham booster from a 94 Cherokee, and were going to use brakes from a 2001 WJ. They have a great 2 piston setup. We will probably keep the stock brakes for this year and hope the parachute does it's job. We do have 2 miles to stop.

Because we are running in a production class we are not allowed to change the body panels at all. you cannot even tighten up gaps closer than the factory spec. We can lower the car and put a cover on the bed.

And yes it is a long bed and it came with the "Metric ton " package which gives you a 2200lb payload and a Dana 44 rear with bigger brakes.

[Plechtan]

We need to drop the comanche allot, going from 28" to 22" tires will drop things 3", so we need to drop the suspension at least 4" more. We decided to make a front drop axle. We found another axle in a bone yard and cut off the C pieces and about 8" of tube. we were going to stack these on top of the existing tube, but the tube was only 2.5" in diameter, so stacking would only give us 2.5" of drop. We decided to make a little I beam out of 2 pieces of channel iron. This would serve as a spacer and also align the tubes.

We tool the stock axle and put it on a steel table, then got the springs buckets level. We then welded the axle to the table and cut off the spring buckets and other parts that were not needed. Finally we cut off the C pieces. Next step was to make sure the channel would sit level on the tube. The final step was to place the new C piece into the channel and set the Caster angle. To set level and the caster angle we used a digital angle meter. See pictures below.

end view.jpg

axle side view.JPG

Caster angle.jpg

We will be using Eibach stock car springs which are way shorter than the Jeep springs

[Plechtan]

Here is a pic of the truck on the Salt

Bonneville-comanche-1985-lo.gif

What do you think?

[Muad'Dib]

looks pretty slick!

[1bolt]

Well I hope you're open to some constructive critisism Pete, that drop axle looks fine for a low rider or a bagged frame dragger... I wouldn't go 100 MPH on it... Let alone 200.

You are relying on two sets of stacked welds with no structural support on top, front or back of the axle... if you look at the knuckle it is welded to the tube 360* because there's lots of force pushing backward on a tire at any speed in addition to the massive stress that will be on it while braking. I would truss that whole drop axle section front and rear with some 2x4 stock cut and relieved for the axle tubes, perpendicular to them. If you've already thought of this then never mind

[Plechtan]

We hade some 1/4" plate that goes from the original tube to the added tube. One piece goes over the end of the existing tube and around the new tube the piece on the other side of the new tube closes that up nas goes down to the original tube. I will post a picture.

To change subjects a little, i got the ITB intake system finished, here are some pictures.

Jeep-Commanche-Project_itbi.gif

Jeep-Commanche-Project_inta.gif

Jeep-Commanche-Project_iitb.gif

[dwg86]

Now THAT looks cool

[mendelmax]

Wow, that's magnificent

But I don't get one thing- are these independent runners planned to join together and go to the air filter or what?

[Plechtan]

I plan to build an airbox, but most people run a filter on each throttle body. Here is a pic of a 240Z. Setup is very similar to the jeep inline 6

Notice the vaccum log on the top. The throttle bodies have a similar fitting on the bottom where you can bring your Idle air in.

extrudabody.jpg

[Plechtan]

The early jeeps like my MJ have only a single diaphram booster. you can upgrade to a dual diaphram form a 94 and up and get much better braking. I have seen some articles on using the 96 and up boosters, but the geometry is not right for the 85-92 vehicles. In the attached article you will see that the brake pedal sits too high, this is not problem if you use the 94-95 booster instead of the 96. The 94-95 booster is the best fit, only requiring the hole in the booster rod to be drilled out to 9/16. You will need a new master cylinder form the same year as the booster. Some fittings are also required. I fould this writeup which describes it pretty well:

http://www.cherokeeforum.com/showthread.php?t=3352

Actually i found a problem with the writeup i linked to. The one adapter fitting specified, #7936 is a M10 x 1 thread. 3/16 brake tubing has a 3/8 x 24 thread, M10 is slightly bigger than 3/8 and a 1.0 mrtric pitch is a little more fine than 24 tpi ( 25.4 tpi actually). The correct fitting part # is 7974. These are all weatherhead part numbers. The list should read as follows:

#7974 3/16 to M12 x1 adapter Edelmann # 265000
#7909 3/16 to 5/16 adapter Edelmann # 258350
#7818 3/16 to 1/4 adapter Edelmann # 258340
#1442 3/16 to M10 x1 adapter Edelmann # 271300

To get the brake pedal the proper height you will have to put a 1/4" spacre between the booster and the firewall. the later XJ's have them, but if you can't find one in the boneyard, you can make one. Here is a drawing.

boosterplatereverse.jpg