CJ8 chevy big block rebuild

[Michel1972]

Since 2009 i am visiting pirate4x4 for all kinds off information and that helped me very much with my build here in the Netherlands.

I got interested in a jeep cj8 after building a cj7 and cherokee xj. So thats what im doing for the last 18 months now.

I bought a cj8 with only 27000 miles on it in october 2010 with the following options.

Poly body with flipnose
Chevy 454 LS6 big block
Dana 30 front axle R&P 2.73
Ford 9 inch rear disk brakes axle R&P 2.73
TH400
Quadratrac transfercase
3 inch bodylift
2 inch shackle lift
33 inch tires

Here is a pic off the car almost 25 years ago.

[Michel1972]

So in october 2010 the cj8 arrived in my garage for a rebuild. I knew that the cj8 was not in a good shape and that it would take a while to rebuild the cj8.

[Michel1972]

In the Netherlands we have to make sure that the things we change about the car are approved by the government. Every year the car is inspected by a garage that checks the car inside out. If they find something that is not allowed or in a good shape they tell you to fix it and if you dont do that you are not allowed to drive the car untill you have fixed it. For example the tires are not allowed to stick out more than 1.25 inches outside the fenders. The lights must not be more than 20 inches away from the widest part of the jeep. The wheelbase must be original and i can go on and on with those rules.

First i started repairing the poly body and flipnose.

[Michel1972]

After the poly body was repaired i started painting the body several times. Also the inside off the body was painted.

[Michel1972]

After i had painted the car it was time to replace the wiring and change the interior. I also placed a soft top and soft top doors. The windowframe, window and wiperset were also replaced.

[Michel1972]

After the interior and body were done the real problems started. I knew that the quadratrac transfercase was not able to handle the torque and power the big block produced and i raplaced it for a dana 300 4:1 transfercase. The th400 had to be adjusted to bolt onto the dana 300 so i bought a novak adapter. When installing the adapter on the th400 we found out that the th400 was not that good anymore. The oil inside the th400 was burned. The th400 was replaced by a chevy4x4 th400 with a stronger inside that could handle more power and torque. Also the cooling was upgraded for the th400

[Michel1972]

I still had heating problems with the engine. After 15 minutes the engine became very hot and i could not find out what caused the overheating. After several changes in the coolingsystem the engine still became to hot. So on a friday afternoon i started looking at the engine. I lifted the heads and they were not that clean anymore.

[Michel1972]

When the intake and heads were removed i tried to look at the 8 pistons. I used a big wrench to rotate the crankshaft but it could not be moved by hand. I had to use hydraulic tools to rotate the crankshaft and that was not a good sign

I took the engine out off the car and placed it on a pallet to bring it to a shop who would inspect the engine. I also was able to check the firewall and restore the poly.

[yz450kid]

Its funny that they have all those rules, yet they allow you to have a Big Block?

[Michel1972]

Originally Posted by yz450kid

Its funny that they have all those rules, yet they allow you to have a Big Block?

The reason is very simple bacause this jeep was build in 1990 and the rules were changed later. The vin registration says big block and that will stay forever and can not be changed back.

[Michel1972]

Within a few days the garage called me and said that the engine was damaged in 2 cilinders and the line boring was not ok anymore. The engine needed a complete overhaul. A complete overhaul here in the Netherlands for such a engine would cost me around the 7500 dollars. That is without the heads. Than i found a other engine for my cj8.

[Michel1972]

This big block gives a lot off power and torque so to reduce some power i used the old LS6 rectangular heads with normal size valves, a single plain intake, 850 demon carb, a mild cam and homemade 1 7/8 headers.

Than i installed the engine into the cj8 and placed some extra cooling systems for the engine and th400

[Michel1972]

When the new engine was placed in the cj8 it was time for a new radiator with fan and shroot. I placed the biggest radiator that could fit underneath the flipnose.

All the cooling adjustments have been done now. I have a 10 quart oilpan with extra derale cooling system with fan, The th400 also has a big oilpan and fluid cooler. The radiator is a aluminium 3 row system. The flipnose has extra hood vents and the intake has some extra water cooling lines.

[Michel1972]

After the engine was installed i wanted to change the axles and R&P axle ratio. I aslo wanted to lift the cj8 and put bigger tires under the cj8.

The axles had to be strong but not to wide. I bought CUCV M1008 dana 60 and 14 bolt 1.25 ton rating axles with a 4.56 R&P, disk brakes all around and lockers in the front and rear. The rear axle had a 63 WMS and the front had a standard 69.5 WMS and needed to be shortened.

I placed some TJ fenders on the cj8 and installed the rear axle first.

[Michel1972]

The rear axle is installed and bolted. It has a 4.54 R&P with locker. The WMS is 63 inches and with the Hummer rims and BFG tires the maximum width is 74 inches. I can not go much wider than that. I installed a traction bar and a genright rear swaybar will also be installed later when all parts arrived. I used goodridge brakes lines

[Michel1972]

The dana 60 front axle is shortened 4 inches. With the hummer rims and BFG tires the front axle has a maximum width off 75 inches.

[CRICKET]

hell yah i love 8 projects. keep up the good work.

[Michel1972]

Due to government rules i am not allowed to dismantle the swaybar. The original cj swaybar is not so thick so i replaced it by using a bigger addco wrangler swaybar. I also placed waggy shockmounts and 1 high steer arm and welded the shockmounts and disconnect mounts. For driving on the road the swaybar is 2.5 inches above the steering linkage and when i go offroad i use my disconnects.

[Michel1972]

Today i adjusted the cables and wiring underneath the flipnose. Everything has to be clean and safe for the coming inspection. Everything works. I have one big oil cooler for the engine with a 2 speed fan on it. I also have a smaller transmission cooler for the Th400. The Derale fan is also 2 speed and can be adjusted inside the car. All extra cooling lines are installed and tested. All nipples are greased and the engine is filled with oil. The firing cables are shortened so they dont hit the custommade headers.Eveything fits well and i keep enough space between the firewall and the front of the cj8 nose.

[scramblerj]

Nice job on the scrambler.

[Michel1972]

With the engine in its original setup it makes to much power. I replaced the alu dart heads, holey 1050, single plane intake and aggressive cam and 2 1/8 headers for a mild setup with original LS6 rectangular 454 heads, 850 demon, 1 7/8 headers and mild comp camp with a 2000 stall converter. The setup was made this way to get more horsepower and torque at lower rpm's.

[Michel1972]

I finally got the papers and can drive in my jeep for another year.

I installed the genright swaybar in the rear

[JayMcJay]

Those are some fine looking hens. A man could be proud of them.


The Scrambler's not bad either!

[Michel1972]

Started changing the original 990 steel heads for alu dart pro 1 heads with 345 chambers.

[Michel1972]

I installed a tire carrrier and bought 4 super swamper tsl tires 39.5x15x16.5.

It is very difficult to find and buy such tires here in Europe because they are forbidden here. My original tires are 37 inches and like most super swampers they are smaller than they use to be.