Bonneville Comanche 4.9 build

[Alex22]

I must have missed something in you're other build thread, Were did you get that intake?

[Plechtan]

Its a Clifford DCOE intake

[Muad'Dib]

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

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

I just did this yesterday on my 90 XJ. I didnt need the spacer, and the pedal seems to be just fine. I got the booster and MC from a 99 Grand Cherokee. It was nice because i used the brake lines from the grand cherokee also. They have about a 3 inch section of stainless steel that helped with the alignment of the lines when measured and flared. Besides having to run new brake lines to the proportioning valve, you have to drill the rod to 5/8", and grind down the end of the rod to actuate the brake light switch. That was the tricky part. I ended up removing just a little bit too much material... but i was able to fix it by adding a small 1/32 spacer between the rod end and the brake light switch.

Just my experience with the install....

[Plechtan]

Well it looks like the intake won't fit on the Comanche. #6 throttle body hits the firewall right below where the gas pedal cable comes through. The fuel rail also hits the firewall. Looks like i need a little work done with a torch and a hammer.

[gradon]

I remember a picture of a clifford intake with the six webers and the ones closest to the firewall didn't extend as much as the front ones or had shorter foam filters--looked pretty rad.

[Plechtan]

I think it's time for some new intakes, maybe somthing that takes Mustng throttle bodies. I think for next year i will scrap the Clifford sna make somthing custom

[Plechtan]

I really don't know where to start, but here goes. For the Bonneville comanche i have to run a manual 5 speed trans and an explosion proof bellhousing. The bellhousings only come with the chevy/ t10 bolt pattern on them. I could use some kind of chevy to jeep trans adapter to match up any number of transmissions. My first thought was to use a TKO600 ( The truck is 2wd like most MJs) The trans alone was $2,200, and it was another $400.00 for a shifter relocation kit. It would be bulletproof with a rating of 600 ft/lbs. It would also bolt directly to the bellhousing. $2,600.00 was kind of out of the budget, so I started looking at cheaper solutions. I had purchased a World Class T5 from a Firebird several months ago, but found out it had the wrong OD gear and wrong shifter location, and the wrong bolt pattern to the bellhousing. Other than that it was fine.

First let me explain, t5 were originally used in amc cars and Jeeps from 80-85. These first units were NWC( Non World Class) and rated for about 240 ft/lbs of torque. These transmissions had a Ford bolt pattern. around the same time GM started to use the T5 in the S10 and F body cars and even the astro vans. These transmissions were also NWC but had the standard chevy bolt patten and input shaft. Ford also started to use the T5 in the Mustang, and in 85 introduced the WC ( World Class) version. these transmissions were rated at around 300ft/lbs of torque. around 1988 GM started to put the WC version into the Camaro, but kept the NWC in the S10 until 92.

In 1992 GM also changed to the Ford bolt pattern and input shaft and went to an electronic spedometer but they were world class units. They came with many different gear ratios. If you want to know what is in one of these , find the metal tag. It will have a number starting with 1352 or 13-52 then a 3 digit number like 221. you can take this number and look up what the trans is on a sitle like this,
http://www.britishv8.org/Articles/Borg- ... D-Tags.htm

So back to my story, i start calling around to different places that work on these. Because they have been used in the Mustags forever, many parts are available and allot people do upgrades. here are the top 3 :
http://www.astroperformance.com/
http://www.hanlonmotorsports.com/
http://www.gforcetransmissions.com/tran_gt-5.asp

Astro was finally able to help me out. he found a 92 s10 world class case with the Chevy pattern (very rare), and had a 26 spline input from a 88-91 Camaro. He will be installing a Mustang Cobra gearset rated for 350 ft/lbs and a .8 OD that he makes himself that will handle 450 ft/lbs of torque. This will bolt directly to the bellhousing and have the shifter in the correct location. The only downside ids the electronic spedo output. This custom built trans will cost me $1,500.00 , $1,100.00 cheaper than the TKO600.

But the reason I Am posting here, is that it occured to me that the Mustang WC t5 would not be a bad trans for a MJ. they are available for a few hunderd bucks and are reasonably strong. The problem is that the shifter is in the wrong location. A s10 tailshaft can be swapped in which will locate the shifter correctly but you have to so some work to relocate the spedo gear. The 85-90 mustang used a mechanical spedo.

You could also use a 92 and up S10 WC trans, ( low first gear) they have an electronic spedo output.
You will need a bellhousing. a Jeep T4 or T5 bellhousing will work. If you can't find one used, they are available new https://www.fortec4x4.com/product.php?productid=2853 for about $250.

If you are really looking for a challange, you could swap in a S10 4wd trans and transfer case. Allot cheaper than the jeep stuff.

[-XJguy-]

Cant use light covers? Or add a smooth belly pan? No front airdam? How about the nose from a newer XJ say for example the much more aerodynamic Jeep XJ 2500?

[Plechtan]

I must admit, i have neglected this thread, but tho answer the questions, you cannot use a belly pan, no streamlining is allowed, all body panels must be in the stock location and must be model year appropiate.

To get back to the thread, Now that i had a trans, i need a flywheel. The flywheel was from McLeod , it is for AMC V8. It did require a bit of machining to properly fit the 258 Crank. Don't even think about using this on a stock 4.0 or stroker unless you plan to relocate the CPS to the front of the motor. The flywheel does not have any notches in it.
Because the Bell housing was for a V8 and the Flywheel was for a V8, i had to use a V8 Starter. I ended up with something from an 80 Wagoneer with the 360 motor.

The Damper on the front of the motor was a ATI unit with a custom hub. I had to make my own trigger wheel with 3 notches to trigger the Haltec ECU. If you are building a motor and are going to have a distributor, Accell makes a distributor with both a cam and crank sensor in it. I could not go this way because my cam did not have a gear on it. My oil pump is gear driven off the cam gear, and I am running coil on plug setup, so i don't need a distributor. Here is a link to a picture of the oil pump gear drive setup http://www.contentedits.com/img.asp?tn= ... D&id=47778
We did drill the front cover and add a cam sensor, we need both a cam and crank sensor to do the coil on plug setup.

[Plechtan]

So why doesn't, my cam have a gear on it? Because it is a custom Billet solid roller, and billet cams eat distributor gears. Plus it would be a small fortune to machine the gear onto the cam. The cam is 270/280 duration @.050 and 300/310 adv. duration. with 1.6 rockers it gives me about .7 lift

shaft_rocker_1.gif

I went with a shaft rocker because of the strength. The intake valves are Chevy LS valves 2.02 the Exhaust valves are 1.60 chevy valves as well. they are extra long to support the high lift. The valve springs are chevy with a 2" installed height. The lifters are Isky red zone solid roller lifters for a Chrysler with custom tie bars. Be careful, some Chrysler lifters oil through the pushrod, so do not. I would not recomm the 1.6" exhaust for a stroker, better flow numbers with 1.550

The motor uses a Hesco aluminum head that has had the valve guides repositioned to move the valves away from the cylinder walls. It is also CNC ported. The block is a 2002 WJ bored to 4" The crank is a 12cw 258 crank that has been offset ground for a 4" stroke. when you do this you have to then use custom rods with a 2" Big end diameter. The rods were made by R&R Racing products. So this is a Square motor with a 4" bore and a 4" stroke displacing about 5.0L

Just a note, we put a couple of inches of Hardblok in the water jacket of the engine block. If you look in the water pump hole , it comes about 1/2 way up. This helps stabilize the cylinders, stiffen the block, and hopefully dampen vibration. Because of this we were not able to run a water pump in the block.

IMG_7121.JPG

IMG_7120-1.jpg

I Took the stock water pump and cut it up, the picture above show it prior to welding the plate on the front. But then came another problem, if you ever change your water pump, you will notice a hole in the block that lines up with a hole on the water pump housing. This hole is a port that goes up to the cylinder head, near the thermostat. So when the engine is cold and the thermostat is closed, water flows through this port and back to the suction side of the water pump. This gives you some water cirulation through the block and moves warm water near the thermostat so it can open at the correct time. Since i gutted the water pump, it no longer had a suction side. the entire housing would be pressurized. I blocked off the area where the port went into the pump, but did allow it to be open to the port for the heater hose. I put a plug in it and decided to solve that problem later.

[SilverXJ]

I really like the different/exotic setups you have going on here.

[Plechtan]

So here was my problem, running numbers through Desktop Dyno and other programs, the limitation to producing more hp was the intake and exhaust flow through the cylinder head. The jeep head was never know for really great flow numbers. If you look at some of the aftermarket heads for Chevy or Ford V8 motors, you can find numbers in excess of 300 cfm with out a problem. Try geting 300 CFM through a Jeep head. Actually the Hill dragster flowed about 315 CFM but I am not aware of any other Jeep head flowing in this range. My head flow about 275 cfm @.7 lift.

here is a simple explanation of my problem. An internal combustion engine will produce a sepcific amount of torque per cylnder firing. the amount of torque would be based on the rod length, stroke, piston diameter , etc. At lower engine speeds, the engine may be a little starved for air because the ports are too large and the air cannot build up enough speed. If you look at ajeep dyno curves you will generally see a torque curve that is very flat, then drops off at higher rpm. The hp will climb up very steady, the start to fall a little after the torque curve falls. the bottom line is that when the torque curve starts to fall, you are running out of air ( air fuel mix). So if you dyno your truck and the torque starts falling off say at 4,000 rpm, you would need to improve the breathing of the motor. So intake, headers , port and polish, new cam , bigger valves are all things you could do to improve things. To get the HP i need my engine will have to flow 2-2.5 times the amount of air and fuel as a standard Jeep engine. Currently i am running 60lb injectors.

But getting back to my problem, i need more than double the hp than a stock jeep engine provides and i cannot use a supercharger or Nitros. so if i only can get a specific amount of torque from one cylinder firing, how would my engine produce more torque than yours? Well first my engine has a 4" bore, yours is probably a little smaller. Second I am running a higher Compression ratio (14;1) and better fuel. these things help, but will not give you double the torque. so how do you get 450HP? well HP = torque/ time. So if you can keep a shaft rotating at a specific torque, and incresae the rpm, the HP increase will be linear. Look at some dyno curves and you will see what i mean. so (more rpm= more HP) if you can keep the torque up, torque is limited by available air/fuel mix. So to achieve my goals, i need an engine that will be capable of operation at at least 7,000 rpm and have about twice the airflow of a standard motor.

Simple right? Well all of the intake systems available for the Jeep are designed to improve stock performance, not to double anything. Same with the headers, head, and cams. I have the additional problem of the cam harmonic @ 5,600 RPM. On the 4th to 5th gear shift, the engine will drop to 5,200 rpm and will have to go through the 5,600 rpm under full load on the way up to top speed.

So that is whay everything is custom, if i had a chevy V8 i could buy everything out of a catalog. No such luck with the jeep motor. Next weekend we will be taking the car to Hesco and putting it on the chassis dyno, it will be interisting to see what we get.

[Plechtan]

So to back up a little more, to get the most HP from a motor, you first try and get the largest piston to work that you can. why? the bigger the bore, the more room between the valves and the cylinder walls , better air flow. . The other reason, for a given displacement, a larger piston will give you more HP than a longer stroke. Look at the jeep 258, the 4.0 (242) produces away much more Hp than the 258 ever did. Bigger pistons. But as we all know a longer stroke is not a bad idea either. My motor ended up a Square motor, 4" bore, 4" stroke. I originally wanted to make a 262 cid motor to compete in a lower class. I was going to use a 232 crank with a 4.0 block. Problem was that they never made a fully counterweighed 232 crank. they only had 8 counterweights similar to the 4.0 Since the next class up was a 5.0L class (305 cid) i decided on going with the 4x4 spec and a 12cw crank from a 258.

Now i needed the crank to have a 4" stroke. about .100" more than a stock crank. The solution was to grind the crank rod journals fron 2.1" to 2" this gives you the stroke necessary, but your rods will no longer work. Solution? custom rods. As long as I was going custon, i had the rods made for Chevy floating pins and chevy rod bearings. Now to get the 4" bore. I checked several blocks, and found that the 2000 and up blocks have thicker cylinder walls. the walls end up about .100 or so in the front and back of the bore, but will generally still have .250 of material on the thrust side. The block i used was from a 2002 WJ. So now I had a 4" bore and a 4" stroke. The next order of business was pistons, custom diamond units.

With the rotating assembly complete, it was now time to look at the cam drive.

[Plechtan]

I went through several ideas on the cam drive and in the end ran out of time. The first idea was to use a standard double roller setup, this was ok, but my block had a cam thrust plate, and a thrust plate seemed like a good idea. All of the double roller setups out there did not use the thrust plate, they used the eariler design with a hollow cam bolt with a spring and rod to hold the cam in place. All of the performance cams available also did not use the thrust plate. I was searching for something that would help with the cam harmonic issue @5,600 rpm. A timing belt like a Jessel makes would absorb some of the vibration and would probably work better than the chain. Chains have been know to break when the engine is used in a high performance application.

So after making many measurments and going through many catalogs, i came up with a basic design. It was going to be very expensive. the first thing that had to be made was a plate that bolted to the block where the standard timing chain cover would. The plate would have to have 2 seals in to to keep the oil from leaking out from around the cam or Crank. But the space between the block and the back of the harmonic Ballancer was only about 1 1/8" if the sealing plate was only 1/8" thick, that would only leave 1" for the belt. I did have a 258 crank with a longer snout, so i could get an additional 5/16 or so, but then my design would not work on a standard 4.0 I did not want to make somthing that would only have application on the race car, i was hoping to make some of the design money back by selling some of the units to other people once the design was proven.

The next problem was the pulleys. You can buy pulley blanks and machine them to your needs. but the blanks come in a limited thickness and tooth count. The way things worked out, I would have to have at least 1 pulley made from scratch. More time, more money. and then you really don't know if it will work.

Getting back to the cam, if i made the belt drive to work with the aftermarket cams available, i woul need a way to restrict the axial movment of the cam in the block. the standard design uses a pin pushing on the timing chain cover, but since the belt drive did not use a timing chain cover, another way would have to be found to control movement.

So timing chain, belts, what about gears? I checked more catalogs and the internet and found that the jeep crank to cam centerline measurment was the same as the ford 351C engine ( I looked forever to try and find a set of the Mopar Performance gears) the Ford gears would work, but the hole in the crank gear was too big, and the cam gear would need machining. The dog bone also needed work to fit in the jeep timeing chain cover. Not the greatest solution either.

Well just about this time Six-pac posted a Hesco gear drive/ oil pump setup in the stroker classifieds. I ended up buying it, it was quick, and i knew it would work. It also solved the problem as to how to drive the oil pump

[SilverXJ]

I went through several ideas on the cam drive and in the end ran out of time. The first idea was to use a standard double roller setup, this was ok, but my block had a cam thrust plate, and a thrust plate seemed like a good idea. All of the double roller setups out there did not use the thrust plate, they used the eariler design with a hollow cam bolt with a spring and rod to hold the cam in place. All of the performance cams available also did not use the thrust plate.

I seem to remember Lee @ Hesco mentioning something on their forum about a thrust plate setup designed for the earlier cams. Some block machining needed. I never followed up on that though.