jeeptester

Im changing out a 2.5 from a 97 tj and putting in a 2008 4.8 out of a silverado.

I have lots of question as Im just starting.

1. Power Steering lines, Anyone have a supplier info if there is a off shelf soluton to use the GM pump with the jeep steering box, or am I going to have to fabricate a line?

2. Exhaust Manifolds, It looks like the oem truck ones are not going to work. Anyone have a link to center dump type or other sujestions?

3. Fuel pump, looks like going to use Walbro 255 LPH Fuel Pump in tank pump. The question is does the 2008 4.8 have a fuel press regulator on the rail or in the tank?

4. Wiring , going to send it off to get it mod to four wire, but going to send the under hood GM fuse box also, and that may make for a more stock look. The same co can flash the vats also.

5. Advanced adapters for the trans adap and the motor mounts.

6. Rad from AA

7. Not sure route to go on gauges yet. I would like to try the GM cluster, but Im told thats a big PIA. SO I guess Im going to do the dual jeep and gm ecu idea for now

8. The vapor line from the tank to the intake. The oem gm one is about a 3/8 line the jeep tj had one also but its a 1/4 line. Ideas? Hook the 3/8 to the 1/4, cap it off, or run new line from engine to the fuel take 3/8? What about the carcoal can I dont have the gm one , get one, or delete that whole system? No smog checks were I live but I am wanting good MPG ( idk if vapor sys has anythig to do with MPG)


Thanks , any help appreciated

Lowell

Pics

http://i620.photobucket.com/albums/t...8-33_929-1.jpg
http://i620.photobucket.com/albums/t...-18-49_974.jpg


end of day one

http://i620.photobucket.com/albums/t...5752194147.jpg

LS1 TJ

My first TJ swap was a 4.8. Stock TJ fuel pump worked fine. Don't remember how I adapted the stock line to the 4.8 fuel rail. The stock TJ pump and regulator is built into the top of the pump.

The truck pressure power steering line with a few tweeks to the metal line fits the TJ steering box.

Gauges. I used the stock speedo. Autometer tach.

Exhaust. Speedway block huggers. Left side around to the front of the pan. Merge with the right side in front of the skid plate to the cat and 2.5" exhaust.

Used Novak for the trans/transfer case adapter. 4.0 HD TJ radiator and mechanical 4.8 fan. Never a problem for cooling.

See attached pics.

StuntmanMike

iTrader: (2)

^^^^ That's so frickin' awesome!! And I bet they get pretty much the same mileage as the 4.0, if you can manage to keep your foot out of it.

I'd LOVE a LS in my '97 ZJ. The 4.0 runs great, but is a slug.

mikesanto70

I bet that 4.8 got better mileage that that POS 4.0L, how bout it LS1 TJ, what mileage did you get and what tranny and gears were you running?

mikesanto70

I bet that 4.8 got better mileage that that POS 4.0L, how bout it LS1 TJ, what mileage did you get and what tranny and gears were you running?

LS1 TJ

The 4.8 had a AX-15 trans. 4:10 gears because that's what came with the 4 cylinder AX-5. I used the stock 231 with the Novak adapter. Gas mileage about 16-18 mostly in town. Never had it tuned. Should have.

Got tired of the 5 speed. Did a body off restoration and added a LS6/4L60E. 241R transfer case out of a Rubi. Explorer 8.8 swap. It gets about the same mileage, about 16-18 depending how I drive it. It's been super dependable.
Been on the Power Tour with it.
I plow snow with it in the winter time. I'd be the first to admit I don't really off road it. It's my daily driver in the summer.

welldonecj7

iTrader: (13)

for the manifolds if you can not use the truck ones, look into later model c5 or c6 corvette manifolds they are more of a center dump style. I know that the c5 had a revision part way through, i believe in 2001 and those flow a little better. I have also heard that some have used fbody manifolds which are more rear dump but they have used them before in jeep swaps.

StuntmanMike

iTrader: (2)

That's so frickin' awesome!! I want one!

And great mileage, I can barely get 16 with my 4.0 ZJ with 31's and 3.73's.

Jeff Smith

iTrader: (44)

Good I am watching on your build-up. I have been think to get Jeep Wrangler..
Please post with the pixes up here.

jeeptester

So I can use the stock pump? Cool I was thinking of just trying it anyway just to see. I have read that the 4.8 2008 model has its pressure reg in the tank. And the tj has it in the tank. There is a diff in press but that might not show up unless its WOT Im guessing IDK

I ordered the adapters and engine mounts today and Im rebuilding the 231 while waiting on the parts.

jeeptester

Thanks

themonkeyman89

iTrader: (2)

Hey there,

I recently finished a 4.8 swap into my YJ and its wonderful! I'm running the AA with an AX-15 (I actually bought the adapter from LS1 TJ, Thanks!) with an Explorer 8.8 w/4.10's and the lsd, super solid, runnin 35" swampers.

I used the truck manifolds, worked fine for me, not sure how different the TJ engine bay is though. As for the steering lines, the stock Jeep pressure line bolted right up to the GM pump, and I just used a generic clamp-on rubber line for the non-pressure return line. No issues after ~6 months of driving.

For fuel since my YJ was originally carbed, I swapped in an LS1 camaro tank after burning up a Walbro, no issues since and its all OEM parts if something does fail.

Hope that helps--Graham

jeeptester

Was the tank swap a PIA? I have heard the walbro is the way to go, any ideas why yours failed?

The Tranfer case parts came in and Im going through it. I had planed on using the bearings back but after finding so much corrosion I ordered a master kit.

I should get the trans to the shop in a few days.

And the motor mounts will next as well.

Here are some pics of progress

compare the chevy or the right, to the 231 jeep 21 spline on the left



the corroded pump was the one i was running, I'll be putting the one on the right in.

jeeptester

Planing ahead what are these?


1. On the passenger side toward the front in the valve cover, I guessing a vent just were did or does it go?



2.

Across the front of the block, goes into both heads and hose appears to have gone to lower right passenger front side. Is this the steam line I have read about? Were did it go or where should I put it?

themonkeyman89

iTrader: (2)

The tank swap was not too bad, I had to cut out a body brace and mount the tank "backwards" IE the opposite way it is mounted in the camaro, so the filler neck is on the correct side. but overall not bad. I think my Walbro died from having too long of a draw to it, those pumps like to push, not pull, but i had mine set up like many others online, so I was pretty confused myself.

As to your pics, the first shot is a line thats part of the PCV system, and there should be an accompanying hose connector on the passenger side of the throttle body, the second shot is in fact the steam line, and should ideally be spliced into the return side of the cooling system, check on here for threads about where to splice it in, there are a few write ups about tapping the water pump for it.

What axles will you be running btw?

jeeptester

Hmm I will look again but I didnt see anywhere the pvc should plug to and I didnt see any unused port on the TB but I will ck again. And I think your right it has to be part of the PCV sys.

Tapping the pump does make a much better looking job than than the in line hose thing, only thing I am a little OMG what if I break the pump LOL

Axles : Stock for now, I thought I would get all this going and then do axles. Im leaning toward a rubi 44. I figured if the stock breaks then I'll be looking, and hey I can tell wife "hey it broke I have to fix it LOL"

I am also going to do a body lift of 1 , 1.5 or 2 inch IDk yet.

themonkeyman89

iTrader: (2)

Ah yeah your motor is a 2008, so its a gen IV, mines a gen III from an 02 silverado, so the PCV routing may be different. Be gentle with the rear axle, i'm sure it will be ok for a while, but anybody on the jeepforums will lambaste you for even considering running the dana 35. Just be easy and no drag-strip launches and it should hold up for you until you can put something else under there. I'm running a, explorer 8.8 and its great, discs, LSD, and plenty of parts availability.

jeeptester

Yea I already have been told many times that on Wforum. And around town too. And I agree the dana 35 was not designed for the extra ,at least 150 hp. I typically get people on the street are like "Your gona break those axles!!" LOL ..And it very well may.

About the pcv line: the hose ran down the way it is in 2nd pic still tied in the oem clips to low right front. But basically it should go to a intake somewhere right? Just does it matter were? Is there a diff in vac depending on were its tapped? and it has be right, no block off?

Thanks

jeeptester

Old mounts cut off


Built rear trans braket onto oem braket, this allows TC to go back to oem location. that allows keeping oem drive shafts


engine set in frame ready to weld mounts.



distance front and rear



I had to toss the ac braket because its too close to axle, may relocate to top of engine


A question about gauges.

i have read that most people use both the gm ecu and the jeep ecu. Using the jeep ecu for the gauges. The question is, I think the display will display the NOBUS code instead of milage. So I assume I am going to tie some of the old sensors to the oem jeep harness to get past the jeep ecu looking for its sensors.

How many of the oem sensors do I have to hook up to stop the nobus?

jeeptester

Trans question,
4l60e is it ok to cool the trans with an external ONLY cooler and NOT run it through the rad????

I'm going to try to use a rad that may be close to too small and I was thinking keeping the trans out of the rad would have to help, but I didnt know if thats enough cooling for the trans.