QI have a ’05 Jeep Wrangler LJ with a sixspeed manual transmission and my 4.0L engine just ate itself. The number six piston ring made its way into the oiling system. I’m planning on doing an engine swap with a 4.0L crate engine. I have several questions:
1. Is it better to pull just the engine and leave the transmission and transfer case in the Jeep?
2. Other than the water pump and the clutch, is there anything else I should replace now while it’s easy to get at?
3. Is there a rule of thumb on how to get the synchronizer (distributor-not-a-distributor) aligned properly? When I replaced the cam two months ago it was something I ended up having to pay someone to do.
That’s all for now—thanks for your time. Oh, and any tips or tricks I missed, I’ll gladly take too!
DAREK CONNOLE VIA FACEBOOK.COM/JOHNCAPPA4X4
ASwapping out a worn or blown engine is usually a fairly straightforward proposition. You unbolt and pull the old one and then sling in the new one. However, there are a few things that you can do to simplify your repower swap. It’s usually easiest to pull just the engine, leaving the transmission, transfer case, and driveshafts in place. Make sure the transmission is properly supported before unbolting the bellhousing bolts and attaching the hoist to the engine. However, in some applications it may be difficult, or impossible, to access the bellhousing bolts. If so, the engine and transmission can be removed as a unit, or you can pull the engine, transmission, and transfer case.
The most important thing is to make sure you have everything disconnected and out of the way. Disconnect all plugs, hoses, and wiring that are routed from the engine to the frame and body. In most cases you should be able to unbolt the A/C compressor from the engine, leaving the hoses pressurized, and place it out of the way in the engine bay. In other cases you may need to have the A/C system evacuated prior to engine removal, and then recharged once the engine and front accessory group are back in place.
You can greatly simplify the engine removal process by swinging your Wrangler hood all the way open. On other 4x4s the hood can be removed. Removing the radiator and grille and maybe even the fenders will offer greater accessibility and ease your engine replacement.
When replacing an engine, it’s always a good idea to replace the water pump, spark plugs, belts, hoses, and clutch. Don’t forget to resurface and properly clean the flywheel prior to installing the new clutch. If the transmission has a lot of miles on it or it makes unusual noises, then it’s a good idea to freshen it up. It’s not at all uncommon for an old and worn automatic transmission to give up the ghost shortly after being backed up to a new engine.
The easiest way to keep the 4.0L camshaft synchronizer aligned is the same as any older distributor-style ignition. Rotate both the new and old engines to the No. 1 cylinder at TDC. Set the indexing mark on the harmonic balancer to 0 on the degree markings on the block. Use a paint pen to mark the 4.0L camshaft synchronizer, internal wheel, engine block, and firewall, or anywhere that will help you get it back to the proper location during reinstallation in the new block before you remove it. It may take a couple stabs and some futzing with the oil pump gear via a long screwdriver, but you should be able to get it properly located using your marks. You can also correctly locate the 4.0L camshaft synchronizer by lining up the two holes under the top cap of the sensor using a toothpick. The toothpick is used to keep the camshaft synchronizer indexed while the engine is at TDC on the No. 1 cylinder. This should allow you to get the engine started, but you’ll likely need to time the engine 5-10 degrees one way or the other for it to run properly.