UNDER CONSTRUCTION...
1. 6 bolt vs 7 bolt
It's commonly believed that the 4G63 7-bolt cranks found in the 2G Eclipse are more prone to developing crankwalk(abnormal thrust bearing wear that promotes side movement of the crank) than the predecessor 6-bolt blocks. What the 2G's have that the 1G's don't is an independent crank position sensor over the crank trigger plate. So with enough thrust bearing and/or crankshaft wear, the trigger plate starts to grind at the crank sensor fouling it and throwing a CEL. This was one of the points that made for a good argument since the 1G 6 bolt owners just didn't have a way of knowing without actually measuring the clearance.
The debate on whether or not the 7 bolt motors are more vulnerable will probably never end. All the theories in the world came up, some good some bad, and fixes promoted from various vendors trying to deceive the naive in trying to make a buck. Why go the route where so many have failed. It's better to listen to shops that actually build the 4G63 for a living than a dozen internet experts. For all I know, all but one shop who claim to have a crankwalk fix recommends investing in a 6 bolt. I'm not even sure that one shop is still around anymore. So many have came and gone with a bad wrap in the DSM scene...
2. 6 bolt Parts Required - block only swap
| - | 6 bolt block and crank |
|---|---|
| - | 6 bolt flywheel (AWD or FWD) |
| MD156465 | Oil pan |
| MD113024 | Oil pickup tube (strainer) |
| MD183240 | Oil pickup tube gasket |
| MS241071 | Oil pickup tube bolts x 2 (if you want new bolts) |
| MD141454 | Lower timing belt cover |
| MD972052 | Water pump assembly w/ gasket and o-ring |
| MD184529 | Cam/Crank angle sensor - '93-'94 black top hall effect sensor (pre '93 optic sensor : MD121786, MD148855) |
| MD164533 | Hydraulic tensioner |
| MD130032 | Hydraulic tensioner arm |
| MD129347 | Front case (for use with straight cut oil pump gears) |
| MD149393 | Front case gasket |
| MD121120 | Oil pump drive gear (straight cut gear) |
| MD125361 | Oil pump driven gear (straight cut gear) |
| MD132912 | Oil filter housing - '89-'90 air cooled oil cooler ( MD157670- '91-'92 water cooled, MD122260 - no cooler). |
| MD149370 | Oil filter housing gasket (universal fit for all 3 types) |
Late year 6bolt front case(MD175762) use helical oil pump gears that are also found in the 1G 7bolt and 2G's (MD174581, MD174582 )
2-1. Modification Required
Oil filter housing selection will depend on the type of oil cooler you plan on using. Use the Water cooled type if you're pertaining the 2G's water/oil cooler.
2G drivers side motor mount will need to be cut to make space for the 1G water pump
1G Lower timing belt cover needs to be cut for the 2G motor mount to fit through.
2G head's bolt holes will need to be enlarged for the larger 6bolt 12mm bolts, especially when you plan on using ARP studs. One of the hole is used as the oil feed source to the head so it's important you don't skip this part just because the 6bolt stud/bolt fit. In most cases it will provide enough clearance but there are other consideration to be made. You may have a non parallel deck that can wedge the bolt and/or find yourself unable to pull the head later on even with minimal warpage.
Wiring the CAS.
When using ARP main studs, the oil strainer (pickup tube) support leg will need to be cut off and the bolts loctited.
On a 95-96 2G head : Swap plug wires 1 and 4 with 2 and 3.
3. Additional Parts Required for block and head swap
| - | 1G head |
|---|---|
| - | 1G intake manifold |
| MD188995 | 1G intake manifold gasket |
| MD190339 | 1G thermostat housing |
| MD145038 | 1G thermostat housing gasket |
| MD130457 | 1G water neck |
| MD184011 | 1G water neck gasket |
| MD147684 | 1G water pipe for use with air/oil cooler (MD163195 - for use with water/oil cooler) |
| MB605486 | 1G lower radiator hose |
MD163195 has another nipple for the oil cooler's water return line near the water pump. Both have a fitting for the T/C water return line.
3-1. Modification Required
Water pipe selection will depend on the type of oil cooler you use and also should consider the turbocharger's water return line plumbing if you're using a water cooled turbo.
The counter weight on the 2G transmission will need to be cut off as it interferes with the lower radiator hose.
Make a bracket to mount the 2G injector resistor pack to the 1G intake manifold.
Since the 1G intake doesn't have any provision for the 2G MDP sensor you'll need to T off the brake booster line. If it throws a CEL just block off the EGR and remove the MDP sensor since it isn't working properly anyway. It has no ill effect on drivability, but you'll probably lose MPG. Another option would be to get DSMlink and just disable the codes including the infamous Random Misfire. It makes things so much easier.
4. Random Misfire
The ECU is flagging a misfire condition because the crank sensor which originally drove the hyper accurate signal for the 2G ECU has now been replaced and simulated by the not so accurate 1G CAS. The only remedies for this symptom once you have it is:
- Wire in a potentiometer on the barometric sensor wire going to the ECU, thereby fooling the ECU into thinking you are at very high elevation (low barometric pressure) so it doesn't check for RM. This sounds simple, but if you don't tune the engine to compensate for the additional timing, you will end up turning your piston's to goo which also kills your turbo. (Not a recommended fix)
- Get your ECU socketed and buy a Keydiver chip. The best choice for the majority who wants plug and play.
- Buying DSMLink and clicking a tiny little checkbox which basically disables the ECU logic that checks for RM. Both Keydiver and DSMLink requires a '95 EPROM ECU.
- Go with a standalone EMS.