Toyota MR2 Message Board - View Single Post - 1986 Mk1 4A-GE to GZE Engine Swap (56k Beware, Lots Of Pics)

TheAmazingDave · 01-02-2006, 01:34 PM

This is my engine swap write-up for a 1988 USDM 4A-GZE into a 1986 USDM Mk1. This swap is straight forward mechanically, but the difficulty of wiring varies depending on model year. If you use your N/A model's transaxle it is 100% bolt in. If you want the S/C model's transaxle you will need to do engine mount modifications not discussed here. This swap write-up has been transfered to several MR2 message boards in hopes that it will help others that may be discouaged by the false conception of extreme difficulty. Unfortunately, all wiring references written here are for 86 model year only, if you use this guide to swap into a different model year be prepared to do wiring diagram research to make sure you have it wired correctly. Due to my inexperience with other model years, I will not be able to provide much assistance if you run into issues. However, I am told by others who have done the swap that all 87+ Mk1's are compatible with any USDM Mk1 4A-GZE. This means the engine harness and body harness are Plug 'n Play.

The following information covers my engine swap. I started on the last Monday of April 2004. I was finished and cruising the streets the following Monday. I only worked several hours a day. I wanted topace myself to make sure all went to plan.

OK! So after months of procrastination, I finally begun my engine swap today. My goal for the day was to have the 4AGE out of the car, as well as the fuel tank. Well, things didn't go as planned. The damned car just doesn't want to come apart!!! So after many hours of fighting and bitching with it, I finally closed shop for the day, the factor being that the only socket I had that remotely fit the 30mm axle nuts stripped out and cracked down the side. My monster 400 lb/ft air impact couldn't break the damned nut loose before it literally ate up the socket!

So here is what was accomplished today.
Below you see the engine compartment is starting to look empty. The battery, and airfilter with AFM are out, and all wiring and hoses and cables that connect the engine to the chassis are disconnected. THe engine wiring harness will remain plugged into all its sensors and everything ont he motor, but it has been disconnected from the ECU and everything, and you can see it draped over the engine.

Not much to see down here. The entire exhaust system, except manifold, have been removed, mainly because everything after the manifold is welded together. On the 88SC that I stripped, the exhaust was all stock so I was able to unbolt it piece by piece and leave the B pipe on, not the case on my 86. It was a bit awkward to remove in one piece, but not that difficult. The hardest part was getting to the nuts that hold the B pipe to the manifold.

That's all I was able to accomplish without removing the axles. They're soaked with Liquid Wrench right now to help penetrate and break them free. I'll give them another spray down before I'm off to the car parts store in the morning for a bigger socket. Check back for updates.

01-02-2006, 01:34 PM	#2 (permalink)
TheAmazingDave Cage Fighter Join Date: Mar 2005 Location: San Jose, CA Posts: 1,112 Thanks: 14 Thanked 7 Times in 7 Posts My Google Map iTrader Rating: (0/0% )	1986 Mk1 4A-GE to GZE Engine Swap (56k Beware, Lots Of Pics) This is my engine swap write-up for a 1988 USDM 4A-GZE into a 1986 USDM Mk1. This swap is straight forward mechanically, but the difficulty of wiring varies depending on model year. If you use your N/A model's transaxle it is 100% bolt in. If you want the S/C model's transaxle you will need to do engine mount modifications not discussed here. This swap write-up has been transfered to several MR2 message boards in hopes that it will help others that may be discouaged by the false conception of extreme difficulty. Unfortunately, all wiring references written here are for 86 model year only, if you use this guide to swap into a different model year be prepared to do wiring diagram research to make sure you have it wired correctly. Due to my inexperience with other model years, I will not be able to provide much assistance if you run into issues. However, I am told by others who have done the swap that all 87+ Mk1's are compatible with any USDM Mk1 4A-GZE. This means the engine harness and body harness are Plug 'n Play. The following information covers my engine swap. I started on the last Monday of April 2004. I was finished and cruising the streets the following Monday. I only worked several hours a day. I wanted topace myself to make sure all went to plan. OK! So after months of procrastination, I finally begun my engine swap today. My goal for the day was to have the 4AGE out of the car, as well as the fuel tank. Well, things didn't go as planned. The damned car just doesn't want to come apart!!! So after many hours of fighting and bitching with it, I finally closed shop for the day, the factor being that the only socket I had that remotely fit the 30mm axle nuts stripped out and cracked down the side. My monster 400 lb/ft air impact couldn't break the damned nut loose before it literally ate up the socket! So here is what was accomplished today. Below you see the engine compartment is starting to look empty. The battery, and airfilter with AFM are out, and all wiring and hoses and cables that connect the engine to the chassis are disconnected. THe engine wiring harness will remain plugged into all its sensors and everything ont he motor, but it has been disconnected from the ECU and everything, and you can see it draped over the engine. Not much to see down here. The entire exhaust system, except manifold, have been removed, mainly because everything after the manifold is welded together. On the 88SC that I stripped, the exhaust was all stock so I was able to unbolt it piece by piece and leave the B pipe on, not the case on my 86. It was a bit awkward to remove in one piece, but not that difficult. The hardest part was getting to the nuts that hold the B pipe to the manifold. That's all I was able to accomplish without removing the axles. They're soaked with Liquid Wrench right now to help penetrate and break them free. I'll give them another spray down before I'm off to the car parts store in the morning for a bigger socket. Check back for updates.