Part I (pictures and more details to follow)
Well, here's the scoop. I just finished my 3.0l to 3.4l conversion (with auto tranny) in my '93 4Runner. Actually I finished it about 5 weeks ago, but I didn't get to start it until 2 weeks ago. That's another story for later. For now, I'll get into some of the details. First of all my impressions. Now that's what a vehicle is supposed to feel like when you want to accelerate. This is an excellent swap. Here are a few of the reasons I did this swap. These are in no particular order.
- more power
- when done the truck is still almost 100% Toyota parts
- easy to work on (3.4l is the Toyota tech's engine of choice to work on)
- Toyota reliability/longevity
- better fuel economy
- even more power, can we say supercharger
Now lets get away from the opinion to the facts. It turned out way better than I thought it was going to. I had several hurdles (some small, some large) in the process, but now that I'm driving it (I've got near 1000 miles on it) the swap was well worth my while. Purchased a '99 4Runner Limited with 60k on it for the donor vehicle. First hurdle was that the engine harness was cut. I attempted to locate an engine harness and after 4 days of calling I found one in GA. (I guess they are rare.) Shipped out and 3 days later I'm over that hurdle. I had ordered the conversion harness from Mike at ORS and was told that it would take 3 weeks. Knowing that this was one of the first retail ones he was selling I had a hunch that it would be late. I had been bugging him about this for 3 months prior to when he finally took my order. Eight weeks after I ordered it the harness was in my hands. Don't get me wrong, Mike did an awesome job. He custom builds each of the harnesses after he has the specs of the donor and recipient. Each one is a little bit different and this is how he can make sure that it will work with your specific application.
In this eight week period I was bored stiff ... er ... I mean I pulled the 3.0l, cleaned the engine bay, pulled the 3.4l and auto, noticed the 3.4l intake was a bit dirty, pulled it to clean it, pulled the pan to see sludge in the bottom of it, also noticed 70% of the pickup screen was clogged, pulled a valve cover to see about .5" of sludge covering the valve train, uggggggghhh!!! Hurdle number 2. I thought this thing only had 60K on it! I guestimate that the owner just added oil when it was low. Maybe 3 or 4 oil changes in 60K.
OK, pull the heads and send them out for a clean and check. Two valves on one head, and 3 on the other were leaking. Full valve job and valve adjust. Pull the pistons and crank and inspect the block. Cross-hatch was mostly gone. Light hone to put the cross-hatch back in. New rings, rod bearings and main bearings. Put the pistons back in. Plastigage the rod bearings and it's just at the top of the clearance range. I decided to go with the next tighter bearings. Taking the pistons back out I break the head off of a rod bolt. Wow am I glad that didn't go at 5000 RPM. This sure is getting interesting (and expensive). I'm thinking that I bought Murphy's truck. Ok, pistons back in, heads back from the machine shop, heads on, and finish assembling the engine. Plug the dipstick hole. New baffle and pickup tube, swap on the 3.0l pan and motor mounts. New (used) harness on engine.
Still waiting for the harness, so install the 2" body lift.
Still waiting for the ORS harness, so I pull apart the t-case. It was an early gear driven one and it needed a 23 spline input shaft. I had weighed the options. Purchase a new 23 spline input shaft or regear it to 4.0:1, 4.7:1, or 5.0:1 gears. I decided that since this was going to be used for off road that the 4.7:1 gears would work nicely. The 5.0:1 seemed like a bit of an overkill with already having an automatic so I went a little on the side of moderation. I grind out the case and install the new 4.7:1 gears. Slap Marlin's t-case adapter on the t-case. A couple of bolts in the kit are ~.0625" too long. They were bottoming out in the holes before they were getting tight. Install the new seal, bearing and spud shaft on the transmission. Test fit the t-case and the spud shaft was .25" too long. Great! You gotta beat this thing just to get it on. It won't go on any further. I contemplate modifying it so that it will work. Do I void the warranty if I do that? Measure the depth of the female splines, measure the t-case input shaft. Sure enough, if you cut off .25" it should go together without any forcing. Pull out the angle grinder with a cut-off wheel in it. Wet rag inboard of the cut to keep it cool and keep any debris out of the trans. I take my time so that it doesn't get too hot and three minutes later re-test fit and it works great. I do enjoy that cut-off wheel in my angle grinder. (SIDE NOTE: Marlin has had some issues with the spud shafts being too long. I was told that this issue had been rectified prior to mine being built. Obviously not. They offered to send out another, corrected, spud shaft but I had already installed mine, and modified it. They compensated me for having to modify it.)
ORS harness arrives with instructions on how to install the harness.
Slap the trans on the engine (on the floor). Put the new trans pan on while it's still out of the vehicle and on the engine hoist. Yes, you can install the engine and trans in one piece. I think I've got a picture somewhere of my friend Sam standing on the transmission, hanging on to the engine hoist and balancing himself with the other hand on the windshield just to get enough angle to get it in.
Half an hour of making sure everything is in the right place. Motor mount bolts in, PS lines on, fuel high pressure hose ... uh, it's male to male, that won't work. Hurdle number ... well I think I stopped counting. I'll stop there for now and leave the solution for that hurdle for the next part.
JC