Background: 97 4runner 3.4L, 5spd, 4x4, and 168k miles. Had overheating problems this summer. I replaced all the hoses, thermostat, water pump, timing belt, radiator, and coolant. After getting all of this done, it idled funny (sometimes normal, sometimes high) and the top radiator hose gets very hot and you can feel the hose is under a lot of pressure. It also has a very subtle ticking sound. Worried that I had blown a head gasket, I did the following :
1. searched yotatech
2. checked engine compression, cold all cylinders were 205-210psi.
3) Did a cooling system leakdown test. Pumped it to 15psi and 1psi leaked down in 3 hours.
4) Removed the thermostat, tested it, and checked that I installed it correct. Flushed and burped the system again. Everything checked good. At the time, she wasn't burning any coolant.
5) Cleaned the IAC valve and inspected for any vaccum leaks. Still idles bad.

With not being able to find any evidence of a head gasket issue, no overheating issues, and no other options for transportation, I have been driving it for the last 1.5mths. I have put on 3000miles and I think in the last 2 weeks it consumed about 1 pint of coolant.
Well, I checked into what it would cost to have a shop replace the head gaskets and found that to be way out of my range for what I am willing to spend on a 168k mile engine. I decided replacing it with a low milage engine from a wrecked 4runner was the best option.

New (used) Engine: I found a wrecked 97 4runner 3.4L engine, Auto, 2wd, with only 71k. It has been sitting for 3 years in a shop and owner had started it 1 month ago. I offered $600 for the engine and he was going to leave it in the truck so I could hear it run. I got there and it wouldn't start...the fuel pump wouldn't come on....but it cranked over very easy, "sounded" good, looked very clean, and i verified the miles on the engine. We drained the oil and it came out brown. I decided to take a chance and buy it. The owner said if there was any issue he'd work something out with me.

The Plan: I have a 1.5wk Christmas Break from work. I am going to keep driving the 4runner, because I have no other options. Meanwhile, I am going to prepare the engine to swap into the 4runner as soon as my break starts.

My Questions:
1. Should I rebuild the engine or just clean it up, replace valve cover gaskets, spark plugs, etc. and swap it in as-is?
I really don't want to "fix" anything if it isn't broke, but I also don't want to have any more issues.
2. Being that this engine came from a 2wd auto and I have a 4wd manual, is there anything special I need to do to the engine or swap over from the old engine? I plan to reuse my electrical harness and ECU.
3. Can anyone point me to some good threads about doing a 3.4 replacement? I found dozens on swapping a 3.4 into other vehicles, but not a replacing an existing.
4. Any tips or advice on doing the engine swap and things I should do while the engine is out?
5. I plan on replacing the clutch while it is out. Any recommendations on a clutch? On ebay, I see exedy for $140, XTR for $95, etc. has anyone used these?

Thank you in Advance!!!! I am really looking forward to getting my 4runner up and running at 100%.

 

Much easier to do a timing belt on an engine stand. Plugs, wires, tstat, water pump, belts and hoses. Been sitting 3 years.

OEM Aisin clutch.

:wabbit2:

 

I would rebuild...

and supercharge.

 

Wabbit, I agree. I will definitely be replacing all of those components. Where is the best place to buy an AISIN clutch?

Bob, I wish the SC was in the budget.

Keep the comments/advice coming guys.... I want to make sure I've got all my bases covered when the time comes to swap it out.

 

Agreed with the wabbit. Do the tune up while it is out of the truck, valve cover gasket are another good idea, let you take a peak inside as well.

Otherwise leave the internals alone.

 

Search for darn motor swap. Thats a good thread and if you run into any issues sdsurfer might be able to help you out. Good luck with the swap!