View Full Version : Rebuild or swap??

03-15-2016, 01:32 AM
As many of you know the All Trac is having heart problems. I've got a head gasket leaking to the outside of the block. The car seriously overheated on me a couple of years ago to the point that when I got it shut down steam blew out between the block and the thermostat housing. The thermostat had stuck shut and I didn't catch the overheating fast enough.

On top of that I've got lower than normal oil pressure. Dumbass me forgot to check the oil once last winter and ran low, like a quart, maybe quart and a half in the pan low. So, most likely I've at the minimum scored the bearing if not the crank. It still holds 50 psi cold at idle. Once it warms up at idle it's show about 12-15 with 5W30. At highway speed its running at around 35-37 psi.

So, here's my dilemma. Do I rebuild the 2nd gen I have, it has around 140K on it, or do I swap in a 4th gen?

I've found the ST215 engines for approximately $850 shipped from an importer in Houston. Added to this would be the timing belt & water pump change and the associated gaskets. Prime MR2 has the maintenance kit for $300 something. The next thing going this route would be either me figuring out the wiring, which I think I might be able to do but it would take a while or I spend another $400 and have Wiregap do it. So at a minimum, if I farm the harness out, I'm look at $1600. I'm also looking at having to come up with some sort of solution for the intercooler as I'm currently running a 205 WTA. I'd really like to keep that as I have it working well but with the side entrance manifold it would be difficult. The center mount 246 manifold would be an option but I'm not sure how hard it would be to find one and how much cost would be involved.

My other alternative is rebuilding what I have. I've done some part pricing, oil pump, main & rod bearing, and seal, and I'm at $300+. I still have more parts to price. I know I need to replace the spark plug tubes and I want to price the cam bearings as well. My timing belt and water pump have about 20K or so, if that much, on them so I'm not figuring on replacing those. I'm figuring that I'm looking at $400-500 in parts, probably more.

This is all given that the crank is not scored to the point of being unusable and that the head is not warped. I haven't had any machining done in a long time so I'm not up on the latest cost for that but I'm assuming that turning the crank and having the head milled is going to run into some serious money.

As far as what I'm looking for out of the engine, right now I've got my boost running at 13 psi and I'm running 3rd gen electronics. I'm guessing that I've bumped the HP up from the base 200 to 230 or so. I've never had it dynoed so I have no idea of what it was putting down at the wheels. I'm not looking for 300 AWD HP but I'd like to be around 250 or so at the crank.

The easiest way to do this would be to go 4 gen. On the surface this looks like it would cost more but in the end I have a newer model engine with newer technology and 240-260 HP stock. IF my crank and head aren't screwed, it would probably be cheaper to rebuild it. But given the possibilities that is probably a big IF.:blink:

The clutch and associated parts get changed either way so they aren't included in my cost estimate.

So, how about some opinions and advice.

03-15-2016, 02:16 AM
The gen4 swap I think has pretty much been done enough to where you aren't going to have many, if any, surprises. The price point is much better too. That's what I would do. By the time you get into rebuilding yours and then something doesn't go exactly right you're back to square one. Id just send the whole car to Prime and let them do it, maybe I'm just sick of working on cars but I feel like just paying them to handle it will mean a faster turn around, better results, and less headache. Worth the extra cost IMO.

03-15-2016, 02:57 AM
I would not rebuild. It always costs way more than you budget because so many things can come up during the process. I would either source a JDM Gen2 and put that in or go for the Gen4 swap. Either way I wouldn't do the rebuild unless your going full out on building the motor you have.

03-15-2016, 07:24 PM
Youre already Gen3 EFI. All you need is a Gen3 longblock, fuel rail and manifolds. Id do that if youre concerned about money.

03-16-2016, 03:28 AM
Finding and getting a good gen3 longblock will cost the same as the gen4 complete engine on a pallet though.

03-16-2016, 04:04 AM
I suggest the 4th gen. If anything, for the COP and higher hp without needing to open the block. Plus, OBD2

03-16-2016, 10:32 AM
I did look up the 3rd gen long block, great idea by the way, and Matt's right. The only one I found was right at $800 plus shipping.

I have thought about just going 3rd gen since I have the wiring done but all the ones that I've found have $1500 or more. Granted they do come with the transmission which would be nice. But after shipping and doing the maintenance items I'm going to be well over $2K.

03-19-2016, 03:04 AM
i would say rebuild or gen 4 3sgte, On one hand you a "brand new" car, on the other you get more power and a lot more potential for future mods. I honestly could go either way

03-20-2016, 04:28 PM
Id say gen4 or 3mzfe

03-20-2016, 07:25 PM
1UZ or bust.

03-20-2016, 11:20 PM
After running some more numbers, I'm going to try and go with the 4th gen. I can sell off some of the good parts left off of the engine along with the 3 gen electronics conversion.

I've thought all along that this would be a better way to go. Newer engine to start with, newer technology. I haven't read anything particularly bad about the swap. I know some people fuss about the rods being weaker than the 2nd gen but I'm not going to turn the boost up to 30 psi anyway so I should be fine.

I'm going to start doing my research and see if I can figure out how to do the wiring myself. I'm not intimidated in doing the wiring, I just want to make sure I've got the schematics and documentation that I need. I've got manual from Prime MR2 and I found the Caldina service manual. Tim fixed that so it's searchable now. I think between the two and the wiring diagrams I have for the All Trac I can figure it out. Still may end up going to Wire Gap or Prime, but we'll see.

If I do do my own wiring, I'm going to document the process and post as much as I can. I've come across several posts where people have bragged about doing it and how it wasn't that bad. But, of course, no details on what they did. In my opinion, if it wasn't that bad to do, share what the hell you did. If I do it, I'll try not to be that guy.

Thanks to everyone for their input.

03-21-2016, 12:51 AM
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03-21-2016, 01:12 AM
I think you'll be pretty happy with that route. Rebuilds can get extremely pricey very quickly, and may or may not gain you reliability if that's the goal. Lots of little benefits, good choice. And I'll second you on sharing what you learn! Looking forward to watching things progress.

03-21-2016, 02:02 AM
How much wiring can you possibly have to change? Is it not the same deal where the harness comes through the firewall and hooks up to the ecu? If the harness is too short or something just change where the ecu is mounted, no big deal.

03-21-2016, 10:27 AM
I don't think there is that much from what I've been able to find out so far. It is mainly integrating the 215 harness into the chassis itself. I think a lot of it is getting it hooked into the fuse and junction boxes.

The other thing will be figuring out where the pins from the existing third ECU plug that goes into the body harness go with the 4th gen ECU. I remember seeing that when we took Bruce's car apart. Two plugs went into the engine bay and the other one went up the firewall.

I've got the entire wiring manual for the All Trac and I think I have the biggest part of the Caldina diagrams. I know I have the ECU diagrams for both.

And Chris, I am looking for reliability. I love the driving the car as much as possible, where ever I want to go. Not having to worry about being left on the side of the road is a HUGE factor for me. I like having power on tap but I'm not looking for 400 awhp. Just something to have fun with. I think the 4 gen will be a great place start. It should be putting out more power stock than what I'm doing now. If I want a little more, adjust the boost up a little.