Hello everyone, I bought a 95 z34 which ran great for all about a day. The car sat for a year prior to me buying it with water and no coolant. The freeze plugs gave out one by one, to which I replaced them all, including the two behind the flex plate. After that a valve seat fell out, not sure how but it beat up the head and piston in 4 separate cylinders. Scrapped the motor, but now that tax time is here it's time to replace it. I've been looking at either a 3800 or 3800 S\C swap, but due to local availability will probably end up with the N\A version, I've not found a suitable 3.4DOHC to replace it with. I have all the wiring diagrams that I could need to do the swap but not sure what all wiring will need to be done on the inside of the car. I'm probably looking at a 98-99 for the donor motor so I don't run into to many issues but I know something has to be done for the OBD conversion, I just don't know what. Also not sure if the lights or abs, or anything like that may have to be upgraded. Milzy sells a complete conversion kit for the car and as you put the info in the price seems to go up. Almost 4000 dollars and that's not including labor. I know part of this is because of the OBD swap, but it doesn't list which parts need to be swapped. The swap itself isn't a concern, but making it run seems like it will require some hidden steps, that I've not found out about yet like the Frankenstein axle. Any things to look for or steps i will need to take to do the swap would be greatly appreciated.

 

Just a thought, in order to avoid the hassles involved in converting from OBD 1 to OBD 2, maybe you could find a good 3800 from the 1994 or 1995 model year. At that time, most of those engines were in Buicks, but some were in a few Oldsmobiles too. This would be the "Tuned-Port Injection" 170-hp L27 Series 1 3800, or perhaps even a supercharged Series 1, which had 225 hp for 1994-5, and 275 lb-ft of torque -- just 5 less than the Series 2 version.
So they're not as common or as advanced as either Series 2 motor, but a Series 1 might be easier to work with on a '95. If my 3.4 DOHC went bad, this is one option I'd be investigating.

 

If you're ok with an l36 anyways, have you considered just buying a 98 or 99 z34? The milzy swap price of $4k+ is just stupid because not a whole lot of 5th gens are even worth $4k anymore. I did a quick search on autotrader and found 7 for sale, all under $4k, and one even under 100k miles. Even if you had to do basic maintenance, you'd be well ahead of having to do a full engine swap. IMO, that's by far the best route to go.

As for the swap, I did it on a 96, but I can't possibly imagine the obd thing would be that big of a deal. Everything under the hood gets replaced with a 98/99 z34 harness. So the only thing you'd have to do is change the wiring inside. You'd likely have to run a few wires to the obd terminal, but I can't imagine anything else would be an issue. You'd just have to look at the wiring diagram from the c100 in for a 95 and for a 98/99 z34 that you'll get the harness from.

The axles are no big deal at all. If you get a 4t65hd, you'll need to make both axles, not just one. You just take the inner for the new trans and mate them to your existing outer/center shafts with a simple boot kit.

 

Little help, where is the BCM on 2000SS?, can I unplug and clean or reseat without going through relearn procedure also can it be tested?


Malcolm
2000SS
San Jose CA


Thank You!

 

Thanks for the info. I only have a thousand dollar budget to try to get a running engine and transmission. I can get an engine and transmission from the junkyard for 350 bucks, and have to rebuild it and still come in at about budget. I'm limited on engine choice as well because when it's time to go to the junkyard what i can find is what I'll have to go with. They have unlimited 3.1 and 3.4 ohv motors and the last time I went they didn't have any pre-series II 3800's N\A or S\C. They did have a 99 Z34 but I doubt it will still be complete when the time comes. Finding a 3.1 shouldn't be a problem but I really don't want to considering it is a Z34. That's the same as putting a v6 in a Camaro and putting SS badges on it to me. But they also have over a dozen series II cars to choose from, just no S\C ones. I will be dismantling the engine and inspecting the mechanicals before installing it into the car, the transmission however, I'm gonna have to rely on a warranty from the junkyard, unless the engine allows enough money to take it to a shop and have them inspect it. Malcom, The BCM is above the parking break under the dash, has 3 connectors to it, don't know of a way to test it without a tech II scanner or equivalent.

 

IMO I would go and grab the engine wiring out of that 99 z34 asap as long as it isn't cut up. That can be one of the hard things to find when it comes swap time, and you can't use the engine harness for a grand prix or something as the plugs aren't in the right place.

Then, when you're ready to swap, you can grab nearly any available 3800 series 2 and it will be plug and play on the engine bay side.

While you're in there, it would be nice to grab the axles so you don't have to mess with custom ones (as long as you don't get an HD trans). Also, if you're really worried about the obd2 thing, maybe you should consider pulling the interior wiring behind the dash as well. At least, id grab the obd 2 plug and a few inches of wire.


As for rebuilding the engine, I wouldnt bother on a 3800 as long as you find something in decent shape that doesn't have 200k+ on it. 3800s last quite awhile, and the parts / machine shop work for a full rebuild is going to really kill your budget. Just do a thorough inspection before you buy it and you should be ok.