Okay, I don't know why this hasn't hit me before. So you have the 1987 Aerotech that focused on 4 cyl engine. And then came the 1992 Aerotech, focusing on V8.
But its stated as using the Aurora 4.0 V8, specifically I've seen it written as the "production" (with some mods to help with installation into the Aerotech) Aurora 4.0 V8.

The Olds 4.0 was derived from the Caddy 4.6 (Northstar) - which was used in 1993 model year cars right? So- is it possible the Aurora V8 4.0 was in testing in 1992?
1988-89 GM started to consider what the successor to the Toronado was to be, and began to draw up ideas for what we know now as Olds Aurora, so maybe?

I have a Dec 1992 Olds press release talking about the Aerotech using a "production 4.0L Aurora V8 engine". It just kind of surprises me that in 1992, they were referring to a future vehicle specifically by name (or at least what they were going to call the engine).

 

That is my understanding. I believe the ETC was the first to feature the engine.

That makes sense. Keep in mind the name Cutlass was created in 1954. 7 years before the model came to be.

 

The 1993 Allante with the Northstar was released in April 1992 so that it would qualify to be the 1992 Indy Pace Car (that's a trivia question for you). The Aurora is simply a Northstar with a smaller bore (87mm vs 93mm for the Caddy version). Everything else is the same (yeah, valve covers are different). Of course these were built and being tested in 1992 and even earlier.

 

Those Northstar engines need oversized head studs to be durable. It's an engine OUT procedure.

 

So all those years later, Cadillac/GM was still missing ...

350 diesel, 8-6-4, HT4100, ... I don't remember the buzz for those, but I definitely remember the Northstar being referred to as state of the art upon release. So, much lauded inadequacy...

 

The block was aluminum and had fine threaded bolts. You can get kits with heli-coils and a jig that allows you to position a drill properly. The replacement bolts/studs have a coarse thread.

https://www.northstarperformance.com/

It's the first thing I'd do if I bought an Aurora.

 

What's unfortunate was that the Northstar replaced the 4500 and 4900, basically right after they got the 4100 right. They replaced a perfectly good engine with another lemon.

 

Not sure when the 4100 was rectified. But my Aunt had an 85 Seville with the 4100, back then. The car was great, 0 issues with engine. Beautiful car and the most memorable part was ride comfort, I have never experienced before or after. It was amazing.

With regards to replacing perfectly good engines with lemons... mind boggling. Back when the 500 cid was new Cadillacs quality was through the roof. 10 years later they were installing junk in their cars.

 

I've owned two 1993 Allantes and neither one had any problems with the Northstar.

 

I had a friend who specialized in Northstar repairs. He had the customer sign an agreement and pay up front before he did a head gasket job. The success rate of the helicoil kit was around 75%. Its a shame- that issue junked a lot of very nice cars and bottomed the value out on the good running cars.

 

Joe, did the Northstars you owned have head studs & heli-coils? I didn't know that the heli-coil kit was a craps shoot.

 

Never had the heads off of either one. The first died a premature death on some black ice. The second was parked when the electronics started getting wonky. That one had about 150,000 on the clock with zero drivetrain issues.

 

The problem is there are 20 holes that need helicoils, and if 19 hold and one doesn't, then you have a paperweight.

 

I had always thought a Northstar would be a good replacement for the 4.0l Shortstar in an Aurora. I also didn't know they had different valve covers. I @$$ume the engine cover from a 4.0l wouldn't fit on a Northstar.

 

The valve (actually cam) covers should be interchangeable. Physically it should be a bolt-in. Obviously there would need to be a software mod consistent with the larger engine. To be honest, I still have one that I've been toying with dropping into the 62 wagon instead of the 215. 295 HP stock. This was a lot more likely when Cadillac Hot Rod Fab was still in business making the RWD bellhousings for the N*. I don't think the OEM RWD N* engines use the same bell as the FWD versions, but I haven't really checked into it. The width of the motor is the other problem. It's probably 30% wider than the 215.

 

Unfortunately another engine that looked great on paper but fell short and pissed off more loyal customers. People have pushed big power under boost with the head bolts fixed properly. I also considered one but saw a lot of negative feedback and their Leakstar nickname made me say no.

 

Joe, you might already know about this supplier, but Ron Francis might have a wiring harness kit for the N* or Short*.

https://www.ronfrancis.com/

It might make transplanting one of those engines easier.