...Sure , but can YOUR engine be driven across Utah on a summer day without coolant?
Okay, I don't know if those test engines were any good for anything else after that, but you really do have to admit that the
concept of selective-cylinder cut-off for heat-exchanging was cool. I honestly don't know if those tests were even legit or not, but I remember the statements GM made about it.
Hey, I already have the car, and just trying to re-engineer what was already engineered on it keeps me awake at night, I honestly can't recommend the project to anyone other than those who wouldn't need a recommendation to begin with. I do think that the N* family is getting a bad rap here though, they certainly have their problems, but all engines do. I would like to hear now what critics will say about the LS4 in ten years.
Info Courtesy of Larry Carley, sourced from Cadillac Forums:
Remarks courtesy of me and my opinions, experiences, and research:
Engine Features:
The Northstar V8 has a die-cast aluminum block with a bottom end girdle that splits along the midline of the crankshaft bearings. This takes the place of the main bearing caps. In model year 2000, GM began using a new high pressure "squeeze" casting process for the lower crankcase to reduce porosity in the aluminum, which may allow oil to seep through and leak (this has been a problem on some engines).
Using aluminum for an engine block has distinct advantages, and certain disadvantages. Pick your side and stay with it throughout the battle, 'cause switching sides mid-stream just gets you shot from both directions. In other words, the issues associated with the aluminum casting of this engine are there as trade-offs for the benefits; the engine is different, not definitively better or worse for this.
The cylinders have cast-in-place iron cylinder liners that are not replaceable. Compression up to model year 2000 was a relatively high 10.3:1. It was lowered to 10:1 in 2000. Each head has two camshafts (one intake, one exhaust) and four valves per cylinder (33mm intakes and 29mm exhausts). Direct-acting hydraulic lash adjusters are positioned over each valve. The overhead cams are all chain-driven, and use an intermediate chain sprocket under the front cover to connect to the crankshaft. Three separate hydraulic tensioners are used to keep the cam chains tight.
The Northstar V8 is an interference engine, which means if a chain fails or is disconnected when the engine is cranked over, the valves will hit the pistons. That's something you don't want to happen with an expensive engine like this!
It is my understanding that the cylinders are now serviceable for overhaul -if that means they can actually be replaced, or just that GM now acknowledges over-boring for them, I do not know. But can you remove the cylinders from a 3100? No. Does anyone expect to, or complain about that? Probably. High compression means more costly premium fuel -it is a trade-off for the higher performance. The complexity of having three tensioners seems a little ridiculous to me, but it probably saved the engineers from putting in an extra idler or two, or having to extend the camshafts to use only one chain. Many, if not most, high-performance engines are 'interference'. Those equipped with a belt-driven valve-train are poorly designed IMO, because belts are either replaced periodically, or they DO fail -chain failures are unlikely. You might as well gripe about having so many pistons in the engine that could fail.
The intake manifold is Nylon 66 thermoplastic, which helps cool intake air by conducting less heat from the engine. Fuel delivery is by sequential fuel injection with separate injectors mounted under the engine's top cover. Under the top cover you'll also find the MAP sensor, intake air temperature sensor and fuel pressure regulator. If the fuel pump relay fails on a Northstar V8, the engine should still run because the fuel pump also can be energized through the oil pressure sending unit.
I don't much care for plastic components on engines -engines get hot, plastic warps and melts. Hey, remember the cussing plastic LIMGs on the 3x00s... There was a brain-trust idea for you! The earlier N*s used a different intake with, IIRC, magnesium, and they were molded in a two-piece design, so you actually could open them up and peek inside. I have one of these engines too, I tentatively plan on putting it into one of my '88 Camaros, if I can figure out how to bypass the huge coolant cross-over housing on the transmission-side of the engine that would hit the firewall on a RWD car. I find it amusing that the author failed to mention that the starter-motor is located under the intake manifold, necessitating the manifold's removal to replace the starter, as that was one of the bigger gripes about the engine.
A four-coil distributorless ignition with a waste spark set up provides spark to the plugs. Two crankshaft position sensors are used (A and B) plus a camshaft position sensor to provide timing inputs. Both crank sensors are mounted in the block and the cam sensor is located on the rear head in front of the exhaust cam. There's also a knock sensor on the rear head between cylinders 1 and 3 to retard timing if detonation becomes a problem under load.
The ignition system has two modes of operation: "module mode" and "ignition control mode." In ignition control mode, the PCM controls ignition timing using sensor inputs. If there's a problem in the PCM or with its sensor inputs, the module mode takes over and runs the engine with a fixed 10 degrees of advance. The engine continues to run (essentially a limp-in mode) but with reduced performance.
In model year 2000, the DIS ignition system was changed to a coil-on-plug design, which eliminates the spark plug wires and waste spark. Each head has its own ignition module that fits in the middle of the valve cover.
The 3x00 engines also utilize two crank-position sensors and a cam-position sensor. I don't understand the earlier comment about needing to replace both CKPs at the same time -why would that be? As I understand the different modes, you can remove the PCM entirely, and the ICM will continue to give the engine spark. This doesn't mean much to the stranded motorist, unless they have a secret gnome in the trunk who is willing to spray gasoline into the engine's intake while driving to help get the car to a service-station, but it is again a cool concept, and may actually make a difference in special circumstances.
Another feature of the Northstar engines is a "limp home" mode that allows the engine to continue running if all the coolant is lost. If the PCM senses an overheating condition, it temporarily disables up to half of the cylinders. This pumps enough air through the engine to keep temperatures from getting hot enough to cause any damage. Even so, GM says the vehicle should not be driven more than 50 miles in the limp-home mode.
This is just plain cool. Was this the inspiration to GM's "DOD", ("Displacement on Demand") feature, found on some of the LS family of engines? Couldn't it be utilized as such with some PCM reflashing on an N*, or possibly with some intake modifications? Hmmm... Naw.
Another unusual feature you may see is a liquid-cooled alternator on the DeVille and Seville. Cadillacs are crammed with electrical accessories that put quite a load on the charging system, so using liquid cooling helps prolong the life of the alternator. In 2001, GM went back to an air-cooled alternator to "eliminate the coolant tubes and potential leak points."
Luckily, both of my N*s have the simpler air-cooled alternators, although if my Indy had the liquid-cooled option, I might not need the cooling-air supply fan for it. Personally, I'll take the simpler route, with the fan.
ISSUES:
Northstar V8s, like other engines, had some problems. According to various sources, head gasket failures are not uncommon. Nor is oil burning or oil leaks.
Cadillac service bulletin 01-06-01-011 deals with oil burning on 1996-'99 Northstar V8s. The cure, says Cadillac, is to do a ring cleaning procedure (seems those long oil change intervals weren't such a good idea after all). Cadillac recommends using GM cleaning kit (P/N 12378545) and Kent-Moore J-45076 induction/evacuation tool to do the job. The cleaner is added into the cylinders through the spark plug holes and allowed to soak the rings for two hours. The cleaner and dissolved crud is then vacuumed out of the cylinders through the spark plug holes, followed by an oil change. Cleaning the throttle body and EGR valve is also recommended.
This sounds like an easy enough procedure, and would be an acceptable trade-off in a maintenance aspect, relative to, say, a timing-belt equipped engine. Personally, I recommend removing the EGR altogether, but that is just me. I have air-filters on my engines because I don't like dirt and crap going into my intakes.
On 2000-'01 Northstar V8s, a buildup of carbon deposits in the combustion chamber can cause a cold knock condition. Bulletin 99-06-01-101A says to use top cleaner to remove the combustion chamber deposits. If an engine has failed and is being rebuilt or replaced, the Engine Rebuilders
Association (AERA) says the plastic intake manifold also should be replaced. The reason? Because of the complex shape of the manifold, it's impossible to tell if any engine debris has been blown back inside it. If the debris works loose and is ingested into the new engine, it will cause a repeat failure. That you don't want.
My engines are both older than that, but it is disappointing that a newer design of the engine was actually made worse in some aspect. As for the intake replacement, shake the thing around, does it rattle? Soak it out with lots of hot water and soap, now does it rattle? This sounds like an insurance salesman recommendation to me. Besides, the older-style intakes don't have that problem at all, IIRC.
No oil pressure on a 1993-'94 engine? Debris between the oil pressure relief valve and its seat will prevent oil pressure buildup. The cure here is to clean or replace the pump (P/N 3543258), which is located on the front of the engine.
"(seems those long oil change intervals weren't such a good idea after all)" Do the maintenance, have less problems. How many problems would a 3.1 have if the oil was consistently left unchanged for prolonged intervals? This was bad politics, not bad engineering.
Oil leaks around the rear main crank seal have been a problem on some 1996-'99 engines, so GM has developed a new rear main oil seal (P/N 12556107) that should cure this problem. It's a press fit seal that takes a special tool (J-42482) to remove and install.
I haven't encountered this, so I don't know how bad the leaks were here. But, I would point out that the clientele of a Cadillac dealership might be pickier about his/her car than the average driver. Without any first-hand experience regarding this problem, it is hard to justify an opinion though.
If you have to pull a cylinder head on a 1993-'99 4.0L or 4.6L Northstar V8 to replace a gasket or do a valve job, do not reuse the old 11mm head bolts.
Even our Quad engines and Twin Cam four-cylinders are not supposed to reuse the head-bolts. Typically, if the engine has an aluminum head, the bolts are torque-to-yield, and only usable once (I believe the 60-degree V-6s may be a notable exception here -I've always reused head-bolts on these, and NONE of my V-6s have ever blown a head-gasket after I bought them). Even Jeep's venerable 4.0 straight-six is only supposed to reuse the head-bolts one time, and that is an iron head on an iron block.
I've only worked on a small handful of N* engines, and unlike
jwevans1024, I've never been a technician at a Cadillac dealership, so I'm sure he knows more about these engines than I ever will, but I don't think the N*s really have a definitive reliability disadvantage as compared to any other family of engines. The real argument here is that the engine doesn't fit well into the Berettas, and there are simpler options available. If you want to do it just to have a unique car, so be it, that is a valid option. Good luck and have fun with that.
Just do everyone a favor, and leave the mufflers on!
Sorry for the super-long post, I was just trying to address the specifics, as I know them. I think this whole topic has been chewed-on ad-nauseum.
Hey, did
I make you read through the whole thing?
Oh, and if you do decide to use a 65, the mounting points are identical.
Wow, that's awesome! Yeah I got my numbers based on what GM Service information said. I figured aftermarket had more but I wasn't too sure. I had an '07 Saturn Aura with the LZ4 V6 and the 4T45E tranny. It always bugged me that the final drive was only 3.09, especially since the G6 GT was 3.25 and the 4 cylinders were even better than that! What bothered me even more was that tranny was too weak for that engine, but it worked. I ended up getting rid of the car because it was a gigantic pile of crap but whatever. That's awesome man, I would love to see your car run at the track. I love it when FWD 6 cylinder automatic vehicles run times similar to V8 muscle cars!
Hey, anyone who is in this community already gets points for that, IMO! And anyone who owns a Beretta for more than 'it was the cheapest beater I could find with four wheels on it' is already above average, and true enthusiast deserve their props for the loyalty. When I first started talking with GTiIndy about acquiring his car, I was thinking long-term. I already wanted a yellow Indy, and had the thought that if I had both the N* Indy and a yellow Indy, then converting the yellow one into a convertible would be a good way to make it unique. Now that I have it, I honestly don't think I could cut it up that way - the yellow Indys are too rare. Travelor, if you do decide to build a completed convertible, you would be a Beretta god! 