northstar swap?

[starfox86]

I was talking to this retired mechanic yesterday, and he said that I could swap a v6 for my 94 sls northstar... an olds delta 88 engine?..or a maybe a buick lesabre one?...He said that the engine would fit right in., right up to the trans and everything. maybe some wire issues, but not many. Is this information correct?...because if so, I'd rather do this because it would be way easier than time-serting and replacing a bunch of gaskets on the n*. (sorry to any of the n* fans..lol...I just need a car to get around town.) if anyone knows any v6 engine that would work, please add!

[Randy_W]

It could be done, but the interface with all the computers, like pcm, bcm, tcm would be a nightmare!!! It would be waaaaay cheaper to replace it with a used Northstar.

[eldorado1]

Swap a V8 for a V6? No child of mine is going to be thinking like that! GO TO YOUR ROOM!

[starfox86]

lol, alright, I am just going to do the timesert job. I dropped the engine out this morning, took about 4 hours. I was able to use permanent jacks with two concrete slabs under them to get the body up high enough and then i slid the engine out. mostly because I didnt have an engine hoist...now, I need a time sert kit. what do i do to get one, just call up and order it from time-sert.com?....or does anyone know of any online site i can order them from?.

[BeelzeBob]

You can pull the engine apart, timesert it, replace the gaskets and reassemble it by the time you get a V-6 removed from the donor car. Bad idea. Fixing the Northstar is MUCH easier than you think and it runs MUCH better than any V6.

[dkozloski]

Bbob, except for the North* VVt V6, of course.

[BeelzeBob]

Originally Posted by dkozloski

Bbob, except for the North* VVt V6, of course.

A V8 Northstar runs "better" than the VVT High Feature V6 in my book. Much more power for starters....and smoother too. The High Feature V6 is a nice motor and is pretty smooth for a V6 but it is no V8...sorry.

The VVT V6 is the High Feature V6 in the GM nomencalture. It was a clean sheet of paper engine. It has little or no commonality to the Northstar engine in any way. From a design architecture it is a completely different engine. No parts interchange except maybe the roller rocker arms.....which are a common corporate part used in a lot of engines. Even the VVT system on the V6 is totally different hardware than that used on the V8.

[dkozloski]

Bbob, it seems to me that I have detected some company "infighting" here. About a year ago the V-6 was referred to on the "GM Powertrain" site as a "Northstar V-6" and now it is the "High Feature V-6". I sense from the way you seem to have bristled up that this may be a sore subject to some folks. I also noticed that the crankcase is sandcast. I guess they decided not to go down the PerMold case route again.

[BeelzeBob]

No infighting or bristling....just making sure that the information presented was correct.

There was a "Premium V6" that was in production for several years that WAS an offshoot of the Northstar engine. It was installed in the Oldsmobile Intrigue and the Olds Aurora. That engine was a 90 degree V6 (like the 90 degree V8 Northstar) and had many similarities with the Northstar. Internally it was oftened referred to as the "Shortstar". So...when you mention a "Northstar V6" most people would consider that to be the Shortstar engine. That is not the V6 in your CTS and is why I mentioned that to make sure that there was no confusion.

I have never seen any official naming of the High Feature V6 a "Northstar".... possibly there was some confusion or a typo in a data or fact sheet or something. Cadillac was marketing the "Northstar System" on cars separate from the Northstar engine so maybe that was part of the confusion.

The Premium V6 block is manufactured using a precision sand casting process, yes. Actually, in that process, there is no cope or drag as is usually seen with sand casting. Instead, all cast surfaces are formed using cores that are stacked together including the exterior surfaces of the block. Since the cores are all very precise and help together accurately it makes for a very accurate casting and enables the inclusion of many cast-in-place internal passages improving coolant and oil flow and minimizing machining.

The precision sand cast process is simply different from the diecast process used on the Northstar block. I would not say it is better or worse....just different. Every casting process has advantages and disadvantages and the goal of the engine designer is to maximize the characteristics of the process to enhance the engine design....or vice versa.

Usually when someone calls a casting a "PerMold" it implies a gravity casting with part of the mold or the cope or drag being steel instead of sand....or the cope or drag has a steel insert (the steel being permanent and used over and over) in it to form a certain part of the cast surface.

The Northstar block is not a "PerMold" casting. It is a high pressue die casting where the large, multi-piece die is all steel and assembles together leaving a cavity in the mold that forms the block. The aluminum is injected into the die and then the die comes apart to remove the casting. This process does not allow any internal passages to be cast (unless they are perfectly straight and can be "pulled" in the direction of one of the die faces) with cores or anything.

The Northstar cylinder heads are a permanent mold casting as the deck face and combustion chamber is cast using a permanent steel insert in the cope to accurately and repeatably form the chambers.

Diecasting is still considered a very good process for blocks and is under develoopment on a new family of engines under study....so no one has "given up" on it in any fashion.

[dkozloski]

Bbob, I was led to believe that sand casting gave less porosity and was not as prone to chilling problems as pressure die casting but was less desirable from a production standpoint because it is more labor intensive. When I looked at the "GM Powertrain" website about a year ago I found the VVT V-6 in the Northstar section and it was referred to as the Northstar VVT V-6. In fact it took some digging in the same section to determine that the Northstar V-8 had become VVT. There was a statement to the effect that the Northstar family now included a VVT V-6. I wouldn't be surprised if this was a product of the website designers and was quickly changed as the site is much different now. Thanks for the clarification. Probably erroneously I was using the Permold term to describe pressure die casting in a Permanent Mold.

[BeelzeBob]

Yea, it depends on what you are looking for in a casting.

Most people refer to a die casting (jokingly) as porosity surrounded by bits of aluminum. In a diecasting the aluminum is injected quickly at very high pressures and it rather rapidly "skins" over on the surface of the die. Since aluminum shrinks when it cools, some slight (mostly microscopic) porosity will form as the aluminum cools further and solidifies deeper and deeper into the cross-section of the part in any given spot. This is just something that diecastings deal with by design and with casting techniques and die design to limit porosity to non-critical areas and control it. Basically it is the nature of the beast if you want to use the die casting process.

Sand casting will generally give you a somewhat denser, stronger part compared to a die casting with better material properties in the aluminum itself. The metal cross-sections in any given area will almost always be thicker with sand casting since the narrow walls possible with die casting are not possible with sand.

Sand castings are much more expensive to make on a volume basis and less repeatable in terms of casting accuracy. Sand cast tooling is much cheaper, however, for a low volume of parts so when an engine is designated for low volume production sand casting is often the first choice. When you are going to make 1200 blocks per day die casting is very attractive. The tooling costs are high (a single block die is about $2 million and you need 8 to run 1200 per day) but when this is amortorized over the tens of thousands of blocks that can be cast off each die it is relatively inexpensive. Sand cast parts have high piece price as it requires extensive cores and molds to be made for each block that are then lost during the casting process.

A good example of using the processes to the best advantage is with the SC Northstar. That block is a precision cast sand casting. Features were required in the block that are not there in the high volume RWD Northstar block (such as oil squirters for the pistons) so a new block casting was required. While precision sand casting has a high piece price the tooling for a very low volume engine was relatively inexpensive and the die cast tooling would never have paid for it. Once the decision to go with the precision sand casting process was made the block design was then changed to incorporate a closed deck and some thicker bulkheads for additional strength to handle the output of the SC engine. As a negative, the cylinder liners are cast into place as with the die casting but the liner location accuracy is not as good as with die casting so additional material must be left on the cylinder liner to account for the slight core shift during casting. As I said, there is no "perfect" casting process and the diecasting leaves the liners in perfect position. It all works and the design accounts for it but it shows to illustrate that there are MANY things to take into account with the casting process and design of the engine and deciding to go one way or the other hinges on far more than simple cost or other considerations.

[caddydaddy]

Bbob, what was the problem in 2000 with the porous Northstar blocks? Did something change with the new engines? I am just wondering since the Northstar in my 2000 STS was porous for coolant under the intake manifold. Was it a defect in that area of the die when casting the block?

[dkozloski]

Another problem with sand casting is that any sand left behind can knock hell out of the tooling and contaminate the engine during the build.

[dkozloski]

The original 260 cu.in. Ford small block engine was introduced as a highly touted "Precision Sand Cast" engine that allowed much thinner sections than had previously been possible in a cast iron engine and thus was lighter than a small block Chevy. It didn't take the hot rodders long to find out that it was also weaker. Much over 250 HP and everything inside the engine that rotated would come out the bottom and hit the ground. Ford by this time was committed to a pushrod "Indy Ford" effort that required reinforced main caps, reinforcing girdles/oil pans, and extra bolts to hold it all together. The DOHC Cosworth Ford appeared as quickly as they could get it going with it's share of tortional vibration problems in the cam drive train. Chevy Ilmor very cleverly decided to drive the cam and accessories off the flywheel end of the engine and avoided all that.

[dkozloski]

Actually if I remember right the Indy Ford DOHC came out as a Ford product and later was jobbed out to a succession of companies including Cosworth(Mike Costin, Keith Duckworth) Engineering and Meyers and Drake/Offenhauser.