Expert: Rob Painter - 6/19/2011

Question
QUESTION: Hi Rob-  I have an 83 Coupe Deville that has approx. 20 K miles.  IT is beautiful.  The first owner babied it and it was always garaged and stored in the winter.  But oh that HT4100 engine.  I'm told that it runs as good as new, which as you know is mediocre at best.

I would like to pull the engine and substitute something better along with a modern fuel injection system and whatever else will make my Coupe run fast, smooth, and quiet, like a Caddy.

Any suggestions on what engine would fit with minimal changes?

Thank You

ANSWER: ,Hello,

I am not trying to talk you out of this, but I am giving you many things to consider before taking on this project. No one considers these things and don't find out until they have a ton on cash stuck in and then things turn out bad. These are just things that need to be considered. Our wonderful government has put the kabash on many of the things we would like to do under the ruse of "environment protection." I could (and have) start a whole new subject on that when it comes to climate change and what comes out of the tail pipe is insignificant compared to the earthquakes, volcanoes and 1945 nuclear bomb tests. That's another story, however environmental protection could dampen your project real quick.

Well, there are many things to consider here far over and beyond the immediate question thinking outside the box. In this scenario the very first thing to look at is if you were to stick all sorts of money into the project, could you recover financially if something happened such as some type of an insurance loss?

This car qualifies as a collector and stated value, in which you could get specialty insurance, but there is a possibility you can't get it as well, because of the modifications done to it. What if you stuck thousands and thousands converting this car the way you want it and some goof crashes into it, destroying it? The insurance company is not going to pay you for what you have in the vehicle unless you have stated value. Otherwise they will pay whatever they feel a 1983 Cadillac is worth. They might give you money for the low mileage, but maybe not because the drivetrain is changed.

Even getting an appraisal for stated value might be difficult with the modification. These days are different than what they were even 5 years ago because of the economy, and so many bogus claims where all insureds are put under the general fraud blanket, where insurance companies are not paying the auto claims they once were.

In fact, earlier this week the Special Investigation Unit thought that the 1993 stolen Suburban thought because the ignition lock was not damaged, yet the left side of the steering column was all blown apart, was not stolen. You have the same crappy steering column in which the car can be stolen with a screwdriver in 30 seconds with no ignition damage. They were looking at this as a fraud claim, when in fact, it was a good theft.



Before taking on this venture, in order to protect yourself, you need to see if the money you may potentially stick into this car can even be recovered in the event of a loss. Most people don't consider this when they venture into their projects only to find out the hard way at the time of loss. Believe me, over the years with a store on the paying end of the claim I saw many upset people when their custom vans were figured not for the customization in a theft claim, only for them to find the insurance company would figure for only a utility van, just as one example. After market wheels, stereos replaced engines, (even with receipts) were not covered and this surprise to the insured was not a welcome one.

Then you have the worthless EPA that poses all this environmental crap, which might make registration and emissions testing virtually impossible once the engine is changed. It doesn't matter if its more fuel efficient. If the engine not designed for the specific car, it may not meet the federal/state criteria as to what they deem appropriate, if you are required to get an emissions test, you might not get the car registered.

Commonly, if the engine installed is not listed or does not work properly for their testing, you will fail. In your case in you are to modernize, you are changing everything including computer SYSTEMS. That's all wiring harnesses because your car has a OBD I and in 1994 (yeah that long ago) GM went to the OBD II, so any upgrade to engine with the newer fuel injection and you would need every sensor for the engine to run efficient or there is no point in even doing this project.

When being checked for emissions, the state would know right away the engine is not right for the vehicle because the diagnostic connector is now different and that is where they plug in for their testing.

With all that said and I probably depressed you, if you notice though at least I kept you from very bad surprises in the future.

Personally, I would probably tell you to keep things as they are because with the mileage and the condition of the car, any modifications will just devalue the very nice car you have.

If you are dead set in making the changes, since it is rear wheel drive any GM engine should go, but you would want the matching transmission as well and the best choice would be to buy a crashed 2005 up Corvette SLR and take the drive train, all harnesses and sensors from it. That would give you the power you need and want.

You should not consider a Cadillac engine just because they are aluminum and the slightest bit of over heating (notorious for just like your 4.1)self-destruct and you won't find a good engine in the junk yard because 9 out of 10 are over heated. I do not even know if the Corvette used cast iron in 2005 up. You would need to check.




This EPA thing I was referring to previously is very real though.

If you think I am kidding, attempt to do what I have. Compressed natural gas is the equivalent to $.90 per gallon. It is not as much as an environmental threat and can extend an engine's life because it burns much cleaner which even something as oil changes, instead of 3,000 mile intervals, might go to 20,000 mile intervals. Its a win/win/win situation except for one thing converting to bi-fuel. The EPA!!! In essence, the requirements to do such a simple conversion are almost impossible to meet, and in that case, the engine is not even being replaced!

The reason that your big heavy car had the 4.1 was that the engine was very light being made of aluminum. Even though it was not a big engine, through the final drive and an overdrive transmission, the engine was sufficient to pull that 4,500 pound car or more along. The 307 Olds V-8 was used in the Fleetwood Broughams, and power was not much better and fuel mileage was worse, but the 307 could survive an over heating event and the aluminum engine won't.

The 4.1 (4100) debuted in 1982 and in 89 went to 4.5 and in 91 or 92 went to the 4.9 and in 1993 the very over rated 4.6 Northstar. In my opinion, the aluminum engines were a virtual gold mine for Cadillac because of the ridiculously priced parts and all the crate engines they sold because people destroyed them over heating them.

Your request was to upgrade the engine and the fuel injection. This is a major undertaking and as stated earlier, its not just going from a throttle body fuel injection to fuel injectors, but every harness, every sensor, so you need a car for all the parts, otherwise I can't even imagine the cost you would stick in trying to put all this together.

Bottom line--I can't see any way it would be cost effective to upgrade this engine. Your 1983 computer system was last used in 1993. Chances of finding a good used Cadillac aluminum engine are slim to none and the insurance issue and environmental issue should be considered.

I get so many questions on these aluminum engines after its too late when people have over heated them needing head gaskets, heads and engine blocks. This is a known fact to any of these engines.

You might want to consider going backwards if you could find a good engine. The mileage wasn't great, but the power was significant. The engine I am thinking of is 1981 0nly in the Deville and Eldorado. It was known as the 4-6-8. This engine had many problems because of the 4-6-8, but disconnecting one simple wire made it run on all 8 cylinders. This 368 CI engine was great!!! Had a couple. Its a bolt in and granted you are running the same injection system, you don't have to change harnesses and only the computer. In my opinion, its the best engine Cadillac ever put out with the 4-6-8 disconnected. Those cars are still around outside of the rust belt.

I hope I have given you the opportunity to be fully informed as to the considerations.

Drive it, enjoy it and keep it out of the sun for long lengths of time. In the 80's GM had a very serious problem with the laquer they used, which was susceptible to crazing. Crazing is cracking to the paint from the sun. The only fix is to strip all the paint from the car, have specialized primer put on and repainted. My black 1983 low mileage Eldorado had this problem, like all GMs of that era.  In 1990, I did all the work and it still cost me $3,000 to have it repainted!

All that wok! The ex knew damn well not to drive the car. She could have driven the Vette, the new Cadillac or her brand new Firebird convertible in 1991. She took my Eldo when I was out of town and managed to damage it! I ended up getting rid of my pride and joy at a loss of thousands of dollars because of her! Never took on a project like this again for myself!

Good luck!

If my answer assisted you here and I hope it was not too confusing, it would be nice to get a rating. I realize I did not make the simple, simple here, but I am just a realist that has learned to plan ahead.

http://www.autotheftexpert.coom


---------- FOLLOW-UP ----------

QUESTION: Rob
Thank you very much for a frank and knowledgeable answer.  It appears that you have saved me from a lot of wasted money and aggravation.  I really appreciate your time and effort.

Regards,
Steven Finkel

Answer
Hi Stephen,

I am just a guy that does not like surprises when doing projects and fortunately for yo and unfortunately for me I have learned the hard way.
Years ago, changing an engine to give the car a couple more horseys was not a problem, Since or damn government has their nose into our business these days, doing something as simple as your request has turned into a nightmare!

It's far better to know what you are getting into up front though.

Thank yo for your rating. Take care of that car, it sounds really nice and enjoy it.

Wait until the a/c quits working and you find out you can't get R 12 anymore. Another great government idea because these idiots have no science to support it (they say they do, but I contend they do not) but it purportedly adds to the hole in the ozone layer as do cow farts. Yes, they are trying to ban cows too!

Walmart sells the R-34a conversion for less than $50. Alert!!! Now they say that there is a problem with 134a!!!

Bottom line, the EPA has become the mechanic's worst nightmare. You may get the impression I have absolutely no use for the EPA, the federal government or the UN and their b.s. green economy.

What is going to happen when someone can't pay their electric bill because it is so damn high and you can't charge the electric junk they are pushing as vehicles that no one can afford?

The times have unfortunately changed and the stuff we did when working on vehicles only 20 years ago can now get us thrown in jail!

Good luck!

http://www.autotheftexpert.com