Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: bobobono on January 02, 2024, 02:12:46 PM

Title: Engine swap options for De Ville 79
Post by: bobobono on January 02, 2024, 02:12:46 PM
Hi All!

Pardon my blasphemous question, but I'm thinking of fitting a modern engine into the body of a De Ville.

It's due to many reasons, the main being a lack of parts in Europe.

What modern (2000-2010) engines would you think are suitable for this purpose?
Title: Re: Engine swap options for De Ville 79
Post by: Eric DeVirgilis CLC# 8621 on January 02, 2024, 02:45:45 PM
The 425 was one of the best engines that Cadillac ever made. Unless there's a major problem with it, I can see no reason for changing it. Exactly what parts are you concerned about? Almost anything it is likely to need is a few clicks away on your mousepad and readily available. The worst you should have to contend with is the extra shipping time and higher shipping costs.
Title: Re: Engine swap options for De Ville 79
Post by: "Cadillac Kid" Greg Surfas 15364 on January 02, 2024, 02:52:35 PM
You did not mention the condition of your 425 motor. If condition dictates replacement a 500 inch motor will drop in without any modifications and if properly built and broken in should be trouble free for a couple hundred thousand miles
Greg Surfas
Title: Re: Engine swap options for De Ville 79
Post by: TJ Hopland on January 02, 2024, 06:35:19 PM
I would guess finding another engine even if it has to come from the USA will be cheaper and easier than any sort of swap unless you are or know some sort of master fabricator. 

Something like a GM LS engine would probably do the job but as far as I know none of the kits that are available for those do you any good with a Cadillac.  None of the mounts or brackets are in the correct locations.  Transmission is different so that is going to take more kits for fab or another swap.  Can it be done?  I'm sure it can but if you don't have a plasma CNC machine laying around and know how to use it plus the electronic skills its going to be quite the project. 

The 70-76 472 and 500 used a different oil pan and pick up tube.  68,69 its a smaller tube too so that would take some minor fab work.  68-76 had fatter exhaust manifolds than the 77-81's so you would likely have to swap that stuff over from yours if you got an earlier motor. 77-81 Eldo would have a different pan too.  There is also a chance you would have to swap the oil pump because of the angle the oil filter sticks out and you would likely swap over your pulleys and accessory brackets but thats it.  The rest bolts up and plugs in.  Way less work than having to fabricate every mount, hose, pipe, and electrical aspect.   
Title: Re: Engine swap options for De Ville 79
Post by: "Cadillac Kid" Greg Surfas 15364 on January 02, 2024, 09:41:01 PM
425 pan fits 5200 (462/500) block. 425 oil pump as well. Absolutely no mods required on mine.
Greg Surfas
Title: Re: Engine swap options for De Ville 79
Post by: TJ Hopland on January 02, 2024, 11:41:18 PM
Just to add more details to what Greg said the '5200' is the last digits of the casting number for the 70-76 472 & 500 blocks.  68 and 69 472 had slight differences like the size of the oil pickup.     
Title: Re: Engine swap options for De Ville 79
Post by: Seville Life on January 03, 2024, 01:01:23 AM
DON'T DO THIS. I live in Europe, Britain and France and have been in Cadillac over 45 years, no problems. Yes mainland Europe is a problem, crazy prices, too many taxes.

Someone else has already said this, the Cadillac 425 is an outstanding engine. It comes from the 472/500 architecture of the late 1960s and is bombproof. Serviced properly they'll outlast you?

What is wrong with your 425 motor? Where in Europe are you? Paul
Title: Re: Engine swap options for De Ville 79
Post by: bobobono on January 03, 2024, 08:09:07 AM
Right. Seems to be a bad idea :D Well, my knowledge of cars is close to zero. I just know of a similar trick on a Land Rover Defender with a BMW engine.

If anyone comes with more suggestions, I'll look into them.
Title: Re: Engine swap options for De Ville 79
Post by: Chopper1942 on January 03, 2024, 11:08:28 AM
Well, here's my 2 cents worth. I've done a lot of engine swaps from hot rods to changing from small blocks to big block motors in the same model vehicle. They all cost a lot of money, even if you can do all the work. You need to keep a note book of ever part that you use for the installation, so if a part fails down the road, you know what you used or modifled to make the swap.

If you are thinking of a later model engine like a GM LS or European motor, you would need to change the transmission, modify the driveshaft, adapt your AC & PS to the engine, and install the electronics to run the engine.

Sure it would be neat to have a V12 BMW in it and take it to a car show and show it off, but what did you do to the value of your original 79?  Over here, you see cars that have been modified and the owner may have spent over $100k to get it done and when he sells it, he may be lucky to 50% of his investment back. But, a restored original will usually appreciate in value.

Unless your engine can not be rebuilt, you could probably buy an engine here in the states, have it completely rebuilt and shipped to you and have less money invested than in a swap.

If is basically sound and it is too costly to rebuild where you live, I would look into shipping it here and having it rebuilt over here. I am sure some members could recommend some very high quality shops.

I don't know about in Europe, but over here a number matched vehicle (engine, trans, and diff numbers match the build sheet) is worth much more money than one that has had a different engine installed.
Title: Re: Engine swap options for De Ville 79
Post by: "Cadillac Kid" Greg Surfas 15364 on January 03, 2024, 11:35:21 AM
I remember Marty from MTS telling me that he was shipping engines to Europe and even Australia for reasonable prices.
Greg Surfas
Title: Re: Engine swap options for De Ville 79
Post by: Eric DeVirgilis CLC# 8621 on January 03, 2024, 11:52:37 AM
OP never clearly indicated whether the present 425 is exhibiting problems or if this is just a pre-emptive "what if" measure. If otherwise healthy, replacing the engine is a fool's errand. And it will almost certainly cost far more than whatever it would to cover basic maintenance that may be necessary while devaluing the car in the process.

When maintained, these engines have been known to last in the multiple 100Ks. In 1993, the world record for the highest mileage car without any major engine repairs was set by a 1979 Sedan deVille with over 500,000 miles.   
Title: Re: Engine swap options for De Ville 79
Post by: Seville Life on January 03, 2024, 12:19:21 PM
What's wrong with the existing engine? Where are you in Europe? Paul