Suppose i have a car that i wish to keep. I decide to buy a junkyard engine, rebuild it, and keep it-when the present engine conks out, I drop my rebuilt engine into it-so i have a new car.
My question: any junkyard engine is liable to have a lot of miles, so, what should i plan on replacing? for example, new piston rings, crankshaft, new valves (or head recondition), new water pump, etc.-the cost of parts mounts up. of course, the labor is free.
Is this a economical way to keep an older car running?
Probably more of an IMHO given the cost to rebuild an engine for anything likely to be considered “older” will probably be greater than the cost of the same year/make/model.
IME, you can budget $500-1,000 to refurbish a 16 valve, 4 cylinder head (dip cleaning and new valves & parts). Unless you’ve done it before and are good at it, just have the shop do the head(s).
For the bottom half you can budget about that again for seals, rings, bearings and various dammits. And if you’re in it this far, there really isn’t much sense in not replacing the starter, water pump, alternator, timing belt, hoses…you get the idea. How much you spend is going to depend on the make (i.e. VW vs. Chev).
All that said–totally worth every penny if you’ve got a reasonable budget and enjoy doing the work because when you’re in that deep it’s more of a Zen art project than keeping a daily driver on the road. If all you want is a car that runs, you can save a lot of time, labor, and money by keeping your eyes open for the occasional $1,000 - $1,500 ride.
How old is the car? How simple is the engine?
If the car is fairly new you may be able to buy an engine out of a wreck that isn’t all run out. e.g. if the car’s a 2012 you can find a wreck with 40K miles on it when the moron crashed it. Buy that engine and you’re getting an essentially new engine; it’d be silly to do any rebuilding on it. Replace any accessory stuff that got bent in the accident then pickle it for use a decade from now.
But …
As **Jester **says, there’s a lot more to keeping an older seriously high mileage car on the road than just the engine. And the relative durability of the rest of the car versus the engine has changed a lot over the years. If you’re an older guy like the rest of us, the “common sense” of your youth regarding durability is just inapplicable to more recent cars.
So I say again: give us more details on the car, its current mileage, condition, etc. And how much you’re experienced and equipped to do engine rebuilds and swaps yourself.
“To keep a car running”… probably not. To me this says the car is already about used up (still running?) and you’re thinking of spending say $500 on an unknown engine plus say $300+ on parts plus lots of sweat. It’s not hard to find a good work car for <$2000 and start over. You may be able to sell what you have plus the rebuild $$ to get another pretty good used car. Knowing that a car is all original and working as one piece is nice too.
If there’s an understood engine failure in a nice car - maybe, even probably. Most junkyards know the mileage of a used engine and you can gauge the degree of gunk in the valve covers or oil fill to get a feel for how it was maintained.
If it’s a collectible car with a reasonable engine cost - yes.
PS - the degree of rebuild you’re describing is scary for less than a racing engine. Remember that you’ll need automotive machine shop services ($100’s ) to prepare for new pistons, bearings, etc. So it would have to be a special car or a restoration project.
I don’t think this is a very good plan. You are stockpiling one part you might need in case it goes out. But what if the transmission goes out instead? Or an air conditioning compressor, differential, control arms, ECU, catalytic converter, shocks, or fuel injection rail? Maybe you should stockpile all those parts, just in case they go out too. Taken to its logical extreme, you should just buy an identical spare used car with all the parts, and swap them out as needed. Of course, buying another car is really expensive and that seems to be exactly what you are trying to avoid.
Here’s another question. What if you total the car in an accident? Now you have a possibly good engine for a car you don’t need at all anymore.
I think the best idea is to drive the car carefully, maintain it well, and bank whatever money you plan to spend on the engine in a repair fund. Then, if something goes wrong with the car, you can fix it and keep the car. If something big and expensive goes wrong with the car, you can decide then if you’d rather replace the car than just fix the problem.
Engines are really dependable today and there are a lot of other systems in a car. There is a very good chance that the problem that finally does your car in won’t be the engine.
These days, used engines are usually pretty good bets. With most newer cars, so long as you keep the oil changed and don’t overheat them and such, the engine will last much longer than the car. Most reputable junkyards (oxymoron?) will compression test their used engines and give you a short warranty in case there is anything not obviously wrong with the engine.
Moderator Action
While you might be able to cite some overall cost figures, I think that this is ultimately going to be a matter of opinion rather than fact. So off to IMHO it goes.
Moving thread from General Questions to In My Humble Opinion.
Stockpiling an engine doesn’t make much sense to me. I did a couple of engine swaps when I was younger, but I did them when the engine had a problem. Those were also older cars that were built when engines didn’t last as long as they do now. Plus, I didn’t rebuild the engines. I just made sure they ran ok before I bought them from the junkyard. Both engines came from wrecks where the back of the cars were smashed and the engine compartment was ok.
Cost-wise, I made out pretty well on both engine swaps.
You do a full engine rebuild, and you are going to drive the cost up, as well as your labor. The labor may be free, but it’s time that you could be spending doing other things. On the other hand, if you enjoy this sort of thing, it may be worth it just for the fun of it.
Unless you’ve really abused the engine though, there’s a really good chance that something else will fail on the car before the engine goes. Engines last a lot longer these days than they did when I swapped out engines.
I don’t know much about cars, but I’m curious about one thing: other than the engine, how much of the car is in decent condition?
I currently drive an 18 year old hatchback with 200 thousand miles, mostly in stop-and-go traffic jams. The engine is fine—but the rest of the car is falling apart.
The car simply will not survive long enough for the engine to deteriorate to the point where it needs a rebuild.
Why couldn’t you just rebuild the engine that’s already in the car?
If you know what you’re about you can swap a like-for-like engine in a few hours. Otherwise, maybe a weekend. If you are reasonably certain the engine is gonna conk out soon, there is a good argument to be made for being prepared to address the issue quickly as opposed to hoping it fizzles at a convenient time for you.
Plus, if you’re a total gearhead you’re modding the back up engine so that, when it’s finished, you beat the hell out of the old one until you have an excuse to put in the new muscle. 
Just dropping in a new engine won’t give you a new car. Everything else is old including the transmission.
For most popular vehicles you can buy a rebuilt short block or long block engine for a good price. The short block doesn’t come with the heads while a long block engine does. You’ll still need to move over the other parts such as manifolds, fuel system, etc.
Back 20 years ago, the engine would wear out long before the rest of the car did, so rebuilding the engine often made sense. An engine with 120K miles was on it’s last legs.
Today, a modern engine made to the more exacting tolerances, can easily last much longer. My Lexus is300 with 115K is just getting broken in.
So, unless you have a collectible car, I just don’t see an engine rebuild making sense for most instances.
Most modern cars aren’t trashed because the engine went, they’re trashed because they fall apart around the engine. Some have notoriously bad transmissions, others have suspension parts made out of balsa wood, etc.
no it isn’t. it was “broken in” at 1500 miles. now, it’s just an old engine.
2 items:
1 it was possible to buy rebuilt engines at auto supply shops - either short or long (don’t remember the difference - the long was a more complete assembly). These had the cylinders, crank, cam, and vales installed (the stuff a machine shop is needed for).
- Japan used to (at least) have a law requiring the engine to be replaced at 40,000 miles or so (producing an artificial market for the industry). The discarded engines were, after some effort, available in the US.
and: back in the day, there was a woman who wanted to overhaul the engine in her beater. She waas told ‘don’t drop the crank - if you do, you’ll have to take it to a machine shop to instally the crank, rods. and pistons’.
She decided she could do anything the shop could do.
To her credit, the engine started in less than a full rotation. It threw the rod a few seconds later.
So: If you drop the crank, really, really take it to an auto machine shop for re-assembly.
I saw a lot of those engines when I lived in England around 1990. Back then there wasn’t much in the way of automotive emission laws in England while there was in Japan. Therefore you’d look under the hood and see all kinds of vacuum hoses blocked off with gold tees and other parts, like air pumps, just hanging on.
I just checked with a local shop-they want $500 to rebuild the head alone (Saturn 1.9 l SOHC). This is ridiculous-I can do it for about $110.00 in parts).
Does “rebuild the head” include resurfacing? What do they charge for that alone? The questions you’ve asked implies pretty well that you don’t have the tools and expertise to resurface the head or block yourself.
I wouldn’t buy one and/or do a rebuild in advance; if its worth the money and effort (to me) is a judgement call of the moment. How good is the body and interior? How good is the rear end and the rest of the drive train? Can I get a commercially rebuilt engine cheap enough not to invest the time? Have I had any accidents? If possible I’m going to scope out the hidden areas (inside the doors for example) before making the final call. I’ve done motors and swaps for a few people and sometimes its worked out really well; one Saturn I know is getting near 300k and the owner is starting to think about Engine #3. But I did another at the owners insistence that it just must be done to have the car basically die with the freshly rebuilt engine under the hood. So wait and when the time comes ask around and see what advice you get then.