Dodge Repair: replaceing car engine and renewed mileage, new car engine, donor car

Question
Hi I am wondering about a certain thing. I'm afriad I'm using up all the mileage of my car and when the mileage runs out my car would not run ad well after that. Hoever I don't really have enough money to buy a new car but thoght replacing car with new car engine would save money.
Do you happen to know if I actually replace my car with a new car engine, that would restore my car with more miles I can use up...or to rephrase the question would replaceing new car engine restore my car's staus to low mileage expenditure?
Thankyou

Answer
You did not say anything about make, model etc. of car so this is a general statement answer.....................if you cannot afford to buy a new car and want to replace the engine with a used one, that is an okay thing to do.....................however, be sure that you get everything with your motor from the donor car.  Also, keep this in mind, let's say that your car has 150,000 miles on it and the donor car has only 50,000 on it; you must remember that even though you would be installing an engine in your car that had only 50k, the rest of your car would still have 150k on it.  

If replacing the engine would cost you more than 70% of the cars present value, then it is not a good idea. and this is srictly from a numbers standpoint.  But, there is alot to be said for having a car and it paid for.  You will just have to drive it out long enough to get your money back out of it.

I remember years ago I had an old 1968 Ford that I paid only $275.00 for, but I drove it to work everyday; what I did was take a proactive stance on maintenance....one month I had all of the brake system rebuilt, then the next month, I had the front end rebuilt, etc.............now these things cost me more than I paid for the car HOWEVER,....this car was taking me to a job EVERYDAY where I was making a very good salary...so even though I was putting more in the car than it was worth, look at the benefit I was getting from my investment.  I was making sure that it would get me to a good job everyday and at the same time I was gradually increasing the reliability of the car through monthly maintenance ( the key to good maintenance is to keep your car up so that it does not break down and leave you stranded )