Remanufactured/Rebuilt car engine quality vs. original engine

Factual Questions
1

From what I’ve gathered from SDMB threads and elsewhere, a remanufactured car engine seems to be of lesser quality, on average, than original car engines. In fact, most auto manufacturers warantee their engines from 36-48 months, whereas most rebuilt engines have maybe one year warrantees.

What in the remanufacturing process compromises quality?

2

it depends on where you get the engine from. Have you tried jasper engines i never had a problem with them

3

It all depends on who does the rebuilding…
I have seen production line rebuilt engines that were junk, and other that were awsome.
If you go to the new engine for $599 installed place, you will be very near the junk end.

BTW, The engines in the cars I work on come with a 5 year/50K warrenty. However if you buy a brand new factory engine (from the same assembly line) carries the standard 1 year 12K warrenty.
Why? ::: shrugs::: Beats me, but that is the way it is. Cars have a 5/50 warrenty, parts are 12/12

If you are going to go to a rebuilder get a list of what parts are installed new, and which are reconditioned.

4

This question is all very theoretical. I don’t need a new engine. It’s just the impression I get is that, ON AVERAGE, a rebuilt/reman. engine cannot compare in quality to one straight from the assembly line.

I’m wondering why that may or may not be true. Thanks.

5

Because they reuse the case…some of them are made from remanf parts too. Ever notice when you buy a used one they ask for the old one? They save a lot of money reusing the old case. BTW, you save thousands of dollars buying a remanf one.

Item with remanf parts: $1000
Item with new parts, reused case: $1200
Item with new parts, reused case, precision tested: $1500

These are example prices from where I work

6

Slightly related hijack:

Is it common for transmissions to die with a new engine due to the sudden increase in power as compared to the old engine?

7
      • The only issue I have heard of with using remanufactured engines (for American cars) is that if you can choose, you want an original-production engine block. The reason is that some of the ones made in Mexico aren’t held to as high of standards-- the metal isn’t as good and the machine tolerances aren’t as high. During the nineties I heard of a few cases where rebuilt engines using Mexico-manufactured blocks leaked, and the blocks basically needed to be “trued up” before assembly.
        …
        Please note that this is not intended in any way as a “Mexico sucks, buy American” sort of response–it is a problem I heard of happening in a few instances. I never heard of it happening enough to know if it was a particular problem with one brand, engine ype pr manufacturing plant but I did read it mentioned in US-based hot-rodder car magazines. Their advice was as said: have the whole block gauged and trued up before beginning assembly.
        ~
8

Interesting, DougC. I was actually under the impression from old Mustang owners that Mexico-manufactured blocks are MORE desirable for their cars because those blocks had a higher nickel content, thus making them strong.

To answer the OP, there’s a rebuilt engine, and there’s a rebuilt engine. I could take a normal factory engine, tewar and down, and rebuild it balanced, blueprinted, with forged crank, rods and pistons, high quality gaskets, etc. It would be WAY better than the original factory engine.

9

From what I understand, a rebuilt engine is just torn apart, the “broke” parts and/or systems are replaced, and the engine is put back together.

a remanufactured engine has the works done to it:

Block, heads, and crankshaft are magnafluxed (checked for hairline cracks with powerful magnetic field), heads and block decks are milled to eliminate warping, cylinders rebored and rehoned, bolt holes re-tapped, crankshaft and camshaft journals are rebored to “true up” rotational play, New camshaft, pistons, rings, valves, bearings, seals, etc installed.

Note, the customer can order the engine specifically tuned for a particular application: torque down low for towing or four-wheelin’, or horsepower up high for racing, etc.

Compared to rebuilt and the standard-factory-option-new-from-the-factory engines, I’d wager a remanufactured engine is the best.

10

A rebuilt/remanufactured engine has a financial advantage over a brand new one in that the block, often along with various other parts, is re-used. The quality of the rebuild/reman is dependent partly on parts used–how many are new, what brand are they?–and partly on the care taken in cleaning, inspection, and reassembly, including machining of the block and head(s). There’s a long list of possible corners to cut.

I agree with dave316 that Jasper Engines is one of the better choices. Go here http://www.jasperengines.com/gasengines.html to see a list of what is replaced and what is done. Some of their competitors are not as thorough. Also, the skill and care provided by the people who actually do the work can be a very significant factor.

There’s a wide range of overall quality, and a (usually) corresponding range of price, in the selection of reman engines available. The better ones typically offer warranties of 3 years/30,000 miles or more. And typically cost, at the wholesale level, three times as much as the “bargains.”