What should you expect from a junkyard engine?

[misterW]

I bought an engine from a junkyard to replace the one in my '94 ranger that had bad compression. They told me the junkyard engine had good compression. I have worked on other vehicles before, but this was my first ranger and my first engine swap, so it took ... awhile. Finally finished, and took it for a drive around. Felt a bit sluggish, so tested the compression. #3 cylinder is getting 120 compared to the 150 in the others. I am pissed off -- the receipt says I can return the engine, but that was a lot of time and effort spent to be back at square one.

So now the question is, how do I prevent this from happening again? Was this an unusual isolated experience or do junkyards frequently try to sell engines that are not good?

 

[kimcrwbr1]

A bone yard engine is allways a gamble i changed mine about 5 yrs ago for $750 put it in and had a loud knocking noise pulled it and when i got the second one in it would not turn the guy at the yard said dump oil in the cylinders and work it loose i said no give me another one. I am still running the third one in it and when I got it all the wires were melted on top so in my opinion the ony guarantee would be one from a car fire because the engine either gets shut off or just stops right away. Or one out of a car or truck with the rear end smashed less chance of it running at WOT from a front collision. A engine fire dont get hot enough to hurt the engine. There are no guarantees and it is a pain if the wrecker is dishonest ask to see the compression before to take it out of the yard if they will do that for you. You probably cant get your money back but they have to give you a good engine sorry I have been there. Make sure it turns over before you install it.

 

[BeaterMan]

I personally would take a compression gauge with and remove all the spark plugs and with a big socket on the crank pully, manually turn the motor over and check its compression before i even would pull out my wallet. the yard by my house always post that they have such and such engines with good compression, components ect but then they have them sitting outside uncovered exposed to all the elements, so its definately a gamble with junk yard engines unless you plan to use it as a rebuidable core or whatnot.

 

[srteach]

I bought an engine from a junkyard to replace the one in my '94 ranger that had bad compression. They told me the junkyard engine had good compression. I have worked on other vehicles before, but this was my first ranger and my first engine swap, so it took ... awhile. Finally finished, and took it for a drive around. Felt a bit sluggish, so tested the compression. #3 cylinder is getting 120 compared to the 150 in the others. I am pissed off -- the receipt says I can return the engine, but that was a lot of time and effort spent to be back at square one.

So now the question is, how do I prevent this from happening again? Was this an unusual isolated experience or do junkyards frequently try to sell engines that are not good?

They sold you an engine with "good" compression. It wasn't even across the cylinders, it wasn't high compression, but it was "good". Just the same, take the engine back and get one with high, even compression. Test it before you take it out of the yard or put it in the truck.

I bought a Ford 4L off the shelf from the a JY I trusted. I still tested it before install. Caveat Emptor always.

 

[misterW]

can you get a reliable enough compression reading cranking it by hand?

 

[steve63]

think the most you can expect out of a bone yard motor is a rebuildable core.

 

[4b316]

If you pul the plgs out you can get a reliable result.150 is a pretty good result if it was across the board,How long did you run it after putting it in?Sometimes a motor sits awhile before someone buys it and they might get a sticky ring.I would drive it 200-300 miles then check it again.how long before you can take it back?

 

[kimcrwbr1]

If you pul the plgs out you can get a reliable result.150 is a pretty good result if it was across the board,How long did you run it after putting it in?Sometimes a motor sits awhile before someone buys it and they might get a sticky ring.I would drive it 200-300 miles then check it again.how long before you can take it back?

Yea it is is getting good oil pressure run some seafoam thru it or I like to pour some water in it at around 3000 rpm about a cup or so at a rate just before it dies then rev it up for a bit or take it for a beat then redo the compression test. could be just some crud in there. you can also pour a little tranny oil while it is running to get the valves spinning again. either the sea foam or tranny oil will make a big puff of smoke for a bit so dont do it in a garage or shop.

 

[schmoo]

you can do a leakdown test without a starter.
you just need an air compressor far enough
away so you can hear a leak in the exhaust.