How many miles are to much.

[Tim in Az]

Starting to look for Mustang donor car. How many miles are to many to just simply drop in and not rebuild.

Thanks Tim.

 

[bmc69]

My rule of thumb is that anything over 80K is suspect and at least needs to be torn down and re-assembled with a 250-dollar 'light', or 're-ring' overhaul kit.

That said..I've torn down 5.0 engines with 120K that were pristine inside and said to myself 'doh!!' for doing it. But I was an automotive machinist many moons ago..and I have a hard time taking short cuts with engines.

 

[Broncobowsher]

I would say about 150k.

Trouble is Mustangs have such varied lives. The more stock the engine is, the more mileage I consider them good for. When stuff starts getting added to them (cold air, exhaust) that generally means that they are driven harder in there life. With a factory tuned and properly working EFI 100k on an engine is nothing like it is on an older carbed engine. I am finding that a stock engine is generally good for about 200k. Over the past decade I have been noting that is a good general life of just about any factory engine under normal conditions without ever taking the valve covers off (and often never replacing a spark plug either). I can think of several engines (my old 2.9 BronoII, friends 5.0 Explorer, Chevy pickup, other random assorted stuff) that was good to the 200k mark but tired after that. So 150k should be good for about 50k of life. If it was driven hard, raced, abused, questionable upgrades, it could easily be dead before 80k.

 

[broncnaz]

As was mentioned it depends on how the PO drove it and maintained it. You may not get the real story and you have to figure that any mustang 5.0 will be over 15 years old. Basically since it is a mustang if it was babied that much then it probably wouldnt be cheap enough to be a donor car or it would have been wrecked.
For the most part these EFI engines last a long time before then need a rebuild. The 2.9L in my dads 88 ranger went 300,000 miles before we rebuilt it and then it only needed new rings and bearings besides getting the heads reworked. So it wasnt a major rebuild.

Still any donor engine I got I would do a compression check and if that was good I would probably put in at the very least a new timing set if it has over 80,000 miles.

 

[Tim in Az]

If I can find one with 80 to 100 k miles in good shape. I guess my next question is how much money would be to much before it just didn't make more sense to rebuild my 302 and do an efi swap?

Thanks again
Tim

 

[broncnaz]

Loaded question as how much is to much is up to you. If I knew without a doubt the history of the motor and it was 100% complete then I might pay $500 for it. Anything else as cheap as possible basically less that $300.

 

[bmc69]

Loaded question as how much is to much is up to you. If I knew without a doubt the history of the motor and it was 100% complete then I might pay $500 for it. Anything else as cheap as possible basically less that $300.

x2. good advice .good numbers.

 

[needabronco]

It all depends on the junk yard. There's one in Prescott that on a 'good day' you can pull a complete engine for $260-300, other day's $5-700 same yard... Wednesday an thursday seem to be the best yard price days for me for some reason.

I pulled a 96' exploder 5.0 a few years ago with 180K on the clock. The cylinders are 'just' out of spec to re-ring. I could re-ring it but in all likely hood it'll be wore out in 30K.

My personal take on this subject is that I'd rather do a complete rebuild on any engine, especially if I was planning to keep it. At least then you know exactly what you have...

 

[Nightstick]

My personal take on this subject is that I'd rather do a complete rebuild on any engine, especially if I was planning to keep it. At least then you know exactly what you have...

I agree...

Mine has snowballed slightly... okay maybe more than slightly but it's still a rewarding experience and I've learned a lot so far.

 

[dbevans2249]

X2 on what broncnaz said about a compression test and timing set. If it has good compression and oil pressure I would drop it in and go. If it ran good in the donor it should run good in the Bronco.

 

[blubuckaroo]

I just can't imagine the faith you would need to just install a used motor without pulling it all apart first unless you knew its history. Rebuilding is just too easy to take that chance. Have you ever noticed that 2/3rds of the used 5.0s are advertised to have 70K-80K miles?%)

 

[bmc69]

I just can't imagine the faith you would need to just install a used motor without pulling it all apart first unless you knew its history. Rebuilding is just too easy to take that chance. )

Exactly. While I mentioned earlier that I have felt momentrily foolish on may an occasion after tearing down what was clearly a perfect engine...something about 'not knowing' always makes me do it anyway.

I helped a buddy replace a 5.0 on a full-size Bronco with one out of a Crown Vic that he picked up (before I could say 'noooo..buy the correct engine.."
He was in a hurry. Only 65K miles said the junkyard. Well AFTER we went to all the trouble and aggravation to pull teh 5.0 knocker out of the truck, swap over all of teh top and front dress to make the Vic 5.0 a Bronco 5.0, put it in the truck..

It ran on 7 cylinders and smoked like a freight train. Turns out the heads on the '65K motor" were absolute toast..we ended up rebuilding the heads from the original motor. And of course since we complete tore down and reconfigured the junkyard motor..no way the 30-day jy warranty was gonna do him any good so he ate the entire job.

 

[bigmuddy]

I have bought many stock 5.0 in the 600-800 dollar range. a few were from mustangs and one was from an explorer. On all of them I ran compression tests and yanked the pan and the valve covers, on a few with higher mileage 100 plus, I pulled the heads to check the pistons. All of them checked out and are still running great today. But with full disclosure I did buy a mustang motor from a non-running salvage mustang and the guy claimed oh yeah it will run like a top. I pulled the covers and the intake off and found at least an inch of sludge in the lifter valley. That motor got a complete rebuild.

gaskets are pretty damn cheap to give you some peice of mind, besides I don't like leaky engines.

With a little checking I would have no issue installing a used motor. Hell my bronco is lucky if it will see 5K miles this year. 8-(

Ben

 

[Tim in Az]

Thanks Guys for all the feedback. My Mechanical Knowledge is pretty limited.
I'm a carpenter buy trade and could build one hell of a nice house but when it comes to wrenching I have to rely on others. I'm just trying to do a little homework for a near future swap.

Thanks again Tim

 

[73azbronco]

where bouts in Az? Scottsdale?

 

[Tim in Az]

I'm out in Mesa. 202 and Gilbert rd.

 

[fungus]

I think if the motor is out and sitting on a stand rebuild it. Stockish rebuild kits are relatively cheap, you'll learn alot about your motor in the process and have great peace of mind when you stab it in your Bronco. My concern is not for the amount of mileage I put on my rig but the situations I put it in. I want to be absolutely confident that my powerplant is reliable and won't leave me stranded in the middle of nowhere halfway up some technical obstacle...