Used engines a bomb ready to go off.

rattlenbang · November 04, 2013, 05:15 PM

A backyard big block guru just told me that whenever you get one of these big block engines from a wrecking yard, that likely has sat awhile, that not only do you need to put in new gaskets and seals, but that you should at least replace the crank bearings as well, as old oil will have corroded the bearing metal. When you start her up, regardless of how few miles she's got on her, the main bearings will pooch in short order. Anyone ever hear this before? Hm?

joev · November 04, 2013, 05:29 PM

I have installed lots of engines that have sat around for years you should replace all exterior gaskets like valve cover ,timing chain,oil pan and front main seal and rear main before you install the engine just so you wont have any leaks creep up later you can check the bearings while you have the pan off but most likely they will be fine

legomybago · November 05, 2013, 10:40 AM

I concur....pull a main and take a look when you reseal. Or...runner til she blows!!!!!!!!!!!!!

Surfinhurf · November 05, 2013, 11:41 AM

Its ALOT of work to pull and replace an engine in a motorhome. I would not spend that time, effort, money, on a motor that was picked up from a junkyard, and have no idea of its history. I would think main bearings and a hone and re-ring at the very least. Also most older big blocks ran leaded gas. Heads will need work for unleaded gas,,seats, valves, etc.

Good Luck

HURF

rattlenbang · November 05, 2013, 02:25 PM

I've never heard it before and thought it strange. But I guess the amount of work and money you put into it is proportional to what you want to achieve. if the original motor was 40 years old with 50 k on it, you can do a simple swap and end up where you were, but with with runner. Or if you want to restore it, then you start tearing things down. But to do it properly means a lot of machine shop work as well, and next thing you know it you've invested a couple of grand in a rebuild, which is more than you paid for the rig and far more than what it's worth. I'm not sure that every old engine needs a rebuild just because it's an old engine, or maybe I'm wrong about that.
I brought up the subject because I had just replace the engine on my Empress. it came with a 413 engine with a rod knock, so I replaced it with a used '78 440 with around again 50,000 miles. Because there was so much going on at the time, I forgot to replace the rear main engine seal. It ran really well with 60psi oil pressure, but off course it developed a leak from the rear seal. My friend was borrowing it but not checking the oil. It eventually ran out of oil on the hyw, and he kept restarting it and driving it until it died, not once checking the gauges. Eventually it wouldn't start and by then the bearings were gone. I could kill him.
So looking at another engine or repairing this one. I want to have it running again, but don't want to drop another 2-3 grand in it, after all the money I've put in it already.

legomybago · November 05, 2013, 04:34 PM

Thats a ruff way to take her out!!!

Just keep tryin, and tryin, but she won't go.....or start...or now it wont turn?? Oh well, just call my friend, he will come pick the motorhome up...Thanks for letting me borrow it! N:(

Oh well, you have the time and money dont you???

Ken · November 05, 2013, 05:09 PM

If anyone in western Canada interested, I have a good usable 1978 (out of a 1979) 440-3. It was running fine when removed. Replaced because running straight propane and little low on compression for adequate power on propane. Replaced with higher compression 440-1. Ideal candidate for rebuild.

jkilbert · November 08, 2013, 06:55 AM

IMHO do it right while it's out. You have it on a stand might as well rebuild it. Master rebuild kits are relatively inexpensive. Also now is the time if you want that new cam. We all know how much of a pain in the

it is to pull the engine in one of these. It only makes sense to try to prevent future headaches. I got caught with a junkyard bomb. The yard told me it ran and it did but since it was out I couldn't hear it run. I put it in the truck and it turned that it had a bearing knock. So back out it came, again. I just don't like doing work twice.
John

rattlenbang · November 09, 2013, 11:29 AM

yea, I'm starting to get shy of dropping another engine in there, although the last one was a very sweet sounding high oil pressure engine. Maybe I got lucky, but the thought of putting another unknown in and hoping...I think I would rather rebuild the one in there that got trashed, if I'm gonna rebuild a core.

Madathlon · November 09, 2013, 12:35 PM

If you buy a used engine you need to all os invest a little money and have it gone through.

No matter the engine I always tear them down and replace all gaskets, rings, bearing and seals. I also have the block flushed, cleaned and checked for cracks. and then at minimal I have the cylinders honed and the decks flattened (Decks are where the heads mount)

Then I also send the heads out and have then cleaned, checked for cracks, surfaced and in many cases with older engines I have new valve seats installed and tri cut.

Then come on the optionable things to do.

Like over sizing. this is a good idea but remember it a big ticket you will need new pistons and rings to go with this.

Upgrading the cam also a good one and it also costly as you need to have new push rods and lifters.

and of course you can change the intake at this time.

Also consider replacing motor mounts. Old one may look good, and they even maybe good, but while you have the engine out replacing them now is the best time.

And why we are in the engine bay you can also replace al those old ratty rubber hoses.

Even consider upgrading the Radiator.

But while you have the engine torn down this is the best time for upgrades.

And a big tip, Do not go cheap. it will only cost you more in the long run.

There a lot that can and needs to be done and your like but that expensive.

But if you do the basics I started off with you will end up with a strong long running engine that wont leave you stranded on the side of the road because you skipped a step and it failed.

Salvage yard engines are not time bombs, they like any other engine have time on them and need going through.

Most salvage yard will get you a replacement if you take your directly to a machine shop and they document a problem.

If you are broken down and have no choice but to put a salvage yard engine in right away, plan on removing it once your home and going through it then.