What to look for in U-pull Magnum?

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valianator

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I'm seriously considering swapping a 318 Magnum into my '68 frankenstien Dart project.

There's plenty of them in the local U-pull yard, and I can pull the pan and heads right there for a look at the cylinder walls, bearings, etc.

Other than the basics, are there any problem areas to be on the lookout for with the Magnum? I remember reading something about heads cracking between the valve seats. Is this visable by looking? I'm assuming it would also make for a suspiciously sparkling clean piston and combustion chamber too.

Anything else?

Thanks
 
Make sure it turns over freely.

I had a magnum engine pulled in a yard, took it all the way home, turned the crankshaft over to find that #1 piston did not move at all..crank or rod was blown. Luckily they had a good return policy and exchanged it for another.

And yes you usually can see the crack between the valves. Bring some scotchbrite, flashlight, wd40, and lots of rags. It's ,most likely cracked anyways, I'd say 9 out of 10.
 
I don't know if it's 9 out of 10, but there are definitely many that are cracked.
 
if you can start it before pulling it that would be best
302 heads 308 heads and magnums get small cracks between the valve seats, it is not a problem, you can run them like that for years and years and tens of thousands of miles,
how many vans and pickup trucks are on the road with 5.2 and 5.9 magnums under the hood running just fine?
 
I am also considering ding a similar swap. My hope was to install a runner and then down the road swap the heads out if they were cracked. Just want a runner with all the wiring for a swap. Bought a wiring harness from Four Eyed Fox on FABO to do this. Just have not had the time to go to the yards and get an engine.
Please keep us informed on how it goes for you.

Mike
 
I pulled 4 darn mag heads at a yard to find them visually cracked, then found 2 that were not, took them to the shop to find they magnafluxed as cracked. Before that, had a set of 308 heads that a bad eng shop did a valve job to, took them to a different guy who started cutting the seats and found both to be cracked in multiple places. I personally don't see the point of a valve job on a cracked head, unless it's going in a stock, low budget farm truck. If I had saved all that time and money on getting cracked heads removed, inspected, and even rebuilt once, I could have almost bought a new set of eddys and been done with it all months ahead of time.

Just my 2 cents.. junkyard heads aren't worth it.
 
txstang84 said:
I don't know if it's 9 out of 10, but there are definitely many that are cracked.
Click to expand...

9 out of 10 aren't cracked enough to go into water jackets. Most of the time from what I hear, there is no guarantee they will ever hit water. Folks tend to sensationalize this.

If they aren't visibly wet, run that sh*t.
 
Yeah - they almost all have cracks. But they do not all get anywhere close to water. The way to properly test these heads is not to magnuflux - but to pressure test. Personally for me - I look for a running engine. I want to listen to it run, see it not smoke, hear it have good oil pressure and be responsive... Then pull the plugs and look at them. If they look good, pull it and don't sweat it. Taking them apart just leads to more pain and cost...lol.
 
PoisonDart74 said:
9 out of 10 aren't cracked enough to go into water jackets. Most of the time from what I hear, there is no guarantee they will ever hit water. Folks tend to sensationalize this.

If they aren't visibly wet, run that sh*t.
Click to expand...

The only experience I can speak from is my own, and I would agree with your statement. I can say however, mine did consume a little coolant, but only when the lead deposits in my right foot were more than normal. My brother has a 2000 Ram 1500 with a 5.2 5 speed...he said basically the same thing...only seems to consume coolant when he's in it hard, and only enough to be noticed after an oil change.

If it's enough of a concern, spring for a set of EQ magnums.
 
I suppose you also have to think about all those magnum engines still running out there today, the majority of those heads are cracked too, and their owners are unaware because they don't have any problems.
 
Thanks for all the info, fellas.
Sounds like I won't worry too much about the cracks as long as it doesn't show signs of ingesting coolant.

The plan is just to find one that looks good inside and out; torque everything back up with new gaskets (and prolly a timing set while I'm there); and let 'er rip.

Of course I'm wagering a bit- just looking for good odds. :wink:

Thanks.
 
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