FedEx Truck 12v Motors

12vfleet

12vfleet

beCummin broke
Joined
Aug 15, 2010
Messages
616
Has anybody on here taken a motor from any of the FedEx trucks that had the 12 valves? We have one and so does a buddy and they have 53 blocks. I thought I remembered seeing on here somewhere that there were some motors manufactured in 97 that had a 53 block and were 12 valves. I guess some of them made there way into these trucks. Both motors have are CPL 1959 and rated at 160 hp.
 
the 12v hung arround longer in ag and industrial applications, so it could be later thank 97-98.. even with a 53 block shouldn't be a bad motor, take the engine number to cummins and see when it was built, could be a later 53 block without the issues...
 
I bought a 97 dodge truck to part one time and it had a 53 storm block in it. It is possible.:poke:
 
Havent heard of too many problems with 53 blocks in 12 valves. Iirc the harmonics of the 24v was thought to cause the cracks.

For what its worth my 98 12v has 150k on the 53 block. The KDP would be more of a concern to me.
 
I have a "52" block. LOL
It's a Brazilian cast "TUPY" NON-Storm later 1997 12 valve block.

Honestly, a "53" block isn't THAT big of a deal IF YOU HAVE IT SONIC CHECKED in the known thin areas and it passes.

I'm also under the impression that if the "53" block makes it beyond 200,000 miles in an automotive application and hasn't already leaked, it never will, but some people won't take the risk, no matter what you tell them.
I've junked several that likely were good, for that very reason.

Mark.
 
kalder said:
Havent heard of too many problems with 53 blocks in 12 valves. Iirc the harmonics of the 24v was thought to cause the cracks.

was aiming to write the above also but typing on my whone sucks parted a 98 stom 12v a few years back 660k just fix kdp
Click to expand...
 
I know of at least one 12v 53 block with issues. I just robbed parts off it yesterday for mine. kept getting coolant in the water. he finally put a new engine in it after trying everything else to fix it. its a brazil casting.
 
On the motor we have, it only had 67k miles on it. KDP was the first thing we did to it and runs fine in the first gen we swapped it into. The motor my buddy has is somewhere over 200k, but that fedex truck's gauge cluster was gone. It started up and sounded fine when it was still in the truck.
 
kalder said:
Iirc the harmonics of the 24v was thought to cause the cracks.
Click to expand...

I put together a 24V using a non-storm 12V Brazil block, and while being thrashed hard it cracked in the same place a 53 is known to crack.

I'm not sure what to think about that. My guess 5k+ and a stock water pump had some influence on it.
 
97rada said:
When do the water pump pressure begins to cause an issue?
Click to expand...

I'm not sure exactly. I've heard rumors of as much as 100psi of cooling system pressure, that combined with roughly 200 sq inches of block on the right side that has water behind it = 20,000 lbs of force pushing out on the side of the block.

That seems like a stupid amount of force pushing on the side of the block, and I've come to this conclusion with simple math. If anyone can reasonably disagree and correct me I'll gladly hear it.
 
K204DR said:
I know of at least one 12v 53 block with issues. I just robbed parts off it yesterday for mine. kept getting coolant in the water. he finally put a new engine in it after trying everything else to fix it. its a brazil casting.
Click to expand...

Coolant in the water? In an automobile?
 
It made me think of a bit from "the front fell off" vid on youtube...

"A wave hit the ship,"
"Is that un-usual?"
"Oh yea. At sea? Chance in a million!"
 
LOL
That exchange of comments is from this vid:
[ame="http://www.youtube.com/watch?v=8-QNAwUdHUQ"]http://www.youtube.com/watch?v=8-QNAwUdHUQ[/ame]

Mark.
 
in reality i think some blocks are going to crack and some wont under the majority of what we use our trucks for.. my 96 ran fine for 200k at 250hp, another 20k at 525rwhp and only made it 5k at 600+ and only up to the max of 700 but it had already cracked in the typical gunline in 53block fashion..
 
Reasonable. I think the motors should be fine because they won't see anything over 400 rwhp with the trucks they are going in.
 
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