P400 Block Assembly Identification

Hello:

Considering purchasing a P400 long block assembly for use as a marine engine.

I'm working with a vendor who has a long block for sale that was ordered from AMG in 2013. According to the vendor, the AMG part number of the block is GEP12562496.

My question is, are there casting numbers on the block casting some where that can confirm it's the genuine item with a forged steel crank and all the other improvements. It's a 506 block as can be seen in the attached images.

Also, how do I determine it has piston oilers for all cylinders?

I'm naively assuming I can fit this engine with a DB2 pump calibrated for 160 hp normally aspirated operation under pure mechanical control and a high volume water pump to keep it cool under continuous use @ 2800 RPM.

Your feedback is appreciated.

Thanks,

Mark

Welcome aboard!

The casting number (ending in 506) appears to be genuine. However, foreign import counterfeits have the same numbers (they counterfeit all of, top to bottom). The pics you posted appear to be the genuine article, and should be fully outfitted inside. You may want to have the seller certify that it is, in fact, the real McCoy.

What you are asking the engine to do has been a marine industry standard since about 1984, with hundreds/thousands still on the water. It should run all day/night for years (and sip fuel doing it), asking no more than that. A HO water pump would be advisable, IF your boat has a closed-circuit cooling system. If your engine is fresh/sea water cooled, you will need a different water pump. An MFI system will require plugging the crank position sensor hole in the timing cover. You are basically asking for a simple, off-the-shelf application. For any marine-specific needs, I recommend contacting Peninsular Diesel (they specialize in marine application GM 6.2/6.5L). Most everything else can be had from TDP vendors (highly recommended) and your local auto parts store.

Howdy
I thought the P400 had block extension/girdle on the bottom end and different main caps?

Please get us a snapshot of the bottom of the engine showing the pan rail area and the pan

There are loads of counterfeit 6.5 assemblies out there but I have never seen a P400 copy

The P400 has the bottom main girdle assembly that comprises all 5 of the main bearing caps and a complete rail that bolts the entire unit to the block.

If the engine does not have the girdle then it is the optimizer 6500, which is the standard engine.

Although a good engine the P400 is the best of the lot when it comes to the 6.5.

That doesn't look like my p400, it doesn't look like the 3" girdle is there..

Who is the vendor selling this??

Also ALL p400's will have a ser # engraved in several places for id traced back to the factory...

Where can one find the factory engraved serial numbers?

Howdy
After looking at the pics closer, the side view shot in particular.
It does not appear to have the block extension.
Judging by that pic, this is a standard 6.5.
That doesn't mean it's not a good long block, but don't pay P400 prices for it.
Good luck!

That does not even look like a true Navistar block - no diamonds cast into the valley. That looks like a clone.

Quote:

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Originally Posted by northwester

Where can one find the factory engraved serial numbers?

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Each head on the flat side, will have a blue & white paint dot, and 2 dril point dimples, one on either side of the bolt hole ...... where the pic you posted has 3 dimples...

buyer beware their are lots of off shore motors floating around these days...

Since the P400 was released in 2008, AM General has produced non-block girdle versions for their service market and as GM replacement engines. These non-girdle engines are known as the "OPTIMIZER 6500 V-8 diesel engine". They are not, however, named P400. Someone else calling a non-girdle engine a P400 could be just a somewhat inaccurate and misleading ad strategy if this is a genuine AM General engine.

Go here to see photos of a P400 display engine shown by AM General.
http://www.thedieselpage.com/features/AMGsnew65.htm

The production P400 was equipped with a cast aluminum oil pan that works for a HMMWV application, but won't fit into a pickup truck. We did a story a while back that shows how to make a deep pan for the P400 that will work for a Suburban/Pickup truck.