Engine codes

[Xavi3r]

Hi folks !

i haven't posted since a lot of time but we are working on our 1970 monaco and I wanted to identify the engine.
i assume everything is matching but we cleaned the bloc and discovered the engine number with some marks.
Can you tell me about the codes ?
The iron cross and X mark, i suppose that someone did it ?

 

[detmatt]

The iron cross/X combo is .010” undersized crankshaft.

 

[CBODY67]

The "decode" for those markings are somewhat hidden in the section of the factory servivce manual where it mentions where the "pads" are where the markings appear on the cyl blocks. As I recall, only that particular engine size string of numbers/letters is mentioned. These markings relate to engine size and other aspects of its machining for production use.

The other set of numbers/letters near the front edge of the pad are not mentioned in the service manual, but have some meanings also. Sometimes, it seems that the definitions of that particular string of numbers/letters might be a bit over-stated, to me, but very possibly relate to camshaft and compression ratio (i.e., items INSIDE the cyl block itself. I suspect some others in here might have more information on that string of stamps.

Just some thoughts,
CBODY67

 

[detmatt]

The "decode" for those markings are somewhat hidden in the section of the factory servivce manual where it mentions where the "pads" are where the markings appear on the cyl blocks. As I recall, only that particular engine size string of numbers/letters is mentioned. These markings relate to engine size and other aspects of its machining for production use.

The other set of numbers/letters near the front edge of the pad are not mentioned in the service manual, but have some meanings also. Sometimes, it seems that the definitions of that particular string of numbers/letters might be a bit over-stated, to me, but very possibly relate to camshaft and compression ratio (i.e., items INSIDE the cyl block itself. I suspect some others in here might have more information on that string of stamps.

Just some thoughts,
CBODY67

F = the year code
The set of numbers and letters towards the front is the date and the HP2 stands for High Performance.

 

[Justin Plant]

So, if the iron cross/X combo means the crank has been turned. Does that mean the engine has rebuilt or repaired under warranty at some point?

 

[Ross Wooldridge]

So, if the iron cross/X combo means the crank has been turned. Does that mean the engine has rebuilt or repaired under warranty at some point?

No, I believe it means it was turned at the factory prior to assembly to fix a minor flaw in the crank.

 

[detmatt]

So, if the iron cross/X combo means the crank has been turned. Does that mean the engine has rebuilt or repaired under warranty at some point?

No, that’s that’s the way it left the factory originally. Not all parts were up to spec when new so it was not uncommon for them to machine them rather than scrap new parts. The original 440 in my Director left the factory with a .020” overbore.

 

[jollyjoker]

From the 1970 Chrysler FSM . . .

 

[CBODY67]

No, that’s that’s the way it left the factory originally. Not all parts were up to spec when new so it was not uncommon for them to machine them rather than scrap new parts. The original 440 in my Director left the factory with a .020” overbore.

Although all of the parts used in engine assy are new, some might not have been originally machined correctly, so if they were within a particular tolerance of "not correct", they would be re-machined at the engine plant and then used in an engine build job. With appropriate markings on the block ID pad.

GM's little known secret, at Chevrolet, was their .008"US cranks, identified by a green paint stripe. My late machine shop operative noted that that size was significant as when the engine was needing rebuilt at about 80K miles, it would be just right to use .010"US bearings. In one case, we sold a new crank to a customer, with appropriate new bearings. It turned out to be a green-stripe crank that needed appropriate bearings (they didn't check clearances BEFORE assembly!), so that turned into a flaky deal.

 

[ayilar]

@Xavi3r -- would you be so kind as to post the fender tag for your 1970 Monaco?

 

[300rag]

From the 1970 Chrysler FSM . . .
View attachment 517603

 

[67valiant 100]

Wow, a '70 U-code Monaco!

 

[Xavi3r]

@Xavi3r -- would you be so kind as to post the fender tag for your 1970 Monaco?

Hi,

ok i'll ask. car is at my friend's house.

thanks everyone for the great answers ! this level on knowledge is impressive

 

[Xavi3r]

 

[Snotty]

Wow, a '70 U-code Monaco!

Not according to the Fender Tag he posted.

 

[ayilar]

Wow, a '70 U-code Monaco!

That is what I thought too, and why I asked @Xavi3r for the tag.

Not according to the Fender Tag he posted.

DH23T0D188234 has been known by @polara71 for two decades, as it went up for sale in Philly twice (to my knowledge) in that period before it was bought by @Xavi3r in January 2016. The fender tag was mentioned in this thread, but the photo disappeared after the picture-hosting service on which it had been uploaded went down.

--> I am, still, puzzled about the apparent mismatch between the tag and the HP stamped on the engine. @CBODY67 @saforwardlook @amazinblue82 @69CoronetRT and others may be able to chime in.

 

[amazinblue82]

Not according to the Fender Tag he posted.

I agree with @Snotty and what others above were obseving.

While I am certain the pictures accurately represent what OP is seeing looking right at the car, the tag is E85, fifth digit T code in VIN indicates car was born with 350 horse 440, not the "Mangum" (E86, U code) 375 horse mill.

All that said, car most definitely could have left the plant with an HP block but otherwise E85 internals due to reworking/re-using common back then -- as was pointed out in other posts above.

I have not seen this latter case in any of my cars, but it happened a few times in old days I am told. So, you wound up with discrepancies in the hard parts/documents (e.g, E85 fender tag, HP block in the car)

I have seen MORE examples (I have owned two such cars), however, of civi cars (non-fleet orders) getting content NOT offered in civi cars (e.g., a Magnum/TNT/Super Commando supposedly unavailable to ordinary retail buyers). The physical car and all its factory documentation show it WAS born with things marketing materials/OEM archive sources said it couldn't get (Uncle Charley's '72 GF E86 coupe on this forum comes to mind).

'70 Monacos could surely get an E85 as an option. I'd be interested in what other self-evidencing/build documentation says about this Monaco

IF camshaft is original, plus a couple other things that may be evident (exhaust manifolds, duals, etc) , that are common differentiators between the "regular" and the " Magnum" 440- equipped vehicles, maybe this Monaco will get sorted out.

 

[Xavi3r]

Waho !
What can i show you to bring more clues ?
I have the build sheet.

I can check on the engine number to see if it is matching ?

I do not see why the car cant leave the factory with a " better " e86 block no? Maybe they were short of other ? If i understand correctly the block is a u code 375hp but marked as a e85 ?

 

[Xavi3r]

Car has dual exhaust, and here the picture of the intake. ( we replaced the holley 4160 that had many problems )

 

[saforwardlook]

Waho !
What can i show you to bring more clues ?
I have the build sheet.

I can check on the engine number to see if it is matching ?

I do not see why the car cant leave the factory with a " better " e86 block no? Maybe they were short of other ? If i understand correctly the block is a u code 375hp but marked as a e85 ?

Unless I missed something somewhere the first step before jumping to conclusions would be what you said in terms of checking the engine number to make sure it matches the vin. Then we can start surmising.