differentiating engine size 5.3 from 4.8

[akajjmon]

After browsing the site for a while it seems as if ya'll might be able to help me identify a later model small block.
It seems I must have too much money, or brain damage, not sure which? I recently bought a 97 jeep wrangler with a small block/4l60(e?) and np231c T/case. I have to do the wiring conversion, but before I start anything, I would like to pin down ,as closely as possible, the exact engine in this beasty.
The ol'boy I bought it from was lucky enough to have the money to take it to a shop, tell them to convert it, and leave, Long story short, after circumstances ran it through a couple of different shops his wife said find a fool and dump it! Now at this point I had found myself facing every gearheads quandary of; Do I keep saving for that really pretty bridge the nice Nigerian man want's to sell me? or do I grab the opportunity to own this wonderfully unique vehicle just reeking with potential? (See "fool" above!) The seller was positive the running gear was from a 2002 or was it a 2003 silverado 1500 and it was a 5.7 liter/348 cu.in. The original guy doing the initial swap( pretty clean job) left the state for family stuff. The second guy pretty much was only s'posed to wire it but used it as a lawn ornament for a year or so while diligently preserving it's current state of "potential" and had no knowledge of the engines history.
So far the only numbers I have found have been the three digit head casting number 706 and a block casting number of 12567392 embossed on the passenger side rear of the engine block 3 inches below the head but outside the bell housing.
The internet says both casting #'s could be either an LR4 (4.8 liter,293 cu in) OR an LM7 ( 5.3 liter,322 cu.in.) The following is from a website called Chevythunder.com
Block ID;
2003 LM7 5.3L (322" cid) LR4 4.8L (291" cid) 12551358, 12567392, 12567393 Iron block with 96mm bore, can be bored to 99mm to make a cheap LS1 motor
Head ID;
LR4, LM4, LM7, L59 2001-2004 12561706, 12569862 1.89/1.55 200/70 61
My question( finally!) is how do I get one step deeper and discern which engine this is 4.8?/5.3? without pulling a head and measuring the stroke? which is,I'm told, the difference.
The last engine I worked on was when the 283 was the hottest thing available :shock: so any help, information or guidance to knowledge of any sort pertaining to fuel injection,computers, and engine/electrical swaps of this variety will be MUCH appreciated.
Thanks guys
J

 

[ChevyHiPro]

Hello and welcome to the forum!!

After reading your post, three times through, I'm pretty sure I'm brain damaged too!!


But, I'm not going to let that stop me! :lol:
I'm gonna take a stab at this one anyway!
First, I've no experience with these V6 engines (I think it's a V6!), I'm pretty much exclusively a Small Block Chevy V8 guy, been around those a goodly, long time.
But, since it's a Chevy engine you find in your Chrysler Jeep vehicle (how'm I doing so far? :lol: ), there are several other numbers that should be on the engine, that will tell us a lot more about it.

You mention, "a block casting number of 12567392 embossed on the passenger side rear of the engine block 3 inches below the head but outside the bell housing."
Typically a Block Casting Number is cast into the engine block, meaning the number digits are raised up from the surface of the block.
Is this what you mean by 'embossed'?
On the V8 blocks, this casting number appears on the rear of the block, usually on the drivers side, this would be between the flywheel and the engine block.
The Block Casting Number for V8's is a 6, 7, or 8 digit number, not sure about this for the V6.

Next, is the Engine Assembly Code, this number is hand stamped on the block, it is a series of numbers and letters and again, on a V8, it is stamped on a raised pad, located on the passenger front of the block, just below where the head sits on the block.
If the engine is fully assembled, this is usually behind the alternator, or other accessory and brackets.

Lastly, is the Partial Engine VIN Number.
This is also a series of letters and numbers, on V8's, stamped below the Engine Assembly Code on the raised pad mentioned above.

Now, to answer your question; "My question( finally!) is how do I get one step deeper and discern which engine this is 4.8?/5.3? without pulling a head and measuring the stroke?"

These codes tell all about the engine.
On these later model engines, these numbers (except the casting number) may be laser etched on the engine, in a dot matrix format.
I think they are normally stamped or etched on a raised pad as mentioned above.

The pad may well be located on the side of the engine (driver or passenger side), or on one side or the other of the front.
It will probably take some looking around to find it, then some cleaning with solvent and a rag.
Be careful about using a wire brush until you can determine if the numbers are stamped or etched!

Apparently the Engine Assembly Code is the one that will tell what the displacement of the engine is.
Of course, not directly, but once it is decoded!
For a V8, the Partial Engine VIN Code will look like; V1126CMD, where; V = Flint, MI (engine assembly plant), 1 = Chevy, 2 = 1972 (model year), CMD (Engine Suffix Code)= 1972, 350 CID, turbo 350 (trans), taxi, 2 Bolt Mains, A Body (full size)

So, the short answer, get a couple of rags, a spray can of solvent and check around the engine for these markings.
Remember, the raised numbers are casting numbers, there may be several, date code, casting factory, and others as well.
For the stamped or etched numbers, there may be several of those as well.
Try to find what you can , be sure to clean well and use a good light when reading them, it is easy to miss read the digits.

Pot what you find in this thread and I'll try my best!
Don't be a stranger around the forum!
Stop in from time to time and keep us updated on your progress with your hybrid Jeep thingy!!

 

[akajjmon]

Thanks for getting back to me so quick!
This engine is a fuel injected V-8. after leaving my posted question here I came across some archived information from what I assume was the original mortec site and according to the raised casting numbers on the engine it is listed as a 2003 5.3 liter with no mention of the 4.8 liter so I think I'm getting closer to a definitive answer. I have found the dot matrix #'s on a machined flat at the drivers rear of the block, totally inaccessible! wouldn't have it any other way!! I am going to try to transfer the code onto a piece of clay and read it in a mirror. if I can get it to be readable I will post it and maybe we can decode it.
This is the website I found the information on;
http://www.crankshaftcoalition.com/wiki ... ng_numbers
The archived stuff from "mortec" is at the very bottom of the page maybe it will be of use to some others looking for casting and code #'s
Thanks again and I will no doubt be hanging around the site as it gets going.
J

 

[ChevyHiPro]

Well, regards the 'quick reply', I was online, on the forum, kind of catching up with things here!
Saw the post pop up and just went through it.

I use crankshaftcoalition a lot, familiar with them, good info source.
Seems like the archived info put you real close on your engine.
From what I learned this evening, seems like the actual displacement of that particular engine causes everybody grief!
Saw a lot of searches for '" . . . s my engine 4.8 or 5.3L?"!
Looks as if yours is pretty much the 5.3L.
Great, no replacement for displacement when making power!
Keep us posted on how it goes with your Jeep project!

 

[akajjmon]

HiPro,
Machined flat drivers side rear of block I found and was eventually able to read a laser dot matrix number
C21395852
That is all there was, no suffix or secondary number Mean anything to you??

I keep reading the engine id #'s are located on the front passenger side of the block on a machined flat in front of the head. I have a raised (cast on) 5 digit number on the lowest of three machined flats on that side of the block it is pretty unreadable. Would the actual dot matrix/stamp be behind the water pump on the front face of the block?
Thanks for your help
J

 

[ChevyHiPro]

First, sounds like you've got a late model block.
I'm not 100% sure when Chevy started the dotmatrix etching, instead of the hand stamped numbers, but I believe it was in the mid to late '90's
GM went to roller cams in '86, a lot of the early roller cam engines ('86 - '89, about '89) have a conventional hydraulic lifter valve train with the roller cam, mostly truck engines and A Body (full size cars, taxis, fleet vehicles and cop cars).
I'm pretty sure in '90 the entire valve train (lifter, ect) were all roller.
The roller cam/valve train engines are capable of producing a large amount of HP and torque with GM parts.
There is a High Output cam, heads with large valves all avail as GM parts a guy can buy through a junk yard for pretty cheap.

The number you posted appears to be a Partial Engine VIN Code, it doesn't decode to actually give much info about the engine itself.
C21395852 - C = Lansing, MI or, C = Southgate CA (vehicle assembly plant), 2 = 1992 = model year (probably 1992), 395852 - vehicle partial VIN (last 6 digits of the vehicle VIN).

So, based on several bits of info and a little bit of historical knowledge, I think your engine is at least a post 1990 model, possibly, probably later model.
I'm not sure on these V6 engines, but the engine casting number is usually on the rear of the block, usually drivers side, it would be under the flywheel.
Yep, the transmission would have to be out to see the casting number number.
And, the casting number would only give us a range of years and displacement.
Not really too helpful.
In the case of these later model, V6 engines, I'm not sure where the Engine Assembly Code would be found.
Typically, especially since the advent of the 'permanent' dot matrix etching of these numbers, they would probably be a raised pad.

If you need parts for the engine, I'd just try using a late '90's year model, '97, '98, or whatever.
And if your trying to replace a part, take the old one in with you to compare.

I feel like this really isn't enough info to help you out, but it's the best I can do.
Let's both try searching around the internet for the location of the Engine Assembly Code for your style and approximate year model engine.
Hopefully, between both of us, we can come up with something and you can find the secret location of this helpful number.

 

[akajjmon]

Thanks hi pro,
not sure why you have referred to this engine as a V-6 several times, it is a late model V-8 electronic fuel injected (PCM/ECM) engine.
I went so far as to pull the water pump looking for the elusive engine codes on the front of the engine and have still found nada?

Going by the ECM service # on one of the units supplied (but not connected) and sorting through conflicting Internet "chart" info I am leaning to the assumption of a early 2003 LM 5.3L truck engine, possibly Canadian built.
Before I dump any money on a custom wiring harness etc. to move this Jeep Project forward I am going to do a leak down test on all cylinders to get an idea of the condition of the engine and based on those results I may just start looking for a different engine, or just sending this one to a machine shop for freshening up at which time I can get all the pertinent information from the crank numbers, bore / stroke etc.
Wish me luck, and thanks
J

 

[ChevyHiPro]

"not sure why you have referred to this engine as a V-6 several times, it is a late model V-8 electronic fuel injected (PCM/ECM) engine."
Just that I'm not so familiar with these later model engines and their displacement.
I'm pretty much old school, have done some engine building with late '80's - mid '90's SBC's, mostly 350's.
Before that, all older hydraulic cam SBC's.
In the research I did, displacement was mentioned, but not cylinder count.
I ASSuMEd it was a larger displacement Vortec V6 truck engine.
Anyway, glad to hear it's a full 8 pack!

Your probably right on the Canadian built engine, a lot of the GM light trucks and engines are built in the Canadian plants.
Interestingly, most of our new pickups here in Texas are in built in Canada and have been for a long time.

So, that late model engine should be full roller cam/valve train.
GM makes an array of high performance roller cams for those engines.
With just normal level of care, these roller cams, roller lifters and such should live out to +200,000 miles.
With various combinations of GM cams and heads, these engines can produce some serious HP and torque for cheap.

I hope some of the stuff I rolled out was of some help to you.
Good luck with your build and keep us posted on how things are going with it.