Identifying your 4.2L engine

[William Oliveri]

Ok, this is what I found out in case anyone is interested.

There are two main codes on a block that can help identify a 4.2L engine

1st. ENGINE DAY BUILD CODE. This is located on the passenger side of the
block just below and between #3 and #2 spark plugs holes. It's a flat plate
and has this format:

The Engine Day Build Code consists of six characters:

1. Year built code
2 & 3. Number of the month
4. Engine size/type code
5 & 6. Day built

Mine is 012C05

Which comes out to:

0=1980 or 1990
12=Dec
C=2v carb
05=day of the month built

See this site for more info:
http://home.att.net/~farna/amtech/amcengcodes.htm

I was unclear on whether this would be a 1980 or 1990 engine. To narrow
it down I located the Engine Serial number (2nd main code) which is located
right behind the O2 Sensor on the Drivers side of the block.

Mine reads: EF3235444

When I looked for this number on remanufactured engine sites I see that
this block serial number started in 1981 through 1990.

Therefore the best determination I can make is this engine is a 1990 made
engine.

Hope this helps someone.

Bill

[Mike Romain]

Umm... Bill yours is a 76-89 258 2bbl carb engine....

That is what the 'C' means.

The '0' means 1980.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

[William Oliveri]

Cannot be. The block casting "444" was not used in 1980. C does stand for
carb though.
"Mike Romain" <rom...@sympatico.ca> wrote in message
news:4038C045...@sympatico.ca...

[Mike Romain]

You are the one that posted the freaking link Bill!

Did you not read it?

I did.

And no 'C' does 'not' stand for carb.

Mike

[William Oliveri]

I stand corrected. C does not stand for carb and it does say the dates run
to 89.

C- 258 2 bbl (4.2L, 76-89)

However, every site I've looked at similar to this one:

http://remanufactured.com/AMC_Jeep_Engines.htm

says that the serial number of 3235444 started in 81, not 80 which is why
it's confusing.

Go to this site http://remanufactured.com/AMC_Jeep_Engines.htm and search
for 3235444 and you'll see what I mean.

Bill

"Mike Romain" <rom...@sympatico.ca> wrote in message

news:40393CF5...@sympatico.ca...

[William Oliveri]

Take a look at these sites:

http://www.monsterslayer.com/jeep/258CastingIDs.htm
http://www.jeepgod.net/258casting.html
http://www.tapcointernational.com/jeep_engines.htm

All of them state that 3235444 started in 81 through 90

Bill

"William Oliveri" <wu...@bigvalley.net> wrote in message
news:c1bmnn$1gt6tl$1...@ID-193866.news.uni-berlin.de...

[Mike Romain]

They warned about that on the first link Bill.

Some of the numbers went on when it was made and some went on for the
actual model year it was sold as or built for.

Here is a quote:

An important thing to remember about AMC engines is that changes were
made on a calendar year basis, not model year. The engine plant ran on
its own schedule! This is why some 1980 model vehicles have the "heavy"
258 and others the "light" 258 -- changes were made early in calendar
year 1980.

Mike

[Lee Ayrton]

On Sun, 22 Feb 2004, William Oliveri wrote:

> C- 258 2 bbl (4.2L, 76-89)
>
> However, every site I've looked at similar to this one:
>
> http://remanufactured.com/AMC_Jeep_Engines.htm
>
> says that the serial number of 3235444 started in 81, not 80 which is why
> it's confusing.

Do you have a plastic valve cover?

[William Oliveri]

Do you know what this means? Heavy 258 and Light 258?

What would really help is to totally exclude 1990 year engines. I need to
find out what the date code stamp is for a 1990 258.

My situation is a little different. The previous owner had the short block
replaced due to him pouring water on a over heated engine. I have all the
receipts. He had the head serviced for over 1000.00 and replaced the short
block with a used one for over 2000.00.

This was in 1997 on a 83 CJ7. If the shop replaced the short block with an
80 year block that would be very bad. Not to consider the smog logs require
a newer or same year engine to be replaced.

I know I have 1/2" head bolts and not 7/16" but that doesn't help either
because 80 and 90 year blocks have 1/2" head bolts.

Bill

"Mike Romain" <rom...@sympatico.ca> wrote in message

news:403A0568...@sympatico.ca...

[Mike Romain]

You can't have a 90, the cranks are different and the transmission will
not bolt up to it without some serious machining or searching for parts.

They changed to the YJ setup in 87.

They used 2 engine blocks for the 1980 year. You got the later one or
the 444 cast.

That does not mean you got a 1980 'engine', just a block from that
year. The crank could be any up to 86.

If this is a built up short block, then the engine cast just came out of
a pile they had around the shop and they put a CJ crank in it.

All bets are off when talking built engines, nothing has to match up
'properly' and a block is basically a block.

Not likely the fool paid $2000.00 for a 'used' short block, that is a
really expensive rebuilt one's price.

Emissions look at the heads and exterior junk.

Mike

[William Oliveri]

Wow, Ok. Even though the receipts do not state "rebuild" but "replaced"
with a used engine, I am hopeful you are correct.

Thanks Mike. That helps a lot.

Bill

"Mike Romain" <rom...@sympatico.ca> wrote in message

news:403A31C1...@sympatico.ca...

[Mike Romain]

One way to tell 'maybe' is by just looking close at the oil pan gasket
or timing cover for RTV or gasket maker.

When someone installs a used engine, they don't mess with those covers
usually. Your compression is also correct for a 'new' engine.

A used 258 short block goes for a couple hundred dollars, not a couple
thousand....

Mike

[Lee Ayrton]

On Mon, 23 Feb 2004, William Oliveri wrote:

> My situation is a little different. The previous owner had the short
> block

There's no "short" version of the AMC 258.

> replaced due to him pouring water on a over heated engine. I have all
> the receipts. He had the head serviced for over 1000.00 and replaced
> the short block with a used one for over 2000.00.

A grand for the head, eh? I just looked at my checkbook: $187.09US to
have my 258 head hot-tanked, the valves ground and new seals installed at
a local speed shop. While it was there they made a pass through the
planer just to be sure it wasn't warped and backed out a broken stud for
me.

Two grand to have a shop R/R an engine doesn't surprise me, though.

> This was in 1997 on a 83 CJ7. If the shop replaced the short block with
> an 80 year block that would be very bad. Not to consider the smog logs
> require a newer or same year engine to be replaced.

It goes by smog system, not individual parts, no?

[KJ]

I have a 1990 258 (now with a Weber carb.). Is there anyway I can lookup
some info. for you guys to solve this mystery?

"William Oliveri" <wu...@bigvalley.net> wrote in message

news:c18lrv$1g1r7h$1...@ID-193866.news.uni-berlin.de...

[William Oliveri]

Yeah, that'd be great. Look on the passenger side of the engine just below
the #3 and #2 spark plug holes on the block. There should be a flat plate
there with some numbers and letters on it.

What does it say?

Thanks,

Bill

"KJ" <he...@there.net> wrote in message
news:t5t_b.110498$B81.6...@twister.tampabay.rr.com...

[William Oliveri]

Correct me if I'm wrong but the term "short block" is referring to the
engine without the head. "Long Block" would be referring to the engine with
the head.

I'll scan the receipts in tomorrow up to my web page for reference. He also
had the carb rebuilt by Chrysler which was also big bucks.

"Lee Ayrton" <lay...@panix.com> wrote in message
news:Pine.NEB.4.58.04...@panix3.panix.com...

[KJ]

063CL06

 

1990 Jeep Wranger YJ w/ 258

 

So, 1990 year model w/ a 1986 block?

 

The C is close enough in stating that it is a "C- 258 2 bbl (4.2L, 76-89)", but the "L" baffles me.

 

Anyone have a clue as to the "L" portion of the designation?  The website info. for the "L" doesn't make sense in this case.

 

When ordering parts, I usually tell the parts flunkies behind the counters it's an 1989....I'll normally get the parts right that way since if I tell them it's a 1990, they screw up more often.

 

 

"William Oliveri" <wu...@bigvalley.net> wrote in message news:c1dq5v$1hmf4l$1...@ID-193866.news.uni-berlin.de...

[William Oliveri]

This number is in a different format than the web site states. Looks like
the format changes in 1990 otherwise your number would be:

Year 1990
Month 63
Day Built 06

Doesn't fit the following format:

1. Year built code
2 & 3. Number of the month
4. Engine size/type code
5 & 6. Day built

However, this information does confirm Mike's position which is now very
clear.

It could be that the day code letters are two letter codes rather than the
single letter codes the CJs have but that's just guessing.

Bill

"KJ" <he...@there.net> wrote in message

news:lhv_b.110535$B81.6...@twister.tampabay.rr.com...

[serg]

bill-here's some more info about the engine-
Oversize or undersize components
look between the ignition coil and the distributor. there may be a couple
of letters stamped on a boss. here are the codes:

B - All cylinder bores (0.254mm (0.010") oversize)
M - All crankshaft main bearing journals (0.254mm (0.010") oversize)
P - All connecting rod bearing journals (0.254mm (0.010") oversize)
C - All camshaft bearing bores (0.254mm (0.010") oversize)

Example: if you see the letters "PM" you have crankshaft bearing journals
and connecting rod journals that are undersize.

this info is out of my factory manual-if you can afford them ($100 in 1998),
get a copy of it. it has sooo much info on everything on your car.

"William Oliveri" <wu...@bigvalley.net> wrote in message

news:c1dq5v$1hmf4l$1...@ID-193866.news.uni-berlin.de...

[William Oliveri]

Thanks Serg,

Yeah, the FSM I have is the first thing I checked but it was not very
telling that year I guess. Probably gets better as the years go by.

Thanks for the info.

Bill

"serg" <no...@none.com> wrote in message
news:L4B_b.1885$3Y7....@newssvr27.news.prodigy.com...

[Lee Ayrton]

On Mon, 23 Feb 2004, William Oliveri wrote:

> Correct me if I'm wrong but the term "short block" is referring to the
> engine without the head. "Long Block" would be referring to the engine with
> the head.

You are correct, I am wrong.

I could make an excuse of mentally tripping over "small block", but really
I was just wrong.

I am still curious if it has a steel or plastic valve cover, though.

[Jeepfam118]

71-81 had the strongest castings for the block

--
For full context, visit https://www.motorsforum.com/jeep/identifying-your-4-2l-engine-28907-.htm

[Shawn]

310cl06

[Steve]

Hey hope someone can help me my engine day built code is 006361 and my stamp on my engine is EF3235444. I have a 1978 CJ7.
Looking for year of motor size and horse power.