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General Forums => The Mess Hall => Topic started by: tallrugbyguy on June 15, 2009, 11:44:50 PM

Title: what 2.5 years are good with others?
Post by: tallrugbyguy on June 15, 2009, 11:44:50 PM
I have have a chance to buy a 2.5 but i do not know the year of the engine. It was rebuilt but has been sitting in buddys garage for a number of years. Just wondering how to tell what year it is. And weather it is ok to go into my 2.5. Are any serial numers i shoild look for let me know please.
thanks alot everyone is great here.
Shane
Title: Re: what 2.5 years are good with others?
Post by: drunkencityworker on June 16, 2009, 01:11:16 PM
Yes info on this would be good . A friend is putting a 5.0 in and I wanna rebuild his old 2.5 for spare. I know I have to swap flex plate cause I have auto
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 16, 2009, 01:20:55 PM
Danget... all my FSM's are 300 miles away... I'll try to find my Chiltons, it's here, just still packed...

As far as I recall, there is a four digit code on the passenger-side of the engine, I'm thinking the last two digits are the year... I'll go look at mine I guess...

Passenger side, just under the exhaust manifold. Last two digits, they're kinda separated from the rest... I think mine said 83...
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 16, 2009, 02:34:40 PM
thanks, i will chaeck that out!
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 16, 2009, 06:36:16 PM
thanks, i will chaeck that out!


oh, and i'm fairly sure that any year 2.5 is compatible with any other. 84 and 85 are probably the exception, due to different head bolt threads.
Title: Re: what 2.5 years are good with others?
Post by: drunkencityworker on June 19, 2009, 04:24:54 PM
so any year yj would be good as long as I swapped my injection stuff over
Title: Re: what 2.5 years are good with others?
Post by: Jeffy on June 19, 2009, 04:33:16 PM
so any year yj would be good as long as I swapped my injection stuff over
Personally I'd go newer if available.  TJ's use different cams but it's usually not a problem.

And yes, all 2.5L blocks should be date coded on the driver side.  Not sure what MR Ramdom is thinking with his passenger side exhaust manifold...
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 20, 2009, 01:57:39 AM
how do i know what the date is from that number?
thanks
Title: Re: what 2.5 years are good with others?
Post by: Jeffy on June 20, 2009, 01:34:25 PM
how do i know what the date is from that number?
thanks
The date should be very obvious.  IIRC, it's xx - xx - xx.
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 21, 2009, 01:04:43 PM
Personally I'd go newer if available.  TJ's use different cams but it's usually not a problem.

And yes, all 2.5L blocks should be date coded on the driver side.  Not sure what MR Ramdom is thinking with his passenger side exhaust manifold...

I LOVE being dyslexic... I specifically told myself to say driver side, but both times I put down passenger side.... I even edited the post, thinking I was correcting it, and put passenger! Ugh...


I think there are at least three different cams, if not four. 87-90 era didn't have as much overlap (EGR was eliminated on later models due to more overlap), 91-95(6) I think had more duration than 97-2001(2?)... There might have been a cam change in 00, some other odd internal things changed then too. I'm fairly certain that the earlier cams would at least make the engine run smoother, if not give a little more power. Also, the compression ratio was bumped down a little in 91... Valve and timing chain covers were also changed between the three years (I believe)


If you're planning a rebuild, then in my opinion it doesn't matter what year you choose... If you're just swapping in a newer motor sans rebuild, heed jeffy's advice.
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 21, 2009, 11:41:39 PM
alright sweet. im going to go see it tommoro and hopfully ill find out the correct date.
i am fairly positive it is a older one. he is saying 86.....not sure when these engins started.
thanks for all the info!
Shane
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 22, 2009, 03:41:45 AM
84 was the first year, 86 is more compatible with later years though. What year jeep will it be going in to? I can probably specify what will need to be swapped/modified to accommodate correct swap-ability.
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 22, 2009, 10:19:05 AM
it will be going into a 95yj. .
thanks again for the help.
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 22, 2009, 01:21:35 PM
it will be going into a 95yj. .
thanks again for the help.

The water pump wont clear the "sight" on the timing cover, it will need to be ground down at an angle. You will have to use a later model 2.5L pulley (a dealer only item unless you swap yours), my solution was to use a 4.0 pulley with a spacer to secure it, as the 2.5 snout is longer than the 4.0. Newer t-stat housing, passenger-side motor mount (I mean passenger this time, don't worry), or you'll have to modify the voltage regulator to mount in a  remote location (i did), a newer valve cover would be preferred, as they are of better design and have mounts for the throttle/cruise cable. One of the holes for the lower alternator brace will need to be bored out to the right diameter for the larger bolt. You'll need to swap over the mount for the ignition coil, and lastly (that I can think of), you'll need the newer flywheel.

Good luck!
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 23, 2009, 12:34:59 AM
wow, thats lots of stuff!
hmmm we shall have to see.
thanks alot for the info, you gave me exactly what i need.
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 23, 2009, 08:53:13 PM
oh, and if yours isn't external slave, if you can you should snatch the bellhousing and external slave components from the 86 (87~94 were internal), makes slave work a helluva lot easier!
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 24, 2009, 08:01:29 PM
hmmm this is turning into alot.
dont have access to  a bell housing and other components...
thanks
Title: Re: what 2.5 years are good with others?
Post by: Mr_Random on June 25, 2009, 01:05:27 AM
hmmm this is turning into alot.
dont have access to  a bell housing and other components...
thanks

Oh, no worries then, I was just suggesting it while it is out. Most likely you have an external slave anyways, seeing as your jeep is a 95. none of that is necessary.
Title: Re: what 2.5 years are good with others?
Post by: tallrugbyguy on June 25, 2009, 09:21:29 AM
ahh i see. thanks