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General Forums => The Mess Hall => Topic started by: eastcoast yj on December 01, 2010, 02:18:48 PM

Title: 89'-90' 2.5l v belt to serp conversion?
Post by: eastcoast yj on December 01, 2010, 02:18:48 PM
Hi,  Im trying to fit a header onto my 90' 2.5l TBI and am having trouble with the brackets for the power steering pump.  The rear bracket that bolts from the intake manifold to the engine block wont work with the header.  I have seen the serp belts on 91' and newer yjs and wonder if any of you have converted to them.  Will all the pully and brackets bolt right in or do I need to do any mods the the manifold?  the header is for a 91' and newer jeep.  Any info would be great!  thanks!
Title: Re: 89'-90' 2.5l v belt to serp conversion?
Post by: Jeffy on December 01, 2010, 08:01:52 PM
I think it should be straightforward BUT you might need to swap alternators.
Title: Re: 89'-90' 2.5l v belt to serp conversion?
Post by: eastcoast yj on December 01, 2010, 08:28:25 PM
I found someone with a near complete pulley set from an 95' yj.  he has the alt. with it but it looks like a different plug.  Could I just change the pulleys?
Title: Re: 89'-90' 2.5l v belt to serp conversion?
Post by: sharpxmen on December 01, 2010, 09:22:39 PM
I found someone with a near complete pulley set from an 95' yj.  he has the alt. with it but it looks like a different plug.  Could I just change the pulleys?


the '95 has the voltage regulator in the PCM, not sure where your's is.
Title: Re: 89'-90' 2.5l v belt to serp conversion?
Post by: Jeffy on December 01, 2010, 10:52:57 PM
Hmmm, the problem is the alt. is on a different mount and might not line up properly.  You can try mixing and matching.
Title: Re: 89'-90' 2.5l v belt to serp conversion?
Post by: sharpxmen on December 01, 2010, 11:02:13 PM
is the regulator built into the alternator on the 89 (or 90, whatever he has)? or driven by the PCM? If it's the latter he can use the control wire off his PCM, is just a variable voltage feed, he could also use an external regulator as well with the '95 alternator.
Title: Re: 89'-90' 2.5l v belt to serp conversion?
Post by: Backroads on December 03, 2010, 08:22:44 PM
I just took all of the serp belt stuff off a later model 2.5 to put my TBI stuff on it.

The crank pulley is different.
The power steering pump is different.
The alternator is different (pulley as well as plug I believe)
the waterpump you can change the pulley...BUT you need to get the right pump for a serp belt setup as it spins the opposite way..
Your going to need the different brackets for the power steering pump, If I remember the alternator brackets are the same.


I would look at modifying that bracket that goes under the header, I actually cut one arm off of mine because I realized after I had the engine hung, that the one mount ties into the motor mount.