Author Topic: 89'-90' 2.5l v belt to serp conversion?  (Read 1293 times)

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eastcoast yj

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89'-90' 2.5l v belt to serp conversion?
« 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!

Offline Jeffy

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Re: 89'-90' 2.5l v belt to serp conversion?
« Reply #1 on: December 01, 2010, 08:01:52 PM »
I think it should be straightforward BUT you might need to swap alternators.
« Last Edit: December 01, 2010, 08:02:21 PM by Jeffy »
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eastcoast yj

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Re: 89'-90' 2.5l v belt to serp conversion?
« Reply #2 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?

Offline sharpxmen

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Re: 89'-90' 2.5l v belt to serp conversion?
« Reply #3 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.
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Offline Jeffy

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Re: 89'-90' 2.5l v belt to serp conversion?
« Reply #4 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.
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"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

Offline sharpxmen

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Re: 89'-90' 2.5l v belt to serp conversion?
« Reply #5 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.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Backroads

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Re: 89'-90' 2.5l v belt to serp conversion?
« Reply #6 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.