Eagle Posted August 30, 2012 Share Posted August 30, 2012 Look up the 2.5 for the 98-01 XJ at the dealer........I believe they are the same as 88. Should be current enough that they still stock. They can't be the same. The '84 - '90 2.5L engines used a variant of the Renix system -- the injection was throttle body but the ignition uses the same CPS as the Renix 4.0L. And the '91 and newer 2.5L engines use the Chrysler multi-port system and take the same CPS as the '91 and newer 4.0Ls. The arrangement of the trigger teeth on the flywheel is completely different. Link to comment Share on other sites More sharing options...
Jeep Driver Posted August 30, 2012 Share Posted August 30, 2012 Look up the 2.5 for the 98-01 XJ at the dealer........I believe they are the same as 88. Should be current enough that they still stock. They can't be the same. The '84 - '90 2.5L engines used a variant of the Renix system -- the injection was throttle body but the ignition uses the same CPS as the Renix 4.0L. And the '91 and newer 2.5L engines use the Chrysler multi-port system and take the same CPS as the '91 and newer 4.0Ls. The arrangement of the trigger teeth on the flywheel is completely different. Yep, you got me on that and I should know better. Link to comment Share on other sites More sharing options...
Pete M Posted August 30, 2012 Share Posted August 30, 2012 junkyard? :dunno: Link to comment Share on other sites More sharing options...
Geonovast Posted August 30, 2012 Share Posted August 30, 2012 If all else fails, Jim has one. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted August 30, 2012 Share Posted August 30, 2012 The 4.0 flywheels ARE convex. I had one redone, 1 year later when it failed, I noticed that the clutch had worn uneven because of the resurfacing. It started sloping so bad that I couldn't get a direct drive between the engine and trans. Link to comment Share on other sites More sharing options...
mountainman Posted August 30, 2012 Share Posted August 30, 2012 Odd. I wish someone could explain the science behind a convex contact surface. If it was something great, then it would become mainstream. But this is the first ive ever heard of it. from every engineering standpoint, it makes zero sense. has me.... :hmm: Link to comment Share on other sites More sharing options...
Eagle Posted August 30, 2012 Share Posted August 30, 2012 Odd. I wish someone could explain the science behind a convex contact surface. If it was something great, then it would become mainstream. But this is the first ive ever heard of it. from every engineering standpoint, it makes zero sense. has me.... :hmm: If it made zero sense, they wouldn't have done it. My best guess is that it makes engagement of the clutch bearing surface more progressive rather than contact/no contact. The goal, I suppose, would be to make engagement smoother. Given that few people actually know how to drive a clutch today (at least, how to drive one well and correctly), this makes sense to me. Link to comment Share on other sites More sharing options...
Geonovast Posted August 30, 2012 Share Posted August 30, 2012 Maybe because the Jeep was designed as an off-road vehicle, they went with a clutch that would be easier to feather on rough terrain? Link to comment Share on other sites More sharing options...
mountainman Posted August 31, 2012 Share Posted August 31, 2012 Been studying and studying and searching and reading on the convex deal.... basically so far nearly zero info. It is mentioned in various places as having existed and is known by some as flywheel crown. It was designed to enhance the takeup character of the clutch which in turn would enhance drivability. Its basically something they tried out and being un noticeable no other manufacturers used it. Now clutch technology is so good ..AND marcel in the clutch disk is designed to provide the same outcome this very light convex/crown did.... they stopped using it and... nobody else ever used it or even tried it. Essentially when it did exist.. the highest portion would take the most wear since it always gets touched first and especially with people riding the clutch at lights and all the other odd driving habits people have it would be worn flat before 100k miles. It was a VERY light crown. Then coupled with the fact that basically nobody is gonna spend the money on a machine to put the crown back on the surface, for one flywheel for one make of car, out of all that exist.... as i said before... as soon as the first correct clutch job is done... the crown is removed on the rock table IF there is any even left on it. Aftermarket flywheels... say centerforce... are made flat and can be used both with their disk and PP and any factory disk and PP. No adverse driving character to be noted. Even friction linings themselves have changed probably close to 10 times since 1991. due to rules and regulations. Stuff just keeps advancing. So to any who would worry, don't. Your fine getting your flywheel ground and putting in a nice new clutch. Your less likely to get chatter that way than if you simply sand the flywheel with sandpaper. Proper break in is also VERY important on all clutches, don't forget that part. :) Link to comment Share on other sites More sharing options...
carnuck Posted September 10, 2012 Share Posted September 10, 2012 It'll depend whether carbed, TBI or MPFI as to which flywheel. Starter changed too. Link to comment Share on other sites More sharing options...
mvusse Posted September 10, 2012 Share Posted September 10, 2012 Don't believe the Comanche was ever available with a carbed 2.5, unless that's what they got in 86. I know in 87 it was TBI. Link to comment Share on other sites More sharing options...
Eagle Posted September 10, 2012 Share Posted September 10, 2012 Don't believe the Comanche was ever available with a carbed 2.5, unless that's what they got in 86. I know in 87 it was TBI. But the 2.5L was introduced in 1984, in the Cherokee. Yes, it was carbureted in 84, 85 and I believe in 86. Link to comment Share on other sites More sharing options...
Automan2164 Posted September 10, 2012 Share Posted September 10, 2012 But the 2.5L was introduced in 1984, in the Cherokee. Yes, it was carbureted in 84, 85 and I believe in 86. '86 Brought TBI to the Cherokee also. The only thing that remained barbaric until '90 was the Wrangler, which retained it's carb, in the 4.2L at least. Don't know about the 2.5L. Rob Link to comment Share on other sites More sharing options...
Eagle Posted September 11, 2012 Share Posted September 11, 2012 '86 Brought TBI to the Cherokee also. The only thing that remained barbaric until '90 was the Wrangler, which retained it's carb, in the 4.2L at least. Don't know about the 2.5L. Oops. That's right. I completely forgot that the 2.5L got EFI a year earlier than the introduction of the 4.0L. Link to comment Share on other sites More sharing options...
Butchershop Posted October 15, 2012 Share Posted October 15, 2012 The 2.5L flywheel can be resurfaced. I'm going to replace the clutch/slaves in a 2.5L Renix. Fairly sure the flywheel has heat-spots, so need to resurface or replace. Prob a good idea anyway. I read there are no problems resurfacing the 2.5L flywheel. Please STOP me if I'm in error. Thanks! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now