Topic: 2.5 project build-up

[hopp]

I'm picking up a spare 2.5L longblock with a broken thrust bearing. I'd like to build this and put it into my properly geared '97 TJ. I have a few questions and I'd really appreciate this boards advice(especially YJ Mechanic who has built his own performance 2.5l).

First of all here are my current performance parts:
1)pacesetter header
2)4.0L TB
3)Jet Power Stage 2 module (for premium fuel)
4)Airaid cold air intake
5)Electric Jeep cooling fan(from an '05).

I drive mostly on rural roads or fairly close fire lane. Most of the time my engine is spinning 2200-2800 or about 1700-2300 in the woods. I'd like to enjoy better torque in those power ranges. My budget not counting the parts above or the longblock as it sits now is $1800(out of which I'd like to take a clutch). I would like to maximize torque in this range while maintaining high reliability. I prefer to run synthetyic oil and wouldn't mind setting valve lash or other frequent maintenance. I would consider building this engine to withstand a fair bit of forced inducton. I've looked at the stroker angle and I can't come up with a cost effective solution via that route. Premium fuel even with some sort of octane boost is not a problem as I don't plan to put more then 12-15k on this vheicle per year. This vheicle is going to be a trail mule and occasional second (year-round)leisure car.

I plan to intake match and bust any casting flash out of the intake.
I'm going to index the plugs. I'd like to blueprint the oil pump.
I'm going to have the rotating assembly balanced.
I'd like to either try my hand at slight port cleanup, exhaust polishing, and bowl blending or get someone else. I need to pick up a free flowing exhaust....any suggestions? I'd like to pick up a higher lift moderate duration cam and springs....MR. YJ Mechanic...What part # is the package you had? Are roller rockers within this budget? Any special considerations on engine prep? For the valve job, can I find any local mechanic to perform a performance multi-angle job or is there a nationwide shop which will do better? Should I be looking for bigger valves? Cast or Forged replacement pistons? Anybody have part # for ARP head,rod and main bolts? Will I need bigger injectors?

I have an OBD-II serial port interface so I can perform some diagnostic tuning once I have the new engine running.

I'm not in a hurry(June 2007 deadline). I want to build this right and have a well-powered 4cyl vheicle. I've rebuilt snowmobile engines and done some simple SBC performance mods. I have my own (deep 1 car un-heated in the frozen north) garage and a seperate tool budget($700 Out of which comes an engine hoist).

I'd appreciate any input.
Thanks.

[snowbrew]

It sounds like you are on the right track. I dont know if you have visited this web site http://www.cliffordperformance.net/index.html
They have some performance stuff for your 2.5L, like a cam.
There is a bunch of little stuff that you can do to the engine to help make hp.
I purchased my larger valves for the cyclinder head from the dealer. I am sure that you can find them elsewhere also.

I have put in larger fuel injectors also....every little bit helps.

You can try this web site www.turbocity.com    they have some performance stuff also.

hope this helps.

[Jeffy]

You know if you really want to help the low end, I'd suggest an inertia ring.  The larger mass will help the engine keep the RPM's up when on and off road.  Offroad, it will be less likely to stall when the tire gets wedged.  At higher speeds, you won't be lose as much speed on hills.

Also, keep in mind that if you have emissions inspections, you won't want to go overboard.  All of Clifford's and Mopar Performance parts are for offroad only.

If you shop around you can find engine hoists for dirt cheap.  I really like the fold up ones but those are $$.  There is also one that doubles as an engine stand.

Honestly though, if you want big gains, I'd really consider a home made turbo.  You can get a rebuilt turbo or even a salvage for pretty cheap.  It would give you the biggest bang for the buck so to speak.

[RedJeep]

turbocharge it. I just ran across this on the jeepforum.com boards. There is 3 pages of critizism aimed at me because I said I wanted to get more out of my 2.5L. They believe its a waste. Suppostly if you run 7psi of boost your 2.5L will grow about 1.5L in power to be just like its bigger brother. Dosent sound to bad to me.
heres the website, send the guy an email, he got right back to me.
http://hometown.aol.com/turbochargedtj/myhomepage/auto.html

[chrisfranklin]

I dunno man.  I used to have access to a Saab 900 Turbo that my family had back when Saab was still a Swedish owned company.  When you'd get ready to turn off the engine, you'd have to idle for a minute to let the Turbo cool down (and prolong its life) and the Turbo had to be replaced once during a rather short 60,000 mile ownership period despite our irritatingly regular care of the vehicle.

 A DIY Turbo for an AMC 2.5 sounds like a lot of fun, but it also sounds like the unwary Jeep owner could be asphyxiated by a deluge of Red Ink if they aren't familiar with Turbos (especially with engines like the AMC 2.5, which didn't come built from the factory with a Turbocharger).  And, the value of the fun involved could be way less than the long-term costs.

Tell the AOl guy to write another manual on AMC 2.5 Turbo installs in about 6 years after he has accumulated about 100,000 miles on the modifieded engine.  I doubt you'll ever see one written.  And, I also doubt you can do an on-road Turbo Jeep 4 that is emissions legal, at least in California and a lot of other states

And, heck, I've heard cost-benefit problems with superchargers on 2.5s too.  Its generally a 4 Banger blasphemy like, "I shoulda just sold and gone with a 4.0 by the time you got through with all the extra costs and service involved over long-term ownership."

But, then again, by doing a Turbo install on a 4, you may be setting a precident that the rest of us will follow in a few years due to fuel prices.