This will help anyone with the 2.5 engine it says jeep but they used the same 2.5 engine just be sure of the year engine it changed over time so watch the Torque Specifications for your year 97 to 02 jeep and 97 to 02 Dakota is exactly the same all around the jeep 2.5 just mounts differently in the jeep.

http://jeephorizons.com/tech/99_25l_torque_specs.html

 

Engine is in now to get an answer to why it will not start.

 

Here she is finished just a few things to get done.

 

Hour and a half nonstop break-in drive today all’s good runs very smooth.

Perfect day only 75 overcast today last week it was 99 all week and starting to cook in Arizona soon 112 it happens fast.

It must be the heat of Arizona but in the 3 weeks my Dakota was down every rubber hose or seal shrunk or dried out rad cap was leaky heater and rad hoses dried up hard I need to replace them all. Rad hoses are getting pricey $35 to $45 each ouch.

 

OK my parts list

NEW

1. Head with 1mm larger swirl ss valves I opened up and ported the head myself everything new springs pushrods rockers so on.

2. .040 over sealed power pistons unfortunately I couldn’t get a .040 piston with thin rings.

3. Special intake manifold I custom opened up and ported.

4. All bearings tri layer clevite or sealed power

5. Comp cams mild lift cam with improved lifters can’t improve too much because of PCM limitations.

6. Timing set with head bolts oil pump

Machined parts

Block decked .011 bored for .040 pistons, rods and crank checked crank polished everything pro balanced I also cut .011 off my new head to improve compression ratio as the head combustion chamber cc was increased by porting.

Fel-pro gaskets Permatex® Ultra Slick™ and Red line assembly lube used

 

Stock crank and rods with new pistons? Or just stock crank? Cutting 22 total mating surface is alot, I'm surprised both of them had that much. What is the CR now, 10.5:1 ?

 

Only 8.8 compression ratio porting the combustion chamber of the head increased the stock 50cc to a 57cc I actually lost compression ratio from stock that is was 9.1.

I wanted to deck more off the block by my calculation allowing the pistons to be on the positive side around +.003 with the gasket crush of .053 netting me almost a stock CR of 9.1 my understanding is a head clearance of .035 is safe.

But super safety won out so a deck of .018 was reduced to only .011 Dan and I came to the conclusion a small loss from a CR OF 9.1 down to a 8.8 was a small lose.

I re used my oem rods

Cam
COMP CAM
200/206 @.050 416/435 113+3lsa

STOCK
188/192 @.050 408/414 108

I used this to get CR answers https://www.jeepstrokers.com/forum/calculator/

My numbers I may be off some numbers

Piston compression height = 1.589
Deck Clearance = +.003
Pin diameter = .931
Stroke = 3.188
Bore = 3.915
Rod length = 6.125
Gasket crush = .053 - .018 = .035
Combustion Chamber = 57cc with .011 curt off the head.
Piston dish = +16cc to + 19cc

Only pistons available were dish unless I spent $400 for custom flat top forged pistons $400 too much.

 

So you have stock crank and rods with new pistons? I assume wristpins are new? Crank was polished to +1?

 

Yes new pistons came with pins they said crank was with in speck a little lose but ok they said standard bearings were OK.
Plastigauge came out .002 thats the preferred gap by the manual.

I hate to say this but choices for the 2.5 are usually two choices support for the 2.5 is low to zero you take what you can get that means you don't get what you want 1/2 the time or worse.

 

Just an update other than my fuel pump going out on me the rebuild is running great no problems she idles a little low but has never died or stalled so I installed a new TPS but no change so I think its ok.