• DCRC 2024

Engine Knock

OB1

OB1

Active Member
Location
West Point
Help! My son blew a piston and cracked the block on his 98 TJ with the 2.5L. We found a motor from a 95 and dropped it in. When we fired it up it had a bad nock coming from what I think is the top of the motor. I pulled the valve cover off and didn't see anything obvious loose or bent. I learned my mechanic skills by just tearing into vehicles I've owned in the past so my skills are limited.
Being that it is fuel injected and that it still has the original fuel rail, injectors and throttle body, could it be detination from a lean cylinder, which may explain the exploded piston? Or is a lifter not getting the oil it needs?
Anyone willing to come take a look or listen will be greatly appreciated!!!

John @ 801 695-five,nine,eight,nine
 
UNSTUCK

UNSTUCK

But stuck more often.
What kind of oil pressure are you getting? I'd bet it's not a lifter. I would think it would just bend a push rod before it took out a piston. What did the top of the piston look like? Could you see where it hit a valve or was there a hole burned into the top of the piston?
 
OB1

OB1

Active Member
Location
West Point
The piston was in peices when I took the head off, a push rod and a valve where bent also. He told me he had good oil pressure before it seized up.
I'm going to put some new injectors in it to see if that helps.
 
mbryson

mbryson

.......a few dollars more
Supporting Member
Location
Bountiful, land of rocks
OB1 said:
The piston was in peices when I took the head off, a push rod and a valve where bent also. He told me he had good oil pressure before it seized up.
I'm going to put some new injectors in it to see if that helps.
Click to expand...

Wait.....is this the old or new engine with the piston in pieces? Assuming old, but.....
 
OB1

OB1

Active Member
Location
West Point
Yes, the old engine had the piston in pieces. The new one is knocking and I was wondering if it was from a fuel problem or something else. I'm replacing the injectors here in a few minutes and see what that does.
 
OB1

OB1

Active Member
Location
West Point
Sorry it took so long for an update. Knock is gone :). New fuel injectors took care of it. My son has had it back a week now and the new (used) motor is running great. I put a new clutch kit in since I had it apart.
 
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