Why are the Pistons on my Jeep Wrangler breaking?

Why are the Pistons on my Jeep Wrangler breaking?

A footnote to the piston issue is that these later Jeep 4.0L inline six engines have a tendency to break piston skirts. This problem has a two-fold cause: 1) short and narrow skirts on the 4.0L pistons and 2) close piston-to-wall clearance (0.0013″ to 0.0015″) to compensate for the short piston skirts and meet EPA/CAFE fuel consumption goals.

How to diagnose piston slap on a Jeep Wrangler 4.0L?

When I rebuild my ’99 4.0L, even though it is a “better” block, I will stick with 0.030″ overbore and sonic test the cylinders after boring. Sonic testing and the right piston-to-wall clearance are especially important for a 4.6L stroker engine.

How long does piston knock last on Jeep Wrangler?

Even after that, there is some knock while engine is cold, that lasts about 2 minutes when engine is cold. After warm up knock is gone. In three years things were not getting worse, even knock is still there.

Why does my Jeep Wrangler 4.0L make a noise?

My 1999 XJ Cherokee’s 4.0L engine has had a subtle noise since we bought the Jeep at 94K miles. It sounds exactly as you describe. The sound could easily be mistaken for a valvetrain noise but goes away as the engine warms. A rod bearing or valvetrain noise will not go away.

A footnote to the piston issue is that these later Jeep 4.0L inline six engines have a tendency to break piston skirts. This problem has a two-fold cause: 1) short and narrow skirts on the 4.0L pistons and 2) close piston-to-wall clearance (0.0013″ to 0.0015″) to compensate for the short piston skirts and meet EPA/CAFE fuel consumption goals.

When I rebuild my ’99 4.0L, even though it is a “better” block, I will stick with 0.030″ overbore and sonic test the cylinders after boring. Sonic testing and the right piston-to-wall clearance are especially important for a 4.6L stroker engine.

Even after that, there is some knock while engine is cold, that lasts about 2 minutes when engine is cold. After warm up knock is gone. In three years things were not getting worse, even knock is still there.

Can a 4.6 Stroker be installed in a jeep?

The answer is to install a Golen Engine 4.6L Jeep Stroker engine. With 270hp and 300 ft lbs of torque, it will bring life back to your Jeep and make it fun to drive again!! Facts you need to know about our Jeep 4.6 Stroker: Built to be a direct bolt-in replacement for factory 4.2 or Jeep 4.0 engines from any year