BANGING: lower front block

[Canoe]

Got the last of the connections worked out and the belts on, so it was time to fire it up for the first time since it got clipped.
After the old gas got flushed out by the new fresh gas, it fired right up.
Only to have a huge banging noise in the lower front block. Timing chain? Bearing(s)? Crank?

The rad was trashed in the collusion, but from being pushed onto the waterpump fan mount. The fan blades aren't even bent. The alternator was trashed, but the A/C pump was fine, as was the A/C condenser. There's no sign of the lower drive pulley being hit.

Ideas?

Can I tell what it is without taking it apart?

[shanebo]

My buddy bought a jeep wrangler at a police auction that had been invoved in what looked to be a pole vs.car kinda thing. He pulled the engine and dropped it in another jeep...when he started it up...the same nasty knock...He tore down the motor and discovered the crank shaft had goted tweaked form the impact. Ive heard of internal engine damage being caused by heavy rear impacts too...the drive shaft being shoved foward can do some damage to internals.

[Canoe]

It's interesting, the rad got enough of a press against the fan shaft that it leaked, but the a/c condenser didn't. Water pump turns smoothly. With the belt off for a test, the noise is lower front block, not the water pump.
Absolutely no sign of any mark on the front pulley and it turns normally with a 1/2 ratchet on it.

One source has an interesting opinion. Simply oil starvation due to long time since last run. He says the pump is at the rear and the front is the longest run from the pump.

Suggests I try what he's had to do with jeeps (I6-258) that have sat a long time:

• change filter, check oil level;
• adding an extra quart of oil (just for low rpm testing/warmup - drain it afterward, but you'll be changing the oil anyway);
• jack the back of the car up slightly to aid in splashing the front of the engine (doesn't know if this helps, but it's what he'd done);
• spray something on the front seal, engine oil, WD40, anything to get it wet;
• keep the rpm as low as possible to keep the forces down;
• start it for 45 seconds, let sit for ten minutes for the heat to soak and the oil to seep; check the oil fill on the valve cover for signs of oil;
• might have to do this ten times before oil is pumped around;
• once the noise is down, let it run at the lowest rpm possible until it reaches normal operating temperature, then let it sit for an hour;
• repeat: low rpm til operating temperature, then turn off and let sit;
• once the last step results in normal engine running noise, change oil & filter;

He points out that if the crank is bent from the accident G-forces while spinning (which he doubts due to the 258 robustness), then you're going to be replacing the crank and bearings anyway, so trying what he's had to do for long sitting Jeeps won't do any more damage.

Given the last statement, why not try?

[Canoe]

o ya, take a look at the harmonic ballancer also. its possible the outter ring got hit, and tweaked it and it may be hitting on the block now.

Will check.
But after the accident, specifically checked and there were no marks on the outer ring.

[Canoe]

Worked!

 

• might have to do this ten times before oil is pumped around;

Three starts and the noise was so low that it was too late to video record it.

Only thing I didn't do was raise the rear end.
Major improvement after 2nd run. Guess that gets the oil all through things. Each start then stop had lots of post run creaking and cracking thro ughout the engine. Lots of oil pumped up on top of the valves.
It was sitting with synthetic oil in it.

... One source has an interesting opinion. Simply oil starvation due to long time since last run. He says the pump is at the rear and the front is the longest run from the pump.

Suggests I try what he's had to do with jeeps (I6-258) that have sat a long time:

• change filter, check oil level;
• adding an extra quart of oil (just for low rpm testing/warmup - drain it afterward, but you'll be changing the oil anyway);
• jack the back of the car up slightly to aid in splashing the front of the engine (doesn't know if this helps, but it's what he'd done);
• spray something on the front seal, engine oil, WD40, anything to get it wet;
• keep the rpm as low as possible to keep the forces down;
• start it for 45 seconds, let sit for ten minutes for the heat to soak and the oil to seep; check the oil fill on the valve cover for signs of oil;
• might have to do this ten times before oil is pumped around;
• once the noise is down, let it run at the lowest rpm possible until it reaches normal operating temperature, then let it sit for an hour;
• repeat: low rpm til operating temperature, then turn off and let sit;
• once the last step results in normal engine running noise, change oil & filter;

...

Next steps are to take it up to normal operating temperature.
Fingers crossed.

[shanebo]

glad to hear it was an easy fix!

[vangremlin]

Great! Let us know how it does at normal operating temperatures.

[Canoe]

Once started, I managed to get the idle down to around 400.
It took two cycles to Normal Operational Temperature (temp needle at 3:15 on my Eagle) to get the noise back to fully normal. Sat an hour between runs.
Only abnormal noise now is tappit noise from one lifter (abnormal? like I haven't heard that before on an Eagle ).

Only glitch was the A/C pump wailing like a banshee (system empty - no lube). Took me 20 seconds to figure out what happened and shut it off. It hadn't done that during the shorter heat-soak/oil-seep cycles. Unplugged the wire to the A/C so I could restart and continue the run to operating temperature. Hope the pump wasn't trashed by that. Clutch works fine.

Rather odd seeing everything running with the rad support on jackstands (front clip not welded in yet). Had to tear it all apart to get ready to weld the clip on tomorrow. Once all is installed, I get to see if the transmission works.

Stupid brand-new over-bore premium master brake cylinder. 30 minutes of pumping it on the bench trying to bleed. Only pumps one output. Time to pull out a used spare.

But, amazingly, the valve cover is NOT leaking any oil! Stock cover, stock torque, naked on a double thick cork gasket which sat on the head with gasket spray adhesive. I'd definitely go buy a lottery ticket, but I've obviously used all of my luck quota up.

Oddly, there was oil sprayed out on the underside of the alternator support bracket. It came from a somewhat loose nut on the timing cover stud that also receives the alternator bracket. Shot out at very low volume through the threads. Never seen anything like that before. No leak at cover seam. Torqued the nut down and leak stopped.