View Single Post
Old 05-04-2019, 06:39 PM   #2
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 42,428
 

2003 L-Series 3.0L Sedan
Default Re: Car starting after timing chain breaks

Interference engines are a result of better engines, raising compression with valves opening lower in combustion chambers where mechanical timing leaves no room for missed timing. If a timing chain breaks while the engine's running, momentum of rotating masses continues with mistimed valves meeting pistons at the wrong time. This usually results in bending valves and/or bashing piston tops with new holes. Most engines stop immediately from catastrophic damage. If the engine was running at high way speeds, high rpm. bending and breaking connecting rods results in engine blocks with new side holes.

If you suspect timing chain damage, the engine should not turn over as a valve or two lock against a piston or two - the camshaft no longer turning locks valves into position, never turning again while the crankshaft turns and rotates connecting rods as pistons move up and down in cylinder bores. The safest way to determine damage is removing the valve cover and examining the timing chain to see if its still connected to the camshafts. You might see broken camshafts too. Another way would be manually rotating the crankshaft using a breaker bar and socket. Manually turning the crankshaft with spark plugs removed (zero compression) should allow easy rotation. Any restriction to rotating the crankshaft like feeling a solid metal to metal sound would indicate damage.

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote