4.0L OHV timing

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Feb 23, 2007 | 11:18 PM

davepiper

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4.0L OHV timing

Is the 4.0L OHV (8th digit VIN=X) engine an interference engine? i.e. If the timing chain breaks, will the piston hit the valves?
Thanks in advance, David

Feb 25, 2007 | 11:36 AM

aquanaut20

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From: BC Canada

Never heard of an X engine losing or skipping a timing chain, why are you worried?

Feb 25, 2007 | 11:50 AM

RangerPilot

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From: Durant, OK (SOSU)

According to my chart, no, it's not an interference engine.

But I'm with aquanaut, I've never heard of a 4.0L blowing a chain.

Feb 25, 2007 | 12:17 PM

davepiper

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Never!? That might disappoint me. I just bought a 99 explorer. PO said it was running fine, then wouldn't start one cold morning, he took it to a mechanic, mechanic said he checked for compression on two cylinders & there was none. I was hoping to find broken or jumped timing chain, so I bought it cheap. Trailered it home , but haven't looked at it yet

David

Feb 25, 2007 | 03:10 PM

aquanaut20

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Are these dead cylinnders ajacent?

I would be more inclined to thing blown head gasket, which are common

Feb 25, 2007 | 05:33 PM

davepiper

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I'm not sure if cylinders are adjacent, I just thought it sounded more like a timing chain since it was running good, then wouldn't start. I guess I'll find out more when I tear into it. Might have to wait for some warmer weather though. Maybe head gasket will be an easier fix than timing chain!?
Thanks, David

Feb 26, 2007 | 09:18 PM

kevin74656

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Timing belts, such as those found on most (if not all) OHC engines, require periodic replacement. These belts are made of flexible material, such as neoprene, and will eventually stretch and break if not replaced at regular intervals (usually something like 60,000 miles).

Timing chains, on the other hand, are made of metal, and should last for the life of the engine. I don't think that I've ever heard of one breaking, either.

Good luck - hope that you get it running when the weather warms up!