Jack Regan
New Member
- Joined
- March 16, 2019
- Messages
- 2
- Reaction score
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- City, State
- Plano
- Year, Model & Trim Level
- 2006 Ford Mustang
I don't normally search for help on internet threads, but I'm getting dangerously close to scrapping this project.
I recently replaced the timing chain cassette and tensioner on my 4.0 SOHC with 150,000 miles. I bought Ford's OTC 6488 for the timing, and it ran great for about 4 hours. As soon as I hit 50 mph something snapped and the engine rumbled then died, it turned over but wouldn't start. I towed it back to the house and removed the valve covers to find the driver side timing chain I had just replaced had snapped. I honestly have no idea how this could have happened. It ran with no issues until I hit 50 mph.
My next step was to find out If I had bent any valves, but without a timing chain on the driver's side I wasn't sure how to do a compression test. Instead, I pulled the Schrader valve out of my compression tester and used a T connector with the pressure gauge and an air compressor to see if the cylinders would hold any pressure. I'm not sure how well this worked, but all cylinders seemed to be holding 90 psi with minimal leakage.
My questions are: What could have caused the timing chain to snap? obviously, it has to be something with the camshaft or valves, otherwise, both sides would have snapped. Could It be that I got the timing wrong the first time? Is there any chance that my janky leak down test was wrong?
At this point, I'm going to pull off the timing chain cover. I'll let you know If I find anything.
Thanks for reading, I'm hoping someone has an idea of what is going on.
I recently replaced the timing chain cassette and tensioner on my 4.0 SOHC with 150,000 miles. I bought Ford's OTC 6488 for the timing, and it ran great for about 4 hours. As soon as I hit 50 mph something snapped and the engine rumbled then died, it turned over but wouldn't start. I towed it back to the house and removed the valve covers to find the driver side timing chain I had just replaced had snapped. I honestly have no idea how this could have happened. It ran with no issues until I hit 50 mph.
My next step was to find out If I had bent any valves, but without a timing chain on the driver's side I wasn't sure how to do a compression test. Instead, I pulled the Schrader valve out of my compression tester and used a T connector with the pressure gauge and an air compressor to see if the cylinders would hold any pressure. I'm not sure how well this worked, but all cylinders seemed to be holding 90 psi with minimal leakage.
My questions are: What could have caused the timing chain to snap? obviously, it has to be something with the camshaft or valves, otherwise, both sides would have snapped. Could It be that I got the timing wrong the first time? Is there any chance that my janky leak down test was wrong?
At this point, I'm going to pull off the timing chain cover. I'll let you know If I find anything.
Thanks for reading, I'm hoping someone has an idea of what is going on.