Cam Synchroniser Gear Sheared

[bluedude2288]

First off the truck is a 1999 Ranger XLT 3.0L V6 FFV. What would cause this? The engine only has 15,000 miles, it was never driven. The one day on the highway i hear tapping and look at my oil pressure gauge and I had nothing, pulled over and got a tow. The engine has lacked power from it being new, its always felt like something was wrong with is, what can it be, do you think it was related to this, what would cause the gear to loose 2 teeth entirely and the rest shaved down to nothing. The oil was always changed at regular time intervals instead of mileage intervals.

 

[ati190]

Cam syncro failures are a common failure. But at 15,000 miles you are an unlucky one. The 3.0 is a dog, but is reliable. Is your truck auto, or manual? Hopefully you didn't do serious engine damage, but usually when you here a tapping, it's too late.. Check to see if you can crank it by hand to determine if engine is seized or not. If not, i'd put a new motorcraft syncro in, and start er up.

Also, without having to type it over.

Wicked_Sludge12-12-2008, 06:47 PM
sounds like you came very close to loosing an engine. luckily your syncro got just got mangled instead.

the events leading to a cam syncro failure are:

1. the plastic bushing that the syncro shaft rides on doesnt recieve sufficient lube and begins to wear out, allowing the syncro shaft to wobble.

2. the flag on the CPS end of the wobbling syncro shaft contacts the CPS, suddenly stopping the syncro shaft.

3. the sudden stopping of the syncro shaft shears off the roll pin that holds the distributor gear to the syncro shaft....or otherwise the gear itself is sctripped out by the camshaft.

4. the syncro shaft is no longer powered by the engine. the oil pump, which is driven by the bottom end of the syncro shaft no longer turns and the engine recieves zero oil flow.

 

[bluedude2288]

We pulled the entire engine assuming that the the bearings were shot, the bearings look good, I think we pulled the engine for nothing, were going to try to just put a new syncroniser and put it back together and see what happens.

 

[evanesce69]

I would bet he just heard the lifters tapping when the cam syncro failed. The lifters are the last to oil next to the rockers so seems logical. If he shut it down quickly when he heard the sound, I'd imagine the mains and rods are still fine. Now if it seized, then "Yes" the bearings would be fried. There is alot of surface area on the bearings and the mains have a groove on the block half of the bearing to hold oil in.

I'm not sure of the following, but I would assume the syncro is splash lubed. I don't think it is pressure fed. Another thing I thought of is whether or not the cam gear is damaged.





Rob

 

[Rearanger]

1. the plastic bushing that the syncro shaft rides on doesnt recieve sufficient lube and begins to wear out, allowing the syncro shaft to wobble.

I would put forward that the tendency of drivers to use higher weight oil, especially the Xw portion, will lead to higher syncro shaft wear and gear failure. I am presently using 0w in all my vehicles to ease oil flow at cold start-up. Oil analysis shows great engine protection using this grade.

 

[laser3kw]

I tend to agree with Rearranger.
It seems most failures in the northern states occur in the colder month's. Mine failed in Feburary , in -20º blowing cold! I suspect the oiling system has a restriction problem and the pump labors heavily, putting to much strain on the synchro gear.
After mine failed I researched the TSB's on the 3.0 and found an unusual amount of TSB's pertaining to oil viscosity. The latest recommended 5w20. Also I am suspecious of the Fram filers. That's just me - your opinion may vary.
I now run 5w20 and only Motorcraft filters.