One of my friends has a 92 F150 with about 155k miles on it. The phenolic cam gear stripped the teeth off last week. Finally got the new one in there and got it back together and running. Good thing to know about the 300 is the valves and pistons didn't hit each other when the gear let loose. I have the gear so I'll take pictures if anyone wants to see what happens when the phenolic cam gear goes out. My 82 F100 had steel in it when I rebuilt it two years ago. Does anyone know what year ford started using phenolic instead of steel? I seem to recall is was 84 or so?

 

please post the photo

did you put a steel gear back in?

 

Ford used the composition gear on the cam way back. They had steel gear sets as replacement parts, at one time they had two different thread pitches about 8 teath to the inch and a finer pitch which I never measured. The courser pitch set was not noisey as some would lead you to believe. Now if you looked at the comp crank gear and though I'll just throw on the cam gear you were in for some noise. They had to be replaced together. kotzy

 

The parts store only had another phenolic gear in stock. To get the steel one it would of taken a few days which my friend did not have time to wait. I did use steel in my 82 F100 when I rebuilt my engine even though the original ones where steel as well. This gear stripped out when the temperature was zero degrees F with a -22 windchill. My friend last time he changed the oil he used 10w30. I don't know if the oil was so cold and thick that it might of had some roll in this failure.

 

The coarse steel gears -do- make noise. I have had two sets that sounded like blowers for years, I did replace both gears with the new set, and did properly install the cam gear.
I have had the fine tooth gears (very hard to find, and expensive), and they were quiet. These were factory equipment on my 69, I know in 78 they had fiber gears, but I don't know exactly when they started using them.
Make sure you change the oil, all those pieces are in the pan. Also, I have seen this failure a few times with synthetic oil on factory fiber gears.

 

I didn't know they had the fiber gears in 78. I thought they came along more when the EFI 300's started. The oil pan on his truck was replaced at this time because the oem pan was rusted so bad. We also removed the oil pump and pick up to make sure nothing get sucked up in to it. Luckly nothing got into the pump. The one thing I didn't know is that the fuel pump eccentric is still on the camshaft on the EFI 300's. When we pulled the cam out it had the eccentric on it. So ford must of never changed the casting of the camshafts between carbed and fuel injection.

 

he is correct, i had to go way back to a 77 F-100 for the steel timing gears.

 

Ford Six, I took care of a fleet with 18 P 500 and 600 powered by 300's all equipped with the Ford course pitch cam and crank gears and they were quiet. As I stated if you mated the cam gear with the steel crank gear which was cut for the fiber cam gear they were noisey as all get out. Yes they sounded like a blower. When you got Fords part number which was a mate to the steel cam gear you never knew they were in there. I think Ford only made the fine tooth set for a short time, as I only ever saw two sets.
By the way the crank gear for the fiber cam gear is easily ID as it has flat tops on the teeth, the correct crank gear for the steel cam gear has the same profile coming to a sharp crown matching the cam gear. kotzy