Originally Posted By: OVERK1LL
The 302 was an interference engine!!! AND it had a timing chain!!!!
...
Yes, I've been quite happy that all of my 302's have been double-roller with cast gears. My 300 I6 on the other hand.... nylon went bye-bye and I tossed the engine.
[/quote]I can't find the 302 on lists that I get from Google for interference engines:
Quote:
FORD INTERFERENCE ENGINES 1984-2003
1981-85 1.6L Escort, EXP
1981-83 1.6L LN7, Lynx
1984-85 2.0L Escort, Tempo
1993-95 2.0L Probe
1986-88 2.0L Ranger
1984-87 2.0L Lynx, Topaz Diesel
1985 2.2L Ranger
1989-92 2.2L Probe
1986-88 2.3L Ranger
1986-87 2.3L Diesel Ranger
1991-98 4.6L Crown Victoria
, but the list I get does say
Quote:
... list are engines that AERA is currently aware of that have exhibited interference. There may be other engines that are not listed ... that have the possibility of piston to valve contact. If the engine you are working on is not listed, do not assume that it is a freewheeling design.
Interference Engine List (many makes) quoted above.
If the 302 is interference, it is not on the list probably because it rarely blows the chain. As you note, double roller. What's the chain on the 4.6? Is it double roller? I suspect not. It seems obvious that the 4.6 has blown enough timing chains to make this list and the 302 has not.
As for the 300 and nylon gear, I understand Ford did that to cut noise. Older 300s (or was it the HD 300) had steel gears and some of the guys who hot rod their 300s put the steel gears on theirs.