3.8 S/c Cam gear blew apart

B

Big E Performance

Registered User
I've got a 1990 thunderbird s/c. hopping up the motor with a cam, overdrive pulley, and exhaust manifolds.

cam is a xtream energy 210/218 (SKU 44-702-9) the grind is half way between S/c performances stage 1 and stage 2.

it fired up for half a second then stalled(no MAF plugged in at the time). when i tried to fire it up again it only turned 1/4 of a turn.

would anyone have an idea what to look at first? the gear is the same on that was in it when the last owner rebuilt the motor. Tomorrow I am going to use an inspection camera to see if the valves hit but I doubt that the cam gear would break and something else wouldn't give before it.
cam gear.jpg
 
Is the cam itself locked up? Did the sprocket split at the keyway?

Did you install one spacer first, then the key, another spacer then the sprocket?

Any marks inside the timing cover?
 
Never seen that happen to a cam gear before , I have never assembled an SC engine, but it looks like a side load that cracked and broke it in two , maybe the way it was bolted down , or just unlucky to get a poor casted piece ?.
You may be extremely lucky and it kept the valve timing out of the pistons .
 
KMT said:
Is the cam itself locked up? Did the sprocket split at the keyway?

Did you install one spacer first, then the key, another spacer then the sprocket?

Any marks inside the timing cover?
Click to expand...
ill have to take the gear off to check I haven't done much after i got the timing cover off.

ill check if I have that order right could be put on wrong and had too much side load
 
Glad you debug'd the problem. Thanks for the followup and good luck w/your SC.
 
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