Thrust Plate Worn So Much Cam Walks 1/4"??

Mmulisha84

New Member
Aug 6, 2017
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Been battling this timing retarding issue for about a week now. Thought it was the cheapo hei yea yea I know it doesn't belong but it was cheap when I needed something. Long story shot I would bring it to 3k and the timing would advance to 35-38 then start to retard and when I let off the throttle the timing would drop down past zero and slowly come back up to 12 which was my initial.
I pulled the hei today to check the gear and while it was fine I shoved a flat head in there and pushed the cam and it moved so I pushed it the opposite way and it walked damn near 1/4".
I just put this motor in from a explorer and had the cam out to swap in the mustang cam I know I bolted the thrust plate back up but I guess I didn't notice any damage to it. Does this sound legit? I read the plates are a common issue but common enough to walk that much? Obviously I will have it apart this week sometime and see what's really going on but just putting it out there for some advice before I get into it. Is there a better thrust plate to buy or is there a button like chevys that I missed? I know I didn't see a button when I tore it down.
I used the mustang cam and timing set but used the explorer plate.
 
The plate is not all that thick itself. The cam gear should pull the cam up against the cam plate and leave it's clearance at a few thousands of an inch. I would suspect that either the cam bolt or the plate bolt has loosened. Definelty need to have a look.

Joe