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Discussion Starter #1
Broke a cam dowel pin and chewed up a thrust plate. What would cause this? Solid roller, has a VERY generous amount of spring pressure. It's a 438" sbf. Its a single pin cam, 7/16 bolt. Used red loctite and torqued it to 65ft/lb. Has anyone ever seen the cam dowel pin back out of the receiver hole in the cam? This is the only thing I can see happening. The cam bolts was still super tight... Not sure exactly what's going on but I'm hopin it didn't ruin a brand new set of titanium valves! Here are some pics if the pin and thrust plate.

 

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Just so I understand. The nose of the cam sits through the thrust plate. The dowel pin clears through the inside hole of the retainer and doesn't touch any part of the thrust plate. Aftter installing the thrust plate you install the cam gear over the dowel and use a bolt in the center to hold the gear on. Did you reuse the fuel pump ecentric or just use a bolt to hold the gear on the cam? If you just used a bolt you need to also use a large diameter flat washer large enough to cover the hole in the timing chain gear so the pin can't come out.
 

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Also, some of the dowels that come with cams are not hardened. I have been told that a single dowel can work with high spring pressures. However, I tried running a single dowel, broke it, and bent all of my exhaust valves. I ALWAYS run two dowel pins now. I also replace the pins that come with the cams with a hardened dowel pins.
 

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X2......I always run hardened pins and double them cost me $50 for machine work
 

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Also, some of the dowels that come with cams are not hardened. I have been told that a single dowel can work with high spring pressures. However, I tried running a single dowel, broke it, and bent all of my exhaust valves. I ALWAYS run two dowel pins now. I also replace the pins that come with the cams with a hardened dowel pins.

Same here .
 

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Discussion Starter #7
Now it's 50$ plus 4 intake valves, couple exhaust valves... And who knows wtf else
 

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How long was the dowel? Was it long enough to bottom out in the cam and go all the way to the washer? Was the cam bolt possibly bottoming out in the cam? I run double pins on my BBF stuff.
 

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Now it's 50$ plus 4 intake valves, couple exhaust valves... And who knows wtf else

Could of been way worse man !!! Trust me when mine did went it was in the middle of the run and it took out pistons ,rods,cam,everything was junk . Atleast you did not do that like me LOL .
 

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How long was the dowel? Was it long enough to bottom out in the cam and go all the way to the washer? Was the cam bolt possibly bottoming out in the cam? I run double pins on my BBF stuff.
2x on the cam bolt bottom out.. just fixed one last week, i saw walk marks on rear face of cam sprocket.. check depth of hole to lenght of bolt, bolt was a tad long.. added hardend washer to bolt..
 

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Discussion Starter #11
The dowel was bottomed out in the cam and came all the way to the washer. The bolt was not bottomed out. Mark at bullet cams said that it was from cam endplay being too tight. Lesson learned. Putting a belt drive on, and going to double pin the cam.
 

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my new belt drive came with an extra hole and hard pin.the comp cam also came with the extra hole and it all even fit!:confused:
 

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The dowel was bottomed out in the cam and came all the way to the washer. The bolt was not bottomed out. Mark at bullet cams said that it was from cam endplay being too tight. Lesson learned. Putting a belt drive on, and going to double pin the cam.
Be sure and replace the original cam pin along with the new one. I use SPS from MSC. I keep a box on hand at all times. All cams come with a soft pin.
 

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Discussion Starter #14
The original one is broken. It's on the table next to the cam plate.
 

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The original one is broken. It's on the table next to the cam plate.
Seen plenty like that. Been replacing them for 25 years and dual pinning for the same time with tool steel pins.

I'm saying you have to replace the pin on a new cam if you should choose to replace the one you have. Sorry if I wasn't clear on that.
 

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i to run 2 dowels on my cam and found funky wear on my dowels and traced it to the hardened retaining washer. the washer cracked ,therefor losing all hold down forcenew pins and new hardened washer and bolt
 
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