Have you ever broken a cam?

[Clois Harlan]

After unloading my car from running at Texas Motor Speedway and after pulling it into the garage my engine just went quiet. I was warming it up to run a leak down test to see what I needed to do this winter. I heard loose metal.

I knew something was wrong when I pulled off my valve covers and noticed that #1 and #5 Exhaust push rods had fallen down about 1" from my adjustable rockers. Further examination (pulled the intake) I found both #1 and #5 Exhaust solid lifters were broken at the recessed part of the lifter (about 3/4" from the top). I fished these parts out with my magnet. I only find the top portion (still haven't got to the rest of the lifters). While fishing with my magnet I could feel and hear what I think is a broken cam.

I intended to refresh the engine over the winter but didn't expect any problems with the top end. I took a few pictures last night and will post some more when I pull the engine next week (gotta wait until I get back in town to finish investigating).

Anyone know what could cause a broken cam and lifters?


Clois

[trularin]

I had this experience once and it was someone elses car.

351 Cleveland, guy had installed an after-market CAM along with intake, carb and head mods.

CAM broke right in half behind the third bearing.

Ended up sending the CAM back to the maker, who as I recall, sent a new one free of charge.

I helped the guy put the new CAM in. PITA on a Pantera.

Clois, I hope this is something simple. Best of luck with your tear-down.

[SCOBRAC]

Yes... But a better story would be my bosses 430 Mercedes OHC V-8 with 800 miles on it. He broke one of the cams. Niello Mercedes (sacramento) was really nice trailering it away and promising it would be good as new in no time.

10 days later it came back and was promised all was as it should be. Except for the quart of oil it used every 500 miles and a noticable lack of power.

He took it to Cole European (walnut creek) where a tear down revealed a badly scored right side cylinder sleeves, and an otherwise substandard repair by the technicians at Niello.

I was in his office when he listened to this message from the Service Manager at Cole, "yes, Mr. X, we are very sorry the experience you had getting your car repaired, rest assured we will be replacing the entire assembly at no cost to you. The good news is a new engine is avaliable, the bad news is it is in St. Louis. We cannot air freight it do to weight, but it will be here in 48 hours. We expect to need two working days to install and fully test the engine.... Of course this is all covered under warranty, but if you were curious mercedes will be reinbursing us for $28,642.11"

It could be worse...

[Steve R]

Clois,
Other than purposely dropping one on the floor to see what would happen (it broke into 3 pieces like it was made of glass), I have not seen this in person.
Thinking about it though, I wonder if your cam journals are in specification as to alignment.
Steve
Re reading your post makes me think the 2 lobes were in the process of failing when the lifters "caught" on the bad lobes and broke off.
How is THAT for a line of B.S.?