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Dead cam... Again!

USSkoval

USSkoval

Thornbirds look cool... Yeah, I said it
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What in tarnation will cause a 350 to eat a cam on three different occasions?!

The first two were not installed by me, so I assumed they were not broken in properly. The second cam failed when I was going down the freeway. A lifter suddenly started ticking, then by the time I got home there was a flat lobe and two others badly worn.

When I installed the new cam, I did everything perfect so it would last. It was a Comp brand cam, USA made quality lifters, special lube on the lifters, break-in lube in the oil, oil with extra zinc, and the valves were adjusted properly. The lifter valley was wiped clean of debris, along with the oil pan. I did the proper break-in procedure, ran it for a few hundred miles, then changed the oil with more high zinc stuff.

Well, roughly 2000 miles later, this motor ate the cam again in a matter of 15 seconds! It's bad too, I wouldn't be surprised if 2 or 3 lobes went completely flat. The truck wont do more than 30mph. It just happened all at once, I don't get it.


I'm NOT putting another cam in this POS motor! I think my Camaro might donate it's aluminum headed 350, then build a 383 for the Camaro. That was my plan anyway, but I wanted the 383 to be ready to go first, so nothing sat engine-less.
 
Proper cam break in as in run it at ~2000 rpm for about 30 minutes?

Rene
 
Ive had a couple go bad in recent years, I had one that worked well for me in two different engines. its a speed pro cam, with the speed pro lifters.

It sucks but theres only one way to truly solve the problem and its to go with a roller these days.

I think theres a problem with cheap cam cores, and the lack of zonc in the oil. however using all the supplements like you did would make up for the oil aspect.
 
tRustyK5 said:
Proper cam break in as in run it at ~2000 rpm for about 30 minutes?

Rene
Click to expand...

Yes, but it varies slightly depending on who you ask. I kept it at 2K, but would bring it up a few hundred rpm for a minute every now and then.
 
Correct valve springs for the application?

Reason I ask, a friend had a ford 351c in his drag car, it ate 2 cams as well. Turned out the springs comp or crane (can't remember) sent him were way , way too much for the cam he was using.
 
79rustyk10 said:
Ive had a couple go bad in recent years, I had one that worked well for me in two different engines. its a speed pro cam, with the speed pro lifters.

It sucks but theres only one way to truly solve the problem and its to go with a roller these days.

I think theres a problem with cheap cam cores, and the lack of zonc in the oil. however using all the supplements like you did would make up for the oil aspect.
Click to expand...

Yeah, somethings rotten in Denmark. The 350 in the camaro is flat tappet, but I installed it about 7 years ago and several thousand miles. I think it would work great in the Blazer, it's a very broad power band. The 350 I have to build a 383 out of is a factory roller block:waytogo:
 
What about your valve springs? whats the installed pressure and open pressures at ? if its to high it will wipe the oil off the cam and flatten it in a hurry
And if your looking for a 383 I have a NEW everything but block 383 with everything you could ask for incl Edelbrock heads for sale, Never run =)
 
jt512 said:
Correct valve springs for the application?

Reason I ask, a friend had a ford 351c in his drag car, it ate 2 cams as well. Turned out the springs comp or crane (can't remember) sent him were way , way too much for the cam he was using.
Click to expand...

That I do not know. The heads were redone, springs installed before I bought the truck.
 
Madspeed said:
What about your valve springs? whats the installed pressure and open pressures at ? if its to high it will wipe the oil off the cam and flatten it in a hurry
And if your looking for a 383 I have a NEW everything but block 383 with everything you could ask for incl Edelbrock heads for sale, Never run =)
Click to expand...

If the crank is for a 1-piece seal, feel free to PM me. I already have Edelbrock heads though on the 350. I was planning on AFR's for the 383.
 
USSkoval said:
That I do not know. The heads were redone, springs installed before I bought the truck.
Click to expand...

I would look into that, could very well be the problem.

Once my friend had the correct springs the 3rd cam was still going strong last I heard.
 
No. you have to remove them (which you can do while on the truck) Check the head to retainer height. Then have a machine shop check them against your cam card. I did the same dumbass thing when I was a kid. I bought a set of use double hump heads that were setup for a solid roller and wiped the lobed of my solid flat tappet cam in a hurry.
 
I'm not sure I even want to mess with it. I could swap in the better motor in a weekend and be done with it. Then I would "need" to go parts shopping for the Camaro:pimp:
 
Madspeed said:
No. you have to remove them (which you can do while on the truck) Check the head to retainer height. Then have a machine shop check them against your cam card. I did the same dumbass thing when I was a kid. I bought a set of use double hump heads that were setup for a solid roller and wiped the lobed of my solid flat tappet cam in a hurry.
Click to expand...

There is a way to check springs on the engine and you cannot check them off the engine UNLESS you know what the actual installed height is.
 
sounds like you may have an answer to your problem.
i would junk those springs and get a new set to match your (next) cam
 
dont know if it means anything now, but i have 3 buddys that on seperate occasions had 3 difference comp cams lose a lobe shortly after install.

all were properly broken in as well.
that was over a seperation of bout 4 years.

all of them have sworn off comp cams now.
 
Only this last cam was a Comp, the previous was a Melling. IIRC, they both had the same markings made into them, like Comp and Melling might get their blanks from the same place.
 
Ive ran into this several times on non roller cams. Over the last few years they have takin all the zink and other minerals out of engine oil. My machinest says that its the cause of a couple of cams goin flat in engines he built for my customers. Maybe you got the same deal goin on.
 
Yeah but he's said specifically that he had the zinc covered in his oil changes and went thru a proper break in procedure. So that shouldn't be an issue....?
 
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