Could also be a poorly machined lifter face. Could also be the lifter wouldn't rotate freely in it's bore. Could be too much breakin lube on the cam lobe or lifter sides preventing the cam lobe from setting the lifter in motion (fail to spin = wipeout in the break-in period) when the engine fired up. No amount of hardening on the cam or lifter will save them when the lifter doesn't rotate in it's bore

 

Had that kind of dealing at work with wiped cam lobes. Engine was a 390 for a 64 Galaxy 500, was rebuilt 10 years ago, came in as it was sitting and we put new tank in it and rebuilt carb. It left came back a month later with a loud ticking noise that kept getting worse, wiped out the exhaust lobe on cylinder 7. Pulled the engine sent it next doors to the engine builder that built it 10 years ago. Got it back after 4 months all fresh and broke it in. Was sitting there idling about an hour after break in and it started to miss. Wiped out exhaust lobe for cylinder 7 again. Pulled engine again sent it over and another 6 months later I got it back installed this past Thursday and got it running Friday no problems as of yet.

Its a big reason why my 306 build I am doing is using a newer style roller 302 block, blueprints shortblock 306 which my engine builder I know through work that we use he keeps telling me to avoid blueprint as everyone he knows that bought one has problems with them. I wont run a flat tappet cam as its too high of a risk for cams going flat today due to lower zinc and due to improper hardening on the cams.

On a side note, the DSII box if you have DSII, hit up rockauto I got a brand new Motorcraft one from them for $9.95 years ago. And if you ever decide to go for a roller cam that requires a steel dist gear, hit up rockauto also they are the only ones I seen that actually has the listing for a brand new Cardone distributor listed with a steel gear for use with roller cams. I got one for my build I need to take apart to put my advance kit in just have to figure out what would be a great starting point as I don't want to pull the dist numerous times lol.

 

I wonder if the cam blanks are imported? Quality of steel, heat treatment, nitrided, it all adds up. Lots of crap parts out there.

 

This had nothing to do with the cam or lifter. This was caused by someone assembling the engine not doing their "due diligence" and checking to see if that lifter (both times) would rotate freely in it's bore. There is a reason cam lobes are parkerized, , this is to allow the lobe to get enough traction on the lifter to rotate it in service. This rotation minimizes the wear between the cam lobe and lifter. The ZDDP in the oil does the same thing.

 

Flat tappet cams are cast iron.

 

Well, OK. Quality of materials.

 

It's possible but i just think it's a cutting corner aspect since flat tappets are old tech.

Maybe, but in the case of the 390 I had to pull twice the first reinstall I noticed one lifter wasnt spinning nor was the pushrod. That love didnt go flat the one that went flat was spinning and it was the same lobe as last time. I can see it being a problem on the builders side but at the same time I can see it being poor quality cams as well.

Yep which is why they are so much cheaper than roller cams.

 

Well, in my case, everything was done by the book on my end since it was the first performance build I had done with new parts. I know I did everything by the book because I had read so much about this exact problem - it wasn't going to happen to me lol. I've done rebuilds where most of the original parts went back in, Including cam/lifters and never had an issue with 40, 50 year old cams. Go figure.

The lifters were primed with oil, ep grease on the lobes and faces only. Lifters were checked for free rotation. Push rod lengths were checked because of the head swap, head/ block machining, different valves etc... Engine oil primed prior to starting. Fuel system primed. The engine e was then dropped in and fired. It didn't sit on a stand for a year, it was assembled and fired in the same weekend.

I strongly believe it's a manufacturing issue with lots of these scams.

The low zinc thing.... I doubt it. Look at the thousands of power plants out there that are still running without issue. Take farm applications for example. How many half tons, 3/4, 1 tons, 3 tons, big old gas job tandems, older gas powered equipment that are out there that work every year for their meal ticket, that I can guarantee many of are lucky to get an oil change once a year, nevermind getting expensive oil with high zinc.

Talk to an old mechanic. You will find that engines in the 60s/70s were rebuilt all the time. Poor oils, no block heaters, poorer cold tuning/running engines in colder climates etc... contributed to shorter lifespans. Engines were rebuilt, slapped back in, fired and out the door to have the rings seated and momma had her car back.

Anyway, mine is running now and it's the meanest sounding 302 I have ever heard. Next thread will be all about looking for help fine tuning. Thanks to everyone earlier in the thread with my ignition issues.

 

I'll bet you got that one confused. I had two cam failures both were single lobe and lifter and neither were spinning in operation.

 

Only thing you missed is flat tappet lifter production went overseas in the late 1990's, and the cam failures started soon after. Poorly machined lifters is a prime suspect in cam failures, specifically the faces of the lifters.

 

No I didn't get that one confused as the one that wasn't spinning was intake for cylinder 5 where the one that went flat twice was exhaust on cylinder 7. Quite hard to get them confused when one is at the back of the motor and the other is at the front of the motor.

 

It may have been rotating slowly. I just broke in a cam in a 351M and some were rotating slower than others, so slow that I had to use a flashlight shining on the pushrod to actually see them moving. Some were spinning like crazy. The two lifters in the failures I had were both exhausts (one a 400, the other a 390) and neither were rotating and both wore through the bottom of the lifters inside of the 20 minute break-in period. One was a Crane cam, the other a Comp Cams cam. On the 351M I just did, one lifter had a nick on the body near the oiling groove and until we removed the nick, it wouldn't rotate freely.

 

One that I saw wasnt moving probably wasnt. I tried turning by hand as running and it wouldnt turn by hand.

It might have done damage but cylinder 7 exhaust probably failed before that love could fail.

I also didnt take the motor apart as it was warranty work so I have to go by with what I was told. I informed engine builder to check thoses other lobes as I was concerned about their lack of spinning, he said he would as he thought it was a collapsed lifter not a lobe that went flat.