Flat cam lobe, what cam now

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twayne24365

twayne24365

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Well after only about 100 miles #6 exhaust lobe is gone on my .590 cam.
Car ran fine but decided to pull the valve covers to adjust lash and found the lash cap laying in the head, so I got it back in and adjusted all the valves and sure enough that rocker barley lifts the valve. Break in went fine, used brad penn break in oil and ran at 2500 for 20 min, guess s*** happens. so I'm going to get another solid flat tappet but not sure what to get, the .590 was the absolute biggest I could go due to seal/retainer clearance. I had the .590 in at 102 and it still seemed I little soft down low.
Engine is
.030 over 383 11:1
Arias dome pistons
Stock rods with arp bolts, steel crank
2.08 1.74 valve 516 heads with bowls cleaned up
Street dominator intake with 750 mighty demon
My converter that was supposed to be about 4200 stall turned out to only flash to about 32-3500
8 3/4 with 4.56 gears and spool
255/60 MT drag radials.
 
Oh, I also have titanium retainers and valve springs came out at 140 on the seat and 370 open
 
Tear down, clean up and reassemble with new cam and lifters. Is this a trick question?
 
Aww,that great Mopar performance quality strikes again...as previously recommended tear it down clean it up put it back together..this cam looks nice Lunati 30200743lk..
 
I think he said .590 was the absolute biggest lift cam he could run due to seal/retainer clearance...that lunati cam might be a touch too big...

I would however agree with recommending something like Lunati that takes better advantage of the big lifters...you could also go with a custom grind since you say it feels a little soft down low.
 
I didn't see a brand mentioned, Inquiring minds would like to know if this is another Comp Cam failure,?
 
Yea it was a Mopar camshaft that failed, I was looking at lunati as well and the comp xs290s,
 
I think younggun2.0 ran the comp 294S (standard 294 magnum solid) in his flat topped 383 with edelbrock heads--I know you have different heads, but tuned right, it would probably run well. The lift is significantly lower, but to be perfectly honest, unless your heads were very well prepped and flowed, they probably stall out around .550 anyway...
 
How about some weak springs for next break-in and don't hold it at such a high rpm for that long?
Those parts need some time to get used to each other.
 
Darthomas said:
How about some weak springs for next break-in and don't hold it at such a high rpm for that long?
Those parts need some time to get used to each other.
Click to expand...

Weak springs or inners removed yea, but I was always told and read that 2200-2500 for 20 min is pretty standard for a flat tappet cam?
 
A couple of questions.

What lube did you use on the cam and how long did you crank on it before it actually started?

There is some stuff sold as cam lube by Sta-Lube that I use for anything but cams.

And I've seen people not have enough timing on start up so they would crank on it too much. Also seen a few guys use the starter to build oil pressure before starting. That's always a disaster. Or using the starter to fill th fuel bowls.
 
A roller cam n lifters would solve all your ills AND make better power.

Just saying..... next flat tappet cam could eat a lobe too.
 
The lube I used was permatex ultra slick. It was the thickest and stickiest kind i could fined, I made an oil shaft priming pump to prime oil as well....and yes it did take a little to get it started.

As to the roller cam, yes that would totally be a better option and solve the worries of it happening again, but the money it would cost me for lifters, cam, rockers, and new springs I'm going to put towards my next build
 
twayne24365 said:
The lube I used was permatex ultra slick. It was the thickest and stickiest kind i could fined, I made an oil shaft priming pump to prime oil as well....and yes it did take a little to get it started.

As to the roller cam, yes that would totally be a better option and solve the worries of it happening again, but the money it would cost me for lifters, cam, rockers, and new springs I'm going to put towards my next build
Click to expand...

But now you will have spent twice on flat tappet stuff. Couldda spent once on roller. Somethin to think about.
 
Also most of what I have seen say's 2000-2500 but varying the RPMs as well.
It makes sense, that the RPM should be up to sling a lot of oil and get a lot of cooler oil to the cam, but it also makes sense that different speeds during the breakin can reduce galling, which starts the lobe getting taken off.
 
Wow...that permatex stuff is made in China....

Origin China
 
permatex ultra slick is too thin and too universal, as an overall lube. how many days did the engine sit from applying to engine fire up? good cam lube is the thick grey stuff from crane and isky. vary the rpm between 2200-2700. what rockers do U have now? after the 20 minute break in do not idle for more than a few moments until more run time has been added. get it to fire up as instantly as possible. in at 102* is too advanced, did U check V to P clearance. the more aggressive the cam is the rougher she is on stuff. my 360 cu. in. 11.5:1 unit with 135# and 340# open is happy from idle to 7000 with the old Comp 306* .555" flat solid in at 107* for the past 20 years-I suggest it for U
 
i see alot of people install that cam between 100-104, yea i checked v to p clearances as well, i have crane ductile rockers.

the motor wasnt sitting more than a few days before i installed it and fired it up, i also primed the oil right before starting it as well. it sucks that it happened but im at peace with it, i know this happens occasionally. an old racer that im friends with sprays his cams with a graphite lube before putting assembly/cam lobe on, i might give that a shot but im going to do the same routine this time around.

im with tony as well, probably a good idea to use the weak springs or remove the inner but that shouldnt be needed.....never done it before, or my uncle, or a ford buddy of mine...
 
I'd be interested to know if the rod bearings had operative oil squirt holes.??

I have a hypothesis that no squirt hole = more likelyhood of wiped lobe, squirt hole, not so many wiped lobes.?

Inquiring minds want to know. ?

Thank-you.
 
inertia said:
I'd be interested to know if the rod bearings had operative oil squirt holes.??

I have a hypothesis that no squirt hole = more likelyhood of wiped lobe, squirt hole, not so many wiped lobes.?

Inquiring minds want to know. ?

Thank-you.
Click to expand...

I don't think that's too far fetched. I know some had them and some didn't but to me, more oil chunked around caint be a bad thing, right? I "thought" that the reason for the skeet holes was to skeet oil on the cylinders but I am sure that's not the only place it gets. You have a pretty good thought.
 
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