camshaft won't last wtf !!!!!
 

Hi all, I'm having trouble with my cam in a 355. The engine has almost 3000 miles on it and I have put (2) yes (2) camshafts in and both have done the exact same F*&#ing thing. Both cams have wiped out #7 exhaust lobe. I don't get it. Both cams were broken in per the instructions using every precaution. Whats up !! Can someone please help. Thanks Kirk.

Re: camshaft won't last wtf !!!!!
 

i dont think its the cams fault.i would look into your head.just a guess but it seems your pushrod is fighting your cam with somthing backing it up. rockers and everything ok? high enuff lift?

Re: camshaft won't last wtf !!!!!
 

yes it could be a spring binding or a bend pushrod or sumtin like that .
does that end get oil on the cam itself (i have seen an adaption where they make a groove in the lifterbarrel so there a constant dripping of oil on the cam itself ) cylinder ?
if that doesnt work i think its time to mount a roller cam

Re: camshaft won't last wtf !!!!!
 

Kirk, what type of rocker arms do you have? Have you actually watched the oil drip from the pushrod onto the rocker? Clogged pushrod?
Bad rocker?

Re: camshaft won't last wtf !!!!!
 

Thanks for the replies, I'm running roller tip rockers and Z-28 valve springs good for .525 lift. All rockers are oiling good. the engine has about 1000 miles on it and the truck has been setting in the shop for about a year. After the engine was built about 2 years ago, on initial start-up it popped thru the exhaust during cam break-in and I blamed it on bad gas, so I drained the fuel tank and put in fresh gas and the popping started going away, so I thought the problem was cured. The truck ran fine for several trips down the track until #7 exhaust started rattleing. Fast forward to this weekend and the new cam, it popped thru the exhaust during breakin . After breakin I checked valve adjustment and all was fine, but the valves were still clattering, so I decided to set the valves while the engine was running and when I removed the driverside valvecover and start the engine BAM what the hell, #7 exhaust valve lobe gone again. I'm thinking valve springs?? Oh the cam has .477/.480 lift. Later Kirk

Re: camshaft won't last wtf !!!!!
 

maibe it pumped up the lifter too mush and it kept the valve open or the camwalk thing i talked about before

the valvesprings still ok not the inner spring broken or anything a sticking valve might do the same thing and would make the lifter slap the cam wearing it out faster too a sticking lifter might be worth checking too

Re: camshaft won't last wtf !!!!!
 

What kind of oil are you using. Todays oils are not meant for anything but a roller cam. Breakin with a can of OES suppliment (if you can find it) and use a good synthetic off road oil like Lucas or the 'real' Royal Purple (not the API starburst stuff in the discount parts houses)
This is exactly why I gave up building flat tappet motors. You can't get the cams to survive with confidence. Besides, the added performance offered by accelerated valve actiuon of a roller is just a plus.

Re: camshaft won't last wtf !!!!!
 

Valve guide binding?

Re: camshaft won't last wtf !!!!!
 

I don't think it's a lube issue. The cam is lubed mostly by oil thrown up there by the rotating assembly. The lifters put oil up the pushrod for the rockers, etc. but I don't think that has anything to do with lubing the cam. I am inclined to agree with the spring/guide/something mechanically screwy opinions. I doubt you could get unlucky enough to mess up the valve adjustment on the same valve twice. I also agree completely about the roller cams. I have been running hydraulic rollers with great success. For my flat tappet 4x4 I run rotella diesel oil in it because it has the zinc needed for the flat tappet. However, they are reducing it in the diesel oils too now . The valvoline racing oil still has it for a more reasonable price compared to some others.

Re: camshaft won't last wtf !!!!!
 

Man, thanks for the replies, they are really appretiated. I think I found the problem, as some have sugguested, its the bronze valve guides are to tight. Since its the same valve and also after a closer look #4 exhaust valve also starting to go on both cams, I believe it's do to the bronze guides are tight ( on #4 and #7 exhaust) and since the exhaust vaves run hotter those 2 valves are trying sieze up. I won't really know until I remove the heads and check it out. About the oil, I used 20w-50w castrol and cam lube that cam with the cam. Thanks again for all relies, Later Kirk.

Re: camshaft won't last wtf !!!!!
 

This is just my opinion. but I doubt it is the guides. I would start checking installed hight.. Whats that factory spacer thing on the ex valves.. I want to call it a rotator... What ever thoughs darn things are called.... they need to be thrown away. I killed three cams in a week with z-28 springs and thats what it was 280/480 comp cam

Re: camshaft won't last wtf !!!!!
 

Well I'm going to get the heads checked out go from there. I'll also get the recommeded springs for the cam. Later Kirk

Re: camshaft won't last wtf !!!!!
 

i hope it will be enough , the only thing left after that in my eyes is checking pushrod length when you put it back together

Re: camshaft won't last wtf !!!!!
 

I had a big block the did the same thing, I found that one of the lifters was hanging up in the lifter bore when it got warm.

Re: camshaft won't last wtf !!!!!
 

I got the heads off today and checked the lifter bores. The lifter bores are nice and smooth, the lifters move and spin nicely. Going to have springs and guides checked in the next few days. Later Kirk

Re: camshaft won't last wtf !!!!!
 

sorry to hear about your trouble hope you get it worked out

Re: camshaft won't last wtf !!!!!
 

call Chet Herbert and get a budget roller set up! I bet you could get cam, lifters and springs for less than 500.00!

Re: camshaft won't last wtf !!!!!
 

The first cam that shot craps was Chet Herbert flat tappet #c4n and it sounded and performed well. I forgot about his roller setups. The second cam was an Xtreme energy from comp cams. It sounded good for the breakin but after that #7 exhaust was wipedout, so I didn't get to see how it performed.
Anyways, I ask our shop mechanic at work last night about my engine and he said it could be the installed valve hieght. I'll know something when I go to the machineshop. Later Kirk

Re: camshaft won't last wtf !!!!!
 

it could be the installed valveheight , its basicly you redone the heads and reground the valves so now there in deeper , when there in deeper the valve stems stick out the top more too so you need to measure each one installed with a micrometer and take bits op the top of the stem untill there right again , that allso means you need to keep the valves in the right installed order

Re: camshaft won't last wtf !!!!!
 

Well, I had the heads checked out and there was know binding of any kind. The valve hieght checked out and the spring pressures were ok. The machinist said there could not be any coilbind either and he saw nothing out of the ordinary. So I guess I'll take a close look at the lifter bore 1 more time and then swap sides with the heads and try it again. If the problem follows the head then #2 exhaust lobe will go next. What do you guys think ?? Later Kirk

Re: camshaft won't last wtf !!!!!
 

that might be a good way to test it yes , did you test the straightness of the pushrods and there length ?
told it before and a saw it again a while ago in a hot rod article about cams and why they wipe out so fast nowadays (i looked it up for you its the hot rod do it youreself series fall 2006 , the article's called when good cams go bad .... you might be able to find it back on hotrod.com ).
it has sumtin to do with the oil wish has less additives (zink dialkyll sumtin sumtin ) theres special oil available wish has those aditives still in it , they advice shell rotella T (in 2006 they might 've changed the formula since then ) and quaker state Q racing oil .
comp cams allso make lifters with tiny hole in the bottom that lays oil on the cam sorta speak , wish sound good in my ears , its an alternative to making a groove in the lifterbore so oil drips down on the lobes

Re: camshaft won't last wtf !!!!!
 

Two friends motors did similar things, the cam manufacture told them to use Rotella T oil for break in. I'd call your cam manuf. and see if they tell you a smiliar thing. Probably somthing like marv D said above.

Re: camshaft won't last wtf !!!!!
 

I used castrol 20w-50w and cam lube supplied with the cam.
the lifter bore checked out ok as well. Thanks for all repies, Later Kirk

Re: camshaft won't last wtf !!!!!
 

this is getting spooky. guides and lifter seem to glide with ease and heads checked out....

Maybe your block is bent.:lol:

Re: camshaft won't last wtf !!!!!
 

Curious that you lost #7 lobe on both cams. The GM motors oil from the bottom up, and the back forward. But..... With no mechanical reason cropping it's head,,,,,,,, read this with regards to ZDDP (the soluable zinc molecules in the oil additive package and be aware Rotella and Chevron Delo just fell under the same EPA knife as every other 'over the road' oil and now has DRAMATICALLY reduced ZDDP levels)
That was in 06, you ought to see where the levels are now. Take a look at your bottles of Castrol and I'll bet a dollar to a donut they are SM rated. The only way I have found to get a flat tappet cam to survive the breakin,,,
1. remove the inner springs of dual spring packages.
2. The GM EOS is almost impossible to find these days, so the only alternative is to dump $10 a quart off road racing oil like Royal Purple XRP (my preferance) Kendal racing oil, Shaffers etc. Not the CRAP they sell in the local parts houses that has the API sunburst, the OFF ROAD oils with the additive packages to support the extreme pressures of a flat tappet cam.
3. IF you can find Gm EOS that's a big plus, but in lieu of OES, I have a couple of cases of old OLD blue label STP oil treatment. Lay a ribbon of that thick honey crap down the lifter valley so it coats the cam before dropping the lifters inthe bores, then finish off the cam across the top of the lifters so the honey flows into the oil drainback holes in the block.

BTW, this is all IN ADDITION TO the heavy cam lube all the cam manufacturets supply,, it ain't enough! Finally, your going to be rolling the motor over to adjust the valves, to install the convertor bolts, and the last thing you want is to wipe the breakin lube film off before you get to startup and breakin. Get timing set to 10 or so degrees, make sure the float bowls are full of fuel, charge the battery, put a big fan in front of the truck to supply fresh air at the radiator, get a bug sprayer to give the radiator a nice mist every few minutes, Be PREPARED to start up and do the 20 minute cam breakin at 2000-2500 rpm and DON'T Fail. If you have a major problem like a oil or water leak, shut the motor down, fix the problem and get back to RPM and the breakin.

As soon as you have the 20-25 minutes at 2500rpm, shut it down, let the motor cool to stone cold, drain the oil, pull the filter , cut it open and check for debris. Anything in the filter is being circulated through the motor. "SOME" machining dust and fine particles are 'normal' if you didn't wash and brush the motor sanitary clean before assembly (to which I say SHAME on you). If you DID clean the casting corectly,,, you might see a flake here and there, and is more 'normal' . If you cleaned the block correctly, anything more than a 'flake' is the cam going away and you might as well stop and pull the motor back apart before you trash the crank and every other machined surface.

Non API starburst oil is surely not cheap, but compared to new cams, lifters and fresh bearings every time the cam wipes a lobe,, it becomes pretty reasonable.
My breakin ritual of a flat tappet motor....
20 minute breakin then dump the oil and filter,

500 miles (10 hours)MAXIMUM and do NOT let the motor idle under 1000rpm with no less than 35-40psi of oil pressure,,,and again dump the oil and filter

Then again at 1500 miles and at 3000 miles you go to a normal 3000 mile schedule.

Excessive??? maybe, but I have never (let me say that again) 'NEVER' lost a flat tappet lobe on a motor I built. In that same breath I have to say that I quit building flat tappet motors about 2 years ago too. You can figure about $1000 to go to a roller package with a good set of Morel hydraulic roller lifters (w/ springs and correct length pushrods) It's $'s well spent IMO,,, but, just my 2cents