Cam lobe going flat...what now?

[Dubob]

That sucks without a doubt, sorry you're having those kinds of issues. Just out of curiosity was the lifter free to spin in the lifter bore? Just wondering if the lifter bore may be a little tight on tolerance to the lifter preventing it from rotating.

 

[nm9stheham]

OP, just curious:
- What oil did you run after the first change?
- What pre-load did you put in the lifters?
- After reading the 440Source FAQ's for their Stealth heads, they recommend no more than .510" lift with their retainers. I looks to be related to things other than the retainers hitting the guides, but did you check retainer to guide clearance at original assembly?
- Just as an observation, if this is a XE cam, then the profile is more aggressive, and puts more peak pressure on the lobe and lifter, and so will have a higher probability to fail, and the oil used gets more critical.
- How DID you get the 70' long crank into the car? LOL

 

[hangn0ut]

Pump only bypasses when pressure exceeds the pressure set by the bypass spring. maybe on first start up in cold weather. filter bypass only bypasses when filter is plugging up. dirty oil is better than no oil.

 

[sbh126]

That sucks without a doubt, sorry you're having those kinds of issues. Just out of curiosity was the lifter free to spin in the lifter bore? Just wondering if the lifter bore may be a little tight on tolerance to the lifter preventing it from rotating.

It was able to spin freely. Even gave me a nice little inward dome on the lifter.

 

[sbh126]

OP, just curious:
- What oil did you run after the first change?
- What pre-load did you put in the lifters?
- After reading the 440Source FAQ's for their Stealth heads, they recommend no more than .510" lift with their retainers. I looks to be related to things other than the retainers hitting the guides, but did you check retainer to guide clearance at original assembly?
- Just as an observation, if this is a XE cam, then the profile is more aggressive, and puts more peak pressure on the lobe and lifter, and so will have a higher probability to fail, and the oil used gets more critical.
- How DID you get the 70' long crank into the car? LOL

I admit that I hadn't changed the oil yet. The purpose of my morning test drive was to warm it up prior to the change and make sure everything was running smoothly before I dumped $70 worth of oil in. I doubt changing the oil prior to warming it up would have made a difference. I'll never know now.

The 440source heads were torn down replaced with all Comp products. Shoulda just bought the Edelbrocks.

 

[sbh126]

OP. For your consideration

During my career, I've replaced cams with worn lobes in dozens of cars of all breeds. Dealerships won't pull an engine apart for a worn lobe, but will maintain the warranty for duration, cuz motors generally aren't noticeably affected by the failure's debris.

It just isn't practical to tear down every engine that eats a lobe. Having torn down engines with worn lobes, I never did find any debris other than grey paste in casting depressions..

I have maintained some of those lobe eating cars for decades, and never had a failed lobe debris issue.

Have faith in gravity and the oil filter.

However that's not to say pulling the pump isn't a great idea.

jmo . . hope it helps

I think I feel comfortable just cleaning up the pan and replacing the pump. I'll also probably blow out the pickup as well. I think the oil pump ground the few bits of iron that got into the system to dust and the filter was brand new so I'm betting nothing substantial made it through. You can see some definite wear on the oil pump.

 

[Mopar Tim]

Pump only bypasses when pressure exceeds the pressure set by the bypass spring. maybe on first start up in cold weather. filter bypass only bypasses when filter is plugging up. dirty oil is better than no oil.

Thanks

 

[zac_F71]

Wait you're running a .545" lift cam measured with a 1.5 rocker? AND you're running 1.6's?? if that is correct you're running @.580" lift at the valve.. YIKES that's a lot. My guess is the heads are not the issue, and are fine depending what the springs were setup for.. like say the pressures and height is setup for .550"?

I woulda changed the oil/filter right after break in to see if the tick went away

 

[Doosterfy]

Wait you're running a .545" lift cam measured with a 1.5 rocker? AND you're running 1.6's?? if that is correct you're running @.580" lift at the valve.. YIKES that's a lot. My guess is the heads are not the issue, and are fine depending what the springs were setup for.. like say the pressures and height is setup for .550"?

I woulda changed the oil/filter right after break in to see if the tick went away

Very good point. I run Stealths on mine and the pushrod holes required a lot of work to get enough clearance for the rods. I run Crane 1.5 rockers and actually wound up using intake rockers with more offset than standard on the intakes to gain more clearance. From what I saw, using 1.6 rockers would have made the pushrod clearance problem worse. One guy I know with Stealths and 1.6s had to go to 5/16 rods instead of the 3/8 in order to gain enough clearance. I've learned the hard way in the past to take my time when setting up valvetrains and check, double check and triple check all the clearances in the valvetrain. Any binding, rubbing, valvespring coils stacking or retainers hitting the guides and failures will be imminent.

 

[d55dave]

When a cam lobe fails it throws debris off, and some of it ends up in the bottom of the cylinders, then gets picked up by the piston and dragged up and down the bore. Ask me how I know, LOL. This is one of the reasons for a full engine teardown, to clean, rehone the bores and check rings and bearings.

Will it run just fine without going this far? Probably, but I definitely recommend pulling the pan, looking for scoring in the bores and pulling / inspecting the bearings and crank journals.

I had a nicely broken in 408 with a Mopar 509 cam. After 2000 miles I changed the oil and mistakenly went to a full synthetic with no zinc or additive. After 10 miles of driving it wiped a lobe. I took the preventative measure of pulling and tearing down the engine as I had a fair amount of cash in it and wanted maximum life out of it. I had to polish the crank, replace con rod bearings, and lightly hone the cylinders.

Just my 2 cents.

 

[nm9stheham]

Pump only bypasses when pressure exceeds the pressure set by the bypass spring. maybe on first start up in cold weather.

Or at high enough RPM's. Positive displacement pumps like this have a fairly linear speed versus output curve; the pressure just keeps going up and up.

 

[nm9stheham]

I had a nicely broken in 408 with a Mopar 509 cam. After 2000 miles I changed the oil and mistakenly went to a full synthetic with no zinc or additive. After 10 miles of driving it wiped a lobe.

Dave, can I ask what synthetic brand AND weight that you changed to?

 

[sbh126]

Very good point. I run Stealths on mine and the pushrod holes required a lot of work to get enough clearance for the rods. I run Crane 1.5 rockers and actually wound up using intake rockers with more offset than standard on the intakes to gain more clearance. From what I saw, using 1.6 rockers would have made the pushrod clearance problem worse. One guy I know with Stealths and 1.6s had to go to 5/16 rods instead of the 3/8 in order to gain enough clearance. I've learned the hard way in the past to take my time when setting up valvetrains and check, double check and triple check all the clearances in the valvetrain. Any binding, rubbing, valvespring coils stacking or retainers hitting the guides and failures will be imminent.

Even with the .580 lift I had adequate piston to valve clearance. The spring compressed height is within Comps recommendations as well. And I'm running 3/8 pushrods without problem with the 1.6 rockers. I had to grind down the aluminum in several places but they fit fine now. As long as everything clears I stand to make additional power from the additional lift. Or is there something I'm missing? Do I need beefier springs for a 7% increase in lift?

 

[Bad Sport]

Even with the .580 lift I had adequate piston to valve clearance. The spring compressed height is within Comps recommendations as well.

What about the open spring pressure at max lift? Was that checked?

I don't know if it would be an issue, just throwing it out there.

 

[d55dave]

Dave, can I ask what synthetic brand AND weight that you changed to?

I honestly don't remember. It was not one of the popular oils, it was European and recommended to me by a parts guy. Big lesson learned on my part.

 

[zac_F71]

I honestly don't remember. It was not one of the popular oils, it was European and recommended to me by a parts guy. Big lesson learned on my part.

European blend oil has a small amount of zinc additive as they still use flat tappet cams today.. Probably wasn't enough though..

 

[qkcuda]

When a cam lobe fails it throws debris off, and some of it ends up in the bottom of the cylinders, then gets picked up by the piston and dragged up and down the bore. Ask me how I know, LOL. This is one of the reasons for a full engine teardown, to clean, rehone the bores and check rings and bearings.

Will it run just fine without going this far? Probably, but I definitely recommend pulling the pan, looking for scoring in the bores and pulling / inspecting the bearings and crank journals.

I had a nicely broken in 408 with a Mopar 509 cam. After 2000 miles I changed the oil and mistakenly went to a full synthetic with no zinc or additive. After 10 miles of driving it wiped a lobe. I took the preventative measure of pulling and tearing down the engine as I had a fair amount of cash in it and wanted maximum life out of it. I had to polish the crank, replace con rod bearings, and lightly hone the cylinders.

Just my 2 cents.

I agree, been there also. I wore the bottom right out of one lifter. The iron filings embed themselves in the piston skirts, and the wrist pins almost seized. That is when I decided to do the stroker........with a roller cam.

 

[Doosterfy]

Even with the .580 lift I had adequate piston to valve clearance. The spring compressed height is within Comps recommendations as well. And I'm running 3/8 pushrods without problem with the 1.6 rockers. I had to grind down the aluminum in several places but they fit fine now. As long as everything clears I stand to make additional power from the additional lift. Or is there something I'm missing? Do I need beefier springs for a 7% increase in lift?

If you checked all the clearances and there's no issues then binding or parts colliding is not the problem. There is one thing I will say about using 1.6s instead of 1.5s. They put more load on the pushrods, lifters and the lifter to cam contact. I've always viewed higher ratio rockers as a crutch. IMO its better to use a cam that gives you what you want with whatever ratio rockers the engine was designed to use normally. I'm not an engine builder or an expert and I know there are plenty of guys running higher ratios successfully but I never do it. Last time I had a valvetrain failure was in the 80s while I was still attending the school of hard knocks learning lessons the hard way. One more thing, thanks for serving our country sir. Thanks to men and women like you the rest of us are still free and able to persue our dreams and goals.

 

[hangn0ut]

Back when,many cam grinders had paint marks on top of their lifters and recommended pulling a valve cover off with the engine running to verify that the lifters were spinning.

 

[SwedeCharger67]

European blend oil has a small amount of zinc additive as they still use flat tappet cams today.. Probably wasn't enough though..

Also in Europe you have to choose carefully if you want oil with reasonable levels of zinc...it's a bit of work to find a good one (i.e. reading lots of data sheets...).

 

[moper]

My impression is it's probably a combination of several things, and not 100% related to cam quality. A few thoughts...
- IQ's correct on the cam finish quality on Comps. I've also found the oiling holes for the top end to be unfinished in addition to casting flash.
- Lifter bore angle in relation to the cam centerline can be a problem, as can a bore with wear. Both can make it harder for a lifter to rotate as it should which will lead to failure. Did you measure the lifter bores to make sure they are all within tolerance? Did you verify that the lifters all rotate with no oil, and no load on them during the lifter replacement?
- You "let the engine warm up"? For how long did it idle? Idle time is what destroys camshafts. Especially new ones. RPM needs to be kept up and idle time limited when any flat tappet engine is new. Break in STARTS the cam and lifter wearing in. Running above idle finishes it.
- If you are running the 924 spring, that is the "just enough" spring according to Comp. Add to the catalog, the "preferred" spring is a beehive, which has about 7% higher spring rate than the 924. Add to the fact that you have a 10% increase in resistance with the 1.6 rocker vs the 1.5 that the cam's operating pressures were figured for, I'd say you don't have enough spring.

If it was one lobe and you caught it, I wouldn't worry too much about particles. Get a magnetic drain plug, or stick a big magnet on the oil filter itself for a few hundred miles and it should pull out anything that passes by. make sure all facets of the build are taken into account when you fix this...

 

[nm9stheham]

Even with the .580 lift I had adequate piston to valve clearance. The spring compressed height is within Comps recommendations as well. And I'm running 3/8 pushrods without problem with the 1.6 rockers. I had to grind down the aluminum in several places but they fit fine now. As long as everything clears I stand to make additional power from the additional lift. Or is there something I'm missing? Do I need beefier springs for a 7% increase in lift?

The one clearance missing from above is the retainer to seal+guide clearance. This may not be any issue in your set-up, but it still needs to be checked.