65silververt

I have broken in a dozen or so flat tappet cams over the last couple of years and i have never had a problem, but i think i might have wiped a lobe this go around and i could use some advise.
Last night i fired up my 427 and broke in the new crane spec 390hp cam. Prior to starting the car, i did have some issues with the carburetor(gasket not sealing around pump shot passage after drying out)and did crank the car over several times, but not anything excessive. After fixing the gasket issue with the carb, the timing was not correct and I had to crank the engine over again about 3 times, probably turning it over twice each time before finally getting it just right. I used tons of crane cams moly paste on the cam and lifters as recommended and used Joe Gibbs 10w-30 break in oil with high quantities of zinc, plus a bottle of crane cams break in additive. So, the engine finally fires last night and i ran it for 25 minutes varying the rpm from 2,000 to 3,000 rpm as per crane cams instructions. All went well and once the 25 minutes was up, i let the car idle, adjusted the timing just right, and it was purring very nicely at 800rpm. I shut the car down and went to bed feeling very accomplished and relieved that all went well.
Fast forward to Tonight.... I decide to start the car up again to listen to the beautiful smooth idle and let the car run a little more, but after running the car for a few minutes, i hear a heavy clatter from the passenger side valvetrain. There was no clatter present last night at all. I let the car fully warm up, but the clatter persists although the engine is still running fairly smooth-slight miss here and there. So, i pull out my stethoscope and yup, the clatter is coming from either 6 or 8 on the passenger side. Next i pull the passenger valve cover, but i dont see anything really all that loose. At this point, I decide it will be best to loosen all of the rockers and readjust them. Upon readjusting the valvetrain, i notice that number 6 intake nut is a bit further down on the rocker stud than the rest, so i loosen it and readjust it again with the same result. I reinstall the valve cover and start the car up, but now it is idling really rough. I go back through the valves again, same scenario. I check the carburetor, timing, and take an unlit propane torch around the intake to check for vacuum leaks, but everything checks out fine. The last thing i did tonight was take a vacuum reading and it is all over the place jumping from 8"to 15" hg spastically at 950rpm up to about 2500rpm where it finally smooths out. If i adjust the idle below 950rpm, the car violently jolts from side to side like a drag car.
Anyway, i am at a loss now and even though im not hearing much chattering after readjusting the valves, I'm pretty convinced a cam lobe or two have been compromised.

Thoughts?

Thanks

AZDoug

I have also had:

A pushrod that kept getting shorter (it got about 1/4" shorter, after two adjustments and perhaps 40 miles driving), and

a rocker arm that was cracking a bit more each time, until it finally broke in half.

Now THAT is a sound that makes you think something really bad happened, when the car has definite miss, and the pushod is banging off the valve cover.

Doug

65silververt

Shorter from bending???

At least when something really bad happens it is more or less obvious. I am still scratching my head wondering if there is another variable causing it to crappy now, but i certainly cant find one. I just dont see why the engine would be fine during and right after break in and then be screwed up today? Why would i not have heard the clacking last night after break in? Why was it suddenly present today?

midyearvette

why?....'cause shet happens!

i would just pull the valve cover and watch the valve action with a remote starter button. you should readily see an issue. if not, remove some rockers and pull some pushrods, i would pay particular attention to the lowered adjusting nut rocker. hopefully, it's not the cam.......

Westlotorn

If your engine was quiet and smooth after the full cam break in and you did not run it at all before tonight when you started it and had these issues I would say it is not the camshaft. Cams wear quickly once a lifter is not spinning but it would take at least several minutes of run time to make it start going away. At this point you would adjust the rocker arm and all would be good for several more minutes when it would start to clack again first quietly and then louder as time passes and the lobe wears more. You could repeat this procedure all night long with a lobe going flat. Adjust, runs perfect, give it time and the noise starts up again, always the same pattern.
In your case it almost sounds like a sticky lifter. Does not adjust properly, then pumps up, then sticks again causing a variety of problems to diagnose.
I will repeat, your noise started quickly and was noisy at the start. This does not sound like a cam failure.
A sticky lifter most times must be replaced. There are a few tricks mechanics use to try and free them up and once in a while it works. With the engine running adjust the Hydraulic lifter all the way down till it bottoms, loosen back up till it is loose and very noisy showing the lifter is at the top of its travel. Repeat this a couple times then set your lash. Take it down till quiet and add another 1/2 turn. If this works you have kicked a small particle out of the lifter body that was messing with its function. Any little spec of anything can stick a lifter. Like it or not a brand new engine has lots of little specs in it when you fire it up. Sometimes they stick a lifter.
How old is the gas in your tank?

Bud2

You’ve used a magnetic drain plug in your pan I hope. Take it out and see if you’ve got any metal on it. If not remove the filter and cut it open. Hope it's a lifter.

Bud.

Vogie

I'm not the ace on the base here, but I wouldn't start that engine again until I had ruled out a wiped lobe. Once the metal is in the oiling system, more things will begin to fail. Keep an eye on your oil pressure. A drop could indicate that bearings have been contaminated. Best of luck to you.

65silververt

Thanks!
My plan is

1. Drain the oil and use a magnet to see if any metal is inside

2. Cut filter in half and check for metal

If 1 and 2 prove there is no metal in the system, then i will refill with new oil and continue to 3.

3. Adjust the lifter in question to the bottom of its travel several times in an attempt to purge or dislodge a particle that might be causing it to stick.



4. Pull the rest of my hair out and plan to yank the engine again.

Westlotorn

Old gas can make the valves sticky in the valve guides. Gives similar issues till they fully stick. If this is the case the old gas burns with a very distinctive smell. Can't describe it but it you smell it you won't soon forget.
UPS in Sacramento converted the fleet to Diesel engines, the on site fuel tank with Gasoline in it sat almost a year before they decided to offer it for free to employee's to empty it. About 15 of the employee's had valves stick right after picking up this load of fuel, some had more gas in the tank to mix it and had no issue. Very expensive free gas.
Just an example of what it can do. I have seen this several times in machine shops with guys trying to warranty new engines with bad gas damage. Unfortunately many of our old cars have gas in them when we tear them down and it gets used to start them when the engine is replaced many moons later. I have seen posts that 10 year old gas has been used with no issue at all, I suspect that means the gas sold 10 years ago was better stuff than we have been getting the last few years.

AZDoug

No, one of the ends was wearing away.

Doug

Westlotorn

When a batch is made and not hardened your problem will show up with every single one. If you run into this insist on a different date code when you replace the push rod. Date codes are usually on the original box close to the part number. My experience, if you run the same date code again you get the same results again.

AZDoug

This was out of a 40 year old motor, no idea how old the pushrod was, it was a problem when i bought the car about a year ago at a steep discount, figuring it was a cam lobe that was bad.

I replaced it and the rocker arm with a 45 YO-ish pushrod and rocker arm out of my old motor parts collection.

Doug

65silververt

UPDATE:

-I drained the oil and ran a magnet through it. No metal was found.

-I then took two paint strainers and poured the oil through them into a container. No metal found.

-Next, i pulled the valve covers back off and measured the length from the tip of the #6 intake pushrod to the point where it passes through the pushrod guide and compared it to the other intake pushrods. The difference was .10"

-I used my scope to look at the lifter and cam and they appear fine, so i decided to pull the lifter in question out with a magnet.

The lifter is stuck. It will not return to its normal starting position. And, as luck would have it, i somehow managed to purchase the only lifters crane makes that don't have a snap ring, but instead use a retainer that is meant for one time use only.
New lifters are on the way. I plan on pulling the intake this weekend.

Thanks for the help!

Westlotorn

The lifter sold by crane with the non removeable retainer is a anti pump up lifter, performance lifter designed to work as a Hydraulic lifter but allows higher RPM.
Glad you found the issue.
Sealed Power sold these also, HT817R was the part number. They were made by Johnson Hy-Lift which sold and was re opened by Top Line.
Good luck, glad it was not the camshaft.
Was the lifter foot still flat and smooth? The foot is the part touching the cam lobe.

65silververt

Yeah, i am not sure how or why i ordered those for a mild street engine, but i did. The Crane Cams tech i spoke with this evening said they are not recommended for street use due to their noise level. He felt bad for me, so he took 30 bucks off the new lifters. Nice people!
The lifter looks just the way it did when i installed it, minus the machine pattern. I'll get a closer look at the lobes and other lifters once i pull the intake.
Thanks again. I did not respond to your tip on the gas because the tank in this car is only two years old and i just filled it up with premium fuel about a month ago.

robert miller

Hope it something small and dont have to pull it back out of her.

65silververt

Robert, the problem turned out to be a lifter. See above. Thankfully it was not more serious. Shew!

Nowhere Man

sounds like what I went thought last year. only I was not as lucky. my problem was there was no oil getting to the lifter and had all the same problems you had. only mine was due to barrings on the bottom end.

Westlotorn

Thanks for the feedback, glad it all will work out. Remember a new set of lifters means you will need to do another camshaft break in procedure just like the first time.

65silververt

Unfortunately this is true!
I have new oil, moly paste, and break in additive on the way. Two cams, three sets of lifters, two gasket sets, almost 150.00 on special oils and additives, and xxx amount of time...the roller cam would have been a good investment.