Last night I was showing off my awesome craigslist find - a new-in-box Comp Cams 260XFI for the LT1. Of course it slipped out of the box, I fumbled for the turnover, it slow-motion fell about 2 1/2 feet, and landed nose-first at an angle on the concrete.
I have heard the tales of proper cam and crankshaft storage. "Store them perfectly vertical or they will bend and destroy your engine!!1!" I don't believe any of that. I have heard that if you drop a camshaft, it will shatter like glass into a billion pieces and you are berkeleyed. I don't believe that any more, because my cam is still definitely one piece.
There is a small nick and a scuff or two. I think I can grind it out with some 400 or 500 grit paper, and go over with a razor blade to make sure there is nothing sticking up. I have heard the "dips" are okay but any "raised" portions could be fatal.
Or maybe I should just bite the bullet and order a $300 replacement.
Hard to say without looking at the thing. My instinct would be to bring it to a machine shop and make sure they get it smooth. Someone correct me if I'm wrong, but my suspicion is that this kind of thing happens all the time to professionals and they're not ordering $300 replacements several times a week.
Berk it. Run it. Wear to fit.
Or was this a motor you give a damn about?
Sorry, guess I'm not much help.
I'd polish out the nick and either take it somewhere to get an NDI or buy a dye pen kit and look for a crack.
Other than that I'd just call it good.
penultimeta wrote:
Hard to say without looking at the thing. My instinct would be to bring it to a machine shop and make sure they get it smooth. Someone correct me if I'm wrong, but my suspicion is that this kind of thing happens all the time to professionals and they're not ordering $300 replacements several times a week.
+1 for this. I highly doubt you could measure any bend in the shaft after a little drop like that.
If it helps my case, it's a nice steel aftermarket cam, not some brittle cast stock piece.
Also, it's just the Challenge car
get it mag-ed... then have it checked for runout. If it isn't cracked, or bent, have the nick removed
I'd polish up and nicks and run it.
NOHOME
PowerDork
3/10/16 10:31 a.m.
Where is the nick, lobe of journal?
If journal, I would say the razor check is a good idea to detect any sharp edges. (kill fire with fire)
If the cam goes in the bearings and does not bind when you give it a spin, its most likely OK. The cam never sees any crazy revs anyways.
jmk015
New Reader
3/14/16 6:28 a.m.
NOHOME wrote:
If the cam goes in the bearings and does not bind when you give it a spin, its most likely OK. The cam never sees any crazy revs anyways.
I agree with this. File/sand the damage smooth then slide it into your block. Make sure that it spins smoothly with no binding once its installed. If it turns nicely once installed, you're good.
I grind for a living. Not the cam lobes, themselves, but I've done stuff equivalent to the bearing journals. I've had to straighten bars, rods, shafts, etc, of various metals, too. I've also dropped a berk-ton of parts, in my 30-plus years of doing this.
I agree with NOHOME. Knock the bump down, check it with a razor, and if it spins freely, you should be good. I highly doubt that the drop bent it. In my experience, there are only a few soft metals that bend, when you drop them. BTDT.
LT1 cams are made of different material than the cams that break. The older cams are easy to bust into pieces by dropping them onto something in the middle. The newer cams are higher grade to allow for the small contact area of the rollers.
I straightened a cam once, with a block of wood, a 3 pound sledge, and a vice. It's still running to this day.
That was in a Harbor Freight engine in my golf cart, so that might not apply in this situation.
I vote polish it up and run it.
Woody
MegaDork
3/14/16 9:17 a.m.
My suspicion is that if you brought a cam to a machine shop and one of the guys who worked there (not RealMiniParker) dropped it, he'd polish out the nicks and you'd never hear a thing about it.
Duke
MegaDork
3/14/16 11:34 a.m.
My buddy's father used to build dirt track race engines. He took every new cam out of the box and purposely dropped it on asphalt paving. He figured if it was going to break anyway it might as well be before it was in the engine at the track.
We once had a trucking company drop an engine. They agreed to pay for a new oil pan and warranty the engine for 3 years.
Six weeks later the flywheel came off the broken crank register under full load. Not much was left. Luckily the operator was running an air tool at the other end of a fifty foot hose.
Clean it and run the thing!
You now have V-TEC on 3 cylinders.
"Dogmeat man, you're dogmeat!"
It's a roller cam, clean it up and run it. Flat tappet and I might be able to see some cause for concern.
Thanks everyone! I feel a little better now.
roller cams don't break when you drop them, but flat tappets will break at each main journal of you drop them perfectly flat... i've won a few $5 bets from a few people betting on what would happen when i dropped a used up small block Chevy cam onto the concrete floor...