Camshaft Lobe

[LuckyHenriksen]

Is it supposed to look like this?

[Bus Ted Knuckle]

No

[big_al_71]

+1

[sick69]

Not at all! It should be smooth and shiney.

I would bet you lost oil to that journal or spun that bearing.

Just my thought

Frank

[LuckyHenriksen]

Hmmm lets hope theres no spun bearings. This is the unknown cam that I pulled out of my 350 last winter, I put in an Edelbrock performer. Lets hope there isn't significant damage to my motor.....






Or else I will have to go LS based

[sick69]

I hate to say it but if the journal on the cam looks like that I would think the bearing looks the same way.


It looks like that is the bearing journal not a lifter lobe,,,correct?

Just my thoughts though,,,

Frank

[71tahoe]

Kinda looks like the very bottom mostly out of the picture is the journal and the lobe with the scoring is for the fuel pump.

[LuckyHenriksen]

Originally Posted by sick69

I hate to say it but if the journal on the cam looks like that I would think the bearing looks the same way.


It looks like that is the bearing journal not a lifter lobe,,,correct?

Just my thoughts though,,,

Frank

I don't know the difference between a bearing journal or a lifter lobe.....

What would my motor be doing if it had spun a bearing? I have been running it for a while and haven't noticed any strange problems, and its still runs!

[truckdude239]

knocking probley

[71tahoe]

Never had a motor that I knew the cam bearings got wiped but it will cause lower oil pressure for sure. Lower pressure will affect the other bearings. Rod bearings will cause knocking right up until the rod cap escapes from the block. Don't ask how I know.

[PanelDeland]

Lucky,a bearing journal will be round or close to it if it's scored like yours.A cam lobe will be oblong or egg shaped.It's what the lifter rides on to move the pushrod which in turn operates the rocker arm to open and close the valve.Also the cam lobe will be smaller overall,thoug it may not be much smaller in a high lift cam.

[LuckyHenriksen]

Ok well it looks to be a cam lobe then.

[LuckyHenriksen]

I don't know what to do about it, im just gonna keep running it and see what happens

[heavy71chevy]

could be a stuck lifter...thats what happened to mine and wiped my number five lobe...just a thought

[LuckyHenriksen]

Whatever it was happened before I bought the truck, cuz I tore out the motor like 4 days after I bought it. I didn't notice anything when I had the heads off, but I have no idea what to look for

[Willys47]

my guess is that lobe is for the fuel pump rod.what dose the end of it look like, cause if it is bad it could take out the new cam and put a lot of metal into the oil.That can cause damage to other parts.

[LuckyHenriksen]

So is the 'stick just scrap metal now? No other use for it right?

[WIDESIDE72]

Originally Posted by LuckyHenriksen

So is the 'stick just scrap metal now? No other use for it right?

Makes a good trot line weight. FYI anyone not doing so needs to run a zinc additive in their oil if still running a non roller cam engine. Search this forum and the net regarding lack of zinc in modern oils. This could be the culprit.

[sick69]

Lucky if you take another pic alittle farther back so we can see exactly which part of the cam that is, we would probably be able to give alittle better thoughts on it. Maybe get at least half the cam including the bad spot in another pic.

If that is a bearing journal and you didn't replace the bearing along with the cam then a good chance of making the new cam look just like that one.

If thats a lift lobe then not much to worry about assuming you replaced lifters along with the cam.

If that is the fuel pump lobe and are still using the same fuel pump rod again you could be makeing the new cam look just like that one.

I guessed at that looking like the bearing journal based on it's size compared to the size of the shorter/smaller lobe directly behind it in the pic.


Frank

[WIDESIDE72]

In the last few years I wasted a cam in two different 350's. These were not a first build. These were around the fourth and fifth engines I had built and happened around 15k- 20k miles after break in. In both engines, when the cams went flat, the main bearings were toast as well as the crank its self due to the metal getting all through the motor... One cam was a Rhoads, the other was a Comp. I broke the engines in as usual, prelubed the engine with a modified distributor, started engine and ran a large shop fan in front of it while varying the RPM from 1800-2800 for around 30 minutes. I have bulit two engines ( one 350, one 383) since this problem, this time using ZDDP additive and Shell Rotella oil. The 383 is in a 79 Malibu and doing fine at 10k miles, the 350 is on a stand and destined for a 72 short step. Lack of zinc in the new oils will screw up a flat tappet (non roller) cam big time.

[LuckyHenriksen]

Umm this was a hydraulic flat tappet, nothing special. The truck had come with a pre-used Edelbrock performer cam, so when I had the motor torn down I stuck that in there, and set the other one back on the shelf. I was just cleaning out and found it, and was looking at it closer and noticed the bad spot. I've been running the motor quite a bit, and taken a few long drives and high RPM powerbrakes and stuff, and haven't seen/heard any signs of trouble. I'll just keep at it until it dies

[WIDESIDE72]

There was nothing exotic or special about the engines I built either. Standard deal of .030 overbore, cast pistons and crank, not balanced or blueprinted. The 383 did get forged parts, and balanced, all the more reason to be careful with the cam break in. ($$$) IMO, if you continue to run that cam, you can plan on replacing the crank as well. Did you use new lifters, or lifters that had been run with that cam in the past, with them indexedso tht they were put with the lifters matching the lobes they were originally used with? This is a good example of why it is never worth using a used cam. $100 is too cheap to go buy a new cam and not take a chance wasting your motor with metal filings from a cam going bad.