Camshaft Lobe - The 1947 - Present Chevrolet & GMC Truck Message Board Network

LuckyHenriksen · 11-24-2008, 04:29 PM

Is it supposed to look like this?

Bus Ted Knuckle · 11-24-2008, 04:31 PM

No

big_al_71 · 11-24-2008, 04:33 PM

+1

sick69 · 11-24-2008, 04:33 PM

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 · 11-24-2008, 04:46 PM

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 · 11-24-2008, 05:46 PM

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 · 11-24-2008, 07:16 PM

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 · 11-24-2008, 07:26 PM

Quote:

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** · 11-24-2008, 07:34 PM

knocking probley

71tahoe · 11-24-2008, 07:45 PM

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 · 11-24-2008, 07:49 PM

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 · 11-24-2008, 07:58 PM

Ok well it looks to be a cam lobe then.

LuckyHenriksen · 11-24-2008, 07:59 PM

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

heavy71chevy · 11-24-2008, 09:34 PM

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

LuckyHenriksen · 11-24-2008, 09:37 PM

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 · 11-24-2008, 09:42 PM

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 · 11-24-2008, 11:02 PM

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

**WIDESIDE72** · 11-24-2008, 11:55 PM

Quote:

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 · 11-25-2008, 09:50 AM

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** · 11-25-2008, 10:42 PM

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 · 11-25-2008, 11:02 PM

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** · 11-26-2008, 12:40 PM

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.

11-24-2008, 04:29 PM	#1
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Camshaft Lobe Is it supposed to look like this? __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here

11-24-2008, 04:31 PM	#2
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: Camshaft Lobe No __________________ Bill BEATERS ARE NEATER

11-24-2008, 04:33 PM	#3
big_al_71 Registered User Join Date: Jun 2008 Location: South Florida Posts: 11,375	Re: Camshaft Lobe +1 __________________ Get your facts first, and then you can distort them as much as you please!!!!!. Sylvester's build thread >>>http://67-72chevytrucks.com/vboard/s...ht=big+rebuild

11-24-2008, 04:33 PM	#4
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: Camshaft Lobe 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 __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

11-24-2008, 04:46 PM	#5
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Re: Camshaft Lobe 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 __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here

11-24-2008, 05:46 PM	#6
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: Camshaft Lobe 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 __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub Last edited by sick69; 11-24-2008 at 05:47 PM.

11-24-2008, 07:16 PM	#7
71tahoe Registered User Join Date: May 2006 Location: Jonesboro, AR Posts: 916	Re: Camshaft Lobe 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.

11-24-2008, 07:34 PM	#9
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,232	Re: Camshaft Lobe knocking probley __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

11-24-2008, 07:45 PM	#10
71tahoe Registered User Join Date: May 2006 Location: Jonesboro, AR Posts: 916	Re: Camshaft Lobe 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.

11-24-2008, 07:49 PM	#11
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Camshaft Lobe 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. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" Last edited by PanelDeland; 11-24-2008 at 07:50 PM.

11-24-2008, 07:58 PM	#12
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Re: Camshaft Lobe Ok well it looks to be a cam lobe then. __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here

11-24-2008, 07:59 PM	#13
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Re: Camshaft Lobe I don't know what to do about it, im just gonna keep running it and see what happens __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here

11-24-2008, 09:34 PM	#14
heavy71chevy Registered User Join Date: Apr 2007 Location: antreville, south carolina Posts: 873	Re: Camshaft Lobe could be a stuck lifter...thats what happened to mine and wiped my number five lobe...just a thought __________________ "Dixie Destroyer" 71 C10 LWB Fleet Future Blown Prostreet Monster Last edited by heavy71chevy; 11-24-2008 at 09:35 PM. Reason: mispelled

11-24-2008, 09:37 PM	#15
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Re: Camshaft Lobe 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 __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here

11-24-2008, 09:42 PM	#16
Willys47 Registered User Join Date: Dec 2007 Location: Nanaimo B.C. Posts: 604	Re: Camshaft Lobe 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. __________________ I was hooked on these trucks since 1982 when I drove my budys fathers 1968 Custum GMC 396 automatic dana 60 rear with a power lock diff what a ride more fun then we will we can ever tell!!



Register or Log In To remove these advertisements.

11-24-2008, 11:02 PM	#17
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Re: Camshaft Lobe So is the 'stick just scrap metal now? No other use for it right? __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here

11-25-2008, 09:50 AM	#19
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: Camshaft Lobe 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 __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub Last edited by sick69; 11-25-2008 at 09:51 AM.

11-25-2008, 10:42 PM	#20
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: Camshaft Lobe 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.

11-25-2008, 11:02 PM	#21
LuckyHenriksen Registered User Join Date: Oct 2007 Location: Sherwood Oregon Posts: 1,908	Re: Camshaft Lobe 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 __________________ 1968 Yenko Chevy LWB 6.0L/TH400 3/4 Drop Senior Project Build Thread Here Last edited by LuckyHenriksen; 11-25-2008 at 11:03 PM.

11-26-2008, 12:40 PM	#22
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: Camshaft Lobe 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.

Register or Log In To remove these advertisements.