Cam pitted and worned
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Cam pitted and worned
I had a known tuner install a cam about 15k miles ago. The car is a '98, Z51, mn6 with stock heads. I had installed upgraded pushrods, titanium retainers and Comp 918 springs. I recently developed drivability problems. The tuner dynoed tuned the car but the problem still exist. They checked the sensors, computer...etc. I brought the car home and there it sat for over a month.
I think I have found the problem. I went into the engine and removed the camshaft. The lobe controlling #2 exhaust valve was deeply grooved and pitted. The lobe controlling #6 exhaust was also grooved and pitted but to a lesser extent. Several other lobes were developing pits.
It appear as if the cam lobes were possibly not made of the same material ( not a billet camshaft). Is that a "regrind" cam- metal added to a cam and regrinded? I am concern about metal in the oil pan and other places. I have decided to go with a complete H/C, valvetrain set up.
I expect performance parts to not last as long as some stock parts but isn't 15K miles a bit too short?
Please don't tell me that I build this engine to make 430-450rwhp I will be replacing parts often and making the car unreliable??
Thanks
I think I have found the problem. I went into the engine and removed the camshaft. The lobe controlling #2 exhaust valve was deeply grooved and pitted. The lobe controlling #6 exhaust was also grooved and pitted but to a lesser extent. Several other lobes were developing pits.
It appear as if the cam lobes were possibly not made of the same material ( not a billet camshaft). Is that a "regrind" cam- metal added to a cam and regrinded? I am concern about metal in the oil pan and other places. I have decided to go with a complete H/C, valvetrain set up.
I expect performance parts to not last as long as some stock parts but isn't 15K miles a bit too short?
Please don't tell me that I build this engine to make 430-450rwhp I will be replacing parts often and making the car unreliable??
Thanks
Team Owner
Joined: Sep 2003
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From: Raleigh / Rolesville NC
There is a thread over in LS1Tech about a F13 cam doing the same at 13K miles.
http://ls1tech.com/forums/showthread.php?t=464304
Guys are mentioning that 13-15K miles is about the limit for big cams. But I think that is
http://ls1tech.com/forums/showthread.php?t=464304
Guys are mentioning that 13-15K miles is about the limit for big cams. But I think that is
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Originally Posted by vettenuts
I was going to refer you to the same threads. Which cam is this, what are the springs and lifters? It appears there may be an oiling issue too.
Any photo's?
Any photo's?
I reviewed the thread and it was very helpful. I purchased the cam from Thunder Racing -224/227 @114lsa. The springs are Comp 918's and the lifters are Comp R. The lubrication system was upgraded using the LS6 oil pump. I have no pictures, however, 14 lobes are slightly pitted and 2 lobes are significantly pitted and "cupped" out.
When I purchased the parts I went with their recommendations (springs, retainers, p/r, lifters and cam). I didn't think I would be going back into the engine so soon!
Aside from a lubrication problem, and I was only running a moderate cam, what is the expected service life of the big cams (ie g5x3 and others) ?
Thanks
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
I would re-visit the thread on LS1Tech and pay particular attention to the discussion on oil starvation. Not sure what your cam/lifters look like but it may be a starvation issue not the cam itself. Even with a good pump, filter, etc. you can still starve for oil. I ordered a set of Morel lifters last Christmas and they will be here on Thursday that I plan to install during my head change to Darts. I would consider getting the Morels since you have it apart and need new ones anyhow.
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Isnt there a MOD that can be done to the OEM plastic lifter retainers. I saw a post a long time ago where a person drilled some oil drain holes in the retainer to help direst the oil on to the cam.
Have any of you ever seen any one do this?
Bill C
Have any of you ever seen any one do this?
Bill C
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From: Vancouver WA
I have seen this problem on my Harley with several cams. I have heard it's because synthetic oil is too slipery and the lifters are draging and not rolling on the cam. (Which I think is BS). IMO, I think it's the heat treatment on the cam. And the high spring rates are breaking the surface of the cam off because they are probably just surface hardened. But I don't think the 918's are that stiff of a spring are they?
But it also could be that something else is giving away! If you get any metal between the roller and the cam, it's probably going to leave a divit or a chip. Check your pushrod ends! I have seen them chip on the ball ends. And check your rockers. Matter of fact, check everything you can.
Hopefully your oil filter caught it all. You may want to take your oil filter off and cut it in half and look at the inside and see what you can find. Also while you are changing the cam, take a close look at your oil pump gears and see if you see any scaring or pitting.
But it also could be that something else is giving away! If you get any metal between the roller and the cam, it's probably going to leave a divit or a chip. Check your pushrod ends! I have seen them chip on the ball ends. And check your rockers. Matter of fact, check everything you can.
Hopefully your oil filter caught it all. You may want to take your oil filter off and cut it in half and look at the inside and see what you can find. Also while you are changing the cam, take a close look at your oil pump gears and see if you see any scaring or pitting.
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Michael S. Palmer
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From: Hobart, WI
Originally Posted by vettenuts
Yes, but that just drains the oil and prevents pooling on top of the lifter. The issue appears to be one of local oil control in and around the lifter.
Drifting
Joined: Oct 2004
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From: "Philly" Pennsylvania
Maybe another more experienced member can chime in on this point. I think I read (service bulletin) that '98's and maybe a year on each side of that had a needle bearing problem in the stock rockers; in his first post above he did not mention replacing the rockers. I believe the teltale evidence would be needle bearing pieces on a magnetic drain plug (or in the bottom of the oil pan). Good Luck, if your rockers are stock - check them for sure.
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Originally Posted by vettenuts
I would re-visit the thread on LS1Tech and pay particular attention to the discussion on oil starvation. Not sure what your cam/lifters look like but it may be a starvation issue not the cam itself. Even with a good pump, filter, etc. you can still starve for oil. I ordered a set of Morel lifters last Christmas and they will be here on Thursday that I plan to install during my head change to Darts. I would consider getting the Morels since you have it apart and need new ones anyhow.
I have 75K miles on the car and I still have the OEM valvetrain. There are no signs of oil starvation. The rollers on the lifters are smooth, the lobes of the cam are smooth ( no pitting ). I modded the engine at 60K miles. I will research the Morel lifters because they do seem to address a potential oil supply problem and they are superior to my current lifters. The aftermarket cam is pitted but all except one lifter (Comp R) appear serviceable. If it was oil starvation would that problem be reflective on the other lifters?
I generally put about 200 mi/wk on the car. Any big cams daily drivers with 25K miles+ on cam with no cam related problems?
Thanks
Le Mans Master
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From: Farmington CT
Cruise-In VII Veteran
that thread on the other board is all over the place, seems like fms had a bad batch of cams from cammotion; i didn't talk to fms, this is only from reading the posts
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Originally Posted by connecticut
the F13 along w/ all FMS cams are made by Cammotion, does Thunder Racing get their cams from Comp?? could be a problem w/ the manufacter of cams, tuners just order the grinds
Crane, Comp or Cammotion??
Crane, Comp or Cammotion??
I'll call tomorrow and find out who is the manufacturer of their cams.
Team Owner
Joined: Sep 2003
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From: Raleigh / Rolesville NC
Originally Posted by RED99
Another thing is if there is any valve float or harmonics, that could play hell on the cam lobes and lifters.
Instructor
Joined: Feb 2004
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From: Nashville TN
I have had a G5X3 112 LSA cam on my car for > 50K miles; Comp 921 springs etc... without a single problem what soever and I run it hard for over 100 miles every day. I would say you have encountered inferior material. Next time; go with LG Motorsports products. Lou runs what he sells. Good Luck!
Melting Slicks
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From: Rhode Island
Originally Posted by connecticut
that thread on the other board is all over the place, seems like fms had a bad batch of cams from cammotion; i didn't talk to fms, this is only from reading the posts
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From: Vancouver WA
Originally Posted by electra
I have had a G5X3 112 LSA cam on my car for > 50K miles; Comp 921 springs etc... without a single problem what soever and I run it hard for over 100 miles every day. I would say you have encountered inferior material. Next time; go with LG Motorsports products. Lou runs what he sells. Good Luck!