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Camshaft lobe gone
https://www.slantsix.org/forum/viewtopic.php?t=6159		 Page 1 of 2
Author:  Rick Covalt [ Tue Jul 01, 2003 3:58 pm ]
Post subject:  Camshaft lobe gone
After replacing my son's camshaft and oil pump, after an oil pump gear failure at 500 miles, I thought our problems were over. However I noticed that the engine didn't sound right the other week and we began to do some adjusting and tinkering to get it ready for Carlisle next week. When we went to adjust the valves we found number one exhaust valve pretty loose (.045-.050) I didn't really think much about it, adjusted it, and buttoned it up. Adusted the timing, and drove it but something was definitely wrong. I dropped off at the local shop to have him check out all the ignition system before we went any farther. Of course it was not electrical ( which I already new) but it was number one cam lobe gone!

Questions:

1) Any idea what could have caused it?
2) What to do to prevent it again?
3) This was the .528 lift cam, installed with plenty of assembly, and new
lifters. Approx. 5000 miles on engine. We ran 10W30 for 2000 miles then switched over to synthetic
4) What break-in procedures are you guys using.

Doug, I'll post back and let youknow what the oil pump gear looks like
when we get the motor out. (Again!!!)

The good news is, all the bolts are well lubed and easy to take out! On second thought, there ain't no good news.

Thanks for all your help,

Rick Covalt
Author:  Doctor Dodge [ Tue Jul 01, 2003 10:51 pm ]
Post subject:  Bad Cams...
There have been a lot of failures with the last group of MP 528 cams. I saw a bunch of them sold for "dirt cheap" so there could have been a problem with them. :?

Question: when the engine was first started did you check to see if all the lifters were spinning? I mark the top of the pushrods with a paint dab so I can look for this. My last engine swap had a "no spin" lifter so I stopped there and swapped in a new lifter to get it to spin before doing the final valve adjust.

On performance Slants I have been grooving the lifter bores and putting stand pipes in the galley's oil drainback holes so I can direct a bunch of oil onto the lobe. I have never had a cam lobe go flat. (Knock on wood)
DD
Author:  Rick Covalt [ Wed Jul 02, 2003 1:14 pm ]
Post subject:  Groove Lifter bores?
Doug,
Thanks for the reply. I didn't check for lifter rotation? What is the normal cause for one not spinning? Especially on a new cam, new lifter, new engine? Certainly I'll check the new one.

How do you groove the Lifter bores, anyway?

Rick Covalt
Author:  Rick Covalt [ Wed Jul 02, 2003 6:27 pm ]
Post subject:  Break in period
What type of break in period are you using on new cams and lifters??

Thanks,
Rick
Author:  Doctor Dodge [ Wed Jul 02, 2003 10:43 pm ]
Post subject: 
I have a special tool to groove the lifter bores. It is a .900 diameter rod with a threaded, counter-bored crosshole, where a toolsteel bit (sharp point) is loaded-in. The hard steel point sticks-out the side of the rod so when the rod is "hammered" thru the lifter bore, it cuts a groove down the side. I use the same tool to put oil grooves in piston pin bores to give them extra oiling.

As for lifters not spinning, there are a number of causes:
1) Tight or burred lifter bore, hone them out hard with a wheel cylinder hone.
2) A flat or concave lifter face, new ones should have a radius (convex).
3) A cam lobe with-out taper, all should have .002 to .004 more material on the rear side of the lobe.
4) Lifter bore or cam lobe position is wrong, the lifter bore is not centered over the cam lobe but offset to make the lifter spin.

Most of the time I find that the lifter bore is tight or the lifter does not have enough radius on it. I have found a few cams with little to no taper ground onto a lobe(s). (I check them with a micrometer, edge to edge)
DD
Author:  Rick Covalt [ Thu Jul 03, 2003 4:15 am ]
Post subject:  Break-in
And for break in I should do what on a new cam? Thanks

Rick
Author:  Doc [ Thu Jul 03, 2003 10:08 am ]
Post subject:  Re: Break-in
Quote:
And for break in I should do what on a new cam? Thanks
Rick
I am the wrong person to ask about SL6 cam break-in....

I just pour oil all over the valve gear right before I start the new engine and then I fire it off and stat tuning it in. I may pour a little additional oil over the rockers once things are running if I don't get oil up top immediatly.

I am not a big fan of the "run it 10 minutes at 2500 RPM" school of thought, that is done for V8 where the cam is up high and where lobes are covered-up in the galley, where splash can not get to them.

My mindset is this:
1) Don't relie on splash, put oil where you need it. (grooved lifter bores)
2) Measure everything and engineer / machine things so it works right.
DD
Author:  bud L. [ Thu Jul 03, 2003 5:51 pm ]
Post subject:  more
something I do, is not put break-in lube or grease on the sides of the lifter, and lifter bore. For those areas I use a light oil, like ATF, or 10W-30. Definitely, look for pushrod spin! If they don't spin, the cam will not live. Take an old v. cover and cut the top off to prevent a mess and allow a good view of rocker ass'y while running. I do lightly hone lifter bores, and check for free movement of lifter in bore.
Author:  Rick Covalt [ Thu Jul 03, 2003 7:43 pm ]
Post subject:  The Damage
We got the engine out again this evening. As suspected, # 1 exhaust lobe is almost gone along with the lifter. All other lifters look perfect. Not a single mark. We are going to put in a Racer Brown Cam in that I traded Dennis for some time back.

The bad news. The hardened oil pump gear and the cam gear are both wore pretty badly! By badly,I mean you can obviously see roughness and wear on both surfaces. My guess is that it would not have lasted 10,000 more miles. It only has 5000 miles on it.

Doug I will send you the gear as soon as we get it pressed off for you to look at.

Now what do we do?? The lobe was probably my fault, but what do I do about the gears?? I removed the stock 130,000 mile oil pump on this engine a year ago and the gear on it looked smooth.

We'll I'm admittedly frustrated and not sure what to do next.

Funny thing is as a 18 year old kid, 25 years ago, I put together a junk slant six with all used parts under a tree. installed a used cam on used lifters , put used headers and used offy intake with a junkyard AFB, and went 6500 RPM flat shifting that thing for 2 full years. Crazy! Yes, But true.

We really tried to do this engine right and we have had it out 3 times now in less than 5500 miles.

Rick

PS. I tried to get pictures to send to you Doug but they are all to blurry to really see the marks in the gears.
Author:  Doctor Dodge [ Thu Jul 03, 2003 9:09 pm ]
Post subject: 
Rick,
Send me the junk cam also, I need to check the gear profile to see if it was cut right.

This oil pump drive gear failure problem is a real PITA, just when you think you have it solved, something else pops-up. :cry:

Did you check the mesh / lap-in the last one? Did the contact pattern look centered?
DD
Author:  Rick Covalt [ Fri Jul 04, 2003 5:59 am ]
Post subject:  Patern Centered
Doug ,
I did lap in the camshaft as you recommended in previous posts. The wear pattern on the cam looks pretty well center also. I'll send you the cam and gear early next week.

Rick
Author:  slantzilla [ Fri Jul 04, 2003 6:57 am ]
Post subject: 
Wow, that really sucks Rick. I decided to go with a Comp Cams Extreme Energy cam this time. I hope I have better luck than you.

I thought I'd be OK with my .528 Mopar cam because it was older. No such luck for me either.

I'm thinking about finding a way to plumb and oil tube that will spray the cam/pump gears. I have a picture in my minds eye of what it needs to be. Now I just gotta figure out if it can be done or not.
Author:  Rick Covalt [ Fri Jul 04, 2003 9:33 am ]
Post subject:  cam # 3
I'm hoping that cam # 3 is the charm. I'm about out of cams!!! HA HA!

Doug ,
I won't get the gear off until Monday now. Should have you the cam and gear by the end of next week.


Rick
Author:  Rick Covalt [ Sat Jul 05, 2003 1:21 pm ]
Post subject:  Cam Problem?
Dennis,

Did you have trouble with your .528 cam also?? I did'nt here about it.

Rick
Author:  slantzilla [ Sat Jul 05, 2003 3:14 pm ]
Post subject: 
Yep, I lost a pump gear out on the tollway and fried a motor. 700 miles and 50 passes on a 528 cam. The oil pump had been in the motor with the Racer Brown cam for over 2 years and looked perfect when I put it back in with the Mopar cam. Doug has the pump now.

I saved the head, rockers, pushrods, pan, and 5 pistons.
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