Major cam problems!!!!

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Coyote Jack

Coyote Jack

Member #55, I'm old
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For those of you that don't know the whole story.
I have a rebuilt 360 with magnum heads. This engine only saw dyno time before I bought it. It sat for 2 years before I installed it. Upon my initial startup everything sounded good, after I installed my exhaust I could hear very loud rocker noise so I investigated and found one lobe had damage and others looked like they were on there way out. All other indications showed no other damage to the engine.
I installed a new cam and lifters. When I broke it in I started to notice some valve train noise from the same side as the first time. Today I took the top of the engine off just to check and make sure things were O.K.
Bad news. I now have 2 useless bump sticks. Although the cam itself isn't damaged bad it is damaged and a few of the lifters are showing wear, enough that they are junk.
When I installed the new cam I used liberal amounts of cam lube and after I had installed the rockers I even coated the lobe's again. I primed the oiling system and was getting oil to all rockers. When I took the valve covers off today there was oil trapped on all rockers so I don't think it is an oiling problem. I used Rotella-T 15-45 and GM EOS as my break in oil.
The engine took about 15 seconds to really catch good on the startup and then I ran it for 13 minutes at 2300 rpm before it started to get to hot. 220 to 230 degrees and I shut it down. The next night I ran it for another 10 minutes at 2500 rpm. During both of these runs I would take the engine up to 4000 rpm for a few seconds and then let it go back down to 2300 to 2500 rpm.
I believe I did everything right. The valve stems look good and all valve heights check out good. The valve springs are rated to .525 lift. The first cam was a Comp Cams XE268H and the second was a MP 284/484 purple shaft. With the 1.6 rockers the first cam had a total lift of .509 and the second cam had a total lift of .516. I checked for coil bind as best I could and did not find any.

Has anybody got any idea's? Could it be a geometry problem? Would going to a roller cam solve this type of problem?

I don't know much about cam theory and any help would be good.

Jack

360 +.040
magnum heads 1.6 rockers
10.5 : 1 comp
M1 intake
no cam
 
Sorry to hear this Jack. Must be real frustrating.

Going roller would eliminate cam break in all together. A set of shubuck lifters would also solve the problem. Neither are cheap.
 
Yup, very frustrating Adam. The wife isn't going to be to pleased either. I have to do something cam wise though. I can't throw away $300 for 25 minutes of run time over and over.

Jack
 
i am sure that some of the smarter engine guys will answer this but have you contacted comp cams to give them the story and see what they say? i would think that they might be able to point you in the right direction. who knows they might even help to replace the original cam. what do you have to lose at this point by asking?
 
Jack do you know what valve springs are on it ? I know there arent to may choices for magnum heads wich is going to be a problem. The stock springs arent good for much over .450" lift. The other chpice are the Mopar Perf. race springs that came on crate motors and over the counter Magnum heads. They're good for around 550" I think.

If you go with a Hyd roller you'll need to find some AMC style push rod oiling roller lifters and you'll need a retro fit kit. Comp Cams and Crane sell retro fit kits and they probably use a push rod oiling lifter. Just ask and make sure. A roller cam will cost you around $300 and lifter will be around the same. You'll probably need a shorter push rod too.

If you go with a solid roller you'll need adjustable rocker arms wich would be a bad idea with any cam over .500" lift. You'll also need a bronze oil pump drive. You'll be over $1000 for a solid roller set up.

The other choice is a set of Shubuck lifters wich are reusable you'll never have to buy a set again even if you change cams. They're around $600. Overkill for your engine but probably the cheapest way of the 3.

I would talk to some one who really knows Mopars and valvetrains. Talk to Ryan Johnson at http://www.shadydellspeedshop.com/ or Scott Brown at http://www.straightline-perf.com/ about a cam/lifters/springs and your problem and see what they say.
 
Adam has very good suggestions here about talking to guys who really know cams. The only thing I can think of that could be a problem is too much spring pressure is possibly wiping the cam lube off before it's getting a chance to let the lifters rotate enough to break in properly. I've heard if your running alot of spring pressure you should break the cam in with a set of weaker springs then switch to the springs your going to run. Lots of work but the only way to go.
 
I am running Mopar Performance springs. Part #P5249464. They are a single spring with dampener. I believe they are rated to .525 lift.

Just checked, they are good to .525 lift but I can't find the pressures listed anywhere.

Jack
 
Coyote Jack said:
I am running Mopar Performance springs. Part #P5249464. They are a single spring with dampener. I believe they are rated to .525 lift.

Just checked, they are good to .525 lift but I can't find the pressures listed anywhere.

Jack
Click to expand...
OK I know what you've got. I had some of them and just sold them. I never knew the exact pressure rate either because I like you couldn't find it listed but I don't think they are all that stiff. That being said I don't think they should be your problem. The ones I have on my 360 now are at least that stiff and I had no problem with my generic cam. I thought just maybe you were running some big honking dual springs or the like. I'd say go with what Adam said and call the experts and see what they say. Sorry I couldn't be more help. Best of luck.
 
I'm definately not a know it all on cams, so i would trust others over myself. I had my shortblock assembled at Hughes engines in Washington, IL, they are just a couple hours drive from me so I went there for my machine work. Dave the owner really knows his stuff. From what I have learned from him, that lifter rotation is very important. If you can't just drop the lifter in with a little oil on the sides there is a problem. Also on the same note if there is too much clearance then there is also a problem. A couple of years ago, he contributed some cams either free or at cost to a group of people on the moparts board, they were building a engine for the popular hot rodding engine master's challenge. Anyway the engine that they were building had excessive clearances and wiped out a couple of cams on the dyno. They finally found the problem and had the lifter bores sleeved and that fixed the problem. might be your problem as well. The only other thing that Dave @ hughes engines makes a big deal about is that the engine must start in the first couple to three turns over. That might possibly be another source of problems, but I would doubt that one, since you pre-lubed the engine, and it started with-in the first 15 seconds. My bet would be check the lifter bores, if they are to loose or to tight that could be your problem. Check out hughes engines and talk with Dave, he'll try to help you out, that is if you go with one of his cams. I haven't had my car running yet, so i can't tell you how the cams work, but I have good things about them. Hope some of this helps you.

Dan
 
I just got off the phone with Comp Cams. They think I have coil bind or the retainers/keepers are bottoming out on the guides. It's something to check. I haven't heard back from Scott Brown or Ryan Johnson yet.

Jack
 
Coyote Jack said:
I just got off the phone with Comp Cams. They think I have coil bind or the retainers/keepers are bottoming out on the guides. It's something to check. I haven't heard back from Scott Brown or Ryan Johnson yet.

Jack
Click to expand...

That is entirely possible. Check for seal/guide to retainer clearance issues. I think you'll find it very close. I normally cut down all guides and install teflon seals, which if done correctly will eliminate any retainer to guide clearance problems. If I remember correctly you may run into clearance problems around .500/.520 lift. With your 1.6 rockers you could be dangerously close. Pop off a valve spring and put the locks and retainer back on and with a set of dial calipers measure the clearance between the seal and underside of the retainer close to the valve. This will tell you without a doubt if there is enough clearance there.
 
Magnum heads usually have reatainer/guide clearance problems at around .523" lift so its possable.
 
Jack, I have the same XE268H cam and springs on my magnum headed 360 and have no clearance issues. FWIW, the 360/380HP crate motors camce with stock magnum heads and a .509 lift cam so I would not think you have a bind issue but check for sure.
 
I talked to Jim at Racer Brown today. He recommended that I pull the engine and take it apart. I am going to do it this weekend and check everything. I am also going to get my spring pressures and installed heights checked. Then I am going to talk to him again and see what he says. I knew somehow that I was going to end up doing a total rebuild. It's been a while, (25+ years), but I'm sure I remember how.

Jack
 
Well, it's a lot of time and expense..But, if you want to be sure, and KNOW, you have to go back to the start, and go from there. Keep us updated on the autopsy.
 
Problem ever fixed.im wanting to run magnum heads on 360 with 484 purple cam.planned on getting the push rods and other things needed from articles with magnum heads on la engines.
 
:thumbsup:

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