Hello everyone. You all have been good to me in the past so i wanted to see what you thought of this: Last week i put in a new camshaft. It is (was) an Iskendarian, nothing too huge. I broke it in properly (~20 minutes at 2800 rpms). When it was done being broke in, i noticed a valve tick on one cylinder. Figuring i had just misadjusted a valve, i re-adjusted all the valves and had the same problem. Long story short, i wiped a lobe on it. So my question is, what did i do wrong? I used cam lube, new lifters, immediately revved to 2800 rpms, and my motor is pretty spankin' new (was vatted). Could a lifter have just seized? I was using crane "anti pump-up" lifters, i have had bad luck with Crane lifters in the past, but didn't think it would be this much of a problem. So, i'm left wondering...did i do something wrong? Or did i just get unlucky? New cam will be here tomorrow so i want to make sure this is the first and last time this happens! ~Chris
By the sound of it you did everything right unless you adjusted the valve too tight . You should probably check for binding in the springs or valve train before you try again . I dont know what springs you are running but make sure they are correct for your application . Or you could just have got a bum camshaft . I feel your pain . What are you going to do about all the steel particles in the bottom of your oil pan ?
Boy, have I been there. After I put my Sprint together, I had to change the cam twice in as many months. The first one was due to spring pressure too great. The second time I got the correct springs, installed and measured them, and still wiped out 2 lobes. I couldnt find any reason for the second cam. Only conclusion I came to is if you use the double springs, you should remove the inner one for the break in period. Then reinstall it. I used Comp Cams stuff and this is not mentioned in any of their literature. To clean out the metal, I filled it with fresh oil, changed the filter, and ran the oil pump with a drill . Then I drained it and inspected the oil . After doing this a second time, it was clear with no signs of metallics. You will most likely never get it all out but its been running great with no problems for over a year now. When I bought the third cam, I went to roller.
That is one thing that is different about my setup this time...i have double springs, plus a damper. The springs are only rated at 125lb seat pressure (installed height), which is only 15 more lbs than the single spring, so i didn't really thing that would be a problem?? I am not worried too much about binding, i have lots of clearance and my springs are supposedly good up to .600 lift with no binding (my cam only had .517 lift). I too was wondering about "priming" the lifters, maybe sticking them in a bucket of oil and compressing them, then letting them suck up some oil? One other guy had suggested that my cam might have been part of the problem--the iskendarians come "rough" on the lobes but smooth on the bearings...he thought that maybe a different brand that already comes "smooth" would help out. I went with a Comp Cams "XTreme" this time, hopefully i will have better luck. As for the oil, i wasn't too worried--should i be? My impression was that the oil goes through the filter first then to the rest of the engine, and i always run good filters (Pure ONE). Am i correct? I also changed the oil immediately after the cam break-in (not realizing what had happened just yet), so i am betting i got most of the particles out when it happened. Well, i guess i'll just cross my fingers tomorrow and hope for the best. Maybe i'll give Iskendarian a call and see what help they can offer.
Well thats not waaaay too much seat pressure but a little . I have ran more but Mavaholic has a good point about breaking in with only the outer springs installed . For the extra hour of work it takes to take out the inners and replace them it wouldnt hurt . I never trust what manufactures say about clearance with their springs . I always measure it as well as valve to piston clearance . A long shot here , but you could still have springs binding if new valve seats were installed and not ground correctly . Priming the lifters is always a good idea . Damage can occur when dry from the hammering they take at first .(Noisy too) Good luck and let me know how it went .
Cam Prob's Here is my take on it, sounds like maybe a mfg. defect, talk to the tech guys and see if you can send it to them for a look see. Should be able to work with them on it, they have been around a long time. Just wondering how you adjusted the lash on the valves, on high lift cams with hyd. lifters I just tighten down the nut until there is no clearance and then only turn it down about 1/8th more. Most cam peolple do not recommend priming the lifters but if you ran a drill operated engine prime before fire up, that should pump them up enough anyway. I have done it like suggested with the lifter in oil and use an old push rod to pump it up, but then you must not adjust the rockers by turning down as the manual suggest. This puts way to much preload on the lifter for aftermarket cams over .500 lift. Then normally the engine runs sluggish because the valve train is to tight. Could be off the mark here but just relating what this dumb a** has done in the past to screw things up
I was talking to an engine builder yesterday about this problem, and he said his break-in procedure for hydraulics is to run some clearance between the rocker and the valve, just like you were using a solid cam. This way, the lifer is not always in contact with the camshaft and it allows oil to get between the lifter and cam and keep is lubed. Normally hydraulic cams constantly run with 0 clearance...that's what they're supposed to do. I asked how much clearance, he said about .005-.010 should be fine. Supposedly in 20+ years of engine building, there was only 1 camshaft failure and it was due to a co-worker's dumb mistake. Sounded good to me, FWIW.
I don't know. When you run a cam at 2500 rpm for the first 20 minutes, you are doing so to set a wear pattern on the cam and lifters. The lifters rotate during normal operation and this is when that pattern is set. I would think leaving too much lash so that the lifter actually leaves the cam may cause more harm than good. More of a hammering than a firm pressure doesn't seem better to me. I bought an extreme energy cam from CC as well, used their lube, springs and lifters and had no problems. Didn't pull any springs either.
I wished I had heard this one before I installed the 2nd cam. It makes sense. My roller cam is set with 1 full turn from zero lash. I have 566/576 lift. Think this is too much too?
One full turn on a 24 pitch thread is about .042" preload. That's a bit excessive, I think they're supposed to be .015-.030" if memory serves me correctly. each 1/8 turn is around .0052". It gets a bit different with 7/16"-20 studs.
I guess starting a new engine with .005 or .010 clearance wouldnt hurt . As the engine warms up the clearance would get become less anyways . Just make sure you readjust the valves when you are done . Engines like 302s with really short pushrods like at least 1/2 a turn of preload in my experience .
You are close sir. To determine the linear travel per complete revolution of a nut or bolt, divide the thread pitch by 1 (inch in this case). ex: 24 threads per inch (TPI - same as 'pitch'): 1"/24 = .042" (one complete revolution will result in .042" linear travel) 1/8 of each turn (.042") = .125 X .042" = .0053" (measurable only by feeler gauge or other measuring device) ex: 20 TPI - 1"/20 = .050" (one revolution will result in .050" linear travel) I smFart that way.
Mavaholic, I'm no expert but i know that 1 full turn is too much. On hydraulics i like to go 1/4 turn, tighten the lock screws down, and then you'll get another 1/8th turn out of it to lock it in place (assuming you have the posi-lock nuts). So, about 3/8" total. You might pick up some bottom end with one full turn but lose top end. Personally i have found the best way to adjust valves is to do so with the engine running--back off the nut until the rocker arm ticks and then tighten 1/4 turn. I haven't figured out how to do this on the "posi-lock" nuts yet (without making a huge mess). Made a "seat of the pants" difference on my old cylinder heads though, and i have heard the same from others. The valves get a little noisier towards the minimum preload but they make up for it in top-end power.
I haven't figured out how to do this on the "posi-lock" nuts yet (without making a huge mess). CaCollo; if you want to save some of the mess, cut the center out of a set of old valve covers. Bold them on with rubber gaskets, and the oil will stay in the head, not on the floor. Earl
