WTF would cause this? April 09, 2010, 11:29:36 PM This is(was) a Comp Magnum 292H hydro flat tappet camthe #5 intake and exhaust lobes are mushroomed down about 1/8". So are TWO lifters. Every other lobe and lifter look perfect?? That's from about 50miles of street use.New Comp lifters were used, and this cam was brand new. Cam was prelubed with moly lube, and the lifters soaked in oil for 3 days prior to installation. Cam was broke in by keeping rpm around 2500 for 25-30min. I used O'reilley 20w50 oil with 1 bottle of ZDDP additive. Oil pressure never fell below 60psi during that time. Bad cam? Bad lifters? Bad luck? Quote Selected
WTF would cause this? Reply #1 – April 09, 2010, 11:58:48 PM Too much lifter pre-load? Quote Selected
WTF would cause this? Reply #2 – April 09, 2010, 11:59:47 PM I have no idea of the cause but you did everything just as you are suppose to.Only thing I can think of is excessive spring pressure? What was the specs on the springs? Seat pressure and rate?Also are you sure you had enough lift potential for this cam? Clearance between the retainer and guide and spring bind?Like TJ302 points out valves adjusted too tight could also do this?TED Quote Selected
WTF would cause this? Reply #3 – April 10, 2010, 08:33:44 AM Preliad was within spec. Springs are TFS "upgrade" single springs good to .542" lift. Summit and Comp said the cam was too big for stock rockers, but I didn't see any sign that they were getting in a bind. If it were more than 2 lobes ground down, I would guess it was something on my part. I believe I got a bad core, and the metal was too soft. Quote Selected
WTF would cause this? Reply #4 – April 10, 2010, 08:55:25 AM I had the same thing happen with an edelbrock cam last year. used the reccomended springs. I had several bent pushrods and a few lobes ground. could of been my fault but who knows. Quote Selected
WTF would cause this? Reply #5 – April 10, 2010, 11:27:35 AM Probably break in related... The NASCAR boys install light springs to break in the cam and lifters for a hour or so on the dyno, before they install the big springs that will be run in the races... Quote Selected
WTF would cause this? Reply #6 – April 10, 2010, 11:45:51 AM I have no idea. #3 Exhaust lifter looked just like that on my old motor, maybe worse, but it made it at least 50k and possibly 185k, not to mention i had bad bearing damage by that point as well. Quote Selected
WTF would cause this? Reply #7 – April 10, 2010, 12:25:27 PM I don't think a soft cam would do the damage it did to the lifters. I would lean toward the spring pressure also. Quote Selected
WTF would cause this? Reply #8 – April 10, 2010, 02:38:38 PM well, whatever it was I'll try again with the new Crane cam and lifters. Maybe put the stock springs back on for break-in? Quote Selected
WTF would cause this? Reply #9 – April 10, 2010, 06:52:27 PM That happened to me with insufficient break-in additives. No synthetic for flat tappet break-in and plenty of zinc/EOS, etc. Quote Selected
WTF would cause this? Reply #10 – April 10, 2010, 07:07:44 PM did you ever get rid of the noise in the video might of been a rocker too tight(if adjustable) and check all your pushrods Quote Selected
WTF would cause this? Reply #11 – April 11, 2010, 08:55:45 AM From the sound of the video, there were some serious valve train issues. Spring bind (stacking)? Push rod bind? Wrong push rod? I don't know, but there was a problem from the git-go.I hope your intent is to pull the engine to inspect it and clean out the metal shavings. It would be a shame to swap another cam into and have low oil pressure in a few hundred miles due to wiped mains.Flat tappet lobe failures are well dospoogeented and frequent these days. Primary causes are lack of proper oil additives in current oil and cheap lifters commonly available.Spring pressure can also kill them. You mentioned a TFS spring upgrade. Was it for a HR or a flat tappet?Though not relavent to to your application. Break in w/dual springs requires two break in's. One with the outer spring and one with both. Oil must be changed (w/new additive each time) between each one (total of three oil changes).A hydraulic roller becomes a cost effective alternative to a flat tappet. That is: After you factor in the cost of a couple flat tappet cams and lifters, pulling down the engine for cleaning, new bearings and gaskets.Though you haven't asked for an opinion, I suggest you go the roller route. Will it cost more: Yes. The advantages are many (modern profiles, broader power band, less friction). The biggest is: You don't have to worry about another flat cam lobe!If you would like more education on valve train, go to sbftech.com, get 10 posts in and go to the myths and rumors section. The axiom there is: do it once, do it right.Sorry to hear this happened to you, hope you have better results on the next go round! Quote Selected
WTF would cause this? Reply #12 – April 11, 2010, 09:23:10 AM The TFS springs are just a single spring. 110lbs closed/320lbs open. I couldn't see them having too much.When the new cam gets here, it should come with instructions. I'll be sure to follow them to the T. Quote Selected
WTF would cause this? Reply #13 – April 11, 2010, 09:50:12 AM I will never ever use a flat tappet cam in anything other then a lawn mower.There is just so many advantages to using a roller. Quote Selected
WTF would cause this? Reply #14 – April 11, 2010, 10:25:19 AM Quote from: 86T-bird;317744From the sound of the video, there were some serious valve train issues. Spring bind (stacking)? Push rod bind? Wrong push rod? I don't know, but there was a problem from the git-go.I hope your intent is to pull the engine to inspect it and clean out the metal shavings. It would be a shame to swap another cam into and have low oil pressure in a few hundred miles due to wiped mains.Flat tappet lobe failures are well dospoogeented and frequent these days. Primary causes are lack of proper oil additives in current oil and cheap lifters commonly available.Spring pressure can also kill them. You mentioned a TFS spring upgrade. Was it for a HR or a flat tappet?Though not relavent to to your application. Break in w/dual springs requires two break in's. One with the outer spring and one with both. Oil must be changed (w/new additive each time) between each one (total of three oil changes).A hydraulic roller becomes a cost effective alternative to a flat tappet. That is: After you factor in the cost of a couple flat tappet cams and lifters, pulling down the engine for cleaning, new bearings and gaskets.Though you haven't asked for an opinion, I suggest you go the roller route. Will it cost more: Yes. The advantages are many (modern profiles, broader power band, less friction). The biggest is: You don't have to worry about another flat cam lobe!If you would like more education on valve train, go to sbftech.com, get 10 posts in and go to the myths and rumors section. The axiom there is: do it once, do it right.Sorry to hear this happened to you, hope you have better results on the next go round!and having said all that, it makes you stop and think that back when flat tappets were the only choice during OEM original assembly at the big 3, they never had to go through all the steps you mention. What your saying makes sense,,, but conflicts the reality of what happened back then.Engines were made, and most of the time were never started or broke in like you describe. Random daily engine samples were tested im am sure to verify a precentage of failures ect. I really think that back then, most engines never saw thier first startup until the car was drove off the line.I may be wrong but from a buisness perspective it would only make sense.This leads me to think the answer to the thread is ,,,,,,,,,,,,,China.,, ie-inconsistent metalergy or quality control insuring each part meets min specs or that testing of random samples is not being done. Quote Selected
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