Cam issue!
02-29-2008, 08:47 PM
#1
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Cam issue! I know this may not be in the right section but i need everyones opinion. I wanted to see what yall guys think could make this happen and maybe why. My car was running like crap so i took it back to the shop and we find out that one of the lobes on the cam is rounded off. We found out because one of the valves was only lifting about .100 Just wanted to know what causes this and why. Its a hydraulic flat tappet cam just incase that helps. Could it just be a bad part or could something be wrong with any of the valvetrain? We already replaced the cam and is getting put back together as we speak. Thanks!
03-01-2008, 03:21 AM
#2
I know this may not be in the right section but i need everyones opinion. I wanted to see what yall guys think could make this happen and maybe why. My car was running like crap so i took it back to the shop and we find out that one of the lobes on the cam is rounded off. We found out because one of the valves was only lifting about .100 Just wanted to know what causes this and why. Its a hydraulic flat tappet cam just incase that helps. Could it just be a bad part or could something be wrong with any of the valvetrain? We already replaced the cam and is getting put back together as we speak. Thanks!
03-01-2008, 03:42 AM
#3
I know this may not be in the right section but i need everyones opinion. I wanted to see what yall guys think could make this happen and maybe why. My car was running like crap so i took it back to the shop and we find out that one of the lobes on the cam is rounded off. We found out because one of the valves was only lifting about .100 Just wanted to know what causes this and why. Its a hydraulic flat tappet cam just incase that helps. Could it just be a bad part or could something be wrong with any of the valvetrain? We already replaced the cam and is getting put back together as we speak. Thanks!
03-01-2008, 07:29 AM
#4
I know this may not be in the right section but i need everyones opinion. I wanted to see what yall guys think could make this happen and maybe why. My car was running like crap so i took it back to the shop and we find out that one of the lobes on the cam is rounded off. We found out because one of the valves was only lifting about .100 Just wanted to know what causes this and why. Its a hydraulic flat tappet cam just incase that helps. Could it just be a bad part or could something be wrong with any of the valvetrain? We already replaced the cam and is getting put back together as we speak. Thanks!
03-01-2008, 10:39 AM
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It is because flat tappet sucks...that is why the world went to roller. Especially if you are running new iols, they dont have zinc and sulpher that oil manufacturers had to cut out due to emmissions. That is a must for flat tappets, there are additives and even companies that still make oil for flat tappets but it is easier to use roller, cost more but worth it. Maybe you didnt break it in right.
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03-01-2008, 02:34 PM
#8
the reason i say that is cause the metal shaving have been cycled thru the motor befor they went to the filter. the rod bearings definately catch some of the material. every old school sbc that ive seen a flattened rounded off cam in started having rod knock issues after 1k miles. not trying to hurt your feelings just letting you know what to be ready for.
03-01-2008, 03:44 PM
#10
Everyone says oil, I say bull ****. If this is a sbc then it could be a number of things. I would lean towards too tight of a lash or to high of a valve spring pressure. What are the specifics of this motor? Cam, heads, etc. Oil is a lame excuse. If the motor had 30, 40, or 50,000 miles on it then maybe oil could be to blame but I dont think this is the case. Josh
03-01-2008, 04:06 PM
#11
Well, it is a fact, you have to use the oil with the high content if you want it to live, it has been going on for a while now, it doesnt have what it needs anymore for the flat tappets, but hell, the valve spring pressure and poor ajustment are possibilitys too.
03-01-2008, 04:25 PM
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the reason i say that is cause the metal shaving have been cycled thru the motor befor they went to the filter. the rod bearings definately catch some of the material. every old school sbc that ive seen a flattened rounded off cam in started having rod knock issues after 1k miles. not trying to hurt your feelings just letting you know what to be ready for.
03-01-2008, 04:26 PM
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Well they used the right oil to break in the cam which is rotella diesel oil. and they break it in right on their dyno as well. So i dont know what can be the excuse. What oil do yall guys suggest i use from now on every oil change? Synthetic?
03-01-2008, 04:36 PM
#15
Here we ago with the oil debate. I just suggest an oil with the current rating. I think it up to sk or even higher, I dont use oil bottles. A good 10w30 would be fine if the bearing clearances arent alot. I used to run 20w50 in my race motors. In my ls1 I run 10w60 castrol tws3. Motor has some miles and I spray it hard.
03-01-2008, 05:08 PM
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355 4 bolt main, 10.5:1 comp, GM performance crank, forged pistons, now since that other cam fd up its got a 240 246 hydraulic flat tappet comp cam, Ported aluminum heads, edelbrock victor jr. intake with a 750 hp series holley.
03-01-2008, 06:10 PM
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Comp cam and it is .507 int. and .510 exh on 1.5 rocker ratio and mine is 1.6 rocker ratio. Dont know what the seat pressure is and what do you mean with too much preload?
03-02-2008, 01:07 PM
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Make sure that your valves springs are installed correctly and still good. They broke it in properly with that oil. Did they run a lifter bore through the hole? I've seen trash get in there before and not allow the lifter to spin correctly.
Other than that, everyone here seems to have the same answers.
Other than that, everyone here seems to have the same answers.