454 Flat Tappet Cam Failure
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
I feel sick in the stomach when I hear about these wiped lobe failures. Being new to American cars and V8's I'm curious as to whether this is a GM V8 issue or does it occur across all the brands. When the cars were new what was the break in procedure when they left the factory? Was cam failure more or less common "back in the day"? Comparing the SBC cam to one of my OHC motorcycles the lobes seem kind of puny for the amount of valve gear they have to move.
I have started my SBC with the valve covers removed and was quite surprised as to how long it took for oil to appear at the rocker gear (OP is 70 psi cold) so am I correct in thinking the cam relies on splash from the crank until oil from the heads arrives back down the lifter valley? I always allow the car to run at high idle for a couple of minutes before moving off when the engine is cold.
I have started my SBC with the valve covers removed and was quite surprised as to how long it took for oil to appear at the rocker gear (OP is 70 psi cold) so am I correct in thinking the cam relies on splash from the crank until oil from the heads arrives back down the lifter valley? I always allow the car to run at high idle for a couple of minutes before moving off when the engine is cold.
Last edited by 63mako; Feb 14, 2015 at 11:04 PM.
Thread Starter
Instructor
Joined: Jan 2013
Posts: 218
Likes: 0
From: Missouri
My engine is back together and the Straub roller cam is great! I want to thank them for everything they did! Engine pulls like you wouldn't believe! I can't even explain the difference from flat tappet cams I have run in the past. I highly recommend their products. Chris treats you very fair and explains in detail about his product. I also spoke with Scott Foxwell who is very good with helping with pushrod length and rocker geometry. I am glad to be back on the road. I will be using them from now on for cam purchases.Here is a video to hear it run.
Last edited by Z06FEVER; Mar 17, 2015 at 11:19 PM.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
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From: Butler Pa
Instructor
Joined: Feb 2012
Posts: 173
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From: Federal Way WA
About a year ago I did a top end rebuild on my 355 SBC. Flat tappet cam, aluminum heads, nice intake, fresh holley carb. 12 miles after the 500 mile break in period, I wiped 2 cam lobe. Used Valvoline VR1 oil at every change, every 2 weeks. Still wiped. The crank is trash, as is the block. The car is still sitting in the garage, collecting dust, waiting for the day I have the moolah again to build another engine. Lesson learned, never cheap out. Do it the right way, just like everyone on these forums (and several others I read) said from the get go. Maybe one day I'll learn.
Thread Starter
Instructor
Joined: Jan 2013
Posts: 218
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From: Missouri
I am saying that out of all the engines I have built, valvoline oil has always been used. I was told to use brad penn since all the zinc was taken out of modern days oils. I did change and wiped a cam lobe. This is the first time it's ever happened to me and I built the engine the exact same way any of the other engines I built. Unless Crane had a manufacturing defect(which they did send me another cam and lifters when I mailed the bad one back) yes, I am blaming the oil, especially after reading the long thesis written by rat540 and his long study on oils.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Seems odd that Crane sent you a replacement cam if it wasn't their fault.
