Quote:
Originally Posted by 242177P
Hmm. More cam isn't going to make it more
detonation prone, it's less cam that does that.
Factory scientists carefully selected a cam for
the 1967 428 ci HO YK Code Pontiac that didn't
detonate. Even inferring that a former gymnast
and his roommate failed to adequately tune the
motor is tantamount to heresy. And 067 heads?
They don't detonate. Ever.
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Mikes Reply:
I want people to know who is speaking and when, sometimes I don't know who is up at bat, now you know why Mikes reply:
One thing that I can add is that I advanced my cam while I was into the Degree Wheel phase.
In one of my last posts, I explained that this motor was in a truck that went off mount Everest, while running Rum to the bearded Tenn, still man with the green teeth. The motor was running at the time it hit bottom and that probably caused the cracked Harmonic balancer. Then I ran this motor to 130 mph, at least ten times looking for the motor's limit. Well, I found that the used "588" Tri-power Cam was worn out so badly and the lobes at # 7 & 8 were not even hardly lifting the push rods.
The metal worn off from the Cams soft metal, is now throughout this engine. But mike cleaned that out with the Trans. fluid and went on. The Cam bearings were perfect, so I put the New "041" Cam in, using the existing Bearings. Seven thousand miles later, I could see that the crank Pin journals at # 7 & 8 were worn, the # 7 more than # 8, but eights Bearing was worse, for some reason. The number 4 Crank bearing is now worn to the copper, on the bottom of the Crank Journal cap. So, all that reciprocating motion, up and down, over the past ten years or seven thousand miles, finally took its toll on the old girl. Can I prove this, "No", but it is my prognosis anyway.
Then the pistons are backwards, adding insult to injury. Now that I am inside this motor, it is telling the story, there was no Piston Slap, and the cyl. walls are smooth to the touch. The Piston skirts have zero lines on them. The rod knock was # 7 & 8 and the Crank bearings on the other Crank Pin journals are normally worn and the lower Crank Main bearings look good except the fourth Crank Bearing is affected from the above, shared journal movement, all this is because the Harmonic Balancer was sending Harmonics and vibration over the years that I drove this car.
It is a good thing that we removed the Heads at this time, because the Exhaust valve that we replaced was ridden with hairline cracks and would have broken and I could have lost this motor. Maybe, it is just as well that we took the lower end apart, as the forum said to do, this I should have done already, thanks to Cliff, you were right and I was wrong, and that goes for all of you that tried to tell me. I won't make that mistake again; I am a true believer that if you build the top end of a motor, you had better build the bottom end at the same time. You can add parts in between without worrying, but the upper and lower end was designed to operate for 100k miles and they are mated to each other and ware simultaneously, throughout the service life. Just like a Cam must ware along with the Lifters, they are mated together and ware simultaneously. That is my observation.