Stopping the knock: Lower compression and ported heads...
With your cam degreed in at 106 when is the intake valve closed on your degree wheel? Do all the open close events on the cam card match the wheel events?
I should have the numbers that I got. I scribbled them on the instructions included in the degree kit. ( The only paper I had nearby at the time)
I plan to recheck the cam timing as I reassemble the engine.
I agree that the pistons show no physical signs of detonation, yet I clearly heard something knocking. After starting several threads, receiving thousands of views and hundreds of responses, I can only say that I still do not have any proof of what is happening.
I have stated several times that the knocking sound only came on once I got past 1/2 throttle. This is where the secondaries feel the most effective. The engine really picks up power at this point.
Is the knocking coming from inside or from somewhere else?
I mentioned that the only times that I was able to drive at WOT without knocking were the following:
Using 110 octane fuel.
Timing retarded to 6 initial, 20 total.
One time after changing a leaky valley pan, I made 3 full throttle blasts on 91 octane fuel. The first 2 were with an engine not quite up to operating temperature and the engine did not knock. The 3rd pass it did, so I continued looking for the problem. I'll add that while the temp guage is original, it seems to be working okay. The engine rarely ever gets past the middle of the guage, never smells or feels hot and has never boiled over.
To understand the problem, I look at what
else occurs at WOT. The air cleaner is close to the hood, but I haven't seen any evidence of them making contact since I'd expect to see scratches or chipped paint somewhere. The engine knocked before and after I installed the fan shroud, so that is a NON issue.
*******************************************************
In May, I replaced the K member with a welded and reinforced unit I had modified. When I removed the original K, I found that the RH motor mount was broken, so I replaced it. This raised the RH side and as a result, the LH header sometimes now made contact at the steering box. I found dimples and scratches in the ceramic coating. The tubes were undamaged prior to changing the K member. At rest, there was about 1/4" of clearance.
As I understand it, under power, the engine
lifts on the left side and goes down on the right. This would mean that any header interference shouldn't actually occur at WOT, right? The headers had no other points of interference. The transmission mount is a spool design that is in good condition. The cross shaft for the shift linkage was secure.
Looking at the numbers, I made a few mistakes in calculating the CR. The pistons were only .012 in the hole when I thought they were .017. I had been using an 84 number for the combustion chamber size when they could have been smaller due to the times I've had the heads resurfaced. Anyhow, at this point, I come up with a 10.94 with a Fel Pro .039 gasket. That is with a .051 quench distance. The .027 gasket bumps it to 11.21 with a .039 quench. The .075 drops me down to 10.07 and quench would be a non issue at .087.