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Flat cam symptoms

4K views 29 replies 14 participants last post by  95snake 
#1 ·
Give them to me. The car picked up a roller rocker knock. I am not driving it until its fixed. I am buying a set of valve covers later today so I can adjust the rockers. I found no shavings in the oil, and there is nothing shiny on the dipstick. The drain plug was clean as well.
 
#8 ·
There is no popping at all. I have driven it about 30 miles. It only loads up, and after changing the oil yesterday from a 10w30 synblend to 10w40 conventional, the rocker knock got stronger sounding. I had the passenger side valve cover off yesterday, and the heads appear to be nearly new. It doesnt have a ton of power, but it doesnt lag or fall on its face, which I read is a symptom. As far as buying new, dont get me started. Ford or Chevy there both the same. 60k my tranny went out in my F150, my wifes chevy stays in the shop. Both or less then 7 years old, and were bought new.
 
#14 ·
Do yourself a favor and find a oil with zinc in it. Today's oils are not very friendly to flat tappet cams. You can also find an additive.

As for systems it may or may not miss, but if you have a rocker noise and its lose and you adjust and it comes back in a few days then I would say you have a cam lob thats bad.
 
#18 ·
Sometimes rocker geometry is off and the rocker will hit the spring/retainer.

Typically, I only find a problem with lobe failures in flat tappet cams only when the break in was done with no zinc in the oil. Other than that, I've not had problems using Royal Purple and no additive after that.

Small Block Chevy's unless they have ridiculous loose oil clearances on rods/mains don't need any oil thicker than 10W30.

Could also have a rocker arm hitting the valve cover. It happens with center bolt valve covers frequently.

Typically, valve train noises from loose lash adjustment are ticks rather than nocks. Another knock that is possible is the timing chain/gears hitting the block and the timing cover when the cam walks in and out of the block. A thrust button will solve that.

The first thing that will happen with lobe failure is the lifter stops spinning and then tracking. You can pull the valve covers and when idling hot, you should see the pushrods spinning.
 
#22 ·
Nope the car is fine, the motor was set up to rev very high. All I am hearing is the wrist pins. I took it to a guy that builds 70's TA's and he knows his stuff. I did set the carb myself, and now its not loading up. I don't plan on keeping this 350 in there for a long time. I have already started to save for a 454.
 
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