new AFR heads need new pushrods?
03-17-2008, 03:44 AM
#1
Staging Lane
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new AFR heads need new pushrods? Just installed brand new out the box AFR, 205, p/n 1510, cnc heads. Mechanic reused the hardened pushrods that were installed about 10k mile ago, when I did the cam swap. Heads are not milled, and used factory GM head gaskets. See signature for cam specs. Heres the problem: heard very loud tapping sound after the car sat for couple days; only had driven about 70-90 miles on head swap. The sound came after car had been idled for about 1-2 minutes, last about 5 seconds, then went away. Sounded like it was coming from top end of engine, but stopped before I could pop the hood. drove the car grand-ma style about 6 miles, and came back home. SES light came on during drive (scan says it is o2 sensor on bank 1, sensor 1), but i want to pull the valve covers and look around. Should i have run a different length pushrod? Im wondering if the sound came from a valve spring, or loose rocker, or something. Shop hasnt looked at it yet, but advised a loose rocker wouldnt stop making noise, once it started. They suggested it might be a lifter pumping up? would roller cam hydralic lifters need to pump up with oil? Thanks for any suggestions.
03-17-2008, 04:51 AM
#2
They should have checked the pushrod length (hopefully they did and then once verified re-used the pushrods). My Morels will do exactly what you stated if it is cold out. When I start they are quiet then they will tick for a couple of minutes and then quiet down again.
What oil are you using?
What oil are you using?
03-17-2008, 05:23 PM
#3
Staging Lane
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Thanks. It was cool that night (high 40's). Im using Royal Purple, 5w-30 in the engine. Is it a loud tick, or more like a muted tapping sound? Mine was loud. And your lifters do that each time? Mine are factory lifters...
03-17-2008, 06:30 PM
#5
They did with the German Castrol, if it was warmer they would do it less. Then I switched to Amsoil 5W-30, they don't do it unless cold out so the Amsoil definitely helped. If it keeps doing it on cooler days, try a different oil. Look at the viscosity at 40 degrees C to help figure out what to try, that will give you an indication of how well it flows on cold start. For example, the German Castrol was a 0W-30 and the Amsoil a 5W-30, but the Amsoil actually has lower viscosity at 40 degrees C which is why it helped me out.
