Don Terrill’s Speed-Talk

In consideration of your vote on the original of this flutter, who thinks 25-30k is the most I should get out of AFRs upgraded beehive springs...on a 340 lobe (.544) with 214 duration? IOW...Is that an aggressive enough lobe that would need new springs after 30k (7yrs). I had hoped they'd last longer. OTOH, I'm not convinced this is valve flutter. Might be something loose in exhaust/cats.

https://youtu.be/RmduyHJSgyM

Have you tested the springs on the engine? How do they compare in poundage to the spring advertised as new? Until you do, most everything you are pondering is a WAGMAR-wild ass guess made at random.

Thanks for making me aware of that option! I wonder what type of shop would have the tool/machine necessary to measure spring strength? I will look into a couple of shops nearby.

That said, the question about the nature of the noise isn't predicated on spring pressure (though it could skew the guess one-way or another). To me, it doesn't sound like valve flutter. Maybe (as an optimistic), I'm hoping for exhaust noise. This has been posted in a couple of forums for a couple of days. Since no one has replied (in either place), that also makes me think this isn't valve flutter....assuming it would be more readily recognizable.

The Monday post above somehow looks like we've picked up the thread in mid-stream, but assuming it is complete, I'd say there's zero chance that it has anything to do with valve springs. 95% likely it's a loose exhaust bracket, muffler baffle or something similar.

Thanks "MadBill". I can see why the wording of my first post seems odd. This IS all of the thread.

My thread was written to solicit 2 pieces of feedback:
1) Dual-hive spring*** longevity (expectancy) on a 214 duration .544 lobe (1.6rr) running less than 5k rpms (peak) -- and --
2) opinions on origin of my exhaust noise.



*** Don't remember what (upgraded) springs I put on my 195 Eliminators. Hopefully they keep records. If I HAD to guess, 155# sticks out in my mind. Can't remember if I upgraded retainers to lighter weight....probably not due to lower rpm use. I picked 155# in hopes of longevity AND control because Bullet's .340 lobe was their most aggressive lobe on a 214 duration cam. (Lots of talk [at the time] about Comps XFI cams maybe, possibly being a hair too aggressive on the ramps).

Sounded like well muffled exhaust popping on deceleration to me but I can't hear crap anymore.