What would stop YTs from causing valve float? After some reading and searching, it seems to be the general consensus that YTs can add to an existing, or in some cases, cause a valve float problem, due to the added weight of the tip. What would help this, stiffer springs? My new setup is below, do you think I'll have a problem (or enough of a chance of a problem to warrant the purchase of an $$$ adjustable setup)?

Engine: 347" Forged, ~11.5 to 1
Cam: 24x/24x ~.61x
Lifters: Comp "R"
Springs: Comp 977s
Pushrods: Chromoly
Retainers: Titanium
Rocker Arms: ??? (Have NIB YTs already)

Do you think my 977 springs will be sufficient to control the valvetrain with YTs installed?

Thanks, Shawn

 

It seems the cure is using the correct spring. Some old threads have people switching to comp 977 from the 987 and this worked. Granted my old setup was POS but with the single 918's and tit retainers I had no float with the YT's,, go figure. I attached my dyno sheet below. While I was losing tq it was in a smooth linear fashion so I do not believe it was float. I see you are using the 977's so maybe you will be ok but your lift is up there also so keep a set of stockers handy just in case the YT's do float on your setup.

 

IMO you'd need a spring with plenty of leeway...i.e. on a cam with .580 lift you'd want a spring good to say .650 lift.

 

Its depends on spring, lift and duration. If the spring your using is at its limits or close to it with your cam and you put a heavier rocker on top of the spring, the spring has to work harder and then causes float since it was already at its limits....

Solution...... Get a stiffer spring or lighter rocker.

 

I've had no float with my YT's.The Cam has .600 lift and is revved to 7000rpm.I ran 918's for the first 2500 miles then switched to Cranes for a piece on mind.

 

Back before I changed over to the patriot gold duals, I ran 918's on my TSP231/237 with the YT's and I didn't have any valve float up to 6800rpms. I've had my car on the dyno quite a bit here in the last 6 months and have never seen any signs of float. I think you'd be more than safe with the 977's. IMO the YT's don't hurt anything, but that is one area that I feel like I "wasted" money on my car.

 

Valve float is really not about those rockers, it's about running the right springs at the right installed heighth. And only a handful of springs work up to (for example) 7200 rpms in a hydraulic application. I am running Y/T's and my motor is setup up to spin to 7300 rpms. I am running Crane springs.