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Mon Dec 09, 2013 4:09 pm

Hi can some one please tell me the signs and symptoms of engine valve float?

Mon Dec 09, 2013 4:46 pm

Sometimes its popping through the intake.

Mon Dec 09, 2013 4:48 pm

How high are you reving it?

Mon Dec 09, 2013 4:56 pm

No more than 5500 rpms but I have a gene berg 307 cam with 1.4 rockers equal to a Engle 100 with 1.25 rockers and am using stock valve springs and would like to know the signs and symptoms of engine valve float so I know what to keep a listen out for.

Mon Dec 09, 2013 5:42 pm

Sputters and pops at low RPM's. Looses power at high RPM's. Maybe nothing except a big clunk and a rod sticking out the top of the case with oil dumped all over the place.

Mon Dec 09, 2013 5:52 pm

Well, you'll usually hit a rev limit over which the car won't produce more power if the valves float. Valve float can damage your engine catastrophically. Check out what sort of springs you need for your setup.

Mon Dec 09, 2013 6:26 pm

Valve float occurs when the piston speed exceeds the valve springs speed in closing the valve..it occurs at high rpm,usually when the engine is under load and then quickly released from load,like declutching with the throttle wide open..when the piston moves up and down faster than the valve can close they come into contact with each other resulting in catastrophic failure..its an extremely rare occurrence in a stock/mild engine..

Mon Dec 09, 2013 6:31 pm

I think the best question is why did you spend all the money on the engine only to bum out on springs? Any time you increase lift or duration stock valve springs should be replaced, along with retainers to handle the extra stress. So stop worrying and install some springs. If you cant any machine shop can for a very low fee I am sure.

But that's my opinion and you what those are good for!!!!!!!!!!!

Mon Dec 09, 2013 6:32 pm

Valve float can happen at low RPM's too. Valve float happens from how quickly you rev an engine. If you hammer it hard at 1200 RPM you can have valve float and damage at 3000 RPM. It's not just from turning high RPM's like everybody thinks. 90% of you guys will blame a broken rod bolt on a failure instead of valve float. More damage is done from not having enough springs then from having too much.

Tue Dec 10, 2013 2:19 am

Volks Wagen wrote: Well, you'll usually hit a rev limit over which the car won't produce more power if the valves float.

yeah a lot like that. Usually noticeable in the higher gears more than lower.
Often the float is worse at particular RPMS, so in the lower gears the engine still has plenty of power to go through that band of RPMS and get past it, but in third/fourth it won't.

go back to stock rockers till you fix the springs

Tue Dec 10, 2013 5:19 am

Thanks for all your help and information I do now understand what valve float is and im showing no signs of valve float but im not going to take the risk to i've removed my heads and am about to fit some single HD springs but will I need better/stronger push rods if I'm using HD springs?

Tue Dec 10, 2013 9:09 am

You can see a valve float video on YouTube...just type in "valve float" and take your pick of several videos...watch the valve stems moving around from side to side, and the springs bouncing around...not very comforting knowing everything could come apart at high RPMs....granted, these are high revving small block Chevys with race prepped engines, but you will see what can happen...just never over rev your VW and never Lug the engine either. :roll:

Wed Dec 11, 2013 4:13 am

Well after seeing some videos of valve float im going to get some hi rev single springs but can I reuse my collects and retainers?

Wed Dec 11, 2013 6:24 am

No...if you are going as far as to change the springs for high performance units, why cheap out now ??....buy high performance retainers and keepers as well...they won't break your wallet....why do it half assed ??