| windjamer | -- 01-08-2010 @ 10:04 AM |
|
Has anyone adjusted the adjustable lifters on a Flathead V8 tighter than stock settings? (Johnsons adjustable lifters) And with what results.
|
|
| wmsteed | -- 01-08-2010 @ 10:14 AM |
|
I can't for the life of me understand why someone would even entertain the thought of setting the valves at anything other than the recommended setting. That is a sure way to burn the valve up. Bill 36 5 win delx cpe
|
|
| ford38v8 | -- 01-08-2010 @ 12:56 PM |
|
Windjammer, I agree with bill. A setting tighter than stock will cause the valves to not sit fully down on the seats when closed. The hot gasses will seek the opening (and there will be one), and burn the valve. Compare it to using a compressed air nozzle between your pinched fingers, only with burning gas. Alan
|
|
| 51f1 | -- 01-08-2010 @ 1:22 PM |
|
Perhaps people think that when valves wear, the adjustment opens up. What actually happens is just the opposite, at least initially. The valve recedes into the seat from the pounding and causes the valve adjustment to close up. If your initial adjustment is tight, the wear leads to leaking and burned valves. If your adjustable cam follower screws are lose, they will, sometimes open up, but you need to replace the follower, not close-up the clearance. Richard
|
|
| Stroker | -- 01-08-2010 @ 1:45 PM |
|
I concur with all the above, as far as burning valves. In addition, if this is a stock cam, tightening up the operating clearance will increase the overlap (period where both exhaust and intake are off their respective seats), and may degrade idle quality and idle vacuum. If you are running an after market performance cam, then you should set the valves to the cam-grinders recommendations rather than the stock Ford clearances. If I were to error, I'd want it to be on the loose, rather than tight side on any engine, regardless of make or type.
|
|
| Pauls39 | -- 01-08-2010 @ 7:31 PM |
|
This old trick did work somewhat on small block chevys. Reduceing the clearance should increase the cam duration a bit and make a little more power on the top end. However a flathead Ford is not an overhead valve chevy. The valve stem will grow quite a bit from heat. With stock lifters, grinding the stems for clearance will cause them to lenghten temporarily from the heat produced in grinding. I suspect the running clearance in a stock flathead is a lot less than what it was set at cold. I don't think the gain would be worth the potential damage.
|
|
| supereal | -- 01-09-2010 @ 9:36 AM |
|
Valve clearance can, and does, fluctuate with temperature and usage. Weak valve springs are also a factor. We prefer to install adjustable lifters, one piece guides, and straight stemmed valves. We improve the guides by machining an extra seal groove, as well. I've given much attention to the old way of grinding for clearance, but almost always end up with at least one noisy valve. Adjustable lifters allow resetting clearance if needed after considerable use. The new adjustables are much lighter, and have positive locks. Rebuilding isn't cheap, so why use an outmoded system.
|
|
| 37RAGTOPMAN | -- 01-09-2010 @ 6:22 PM |
|
hi when ajusting the valves you can use a go no go guage, it is a stepped feeler guage, it has the correct size and one size up,this way you know, if the one goes in and the one a 1-2 thousands higher, does not go you have it ajusted correctly, or have 2 feeler blades, one the right clearance and another feeler blade 1-2 thousands higher also will work, hope this helps 37RAGTOPMAN
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=575 |