03-27-2009, 01:46 PM #1
Installed height of valves? Ferreas .020 longer?
Help ... my manuals are an hour away unfortunately and my machinist called and said the new Ferrea valves are twenty thousands longer/higher than the stock ones he pulled out. He wanted to know the acceptable range of size/installed height of the valves to make sure I don't hang a valve open. He can tip the valves to get them to spec, just wondering what the spec is for the valves ... anyone know or have a manual within reach?? My cell is 616-862-7666 if that is easier ... thanks!
03-27-2009, 03:24 PM #2
I just read through the Technical Specifications and the Cylinder Head section and neither mention an installed height, just the free length.
if he knows the installed height is less I would say to shim it...
OOPS, you're talking about the tip of the valve, not installed height of the spring. that info isn't there either.....
Last edited by GTXX; 03-27-2009 at 03:28 PM. Reason: correction
03-27-2009, 03:57 PM #3
Funny, I have the manual too and it is just not in there that I can find ... where did you find free length? I could not find that even. He can make the valves work by grinding down the tip so it matches the length of the stock valve, but I wondered if this was common and what others do or if .020" longer valve is 'normal'? Seems a bit much for 'normal' to me ...
03-27-2009, 04:37 PM #4
I posted that about free length when I thought you were asking about spring height, so it's free length of springs spec that's in there. that's not going to do you any good. he needs to make sure the extra .020 is above the retainer before he tips the valves. if it's not and he wants to tip the valves, you might want to check rocker to retainer clearance while spinning the cam, I haven't looked at one enough to remember how close it is.
.020 is a lot of extra preload to be putting on a hydraulic lash adjuster, could make it more prone to pump up at high RPM.
03-27-2009, 05:08 PM #5
He said the stock valves varied in length by .002 - .003" so that seems to be allowable without any issues. The Ferreas have approximately .013" additional length from the top keeper groove to the tip, so that is where most of the additional height is. He is going to tip the valves so their length is the same as the stock valves. I will check retainer to rocker clearance once assembled tho, good point.
He did say the Ferreas are pretty much the only valves he uses for anything hi performance and that they look much better than our stock valves. He also said the ports overall look very good and that the performance design of the head is very good. Compared to other heads, he felt significant gains from porting would be harder to come by since the 4 valve design and port shapes were already good.
Made me think a little ... our 1.5 liter engines with 13-14 lbs intercooled boost produce roughly 300 hp at 8500 rpm. On a 5.7 liter 350 SBC that comes out to 1140 hp ... I don't recall reading about too many SBC motors that made 1140 hp on pump gas and 13-14 lbs boost, although it should be possible with very good heads. If nothing else, it does show that the 4-tec head design is very good, flows very well and makes good hp.
03-27-2009, 06:12 PM #6
sounds like he's got it under control. since most of the extra length is above the retainer and he's going to cut that off, there probably is no need to check clearance. the horsepower per litre is way up there on these motors for sure.
03-27-2009, 07:29 PM #7
i've been searching thru my folders on my computer and my little PWC notebook i keep for the installed height... i know i have this somewhere from when i had my valve seats and faces cut by a friend and he wanted the installed height!! it's driving me crazy. on a mission to find it, been looking for 20 minutes so far
03-27-2009, 07:33 PM #8
03-27-2009, 08:04 PM #9
I bought the valves new in the Ferrea box (and individually sealed in Ferrea plastic bags) from a GH forum member. My engine builder uses hundreds of Ferrea valves each year and said they looked great and fit right other than that they were 20 thousandths longer than the stock valves ... all the plastic bags were 100% factory sealed. Maybe they were for another app that was close but not 100% the same as 4-tecs, or others don't measure, or bad batch, or?
03-27-2009, 10:21 PM #10
I always cut mine from blank lengths.
You need .05 inches free clearance before Coil bind as a general Rule.
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