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By Rono - 12 Years Ago
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I can't remember ever having this issue before, but today when I started setting the initial valve lash, several of the adjusters had to be backed-up way to far. I was following the Eichman book and started at TDC. I'm using 5/16" 500# tubular pushrods and I thought I may have the wrong length, but they are about 8 &1/8" long from the tip of the ball at the bottom end to the top of the cup on the top. The earlier pushrods I think are 8&1/4" or longer. The heads (471) have been milled more than once. The bosses now measure just a hair under 1.000" and the cam has a .491 lift. When I first saw I was having this problem, I stopped and tried to remove a pushrod to measure it's length, but I had to remove the rocker shaft from the head. Pushrods wouldn't come out even if the adjuster was all the way out of the rocker arm. Vern Schumann can make up pushrods any length you want, but I'm wondering why or if I shoud have to do this? I gave him a call today and he said I could try using the oil drip pans under the rocker stands. I do have a set of those and I think they are about 0.040" thick. I'm a little concerned about using them because I'm already at .491" lift on the cam and have John Mummerts #105 springs which are good to a .500 lift. So, if I use these drip pans would I have to go with a heavier valve spring?? Anyway, any thoughts anyone might have would be appreciated. Thanks, Rono
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By The Master Cylinder - 12 Years Ago
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Rono, The oil drip pans will not effect your springs. All they'll do is raise the rocker shaft.
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By Y block Billy - 12 Years Ago
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Rono, Way back Ted did some articles on Rocker geometry you may want to do a search. Using the drip pans will not have any affect on the springs, it will just change the geometry. ultimately you want the rocker face that contacts the valve to rock back and fourth equal distance from center line of the arc. First of all are you using stock rockers or roller rockers?
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By charliemccraney - 12 Years Ago
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If you can adjust them, and the cup has adequate clearance between the rocker arm throughout the entire range of motion, then it really is not a problem.
Having the adjusters are far out as possible is beneficial because it gives you a larger ratio which means a little more lift and, I think, duration at the valve. This aspect could pose a problem since you are already so close to the limit.
The oil drip pans will give you extra room for adjustment but will alter the geometry which will affect the lift which may or may not put you beyond the .500 limit.
You can always put a dial indicator on a couple of the valves to verify the lift you are getting.
Another thing to be careful with is the rocker ratio used by a cam manufacturer to determine the actual lift. Often, it is 1.5:1. If you're using 1.54 or aftermarket 1.6 rockers, then you may already be over the .500 limit, particularly with the adjusters out and the increased ratio.
Further, the valve guides should have been machined for the increased lift. Were they? Make sure the retainer will not hit the guide.
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By Rono - 12 Years Ago
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Thanks guys. I'll try the oil drip pans. The rockers are stock 1.54:1 ratio, but I will still use a dial indicator after all is said and done to see what the actual numbers say. I think the guides should be okay, but that is a scary thought about the keepers being forced out Rono
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By Ted - 12 Years Ago
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Add this to all the other suggestions.
Stock length valves or scrub or other retrofits? Longer or shorter than stock valves will play havoc with the rocker arm adjuster locations if trying to use standard length pushrods. Also upsets the rocker arm geometry. For valve adjustments, are you starting on #1 compression or #1 overlap? While stating the obvious and may not necessarily apply in this instance, this makes a big difference when trying to adjust the valves. Each piston needs to be at TDC at the tail end the compression stroke for setting the valve lash for that particular cylinder. And be sure you're referencing the Ford #1 cylinder location and not that of another marque. Here’s the link to a past thread on setting the valves. As with most operations, there are several different ways to perform this and still get satisfactory results.
http://forums.y-blocksforever.com/Topic8614.aspx
Here are a couple of links explaining more about the geometry and the effect pushrod length has on valve lifts.
Rocker arm geometry Pushrod length and its effect on the rocker ratio
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By DANIEL TINDER - 12 Years Ago
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Rono (1/3/2013)
Thanks guys. I'll try the oil drip pans. The rockers are stock 1.54:1 ratio, but I will still use a dial indicator after all is said and done to see what the actual numbers say. I think the guides should be okay, but that is a scary thought about the keepers being forced out Rono
Be aware, if trying to dial in the geometry precisely, those drip pans vary in thickness (different manufacturer sources/lots?).
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By Rono - 12 Years Ago
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Well, adding the oil drip pans under the rocker stands made a huge difference. All adjusters are sitting about mid way in the rocker arm. I read the additional information Ted posted after my last post and will go back and double check everything and take a closer look at the positioning of the rocker tips. I should ad that these were John Mummerts valves (1.940 on the intake and 1.600 on the exhaust with stock length stems), but when I think back on the machining of the heads, the machinist told me that the valve face was not set flush with the rim of the new hardened seats. They were just a bit (a few thousands) above it. He did do a 3 angle valve job on the valves and seats and I had no reason to question why they were not flush with the seats. Hopefully everything will be good as that machine shop was in Montana and I now live in Maine! Rono
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By Jeff - 12 Years Ago
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I have a novice question, what are the "drip pans" that have been referenced in previous posts?
Thanks
Jeff
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By lyonroad - 12 Years Ago
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Jeff, here is my novice answer. They are roughly triangular shaped plates (called oil baffle plates in the shop manual) that mount under the rocker shaft support brackets and they direct oil, either away from or on to (I can't remember which) specific areas.
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By MoonShadow - 12 Years Ago
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They direct the excess oil flow from the rockers to the valve stem. Chuck
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By The Master Cylinder - 12 Years Ago
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MoonShadow (1/4/2013)
They direct the excess oil flow from the rockers to the valve stem. Chuck
Huh????
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By Ted - 12 Years Ago
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I’m sure Chuck meant that the rocker baffles direct oil away from the guides.
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