Piston to Valve clearance. December 18, 2006, 02:47:10 PM Well as some know I put a new top end on the SO bottom end.I installed E7 heads from a Lincoln Mark VII, new lifter, pushrods, and a Cobra intake.Now my question. I had to replace the timing chain. When we turned the crank to line up the marks we had problems. It would act like it washiznitting something. So we turned the cam. Then the Crank would turn again. Is there any way I would have Valve to piston clearance problems? It starts runs and drives. So its bo big deal for now. But when the chain starts to get sloppy it could be a different story. Another question would be is it possible that the previous owner could have installed a high lift 351 cam? Quote Selected
Piston to Valve clearance. Reply #1 – December 18, 2006, 04:01:07 PM here is my redneck solution to the valve issue.remove valve a valve coverrotate engine until any given intake rocker arm is all the way down(open valve)by hand, push real hard down on the valve side if the rocker armif your able to move push down and feel the valve hit,, then you have some undefined amount of clearance.if you can't,, its likely that the valve is sitting and touching right on top of the piston.as for the cam,, thats all speculation and i have yet to figure out "shade tree" mech way to verify what type of cam something is other than pulling it. Quote Selected
Piston to Valve clearance. Reply #2 – December 18, 2006, 04:50:31 PM I put ported E-7 heads on my H.O (an '86 with forged flat tops),and have had zero problems.I'm uysing the beehive springs and they have been great. Quote Selected
Piston to Valve clearance. Reply #3 – December 19, 2006, 09:54:54 AM Long shot but after all your lifters are in place and tighten down leave them be for a while 30 plus let the hydraulics in the lifters settle then rotate motor again. Maybe it will work. Oyea you are using 1.6 rockers right. Quote Selected
Piston to Valve clearance. Reply #4 – December 19, 2006, 09:59:14 AM I'm using what ever rockers came on the heads. I don't have a problem with the car runnig. It runs and drives fine but I was just wanting to know becasue if the valves start to float or the chain gets loose I will have a problem. But just starting and letting it run its fine. Quote Selected
Piston to Valve clearance. Reply #5 – December 19, 2006, 10:16:45 AM Quote from: slamedcat;119244I'm using what ever rockers came on the heads. I don't have a problem with the car runnig. It runs and drives fine but I was just wanting to know becasue if the valves start to float or the chain gets loose I will have a problem. But just starting and letting it run its fine.What I’m going to tell you is a pure roll of the dice or a gamble so don’t take this as fact.But you are probably fine as for floating the valve don’t do 6400 witch is hard to do anyway and don’t free rev the car cause that always floats them little I’m assuming you don’t have a stick so you don’t have to worry about missing a shift.Just a little fact all race engine flirt with the limitations of valve piston clearance and they do account problems. But I always laugh at the end of every Nascar race the winner does a burnout in celebration and the engine builder starts sweating Quote Selected
what cam is... Reply #6 – December 21, 2006, 06:11:29 PM "as for the cam,, thats all speculation and i have yet to figure out "shade tree" mech way to verify what type of cam something is other than pulling it.".....remove the rocker cover. Place a dial indicator on the valve side of the rocker arm as close to center and paralell as you can with that valve in the closed position, zero the indicator, rotate the crank and note the highest( or in this case lowest) measurement registered on the dial-that's your lift- or pretty darn close to it. Quote Selected
Piston to Valve clearance. Reply #7 – December 22, 2006, 09:22:12 AM reading the cam like that would be botched to say the least. Too many variables like all the gaps between the piece parts leading up to the rocker ,,not including the lifter itself cause it compresses.now that you mention it though,, i guess a dial indicator would work if the rocker were removed and the pushrod alone was used to relay the distance up/down by turning the crank.,,should be farily good to measure like this since there is no presure on the lifter anymore id say. Quote Selected
Piston to Valve clearance. Reply #8 – December 22, 2006, 04:58:32 PM No, the push rods are loose in the heads with the rockers off, and I guess I'm assuming that the motor had run before with the lifters in it, aka= pumped up.If not, well then there...PUMP THEM UP- If they bleed down that fast you need new ones. Quote Selected
Piston to Valve clearance. Reply #9 – December 22, 2006, 05:02:00 PM Plus if you have "variables" there in your valve train-like clearances, aka LOOSENESS, you've got other issues to deal with. Quote Selected
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