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Discussion Starter · #21 ·
Hmmm... May give more thought about how to go about the p/p heads now. So even if you get new valves, they can still require more work, or do places just alter your stock valves? It seems like getting p/p heads is the ideal time to have this valve work done as well, but it also seems like it isn't overly necessary.
 

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If you go to larger valves, you will have to get the valve seats machined to match the increase in valve head diameter. If you are going F/I, and getting the heads ported, this would be the time to have the heads machined for the bigger valves. Even if you stay with the stock valve size, a valve job needs to be done after the heads are ported. You can pick up some significant flow gains with a good valve job, especially at the low and mid lift points.
 

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I see that people have said to pull the engine. But has anyone tried to pull the heads with the motor in the car? Just asking because we put a set of patriot performance heads on my buddys 03 sn95 and everyone said the same thing.
Sure there is not much room but we took or time and disconnected the motor mounts jack it up a little and the rest was history.

Im not saying you guys are wrong but just wanted to see if someone has tried.
 

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In my case...

The motor was in the car for the whole procedure.

My engine builder that P&Ped and put together my heads did recomend NOT to put in larger valves as there is very little material to open up the stock 3V heads for lager valves...
 

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I see that people have said to pull the engine. But has anyone tried to pull the heads with the motor in the car? Just asking because we put a set of patriot performance heads on my buddys 03 sn95 and everyone said the same thing.
Sure there is not much room but we took or time and disconnected the motor mounts jack it up a little and the rest was history.

Im not saying you guys are wrong but just wanted to see if someone has tried.
A lot easier but not real good for the drivetrain.
 

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Hopefully this isn't off topic, but am I right that the OEM valves begin to "float" after about 500 HP and that that's mostly do to the springs involved ?
Depends on how you get to 500 HP.... NA/NOS posibly. FI not as.... thinking it is RPM related

And yes I guess it would have to do with too weak springs and too little room for the expanding gases....??
 

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Valve float is rpm related, not horsepower related.
 

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As mentioned in the previous two posts. The engine RPM is too fast for the valve springs to be strong enough to reseat the valves inbetween strokes. They flutter or float, never get in the correct position with the engine runing as you can imagine... it is NOT good and will lead to failure if it runs as such... you can get head pieces in your cylinders or piston pieces in your heads, or if you're lucky a combo.... ;)
 

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My shop had this problem on their drag car. It has a procharger with 650RWHP auto, it was fluttering on the dyno with the stock valve springs.
 
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