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Discussion Starter · #1 ·
I switched to Morel lifters after a second bad Crower Severe duty solid roller lifter. While discussing this with a builder, he ask how close I was to coil bind. I said oh not too close, and he said you need to be within .060 to .080 or over .200. He said it had to do with oscillation of the spring and that getting near coil bind would help to better control the forces and reduce the punishment the lifter takes.

I called PAC about my springs, and they told me the true coil bind measurements, which was slightly more than that listed in the catalog. I was at about .120" from bind at 1.950" installed height. So I've ordered a set of -.050 locks so that I can get down to 1.900". That should put them at .070" from coil bind, and hopefully I won't have to replace another lifter.

Anyway, thought you might find it interesting. It's not always the parts that are the problem. Crower makes good some stuff, and at over $500 a set they should last longer than they did. Now I know why, and perhaps these $600 Morels will last even longer.

http://www.racingsprings.com/mov10kvst.asp

http://speedtalk.com/forum/viewtopic.php?t=2474&highlight=
 

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Discussion Starter · #5 ·
Glen......what was the part # of those Crower lifters :eek: ?!?!?!?
Kevin, these are BBC lifters. Part no. is 66291 http://www.summitracing.com/parts/CRO-66291-16/

BTW, when I called PAC, they confirmed what the builder said. Apparently the range between .200 and .080 produces a very bad harmonic and is to be avoided. I'm amazed by all the things I've learned in building this new engine. Fortunately I had good resources so that hopefully the price of knowledge isn't going to be too steep. I spent almost $5,000 on the rotating assembly alone on this build. I don't want to do that again if I can avoid it.
 

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Discussion Starter · #11 ·

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Discussion Starter · #20 ·
Big Blocks are going to take more spring than small blocks but almost 350 closed most likely puts your open pressure around 700 to 800 hundered on a big block with the added lift they run. You better have some super duper pushrods, shaft rocks and the best lifters you can buy and it still may break that stuff. Those are pressures we use to run to turn a BB 8500 RPM's and it ate valvetrain parts doing it. You really flex stuff bad at those pressures.

Go with what the cam company says to run. They have done the testing to know how much is enough to keep everything working correctly. All my point was if you are breaking valvetrain parts now, adding spring pressure will only make that problem worse unless you have too little spring pressure and the lifter is floating off the cam at higher RPM to cause the lifter damage.
These were good lifters, and the Morels have an even better reputation. I am running shaft rockers, and these are Terry Manton .120 wall tool steel push rods, primarily due to the plan to run N2O. The valves are 11/32 and Ti retainers to help reduce weight.

I've always heard that more spring pressure is better. I would agree that more pressure would take more power to turn, but not that much when considering the effects of all the springs helping out as well. With just a couple of rockers installed, it can be difficult to turn the crank against the springs, and the springs can actually spin the crank on the valve close. But when all of the rockers are on, it turns fairly easily as the closing valves help counter the force of the opening valves.

As for the how close to coil bind, all I know is to avoid the range of .080 to .200, and to not go less than .060 for a BBC. Perhaps the range is different for an SBC. Not sure.
 
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