Speed master spring issues.

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MerlinsMopar

MerlinsMopar

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I got a set of the aluminum heads and had them reworked to assure they were good to go. Recut, port matched etc..
My problem is I decided to use the lunati voodoo 703 cam and bought the recommended springs for the cam but when I went to change the springs over, I noticed they are not the same height as stock heads. Quite taller. I haven't started measuring yet but looks like I have to get some more info before I get to do the break in. Anyone deal with this? Always something when you buy aftermarket crap but I already dumped a grand into these heads after purchasing them and I got to figure out what is my next step.
 
The unsprung height of the spring is immaterial. Install it at the height the vendor recomends. If that height isn't compatible with the valve length, you may be able to use different locks. Springs are designed to exert a certain force through a certain height range.
 
A cheap valve spring mic ($20) will tell you what installed height you currently have. Lunati can tell you what that spring should be installed at. There are many options to get you there.
 
To further the point, if you are using the same valves, keepers, and locks that cam on the SM springs, the Lunati springs will go in at the same installed height as the SM springs were. Those parts (plus shims) set the spring height. You have to detirmine if the SM factory setup is in the ballpark for the Lunati springs. As mentioned, a spring mic make it all a lot easier.
 
I recommend everyone buy themselves a Jegs or Summit brand 'AKA cheap' vice style spring pressure tester.. and a spring mic...one that's the correct diameter for your retainers.. so you can get an accurate height and pressure.
 
Doesn't matter what the springs measure new. What matters is what cheap springs measure after they have run 500 milers.....
 
Any spring will lose about 4 to 9lbs after a heat cycle. Some will even tell you do not run them all out and to just run them through an idle/cruise cycle..for break in .
 
My concern was that the length between the seat and retainer was longer than a stock head. Probably about a 1/2". I have tested spring psi before and after all the head work, the shop had reinstalled the original springs that the heads came with. I explained that I bought springs along with the cam that lunati suggested but that was before I decided not to use the stock heads. They simply changed out the springs with the lunati ones. I also requested to remove the inner ones for break in. Lunati suggested that. I was going to do the break in myself but noticed that the dampeners were removed and they were supposed to stay so I was reinstalling them and noticed the difference in valve length. I guess I need to measure the spring psi at the different heights and see if it is where it is supposed to be. I would imagine that the psi will be different at the lesser compressed length, hence probably will need different springs.
I will probably just go back to the shop now and let them install the correct springs and just run it in there.
 
IIRC the installed height on the SM springs is supposed to be in the 1.900 area. OEM J/X are in the 1.65 area.

Find a suitable spring with the proper installed pressure and rate of the Lunati spring components.

.250 of shims isn't a goods approach
 
Just take one of each spring back to the machine shop and have them measure the open and closed pressures , if you are with-in 10 lbs. or so of spec you're good.
 
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