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Valve Springs

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What is everyone doing for a replacement interval on stock Boss valve springs?

For those of you who have done it, was the head removed or were the springs replaced while the head was installed on the engine?
 
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No, I have not. I found out that Roush Yates was using them to help improve duribity between refresh/rebuilds. PAC is the go to company for top tier racing engine builders. Definitely not cheap. Total over kill. I am the kind of nerd that would install them even though I don’t need them.....
 
I am planning on using the stock Boss springs as I have not been able to find an aftermarket spring with comparable seat pressure to the stock spring. Any thing much over stock spring PSI is overkill and leads to unnecessary wear on stock components. If I was going to an aftermarket cam, say comp cams, with a more aggressive ramp, I would then consider PAC springs.

What I am really looking for though is how often we should be replacing our springs on a road course, HPDE, car.
 
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I replaced my springs with another set of Boss springs after about 15,000 track miles. The heads were on, but the cams were removed. I also replaced the keepers, retainers, and valve seals. The motor was also out of the car, which definitely saved Steve Esposito's and my backs from aching.

The PAC springs are not as bad as they look cost wise if they come with keepers and retainers.
 
I replaced my springs with another set of Boss springs after about 15,000 track miles. The heads were on, but the cams were removed. I also replaced the keepers, retainers, and valve seals. The motor was also out of the car, which definitely saved Steve Esposito's and my backs from aching.

The PAC springs are not as bad as they look cost wise if they come with keepers and retainers.
Good info, thanks.
 
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If you swap the valve springs with the heads on, you will need to pressurize the cylinder with approximately 50 psi of compressed air continuously to keep the valves from dropping into the cylinder bore. The Freedom Racing valve spring compressor tool works well.

You can replace the springs with the cams installed, but it is a lot harder and time consuming. It is probably still less time than removing the cams, timing chains, and re-timing the engine.

Make sure you stuff paper towels into the oil return passages to make sure none of the keepers fall into the engine. Use paper, not a shop rag. Lint from a paper towel will break down in the oil, lint from a rag won't and will clog the oil filter. I would suggest an oil and filter change after you fire the engine back up.
 
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I should have been more clear. If you can get the PAC springs with the keepers and retainers for the price listed above, its not that bad of a price compared to OEM Boss springs, keepers, and retainers. I did not check / verify the price listed above.
 
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Looking online, PAC springs and retainers run about $650. This does not include the locks / keepers. I am not sure if they are compatible with OEM keepers and retainers.

For a track day car, I would use the OEM components.
 

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