Thanks guys. I did in fact purchase a set of Comp 26113-16 springs and have them in a box ready to install but for a number of reasons, they did not get put in.
With regards to the retainer, I hope the 262AHs with 0.550" valve lift don't come perilously close to the oil seal; no spring is going to fix that. I've not really heard much chatter about the retainer being upgraded along with the springs, just the springs themselves.
I can see me doing the springs later but I want to get a good spring and summer out of it before submitting it for surgery again to do them.
The installed height of that spring is .026" higher than the stock spring. That means at .550" lift on the aftermarket spring you will actually have .026" more retainer to oil seal clearance than the stock setup.
If you are going to take the time to do the springs, I would definitely spring the extra couple hundred bankroll, and get the Ti retainers and locks. The better you control the valves, the more power you will make and the easier it will be to tune.
Sorry, please explain.
My understanding: The installed height has nothing to do with the spring itself. It may be a recommendation from the manufacturer of the spring but the height from the underside of the retainer to the spring seat is determined by the mechanicals of the valve seat in the combustion chamber, the length of the valve stem, the position of the keeper grooves and so on. I could take the spring out completely and push the valve closed with the retainer held in place with some grease or something. I could then move the valve 0.550" open and measure the distance between the seal and the retainer and this would be some value that is independent of the springs.
The recommendation for installed height from the manufacturer largely helps ensure adequate on-the-seat pressure and assurance that at full-open, coil-bind won't happen.
Now, what do you mean?
Yeah, I've thought about that eh? I mean, the retainers and keepers will be right there, in hand. Why not swap them?
The installed height has everything to do with the spring. It is the actual measurement of the distance between the bottom of the valve spring retainer to the spring pocket when the valve is seated.
It is not a recommendation by any means. It's the actual height as measured with a stock length valve and stock valve seat.
Now if you have some work done to the valve seat or use a custom length valve, then all of the numbers will of course change.
Say you go from the stock 4.650" OL valve to a 4.705" OL valve. Not only does that change your margin, taper, and underhead radius/angle, but it also changes the installed height because of the change to the tip length. That's without touching the head itself.
Now of course if you do a valvejob or shim the springs, then the installed height goes even higher.
Say you go from the stock 4.650" OL valve to a 4.705" OL valve. Not only does that change your margin, taper, and underhead radius/angle, but it also changes the installed height because of the change to the tip length. That's without touching the head itself.
Now of course if you do a valvejob or shim the springs, then the installed height goes even higher.
Trinity nevermind, I had you confused with somebody else on here who asked me about the installed height difference with different valve. That's what happens when you get 60 emails and PM's a day.
So yes, the installed height will of course not change if you do not touch the head, don't use shims, and use the same retainers and valves.
Wait a minute, I just saw that this camshaft (262AH) has a .550" lift. According to my personal measurements on these stock valvesprings, you are going to coil bind them with that much lift. Ironically I just had this same conversation with Tim at MPH and Ron at Fox Lake the other day and they said the same thing.
.550 is way too much on a stock spring. IF, and I mean IF, you guys actually have a motor that has been running for 50k on the stock springs with .550" of lift, count your blessings. These motors are setup with about .120" - .150" preload, so that is the only thing that is likely saving you from valvetrain failure. The stock hydraulic lifter can actually absorb most of that 120-150 preload if the springs are in fact binding, which I am certain they are.
Tim and Ron have installed quite a few more of these cams than I have, so you might want to give them a buzz.
I asked my shop to check for coil bind and they reported none though they didn't tell me how much space there was at max lift.
In looking at say:
http://www.rpmoutlet.com/musv8compcam.htm
I see that for the Stg 1 cams (the 262s, the ones I've got), they say "Valve springs recommended" (emphasis mine.) Same with the 270s. For the 278s they say "Valve spring upgraded required". I presume that the requirement on the 278s comes from more aggressive ramps since the gross lift is the same for all 3 cams (0.550")
If the lift was the cause of the "requirement" on the 278s, it would apply to the 262s as well but for that, and the 270s, they only "recommend" a spring upgrade.
Sean Hyland also uses stock springs up to 0.550", so I've read. Whatever you think of the guy, he's been doing these things for a while now and if he's willing to use them, I should be okay...
Mine are actually the 262H...I have a 96 GT. The lift on these cams is .500. I never really looked at the 262AH's. Didn't realize the lift was different when I said I had no problems..550 is way too much on a stock spring. IF, and I mean IF, you guys actually have a motor that has been running for 50k on the stock springs with .550" of lift, count your blessings. These motors are setup with about .120" - .150" preload, so that is the only thing that is likely saving you from valvetrain failure. The stock hydraulic lifter can actually absorb most of that 120-150 preload if the springs are in fact binding, which I am certain they are.
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