supertech springs, which

[aeronaut]

I'm in a discussion with a supertech distributor AND an engine builder. And I'm getting slightly different advice of course. (FYI, it's barely a discussion. I've asked for advice, and they've given about 5 minutes worth each.) So, I'm looking for 5 minutes more advice here.

S50 w/Shrick 264/256.

It comes down to which supertech springs to use. Popular with folks on this forum seems to be (and what the engine builder recommended, because that's what his company sells) is the well loved SPR-H1000D/BM:

• Press.Seat: 80 @ 35.70
• Press.Open: 195 @ 10
• Max Lift: 14.50
• Coil Bind: 20.70
• Rate: 11.50

The distributor says the NASA GTS guys use and love the SPR-H100DR/BM

• Press.Seat: 67 @ 35.70
• Press.Open: 192 @10
• Max Lift: 17.20
• Coil Bind: 18.50
• Rate: 12.9

My only pause with the H100DR is a) it has a high seat-pressure to open-pressure ratio, which I'm not sure means a thing, but it does, and a) folks on here use the other one. But I like that the H100DR has a lower seat pressure. I believe the OEM behive has a seat pressure of about 62lbs. FYI, I have no idea how to make this decision other than trust someones recommendation.

Bluntly, at this point, I'm thinking about just going with VAC's "OEM style +10lb" springs. But I *think* the supertechs will give me a touch more over-rev protection?

Any opinions?

I just want to minimize the kaboom factor.

[pbonsalb]

Fresh stock springs are fine for Schrick 264/256. If you want to go aftermarket, use the 67 lb not the 80. Why load up your valve train with more friction than you need?

There is no protection against mechanical over rev such as from a mis shift or landing after being airborne.

I don’t think anyone has experience float with stock springs and 264/256 Schricks even at 7200 rpm.

Maybe for your track use there is benefit to 67 lb springs. Or maybe they don’t cost much more than new stock and they give you peace of mind. Are they triple groove keepers for stock valves or single groove for aftermarket valves? Single groove are a pain to install compared to triple groove.

I run super tech +1mm valves with single groove keepers. My springs are 84 lb, I think. With Schrick 264/256 and 7200 limiter. I chose the 84 lb springs only because I run as much as 25 psi boost.

[aeronaut]

Tripple grove.

The odd thing about the 67lb springs are they have 12.9 spring rate, compared to the 11.5 spring rate of the 80 lbs.
Basically, the 67 lbs springs are a STIFFER spring but with less preload when closed. So I'm not sure which one causes more load or friction in the valve train.

OEM style springs would save me a chunk of money, I could re-use the retainers I installed 2 years ago.

[bimmerboy318]

Fresh OEM Springs has worked for many running that Schrick Cam. Sometimes it’s better to leave the hot rod stuff for when you are hot rodding an engine. Cams and a tune with fresh springs and newer retainers and keepers would what I would go with. But what do I know, I had to think of budget and reused everything except retainers and keepers when I did my head refresh. But Autohead Performance said everything looked great at 170k.

[aeronaut]

Oh all these "options" are juggling in my head. Here's some accounting:

New OEM springs: $380
New OEM style springs +10lb rate from VAC: $386
Supertechs: Racer friend that's a distributor price, lets call it well under $600.

So price isn't in this decision, it's what's best to keep this engine together for hundreds of hours of track time.

Once again, thanks to all the info and any other thoughts.

[aeronaut]

For the record, I emailed Schrick and asked. They responded within 24 hours.
Not sure I learned anything you guys haven't told me. I wish I knew what they meant by that last sentence. lol.

Technically you can use both springs.
Unfortunately we have no experience with this springs so we can´t give a recommendation.
The camshafts was designed to work with the original springs also.
For race track it will be good to change it.

Best regards

[aeronaut]

...
There is no protection against mechanical over rev such as from a mis shift or landing after being airborne.
...

I am curious about this statement. Do you mean, there's no protection if the engine is revved to something insane, like 8500, or do you mean stiffer springs provide zero extra over rev protection?

[ScotcH]

I am curious about this statement. Do you mean, there's no protection if the engine is revved to something insane, like 8500, or do you mean stiffer springs provide zero extra over rev protection?

Lol 8500 is not insane ... our M54s used to rev to 8400 normally

Insane is 12900, what I hit during a 2nd instead of 4th misshift a few years ago ... engine survived with only a broken vanos tooth gear. Did the supertech springs help? No idea, but probably helped keep the valves from hitting the pistons. Did a similar thing on a stockich M52 years before that, and it sounded like a subaru afterwards with a bunch of bent valves. We use the 80lbs ones in all our race engines, but those have huge cams usually, and spin to 7800-8000 rpm regularly. They're cheap enough and if they help even a bit, then it's worth it.

[aeronaut]

Impressive.

[pbonsalb]

Lol 8500 is not insane ... our M54s used to rev to 8400 normally

What is the rpm limit for hydraulic lifters or is the limit more a matter of cam profile?

[pbonsalb]

I am curious about this statement. Do you mean, there's no protection if the engine is revved to something insane, like 8500, or do you mean stiffer springs provide zero extra over rev protection?

If you mis shift, there is a mechanical over rev that usually results in valve to piston contact if the rpm difference is great enough (I suffered a 3-2 instead of 3-4 shift at the drag strip a few years ago and dinged a stock intake valve that was controlled by a low mileage stock spring). A rev limiter won’t save you from that, but maybe ScotchH is onto something in that a very stiff spring may be able to handle the shock of a significant mechanical over rev better than a stock spring, and prevent the piston from contacting the valve. If he is using aftermarket pistons, they may have deeper valve reliefs, which could also be a factor.

[ScotcH]

What is the rpm limit for hydraulic lifters or is the limit more a matter of cam profile?

Yeah, those were solid lifters of course in our high rev engines. In the S52 we run hydraulic OE lifters, and that engine runs pretty happy to 7500 rpm with Cat cams (12.5 lift, 290*). I think in that one we have the bigger M50NV lifters and trays though. It's only got ~10 races weekends, so not sure about long term wear, but as far as performance and durability, so far so good. The Cat cams are supposed to be used with solid lifters, but so far we've seen no issues for the OE hydraulic. Definitely the cam profile affects the ramp up speed, which can affect how fast the hydraulics "lock" the oil in ... but I'm not sure how exactly that works or what the limits are. I'd say nothing above 7500 rpm with hydraulics, regardless of cam profile.

[pbonsalb]

I wonder how the hydraulic lifters in the 8250 rpm S85 and 8400 rpm S65 differ? I run my S65 to 8600 rpm—even a conservative Dinan tune goes to 8600.

[NeilM]

I wish I knew what they meant by that last sentence. lol.

For race track it will be good to change it.

I would interpret that to mean suggesting the use of fresh, new springs. Not your existing used ones.

Seems like good advice.

FWIW, I've had the Schrick Sport cams (264/256) in my car since 2003. The car had relatively low miles at the time, maybe 60K, and I didn't change anything else in the valve train. I'm even on my original VANOS. Mine is also a street legal HPDE car, not a race car, so it doesn't get beat on like you racers do. Still seems happy enough at 7200 rpm, but since it's a 3.2 I try not to go there too often or spend too much time up there.

A good friend of mine had a 97 M3 racecar that suffered a series of unfortunate events involving aftermarket valve springs and retainers, rapid unscheduled disassembly, ineffective yet still very expensive remedial work — all repeated twice more. That has made me fairly conservative about faffing with those parts. That said, I don't think mildly stiffer valve springs with steel retainers could hurt anything, but they're definitely not necessary.

Neil

[aeronaut]

GREAT info guys, thanks!!

"rapid unscheduled disassembly"
HA!!

- - - Updated - - -

...but maybe ScotchH is onto something in that a very stiff spring may be able to handle the shock of a significant mechanical over rev better than a stock spring, and prevent the piston from contacting the valve. If he is using aftermarket pistons, they may have deeper valve reliefs, which could also be a factor.

This was my understanding. In addition, the guy at Achilles said that the OEM piston/valve clearance on the S5x was the week point of the design. Anything else is a (sometimes helpful) bandaid.