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Wanted: anecdotal experience with valve spring pressures

S

Stiggy Pop

In the cool kids club
Joined
Feb 27, 2011
Location
Granville, MA
I'm working on a custom valve train with Ferrea Racing and we are trying to walk ourselves into a good spring selection (beehive or conical). I do not have much to draw from when it comes to spring pressures, so thought a straw poll here to see what others have done might provide some data points.

context:
8v head
48mm intake, 40mm exhaust valves
.490" lift cam
SuperTech cam followers (https://www.supertechperformance.com/p19472-cf-37-3-9-cam-follower)
7k rpm & 30psi boost pressure ceiling

The previous setup was RSI bugpack springs which had 95lbs closed and 205lbs open pressure. This poorly chosen combination caused problems inherently, but interesting to note that after ~5k miles run time the springs showed 86lbs closed, 185lbs open. A ~10% loss.... junk.

Some of the springs we've looked at initially would net somewhere around 120lbs closed, 250lbs open. My primary concern is with open pressure, and whether or not I'm going to wipe out the cam or the buckets.

Recognize I'm not running anything stock but would still be interested to hear what people have done with stock Volvo buckets and shims.

Anyone changed guides to run 7mm diameter valve stems?
 
I don't have volvo expertise in valve springs per-say but 10% pressure loss sounds about rite, The fast the opening and closeing ramps is murder on valve springs. , I would recommend the bee hive valve springs and retainer set , It takes a few grams of the top and don't require a inner damper spring, that helps oil temps and the little bit of metal shavings because they do rub together, I would ask the cam grinder what do THEY recommend you don't want any more open pressure then needed to help prevent wear on the buckets ,cam lobes, even the timing belt itsel, But at the same time you want enough to keep the valve from bouncing on the seat when it closes. I change the valve springs in my big block chevy every other year at the same time I pull the lifters for inspection/replacement as it's a aggressive solid roller
 
freevolvos said:
I don't have volvo expertise in valve springs per-say but 10% pressure loss sounds about rite, The fast the opening and closeing ramps is murder on valve springs. , I would recommend the bee hive valve springs and retainer set , It takes a few grams of the top and don't require a inner damper spring, that helps oil temps and the little bit of metal shavings because they do rub together, I would ask the cam grinder what do THEY recommend you don't want any more open pressure then needed to help prevent wear on the buckets ,cam lobes, even the timing belt itsel, But at the same time you want enough to keep the valve from bouncing on the seat when it closes. I change the valve springs in my big block chevy every other year at the same time I pull the lifters for inspection/replacement as it's a aggressive solid roller
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unfortunately the cam came from RSI so that's a dead end road. Any other Volvo cam makers out there with a similar lift profile that I could pull from?

Quality springs should see a 3-5% loss from my conversations. There's a lot of other issues with the springs in the application; they don't fit the seats properly, they don't fit the retainers properly, they are miles from coil bind at full lift.. just a really poorly engineered setup that I gotta fix right :-D
 
Send the cam to shoe string? Have him degree it and get the lift and duration, according to his thread he will even ship it back to you for free. I wonder if rsi came up with the lobe profile or just swiped one from someone else, I know you can look in the comp cams catalog and pick what lobes you want and they all have a number...I want xxxx intake lobe xxxx exhaust lobe, you really really need to know what that cam is before you can choose the proper parts to work with it. Comp and isky have been great to work with for me but I do not know if they sell Volvo stuff. As far as valve spring fatigue that's also super dependant on use. I know of you float then once or twice that really taps the life from them. The more aggressive the cam the shorter the life...I'll also say this has been my experience with big block chevy/mopar valve trains. I have to control a 2.50 intake valve with a 8mm stem,a heavy roller rocker, push rod, and lifter at the same r.p.m. 7000
 
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120lbs seat for these OHC applications seems heavy. I stand by the spring recommendation I made to you, unless the cam profile you choose turns out to be just crazy. I used a softer beehive in a 1 bar boost application with an RSI stage II with good valve control to 6000 rpm. The same soft springs in our N/A application run to 6840 rpm no sweat and have about 10,000 race miles on them. If you're staying with an 8mm valve stem, it's the way to go.

I think your application deserves a custom cam, ground by someone like Enem or KG Trimning in Sweden. I had KG grind us one and correspondence was good, and they wanted to know lots about the engine and intended usage before proceeding. If you do pick an off-the-shelf grind, pick one from over there, where there's competition between manufacturers and poor results yield loss of market share. Domestically, you're limited to boutique providers (or not at all) and it's more of a "take it or leave it" situation.
 
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Years ago I had a head built with isky double valve springs. It is using an enem V16 turbo cam. I haven't used the head because the more I learned, the more I realized 125psi seat pressure is too much. I bought a set of the beehive springs with the group buy from yoshifab and will use them. I forget what the specs are but Gary (gsellstrm) or yoshifab should have information on them. Now I just have to figure out how to get the cam out of the head without breaking it.
 
I don't have the specs on the Yoshi spring kits but Josh should have them. Josh's kits do have custom seats and retainers in them as well.

In my case I got one of the sets Knox used to sell years ago. Beehive's, wanna say Ford 4.6 or something like that, could be way wrong. Anyway, don't have open pressures on those (notes are long gone), closed pressures were right around #95. Stock was around #55 if memory serves. I've had them in the car on stock buckets and shims for around 20k so far, no discernible wear on the lobes. One thing I would suggest is running a kevlar round tooth belt though, since you'll be upping the load on it quite a bit.
 
gsellstr said:
In my case I got one of the sets Knox used to sell years ago. Beehive's, wanna say Ford 4.6 or something like that, could be way wrong. Anyway, don't have open pressures on those (notes are long gone), closed pressures were right around #95. Stock was around #55 if memory serves. I've had them in the car on stock buckets and shims for around 20k so far, no discernible wear on the lobes. One thing I would suggest is running a kevlar round tooth belt though, since you'll be upping the load on it quite a bit.
Click to expand...

This sounds like the spring Brian Tooley Racing sells that I recommended. They do in fact fit Ford 32V 4.6. Stock Ford 32V have the same spring pressure and rate as the OE Volvo spring, but with a beehive design.
 
Morning guys. Thanks for the chat.

shoestring said:
120lbs seat for these OHC applications seems heavy. I stand by the spring recommendation I made to you, unless the cam profile you choose turns out to be just crazy. I used a softer beehive in a 1 bar boost application with an RSI stage II with good valve control to 6000 rpm. The same soft springs in our N/A application run to 6840 rpm no sweat and have about 10,000 race miles on them. If you're staying with an 8mm valve stem, it's the way to go.

I think your application deserves a custom cam, ground by someone like Enem or KG Trimning in Sweden. I had KG grind us one and correspondence was good, and they wanted to know lots about the engine and intended usage before proceeding. If you do pick an off-the-shelf grind, pick one from over there, where there's competition between manufacturers and poor results yield loss of market share. Domestically, you're limited to boutique providers (or not at all) and it's more of a "take it or leave it" situation.
Click to expand...

I hear ya. And we're on the same wavelength on the cam, it was really on my mind yesterday. Unfortunately I just don't think I can do it right now, well, I CAN but I really shouldn't. I'm setting myself up to reinvest a pretty significant amount of money in the car this year, and I have to try and draw some lines (the headwork is going to add up, and beyond that I have upholstery work being done, and I'm looking at some pretty seriously expensive turbos...). What I need to do is set up the valve train so that I can change cams at a later date without too much struggle (i.e. just grinding lash caps).

You've handled a bunch, the RSI cams are full base circle relatively, correct?

gsellstr said:
I don't have the specs on the Yoshi spring kits but Josh should have them. Josh's kits do have custom seats and retainers in them as well.

In my case I got one of the sets Knox used to sell years ago. Beehive's, wanna say Ford 4.6 or something like that, could be way wrong. Anyway, don't have open pressures on those (notes are long gone), closed pressures were right around #95. Stock was around #55 if memory serves. I've had them in the car on stock buckets and shims for around 20k so far, no discernible wear on the lobes. One thing I would suggest is running a kevlar round tooth belt though, since you'll be upping the load on it quite a bit.
Click to expand...

I actually believe the beehive the guy at Ferrea pulled up initially was a Ford modular v8 application, so probably looking up the same alley. I'm going to give Josh a call when the West coast wakes up, he's always been very helpful in the past, for some reason hadn't thought of getting his 2c directly.

So I think there's two things that narrowed the field of view on spring selection; the 8mm stem and the install height. My RSI head was machined to sink the spring seats so my install height is up like ~1.750" (going to quadruple check that this weekend). So two considerations right now are to step the guides down to 7mm which opens up valve options and spring options which are considerably lighter than some of what he was finding with 8mm. The other consideration is making some custom spring seats to bring the install height back down to wherever we want it for an ideal spring combo (compensation could also be made there with keeper location since the valves are custom).
 
The lower seat was an issue on the ones I got from Knox as well, largely because of the guide OD. My machinist found I think it was Dodge 4.7 or 5.7 lower seats with integrated stem seals fit pretty close if you trim the seal portion off. They had around .060" or so clearance to the guide OD and fit the springs pretty well, and they fit the springs nicely. The retainers were something designed to fit the 8mm stems but with a larger ID spring, then the step on the retainer was turned down to fit inside the beehives.

Might be worth shooting a pm over to Fidel as well, get his take on things. He very well might have some good info as well.
 
Thanks I'll look him up, I actually thought Fidel was off the boards/out of the game.

Anyone know the stock guide OD offhand? Little slow at work and would like to go see what I can find for a drop-in guide for a 7mm valve.
 
For the BTR and Ford stuff, the stock Volvo seat/shim works mint, and then I just shim for height. On stock height stuff, these springs are a drop in when used with Ford 6.2 Raptor spring retainers. I open up the top of the spring with a Dremel tool about 0.5mm to fit the retainer. It takes me about an hour to do a set of 8. I can hear you making a face about this, but like I said, we have about 10,000 race miles on this setup. Don't nick any part of the spring that moves and you'll be good. These retainers use the exact same keeper as the stock Volvo and are like $4 each.

I have yet to measure an RSI cam.

Still waiting for one to come my way...
 
Stiggy Pop said:
Thanks I'll look him up, I actually thought Fidel was off the boards/out of the game.

Anyone know the stock guide OD offhand? Little slow at work and would like to go see what I can find for a drop-in guide for a 7mm valve.
Click to expand...

0.532" is the OD. It's a very odd size, and very large compared to most domestic engines.
You can try reaching out to SI Valve, they can send blanks that you open up to whatever diameter. SI guides are manganese-bronze, and very nice.

I'm also using the BTR 32v ford springs. Used them on the 16v rally engine, and using them on some big cam 8v engines. I just machine the stock retainers to fit the springs. It takes about 2min per retainer.
 
shoestring said:
I can hear you making a face about this, but like I said, we have about 10,000 race miles on this setup.
Click to expand...

:rofl: you picked up on my personality pretty quick. We gotta grab a beer someday.

culberro said:
0.532" is the OD. It's a very odd size, and very large compared to most domestic engines.
You can try reaching out to SI Valve, they can send blanks that you open up to whatever diameter. SI guides are manganese-bronze, and very nice.

I'm also using the BTR 32v ford springs. Used them on the 16v rally engine, and using them on some big cam 8v engines. I just machine the stock retainers to fit the springs. It takes about 2min per retainer.
Click to expand...

Thanks doc
 
I actually talked to Lawrence (fidel) a few months ago. He's still around from time to time, starting to get his life back to a good place and getting the bug to start playing with cool Volvo **** again. Definitely shoot him a pm, tell him I bounced you over to him. lol
 
gone back and forth with Enem a bit. For their hot cams they run a 37mm bucket same as I have, and use double springs with 88lbs closed and 275 open.
 
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