My lack of experience is showing through, I appreciate the input from seasoned builders such as yourself.
I do like the cam so I'll march ahead by shimming the springs.
5.9 stroker build
- Thread starter RBConvert
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I do like the cam so I'll march ahead by shimming the springs.
This is an interesting way to measure installed height. If I'm reading it right, you put this in place of the spring and rotate the collar until the valve is seated and the collar cannot turn anymore. Let's say that at that point, you get a 1.910 number and the number you're aiming for is 1.890, you would just need a .020 shim to get the proper installed height.
mopowers
Well-Known Member
Correct.
I have to do a reset. Sorry for leading everyone down a dead-end path. After taking it all in, it didn't sit right with me that a head that was built specifically for hyd roller cams could have spring pressures so far removed from Hughes Engines' specs. Today I spoke with Jeff at TF and got the right answers. I was referencing the wrong spring p/n. In my defense, I was using the p/n that was at the top of the list of spring options that were included in the instructions. Turns out I was referencing a hyd FT spring. Never assume, always go straight to the source. For those who may be interested, the correct p/n is 16094-16.
The installed height is still 1.900". But the seat pressure is 150# and the spring rate is 427. Aligning with the cam card, spring pressure at .550 lift is 385# ((.550 x 427)+150); 40# greater than what's called out on the cam card. Rather have a little more than less spring pressure.
Coil bind is 1.190"; from the 1.900" installed height leaves .710". Max cam lift is .587, leaving .123" safety margin. But how does lash affect the safety margin? The recommended lash is .080"-.095"; is lash added or subtracted from the safety margin?
Newbomb Turk
Well-Known Member
You mean .080-.095 from coil bind.
I try to stay close to that if that’s what the spring calls for.
The more aggressive the car, the greater the spring load and the more rpm the more critical that is.
If you are .110 away from coil bind you’d be fine.
I need to look at your numbers again.
I used the wrong terminology. Hughes requires .080-.095 lifter pre-load; does that affect the coil bind calculation? As I understand, .060-.120 is an acceptable coil bind safety margin.
I was watching a YT video from Powell Machining and Cams. Too much safety margin isn't good either as it creates distortion and harmonics in the spring.
The owner (can't remember his name) specs his builds on the tight side of the safety margin to create more spring compression.
Newbomb Turk
Well-Known Member
No, it doesn’t affect coil bind and that is an acceptable safety margin.
Newbomb Turk
Well-Known Member
Daniel Powell.
I agree with his premise but with hydraulic lifters you can’t always close up coil bind without getting too much seat load, or open load or both.
You have to balance all that.
TT5.9mag
Two atmospheres are better than one
This is what I was going to say. You want to run it closer to coil bind than that. But for what you’re doing it probably won’t make a big enough difference to worry about. On any race stuff, or higher rpm stuff, you need to run em closer to coil bind and that dampens spring harmonics that aren’t otherwise controllable.
mopowers
Well-Known Member
Double check those numbers. Here's what the specs say in the instructions. I know my TF heads (setup for hyd roller cam) and they were indeed setup for an installed height of 1.950". Not sure if they use +.050" keepers or what.
On that note, in the video Powell was referencing LS engines with way over .600 lift, revving to over 7,000.
TT5.9mag
Two atmospheres are better than one
Yea. And even that’s not a big deal these days on an LS.
I caught some discrepancies in TF's specs, depending where one looked. The 150# seat pressure was given to me by Jeff; there is no reference to seat pressure in any TF literature. I them asked him why the instructions state 138# seat pressure. He said that when the springs are installed on the head, they're compressed about 0.050", increasing the seat pressure.
Below I copied the specs for the 16094 springs from the TF website:
Brand: Trick Flow Specialties
Manufacturer's Part Number: TFS-16094-16
Head Part Number: 61417802-C00
Product Line: Trick Flow® by PAC Racing Dual Valve Springs
Valve Spring Style: Standard
Number of Springs Per Valve: Dual
Maximum Valve Lift (in.): 0.625 in.
Spring Rate (lbs./in.): 427 lbs./in.
Coil Bind Height (in.): 1.190 in.
Seat Pressure (lbs.): 150 (I added this line for my own reference)
Retainers Included: No
Outside Diameter of Outer Spring (in.): 1.550 in.
Inside Diameter of Outer Spring (in.): 1.130 in.
Inside Diameter of Inner Spring (in.): 0.757 in.
Damper Spring Included: Yes
Locks Included: No
Valve Stem Seals Included: No
Valve Springs Coated: No
Remanufactured: No
Quantity: Sold as a set of 16.
Notes: Up to .625 in. lift @ 1.900 in. installed height.
A few things that stand out: the last line references 1.900", but only .625 lift. The instructions say .680 max lift. The spring rate is different between the instructions and the spring specs.
Later I'll go out to the garage and measure the springs with my calipers.
The 138# is a touch lighter than Hughes' spec, while the 150# is slightly more. With the high spring rate, the over-the-nose pressure catches up and surpasses Hughes' spec, no matter which combination of TF's specs are used. I went over the cam card specs with Jeff and he assured me that their springs are right in the ballpark of Hughes' requirements.
mopowers
Well-Known Member
Their "max lift" specs depend on installed height. If a given spring is installed at 1.900" it'll have a shorter max allowable lift than if it was install at 1.950". Since their inconsistent documentation mentions two different installed heights, that's probably why you see two different max lift numbers. The max lift number is a bit irrelevant anyway. That's just a calculated number based on the coil bind height + clearance and installed height.
I'm curious what the installed height of your springs actually are. I'd bet they're 1.950" ± .010" or so. Post up that number when you get a chance to measure.
I'm curious what the installed height of your springs actually are. I'd bet they're 1.950" ± .010" or so. Post up that number when you get a chance to measure.
Newbomb Turk
Well-Known Member
Listen, I’m going to give you a hint. I think you are young enough to not know the history behind these discrepancies.
1. I don’t give a runny crap what Dave or TF or Comp or you name them about what they think the spring loads should be. On any cam. I’ve run 180 on the seat with a SFT and it lived. I wouldn’t do it on a car that saw very much street time but for a bracket car I’d do it again if I was forced to use SFT lifters.
2. Back in “the day” cam grinders would lie to your face. Hell they do that today. If you were using (I’m picking names here but this is a hypothetical) say a Crane cam and you started breaking the buttons off the lifter (taking roller cams) and you call say Comp.
Rather than Comp telling you the truth, they tell you “that Crane cam has parts breaking lobes. We don’t make lobes that break parts. By my **** and you can rotate the earth, never lash the valves again and you’ll get 1,000 passes on your springs and then you can shim them and go another 1,000 passes”.
You can insert any cam company name in either side of the equation and it’s true. ALL OF THEM DID IT and they still do it today.
The issue never was the cam was too “aggressive”. The fact is the spring pressure fell off, the lifter went out of control, causing the lifter to try to turn in the bore and pop! Off comes the link bar button and now you’ve got a big poop sandwich on your hands, and you get to eat every bite.
They all say “our lobes will run with 180 on the seat and 480 over the nose to 8500 all day long. Maybe in 1975 but not long after that.
In 1985 I bought a set of springs that went 240 @ 1.900 and I forget what they were open. This was when anything over 180 was taboo. Over 200 and people were sacrificing chickens, speaking in tongues, doing voodoo magic and poking pins in a little doll that looked just like me.
I’m serious. It was THAT bad. By 1997
I was 280 on the seat and by the 2001 I was 340ish on the seat and almost 900 over the nose, depending on what spring I could get, installed height etc. Some people today still lose their mind.
Bet your ***, your house, your dog and anything else that if I had **** unhappy in the valve train it was the springs were losing load. With one exception. I won’t go into that here. But there is one exception I learned in 1996. And Crane was the biggest purveyor of cam and spring bullshit there was. I’ll leave that here.
My point is ALL cam companies think it’s a selling point if the spring pressure is lower than another cam guys lobes need. It’s ignorant.
Like I said, there are some limits. With flat tappet cams you just can’t get that much load on them. 150ish on the seat for street/strip stuff is it. And that’s a SFT lifter. HFT lifters get pissed off over 140.
Hydraulic roller lifters can take more spring load than SFT or a HFT. But NO cam guy will say that.
My point is regardless of what the cam guy wants they always always call out too little spring load for rollers.
If you are higher than what Dave says on the seat who cares as long as you aren’t over 180?
Over the nose…400 is ok.
Just my uneducated .02 cents.
I assume that was a solid roller cam?
I agree with all your points. I'm more than okay with spring rates being a little heavier than lighter
I talked to Mike Beachel at B3 Racing today. What a wealth of knowledge, and one of the truly nice guys in our hobby. We talked for over an hour, starting with rocker arms and spacers, then delving into cams, ignition timing, how to solve detonation issues.
Some interesting subjects came up, such as he uses the same cam lobe manufacturer as Hughes Engines, among others. Mike touched on the HS rocker assembly, specific for TF heads for our SBM. He said that those rockers are not specific to TF, they're a copy of Edelbrock's rocker assembly. If I want a true made-to-fit rocker assembly, only T&D has them. But they're pricey.
We talked about cams and builds, I brought up your name @James Clews, and he of course remembered you and the cam specs of your engine. Mike is a big proponent of a wider LSA for the street to broaden the torque curve and help avoid detonation.
I could go on, but bottom line is I'm going with his PRW bushed, steel rockers and spacer kit.
Some interesting subjects came up, such as he uses the same cam lobe manufacturer as Hughes Engines, among others. Mike touched on the HS rocker assembly, specific for TF heads for our SBM. He said that those rockers are not specific to TF, they're a copy of Edelbrock's rocker assembly. If I want a true made-to-fit rocker assembly, only T&D has them. But they're pricey.
We talked about cams and builds, I brought up your name @James Clews, and he of course remembered you and the cam specs of your engine. Mike is a big proponent of a wider LSA for the street to broaden the torque curve and help avoid detonation.
I could go on, but bottom line is I'm going with his PRW bushed, steel rockers and spacer kit.
Newbomb Turk
Well-Known Member
Myself and many others on here have said the same.
Pretty hard to find a nicer guy, or a smarter guy.
No one and I mean no one should be using ANY roller rocker without talking to him first. And then using his geometry correction kit. No one.
If that were the case, there’d be way less unhappy valve train components out there.
And, if you buy the rockers from Mike you get the updated PRW rocker, that Mike helped them with.
You can’t beat that.
Parts are trickling in. Contacted SST for the clutch kit and 130T neutral balance flywheel. I have an older Keisler Engineering model, 10 spline shaft.
With the planned increase in hp and torque, I stepped up to the McLeod Super Street Pro clutch kit, good for up to 550 hp.
The old disc was in need of replacing anyway...
With the planned increase in hp and torque, I stepped up to the McLeod Super Street Pro clutch kit, good for up to 550 hp.
The old disc was in need of replacing anyway...
That new clutch seems like it would be grabby but oddly, they grip and feel like you'd hope that they would, No chatter, no overly aggressive engagement, they just feel normal.
But they hold!
Mine from my SST kit in 2021:
But they hold!
Mine from my SST kit in 2021:
I measured with digital calipers, which isn't the most accurate way. But on all cylinders the height was consistently 1.950" ±.
mopowers
Well-Known Member
Thanks for following up. It's weird to me how none of the valve spring numbers add up. If those springs were 138# at 1.950" with a 420 spring rate (listed in the instructions), they'd be 159# at 1.900". If they were 150# at 1.900" with a 427 spring rate (from Jeff), they'd be 129# at 1.950".
Do you plan on shimming them at all to get the seat pressure up?
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