Isky 295-D Tool Room Springs Without Inner Damper

[enigma57]

Just wondering if anyone has checked seat pressure and open pressure of Isky 295-D Tool Room valve springs with inner damper removed? Either at 1.775" or 1.800" installed height? My cam is a solid lifter flat tappet grind having 0.487" lift.

Isky online catalogue specs these springs (with damper) as follows......

#295-D Tool Room springs - Single w/damper - Outer OD 1.260"/0.886" ID - 135 lb. on seat @ 1.775" inst. height - 350 lb. open @ 1.175" - 360 lb. rate per inch - 1.100" coil bind - 0.600" max lift

Thanks,

Harry

[leahymtsps]

I just checked 1 spring
1.775 - 126
1.8 - 119

Tom

[ProPower engines]

Why would you remove the dampener spring???
Is this to fit a un-modified GM vortec head???
Seems like a bad idea to remove it and chance breaking the spring but it has been done many times when the extra machine work is forgotten about till assembly of the budget don't allow for it at that point in the game.

[af2]

Why would you remove the dampener spring???
Is this to fit a un-modified GM vortec head???
Seems like a bad idea to remove it and chance breaking the spring but it has been done many times when the extra machine work is forgotten about till assembly of the budget don't allow for it at that point in the game.

Not to be rude or to the sort. Many engines have a single spring including all the Bee Hives. A good spring is what is needed.

Harry I will go through the few sets I have and PM you. They are going to be in the 1.5" though.

[enigma57]

Thanks, Tom, ProPower engines and Adam! Much appreciated. The reason I asked is that I am building a 292 inline 6 and am looking for a durable spring (its going in a road car). These inline 6's are somewhat different than small blocks in that they use small block V-8 valves, springs, retainers & locks but have 1.72 rocker ratio same as big block...... But with 3/8" rocker studs. Standard practice is to machine these heads for screw in rocker studs, and upgrade to big block rockers and 7/16" rocker studs.

Will be running a reworked OEM cast iron head. Due to available space and cam grind I will be running...... Decided to use a spring that will drop in rather than machine head for larger dia. springs. Will be running light LT4 hollow stem valves. So don't need a lot of spring...... But would like the added durability and service life of the Isky Tool Room springs if I can get seat and open pressure of the 295-D spring a bit lower.

Spring Isky specs for this cam is the 6005......

#6005 - dual w/damper - Outer OD 1.430", inner ID 0.730" - 135 lb. on seat @ 1.750" inst. height - 285 lb. open @ 1.200" - 275 lb. rate per inch - 1.120" coil bind - 0.550" max lift

By way of comparison, the Isky 295-D specs are......

#295-D Tool Room springs - Single w/damper - Outer OD 1.260"/0.886" ID - 135 lb. on seat @ 1.775" inst. height - 350 lb. open @ 1.175" - 360 lb. rate per inch - 1.100" coil bind - 0.600" max lift

As you can see, the 6005 is a dual spring with damper and has same seat pressure but less open pressure than the 295-D single with damper. I am thinking that with the damper removed, the 295-D should be very close to what I need, though. And would not require machining head for larger diameter spring seats.

I do realize the damper is there to deal with valve train harmonics as well as contributing somewhat to spring rate, but with a mild cam grind, 0.487" lift and redline in the 5,300 RPM range, (these long stroke 292 engines are stump pullers, not high revvers)...... I am thinking that valve train harmonics might not be so bad?

With the 295-D spring...... If installed at 1.775" (with the damper) and seat pressure is 135 lb...... Even with 360 lb. spring rate...... Open pressure with 0.487" lift would be only 310.32 lb. if I am calculating this correctly.

That is why I am wondering what seat pressure for the 295-D (both at 1.775" and at 1.800" installed height)...... And open pressure at 0.487" lift with damper removed work out to be.

Thanks to all,

Harry

[ProPower engines]

I use the 295D in place of the 6005 often just to make the job easier when there is a budget.
The 295D works out the same rate in both cases with the retainer installed for testing.
If you want to know what the spring rate is at max lift let me know what retainer you have or how deep the 1st step is on the retainer you want to use. I have some sets here as well as a mock up pair with and with out a dampener to
compare to

[enigma57]

Much appreciated, ProPower engines! I plan to run Isky #707-STA valve spring retainers with the 295-D springs.

Thanks,

Harry

[ProPower engines]

Much appreciated, ProPower engines! I plan to run Isky #707-STA valve spring retainers with the 295-D springs.

Thanks,

Harry

Confirm the step distance just to be safe.
Not what the book says but if you got the retainers in hand check that and get back to me.

[enigma57]

Sorry, ProPower engines ...... Don't have retainers in hand as yet. Am piecing valve train together, cam first (have cam)...... Then matching springs to cam and head...... And retainers and locks to springs and valves...... In that order.

Isky specs the #707-STA valve spring retainers for use with their 295-D springs and 11/32" valve stems, so am planning on using those retainers.

Thanks for your assistance,

Harry

[leahymtsps]

Morning Harry,
295-D spring with damper and 707 STA retainer
1.775 - 139.5
1.175 - 361.4
Spring (less damper) with retainer
1.775 - 127.7
1.175 - 329.5
Tom

[enigma57]

Thanks, Tom! Much appreciated. So the Isky 295-D spring installed without damper should work out to......

127.7 lb. seat pressure at 1.775" installed height using the #707 STA retainers

288.17 lb. @ 0.487" lift (my solid lifter cam)

That should be just about right with the light, hollow stem LT4 valves so long as removing the damper doesn't cause valve train harmonics issues. Also...... Will be running solids with EDM oiling on intake side and Rhoads V-Max lifters with oiling flat on exhaust side. From my research, the Rhoads lifters are designed to function with open spring pressure 300 lb. or less. So this should work well.

Best regards,

Harry

[enigma57]

Well, Monday was an interesting day here. Our area was to be under a 'stay at home' order except for necessary trips to work, to bring in provisions or to address medical issues. As it turned out, the County Judge has postponed issuing that order until Tuesday morning......

https://www.houstonchronicle.com/news/h ... 151465.php

However, we were unaware of the postponement, so my wife worked from home via computer and I spent much of the day reading and learning about the pros and cons of removing the damper from valve springs. Natural harmonics occurring in multiples of resonance frequency, free vibration and forced vibration, etc. And various reasons valve springs break at times. Time well spent.

Having done that and all things considered...... If I run the Isky 295-D valve springs...... I will run them as designed and retain the dampers. Will also detail and deburr the ends of the dampers so they won't chew up valve seats and retainers.

With the 295-D spring and #707 STA retainer...... If installed at 1.775" (with the damper) and seat pressure is 135 lb...... 360 lb. spring rate equates to open pressure with 0.487" lift (for my cam) of only 310.32 lb. And if I install same springs at 1.800", this will lower seat and open pressure by 9 lb. and put open pressure (with my cam's valve lift) near 301 lb.

That should allow me to run the 295-D springs and gain the durability of Isky Tool Room springs whilst keeping seat and open pressure (with my cam's valve lift) where I need them.

Thanks to all who have offered their assistance. And my apologies for being a little slow on the uptake here. All these years, valve spring choice in my case was pretty much...... 'OK, I'm running (insert cam grind here). Cam grinder recommends (insert spring here) set at (insert installed height and pressure on the seat here)'. And at this late date, I am finally reading and asking questions and learning more about spring choice.

Old dog learning new tricks here,

Harry

[frnkeore]

I recently ordered a custom cam from Howards. In my discussion, we talked about springs and he told me that race springs, w/o dampeners, are designed to have their most, self dampening effect, at ~.060, off coil bind and that if you run them, to much off that figure, they will generate more heat, than designed to.

My build is a high rpm one, 7500+ so, if true, it may not effect a 5300 rpm spring.

Is there a consistences on the info that I was given?

[canuc]

Harry
I think your old way of using the spring that the cam grinder specs still stands . What has Isky recommended ? Why aren't the 205d adequate ? For sure you don't want to take the damper out unless you tighten up to minimum like frnkeore posted above .

[enigma57]

Well, I am certainly no expert on that subject, frnkeore. Just doing what I can to learn enough to make an informed choice when setting up the valve train on this 'last build' on a type of engine I have never built before. But I did read whilst doing my research that keeping lift and spring bind near those limits (whilst allowing for 'enough' clearance short of spring bind) was desirable. I suppose there might be something of a self dampening effect as you say. Same was said of the lower several coils of conical springs (also without damper).

I am not sure why running springs having over 0.060" between valve lift and coil bind would generate excess heat unless they mean running without a damper to dampen the oscillation of the springs at certain RPMs might allow resonance frequencies to create heat as the valve spring passes through those frequencies.

Every solid object has a resonance frequency. The more an object vibrates, the more it tends to generate heat and fatigue. Valve springs are no exception. If the rate the springs open and close match the resonance frequency of the springs, they will pick up a harmonic. Sometimes it's minimal and others, stronger. Also...... The harmonic frequency of a given spring (its resonance frequency) repeats every octave, so if the resonance of the spring is 40HZ...... Multiples of that...... 80HZ, 160HZ, 320HZ, etc., will cause it to vibrate as well.

Sorry...... That is the best I can do at explaining this. I discovered beer, fast cars and faster girls my sophomore year in high school (1964) and except for some technical schools later, in military service...... That is as far as I got education wise. Hell, I wanted to sign up for the Marine Corps as soon as I turned 17 and if it hadn't been for my folks and several teachers talking me into staying in school and graduating before leaving for the service, I wouldn't have gotten that far in school.

Canuc, the way I designed this cam, I used a Dyno2003 computer program a buddy gave me back then. It makes no recommendations. You just put your engine specs and head flow numbers in and try various cam specs, etc. until you find what works for you. I have no idea how accurate it is as regards absolute HP and TQ values. I suspect that its strong point is in predicting trends rather than specific HP and TQ values as you manipulate valve timing events, static comp. ratio, etc.

In this case, I am building a '66 292 inline 6 truck engine and will be swapping it into my '57 Chevy sedan. Its a driver and I will occasionally pull a boat trailer up some fairly long and steep grades in the Texas hill country. These long stroke engines have harmonics issues if you spin them above 5,500 RPMs...... Tend to sling flywheels and such. So what I wanted was to cam it to provide as broad and flat a powerband as possible from off idle to redline of 5,000 or 5,300 RPMs. Not looking for max HP and TQ numbers with short peaky curves on the graph. Looking for the most average HP and TQ in that RPM range and have purposely sacrificed higher peak numbers in favour of higher average numbers over the engine's operating range . State of tune in the 1 HP per cu. in. range running on pump gas with 9.5:1 static compression ratio. Should be able to keep it together in a road car at that power level.

Anyway...... Cam specs came out very close to the old Isky E-4 solid lifter grind that was popular in the '50s. What we used to call a '3/4 race cam'. In fact, I am running E-4 exhaust lobes and same LSA along with a similar intake lobe having slightly (2 degree) earlier closing angle. Lobes have only 0.283" lift at cam, but the inline 6 engine runs 1.72 rocker ratio same as big block Chevy. So I have old school gradual ramps but higher lift (0.487") and faster opening/closing rates (at valves) due to the 1.72 rocker ratio (original E-4 was designed for 1.5 rockers).

On springs...... Isky recommended their #6005 springs. These are a double spring with damper and are 1.430" diameter. 135 lb. seat pressure, 285 lb. open @ 1.200", 275 lb./in. spring rate, 0.550" max lift. A good spring, but I will be running a reworked cast-iron head and thought I would use springs that wouldn't require widening the spring seats.

I did look at the 205-D and the 235-D springs as well as beehive springs having spring rate, seat pressure, open pressure, spring rate and max. lift that would work.

The 6005 springs and beehives would require adjusting seat width and no significant performance nor durability gains that I can see for the effort.

205-D springs will drop in but are a bit down on pressure and would be pretty close to max lift with my cam.

235-D springs will drop in and are good regarding pressure and max lift.

Settled on 295-D springs because they will drop in and because I believe the Isky 'Tool Room' springs will last a good long time. Do not anticipate stepping up to a hotter cam in future, given the intended use of this engine but the 295-D springs would allow for that if I were to do so and have sufficient room for added lift.

Seat pressure is spot on and even if retaining the dampers, with valve lift of only 0.487", that equates to 310.32 lb. open. And about 9 lb. less on seat and when open if installed at 1.800". I will be running light weight hollow stem LT-4 valves and would like to keep max. open pressure (with my valve lift) at 300 lb. max or very little more. Will be running Rhoads V-Max lifters on exhaust and they are designed to work with 300 lb. (or less) spring pressure.

6005 springs are 1.430" diameter. 135 lb. seat pressure, 285 lb. open @ 1.200", 275 lb./in. spring rate, 0.550" max lift.

205-D springs are 1.260" diameter. 115 lb. seat pressure, 268 lb. open @ 1.210", 310 lb./in. spring rate, 0.490" max lift.

235-D springs are 1.260" diameter. 130 lb. seat pressure, 320 lb. open @ 1.200", 350 lb./in. spring rate, 0.550" max lift.

295-D springs are 1.260" diameter. 135 lb. seat pressure, 350 lb. open @ 1.175", 360 lb./in. spring rate, 0.600" max lift.

Best regards,

Harry