Help with Valvesprings and valve float. Noob

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340Duster247

340Duster247

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Hey guys I'm still learning alot when it comes to valve train geometry ,so bare with me. I'm still having an issue with valve float @ 5800 after installing new springs and I wanna make sure the springs I installed were the correct ones for my application, and if I even did it right. First of all my engine combo:
408
Eddy heads. Ported /super Vic intake
Lunati 60405 HYD flat.
242/252@50
Around 600 lift with 1.6 roller rockers.
Now the cam card list the use of lunati springs with these dimentions installed @ 1.65
  • OD: 1.440"
  • Inner ID: .750"
  • Seat Load: 120 lbs/in @ 1.650
  • Open Load: 319 lbs/in @ 1.250
  • Coil Bind: .950"
  • Rate: 363 lbs/in
We couldn't get thoes springs, so my "engine builder" told me to get the comp 987-16 with these specs:
  • I.D.of Outer Spring: 1.070"
  • I.D.of Inner Spring: .697"
  • Seat load: 121lbs @1.80''
  • Open load: 343lbs @1.200''
  • Coil bind: 1.150''
  • Rate: 370lbs/in
I was told to install them @ 1.8 ( the same as the factory eddy springs were installed at)
Now this was over a year ago when I little knowledge about valve train and just learning from what I was being told to do.
Turned out I still had the issue, so i started thinking maybe we had an ignition problem or something else was going on. I live in Calgary where we get short summers and not much play/track time to test the car and see what's going on. Long story short after replacing all ignition and fuels system I find myself a year later coming back to the conclusion that it must be mechanical and getting valve float/lifter pump up....
I'm sorry if Im missing information or doing something completely stupid but I never did learn much about valvetrain..I've just been going by what I've been told to do and never had an issue go on this long that can have so many different causes.

FYI. What this misfire/valve float feels like
-happens in every gear above 56-5800 rpm
-feels and sounds just like hitting a rev limiter.
I have a data log recorded if anyone needs to see it

Thanks guys.

Edit because I copy pasted specs from Jegs.
 
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At 1.8 installed you are just barely over 100lbs on the seat. It looks like if you shim them you will be at coil bind with that cam.
 
You don’t have enough valve spring in it now....... but, that being said....... high rpm, hyd cam, higher rocker ratio......often doesn’t add up to high rpm bliss.

Howard’s 98445, installed at 1.800-1.820.
If that doesn’t allow the rpm you’re after, put a solid cam in it.
 
Ask Lunati if those substitute springs will work.
The data logger should show it.

In my experience;
When the valves float using a HFT cam, the lifters take up the slack right away. And now the valves will not seat closed.
If while in this state, you allow the revs to come down, she will not idle, cause there is little to no cylinder pressure. It may still run at higher rpms just poorly. When the engine shuts down, it may take hours for the lifters to bleed down. And finally, depending on your PV clearance and lifter preload, it is possible for the valves to get bent.
I have never had a fuel problem cut-off at a particular rpm.
Now, if you hit a rev-limiter or the ECU has an issue; none of the above comes into play. You just back off the revs and everything is normal again, exactly what you described. Grab another gear and away you go.

I think you were right in thinking this was an electrical gremlin.
Perhaps you would want to verify your tach reads correctly.
Some tachs cause reving issues.
Some tachs have built-in rev-limiters
Sometimes an Ecu might crap out like that
Some tachs are incompatible with some ECUs/power-amps.
 
AJ/FormS said:
Ask Lunati if those substitute springs will work.
The data logger should show it.

In my experience;
When the valves float using a HFT cam, the lifters take up the slack right away. And now the valves will not seat closed.
If while in this state, you allow the revs to come down, she will not idle, cause there is little to no cylinder pressure. It may still run at higher rpms just poorly. When the engine shuts down, it may take hours for the lifters to bleed down. And finally, depending on your PV clearance and lifter preload, it is possible for the valves to get bent.
I have never had a fuel problem cut-off at a particular rpm.
Now, if you hit a rev-limiter or the ECU has an issue; none of the above comes into play. You just back off the revs and everything is normal again, exactly what you described. Grab another gear and away you go.

I think you were right in thinking this was an electrical gremlin.
Perhaps you would want to verify your tach reads correctly.
Some tachs cause reving issues.
Some tachs have built-in rev-limiters
Sometimes an Ecu might crap out like that
Some tachs are incompatible with some ECUs/power-amps.
Click to expand...
It's definitely not hitting a rev limiter. Holley efi, the catalog shows that the limiter is not being engaged. We've even turned the limiter off to verify. Replaced Msdcoil with Holley hyperspark coil, replaced the MSD distributor with a Holley dual sync, also replaces the MSD digital 6 plus with a plug and play Holley hyperspark box. Replaced wires, and of course plugs many times.

When I'm at the track I have to short shift it at 5700 but by the time you get to the traps at the top of 3rd it just sounds awful going threw the lights. Won't rpm any higher smoothly. In the datalog the rpm obviously rises fine but once it gets to around 5800 it starts to scatter and the rpm will raise to 6000 then drop to 5900 then up to 6300 then down to 6000 then up to 6200...sounds awful in the car and you can feel it too.
 
PRH said:
You don’t have enough valve spring in it now....... but, that being said....... high rpm, hyd cam, higher rocker ratio......often doesn’t add up to high rpm bliss.

Howard’s 98445, installed at 1.800-1.820.
If that doesn’t allow the rpm you’re after, put a solid cam in it.
Click to expand...

I agree with PRH. Also to note, with your current setup you are probably very close to coil bind.

I will also add that a 408/eddy head motor with a small hydro cam doesn't need to get spun up that high to make good power. I agree that it should be able to pull to 6000, but it will probably max out below 5800.
 
Do you have a fuel pressure gauge that you can monitor down track?
 
flyfish said:
I agree with PRH. Also to note, with your current setup you are probably very close to coil bind.

I will also add that a 408/eddy head motor with a small hydro cam doesn't need to get spun up that high to make good power. I agree that it should be able to pull to 6000, but it will probably max out below 5800.
Click to expand...
I agree but I should be able to wing it without it scattering to hell and sounding like death. I can't even get to the end of the track before it falls apart.
4:30 gear. 28" tall tire.
I have friends with stroker small blocks with similar set ups and zero issues. Same gear tire combo.
 
I do have a crappy in car video that you can hear it at the top of 3rd if anyone wants to see. You need to listen closely tho. It's not the best video I just stuck the camera down in hopes I could hear it on camera.
In person it's much more noticeable.
 
Well then there could be your problem;
115 should be 5930@ zeroslip.
The TC might slip in the neighborhood of 5% to 8% making your trap rpm 6230 to 6400
Yur tach is saying 6000 to 6300
I vote disconnect the tach.
 
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sounds like fuel problem to me ,maybe to lean on pinging
 
teringer said:
sounds like fuel problem to me ,maybe to lean on pinging
Click to expand...


Usually (I say usually because weird things happen) when an engine is lean at higher RPM's it will pop and bang. I call it "shooting ducks".

If they are rich at higher RPM's the engine will usually lay down and not pick up RPM and it will grumble in the pipes. By that I mean you can hear it in the headers. It grumbles and stumble and sounds weird. It can me mistaken for valve float.
 
My catalog shows the 60405 is a fast rate hyd cam in the Voodoo series.
Again, looking in the catalog........I’m seeing they show the non-premium valve spring to be a 73195, which is the same spring as the Comp 995.
This is a 402lb/in spring designed for the short installed height of the stock head.
Now you added 1.6 rockers to the mix, which requires increased spring load to achieve the same rpm that those springs would reach with a 1.5RR.
You need more spring than what’s recommended to compensate for the higher rocker ratio.

There is no mystery that the current springs, which are set up with less load than the recommended spring, and have a lower rate as well, aren’t allowing the motor to reach a very high rpm before the valvetrain becomes unhappy and the motor lays down.

100lbs on the seat isn’t going to get it done with that cam and that RR.

I’ve been testing motors on the dyno since 1990......... I see this **** play out all the time.

Put in the bigger springs, then iiwii.
If you need more....... swap to a solid.

Mild-Mannered 440 Mauler - Dyno Test - Mopar Muscle Magazine
 
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[
teringer said:
sounds like fuel problem to me ,maybe to lean on pinging
Click to expand...
Im very certain it's not a fuel problem. Issue was there when I had a carb, and there with EFI. I have a very stout fuel system on the car now with a Holley digital dash that monitor s and records everything. Also when reading plugs all is good. Data logs also show fuel/AFR is where it should be.
 
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PRH said:
My catalog shows the 60405 is a fast rate hyd cam in the Voodoo series.
Again, looking in the catalog........I’m seeing they show the non-premium valve spring to be a 73195, which is the same spring as the Comp 995.
This is a 402lb/in spring designed for the short installed height of the stock head.
Now you added 1.6 rockers to the mix, which requires increased spring load to achieve the same rpm that those springs would reach with a 1.5RR.
You need more spring than what’s recommended to compensate for the higher rocker ratio.

There is no mystery that the current springs, which are set up with less load than the recommended spring, and have a lower rate as well, aren’t allowing the motor to reach a very high rpm before the valvetrain becomes unhappy and the motor lays down.

100lbs on the seat isn’t going to get it done with that cam and that RR.

I’ve been testing motors on the dyno since 1990......... I see this **** play out all the time.

Put in the bigger springs, then iiwii.
If you need more....... swap to a solid.

Mild-Mannered 440 Mauler - Dyno Test - Mopar Muscle Magazine
Click to expand...
Bare with me as I'm still learning... So my current comp springs are installed at 1.8 which is a seat pressure of 121#... Now the springs the cam card suggested should be installed at 1.65 and a seat pressure of 120#.
 
PRH said:
My catalog shows the 60405 is a fast rate hyd cam in the Voodoo series.
Again, looking in the catalog........I’m seeing they show the non-premium valve spring to be a 73195, which is the same spring as the Comp 995.
This is a 402lb/in spring designed for the short installed height of the stock head.
Now you added 1.6 rockers to the mix, which requires increased spring load to achieve the same rpm that those springs would reach with a 1.5RR.
You need more spring than what’s recommended to compensate for the higher rocker ratio.

There is no mystery that the current springs, which are set up with less load than the recommended spring, and have a lower rate as well, aren’t allowing the motor to reach a very high rpm before the valvetrain becomes unhappy and the motor lays down.

100lbs on the seat isn’t going to get it done with that cam and that RR.

I’ve been testing motors on the dyno since 1990......... I see this **** play out all the time.

Put in the bigger springs, then iiwii.
If you need more....... swap to a solid.

Mild-Mannered 440 Mauler - Dyno Test - Mopar Muscle Magazine
Click to expand...

Weird my cam card says to use Lunati Springs part # 73949 with the rate of 363.
 
I’ll repost what I said the first time around.
I encourage you to read the article in the link.
You can draw your own conclusions from there.
high rpm, hyd cam, higher rocker ratio......often doesn’t add up to high rpm bliss.
Click to expand...

If the valvetrain is stable, as in........ lifters not doing things they’re not supposed to....... pulling clean well into the 6000 range is no problem.

Pump gas 360 with bowl ported J heads, dual plane intake, small solid cam, comp 995’s set up at 130lbs on the seat:

D66C387A-4178-4822-AD88-623E32D2D1D2.jpeg
 
Ok, first, what rockers are you running, and has anything been done to correct rocker geometry? It is possible you don't have enough spring, but throwing more spring at an unstable valvetrain is a waste of time. I've had more than 600 rpm increases during dyno testing, just from correcting geometry, on a soft spring. Make sure the geometry is correct, and then if it still needs more spring, swap them out.
 
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