Help with Valvesprings and valve float. Noob
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340Duster247
Well-Known Member
Wow guys lots of good info here. Thanks alot for all the insite. Now this answer is probably right in front of me but can someone school me on where or why I loose 18#s on the seat? You guys keep telling me I'm just barely over a 100# installed @ 1.8 but the spring specs from comp say 121lbs @ 1.8.... sorry guys I'm just a little lost there.
Now as far as my rocker set up. Unfortunately when I needed to purchase roller rockers I had a very limited budget, so I have PRW rollers, with Smith brother push rods. Now my engine builder sent his assembly guy over to my house when I switch too the 1.6 rockers to measure for pushrod length ect. During this time I had very little knowledge of valvetrain. No hands on experience just whatever I could learn from YouTube videos lol. He set everything up so that the rockers were alliged perfectly with the valve stems.(ink on the valve stem method)
I agree with everyone that these springs are not up to the task. Thanks again for all the replys and help thus far.
Now as far as my rocker set up. Unfortunately when I needed to purchase roller rockers I had a very limited budget, so I have PRW rollers, with Smith brother push rods. Now my engine builder sent his assembly guy over to my house when I switch too the 1.6 rockers to measure for pushrod length ect. During this time I had very little knowledge of valvetrain. No hands on experience just whatever I could learn from YouTube videos lol. He set everything up so that the rockers were alliged perfectly with the valve stems.(ink on the valve stem method)
I agree with everyone that these springs are not up to the task. Thanks again for all the replys and help thus far.
nm9stheham
Well-Known Member
Post #1 says 121 lbs at 1.750", not 1.800". With a spring rate of 373 lbs per inch, that extra .050" installed height works out to 18 lbs less spring pressure. 121 - 18 = 103 lbs of closed pressure.
Now if the catalog says 121 at 1.800" then that is right. But that is not what was posted in your post #1.
Edit to add: Actually the COMP catalog says 139.5 lbs seat pressure with an installed height of 1.8", so none of the data posted has been correct. No surprise that things are confusing...Dual Valve Springs: 1.430" O.D. Outer, .697" I.D. Inner-3
Just a precaution: NEVER takes data like this from a distributor website. Always go to the the parts mfr's catalog.
Now if the catalog says 121 at 1.800" then that is right. But that is not what was posted in your post #1.
Edit to add: Actually the COMP catalog says 139.5 lbs seat pressure with an installed height of 1.8", so none of the data posted has been correct. No surprise that things are confusing...Dual Valve Springs: 1.430" O.D. Outer, .697" I.D. Inner-3
Just a precaution: NEVER takes data like this from a distributor website. Always go to the the parts mfr's catalog.
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nm9stheham
Well-Known Member
If 'aligned perfectly' means that the sweep pattern was centered on the valve stem as the roller swept from inside to outside and back during the valve lift cycle, then it might actually be very poorly set up. The centering of the roller on the valve stem is not all that important.... it is the width of the sweep being as small as possible that is the most important.
Can you recall which parameter the assembly guy was optimizing? Centering of the sweep pattern, or sweep width or ??? This is what B3RE has been driving at with talk about geometry.
Post #1 says 121 lbs at 1.750", not 1.800". With a spring rate of 373 lbs per inch, that extra .050" installed height works out to 18 lbs less spring pressure. 121 - 18 = 103 lbs of closed pressure.
Now if the catalog says 121 at 1.800" then that is right. But that is not what was posted in your post #1.
Edit to add: Actually the COMP catalog says 139.5 lbs seat pressure with an installed height of 1.8", so none of the data posted has been correct. No surprise that things are confusing...Dual Valve Springs: 1.430" O.D. Outer, .697" I.D. Inner-3
Just a precaution: NEVER takes data like this from a distributor website. Always go to the the parts mfr's catalog.
Wow! Time for the Rimac! I was going off the the OP's specs in the first post, then you post this, so I dug out my Comp catalog. Look about mid page. Time for the Rimac!
Now if the catalog says 121 at 1.800" then that is right. But that is not what was posted in your post #1.
Edit to add: Actually the COMP catalog says 139.5 lbs seat pressure with an installed height of 1.8", so none of the data posted has been correct. No surprise that things are confusing...Dual Valve Springs: 1.430" O.D. Outer, .697" I.D. Inner-3
Just a precaution: NEVER takes data like this from a distributor website. Always go to the the parts mfr's catalog.
Wow! Time for the Rimac! I was going off the the OP's specs in the first post, then you post this, so I dug out my Comp catalog. Look about mid page. Time for the Rimac!
yellow rose
Overnight Sensation
Yup...if the OP is using roller rockers and doesn't have the B3 kit or machined stands and blocks his rocker geometry is wrong. Very wrong.
OP...DO NOT BUY PUSHRODS until you correct the geometry.
nm9stheham
Well-Known Member
Yeah.... must have changed? Spring rate is higher in the current online catalog too: 373 vs 344 in your paper catalog. IDK which is right..... Bottom line: Page 3 and we still don't know for sure .....
BTW Mopar Sam.... I just read your byline.... "When you're dumb, you gotta be tough!" LOL
PRH
Well-Known Member
The “best” way to know what your spring loads are is to test the springs on a high quality spring tester, preferably one where there is a calibration spring that’s used periodically to verify the readings can be trusted.
In my Comp catalog, in the dual spring section, the 987 is listed as 121@1.750/343@1.200, 370 rate.
In the springs specs listings it’s shown as 121lbs at 1.800 and 1.750.
Obviously it can’t be both.
The 370 rate doesn’t work out for 121/343 and .550 lift(1.750-1.200), but it does for .600 lift(1.800-1.200).
So, how much spring load do you really have?
Imo, only one way to know for sure........ and it’s not by looking in a catalog.
However, I’m not optimistic that the 987 spring is capable of getting you the results you’re after when used with a Voodoo cam and 1.6 rockers........ no matter how you have it set up.
There are several springs that have gone through multiple revisions through the years, and that’s one of them.
If you look at the catalog page Sam posted, you can see they list the two springs that are used to comprise the “987”.
It’s a 984 single spring and the 975 inner spring.
In the current catalog they don’t show that info any longer, but the current specs for those two springs are 200lbs/in for the 984, and 130lbs/in for the 975.
I wonder how 200 + 130 add up to 370?
I don’t know if the current 987 uses those two components or not, but dimensionally they are exactly the same.
The 986 specs from Sams old catalog agree with the two component specs in the current catalog.......200lbs/in + 96lbs/in= 296lbs/in.
However, the current catalog shows the current 986 to be 322lbs/in.
Frankly, I wouldn’t trust any of it to actually be correct.
Sam, in your old Comp catalog, what are the listed pressures and rates for the 984, 974, 975 springs?
In my Comp catalog, in the dual spring section, the 987 is listed as 121@1.750/343@1.200, 370 rate.
In the springs specs listings it’s shown as 121lbs at 1.800 and 1.750.
Obviously it can’t be both.
The 370 rate doesn’t work out for 121/343 and .550 lift(1.750-1.200), but it does for .600 lift(1.800-1.200).
So, how much spring load do you really have?
Imo, only one way to know for sure........ and it’s not by looking in a catalog.
However, I’m not optimistic that the 987 spring is capable of getting you the results you’re after when used with a Voodoo cam and 1.6 rockers........ no matter how you have it set up.
There are several springs that have gone through multiple revisions through the years, and that’s one of them.
If you look at the catalog page Sam posted, you can see they list the two springs that are used to comprise the “987”.
It’s a 984 single spring and the 975 inner spring.
In the current catalog they don’t show that info any longer, but the current specs for those two springs are 200lbs/in for the 984, and 130lbs/in for the 975.
I wonder how 200 + 130 add up to 370?
I don’t know if the current 987 uses those two components or not, but dimensionally they are exactly the same.
The 986 specs from Sams old catalog agree with the two component specs in the current catalog.......200lbs/in + 96lbs/in= 296lbs/in.
However, the current catalog shows the current 986 to be 322lbs/in.
Frankly, I wouldn’t trust any of it to actually be correct.
Sam, in your old Comp catalog, what are the listed pressures and rates for the 984, 974, 975 springs?
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Yeah, I've been told I'm pretty tough!
PRH
Well-Known Member
Thanks.
Wow!!! More erroneous info!!
Your catalog shows the “987”, which is made up from a 984 and 975, to have a rate of 344bs/in.
But......the two individual springs have a rate of 228 and 144..... which adds up to 372lbs/in....... not 344.
The “986” is listed as 296lbs/in....... buuuutt 228 + 96 is 324..... not 296.
This is just another example of why you can’t go by the catalog.
Test the springs....... they are what they are...... regardless of what the catalog says.
PRH
Well-Known Member
Before Crane had all their financial troubles, my go to spring for this type of application was the 99893.
Ive used countless sets of those through the years.
You couldn’t get them for a while when Crane was in limbo.
The Howard’s spring I mentioned earlier is very similar.
I see you can again get the Crane 99893’s now, so those would be another option....... and they’ll also work well should the OP decide to step up to a solid lifter cam(well..... at least the old ones would. I haven’t had a set of the newer ones in my hand).
Ive used countless sets of those through the years.
You couldn’t get them for a while when Crane was in limbo.
The Howard’s spring I mentioned earlier is very similar.
I see you can again get the Crane 99893’s now, so those would be another option....... and they’ll also work well should the OP decide to step up to a solid lifter cam(well..... at least the old ones would. I haven’t had a set of the newer ones in my hand).
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yellow rose
Overnight Sensation
PRH
Well-Known Member
The old 99893 was rated at something like 120@1.875/374@1.225.
The new ones are shown as 130@1.850/402@1.150, 391lbs/in.
The numbers work out the same between the two, but I have no idea if they’re buying from the same source as they used to or not.
Back in the day....... the wire was blue.
The new ones are shown as 130@1.850/402@1.150, 391lbs/in.
The numbers work out the same between the two, but I have no idea if they’re buying from the same source as they used to or not.
Back in the day....... the wire was blue.
340Duster247
Well-Known Member
Some websites for the springs say 1.75 and others say 1.80.
Sorry first post I copied and pasted from Jegs website specs on that cam.
I dug up my camshaft box
Sorry first post I copied and pasted from Jegs website specs on that cam.
I dug up my camshaft box
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340Duster247
Well-Known Member
Ok I'm gonna back track here a little bit. Just so everyone know what's going on.
A couple years back decided I needed to ditch the factory rockers and install a set of 1.6 rollers. Keep in mind at the time I know nothing about valve train,geometry,a I'm just going by what my engine builder is telling me. They had just finished porting my heads, and I asked the old man owner "will the factory eddy springs be up to the task for the close to 600 lift the camshaft will be producing with the 1.6s." he then pulled a spring off the head checked it and said it's close but should work". Ok his assembly guy comes to my house measures for push rods and sets up everything.... That spring comes along and sure enough have valve float issues.... At this point I've become friends with the Engine shops assembly guy. I tell him what's going on and he tells me to buy the 987 - 16 comp springs to fix the issue. tells me to install them at one point eight and I should be good to go. Fast forward a year later (because I don't get the car out that often) and we finally got the car to a race track, and long behold still having valve float issues.... Now I've tried to do as much learning as I can since then, and obviously this engine shop does not know what they're doing when it comes to Mopar..who knows.
Now all this new information you guys are giving me, is brand new to me. I don't even know what a b3 thing is I've never even heard of it before. If it's a mod I've never even read anything about it. So bare with me.
I'm going to do some research on
the b3 geometry kit now
yellow rose
Overnight Sensation
b3racingengines.com and read all his tech pages.
I'm fully convinced that a great majority of engine builders don't understand valve train geometry, especially with a shaft.
Mike has his stuff wired tight. And he's a super nice guy. Read his stuff and let him help you. Your valve train will love you for it.
340Duster247
Well-Known Member
Thanks!!!
Not discouraging looking into this, as it is important....but there are thousands of us out there that have never spent a dime on geometry correction. Have a look at yours, have a look at your budget, you decide....but I will say it is not mandatory.......My car runs runs just fine without any of that stuff (and the rocker sweep looks good), just saying.
yellow rose
Overnight Sensation
And this has driven me nuts my entire life. Why run good enough? If your sweep is wider than .050 the geometry is off, wrong, incorrect. Why not fix it?
It used to be expensive. You used to mill the stands off, buy the offset blocks and stands and correct the geometry that way.
With Mike's kit, it's almost a simple bolt on. You may have to grind the holes in the shafts offset. But that's about it.
I've seen more junk come through the shop with "good enough" geometry that beats the seats and guides out. I've seen broken valve locks and retainers so ate up from harmonics that I was surprised it didn't fail.
I've seen valve springs get blamed for failing, when the geometry was off and the spring was taking the brunt of the load.
I've seen an engine pick up over 500 RPM of USEABLE HP just by fixing the geometry. And the curve of the graph was smoother.
I can sit here and continue to preach on this, but the guys who've been doing it wrong and getting away with it, who won't admit they are getting lucky will continue to foul the Chrylser world with anecdotal nonsense about how so many guys do it.
I know for a fact, that there wasn't a Super Stock guy in the country who wants fixing their geometry back in the 70's and 70's. How do you thin I learned it?
Fix your geometry. For the simplicity and cost effectiveness of it, there is NO REASON to not do it. Ever.
Unless you are running stock rockers, stock lift, stock installed height, your geometry needs to be corrected.
I'm actually not disagreeing with you, get the geometry correct, it is important. What I am saying to the OP is, look at it and decide if it is what you need. I have seen way too many folks lead down the path of "spend your money on this new thingy to go faster" over the years from internet peer pressure, only to find the car runs the same or slower (insert the name of any fancy carburetor you want, or the name of any fancy shock you want). In this particular case, better geometry is better for the over health of the motor....but your motor will probably work ok IF it isn't way off (if it is way off, fix it...easy enough).
Just trying to keep it real.
nm9stheham
Well-Known Member
Just my take.... at .500" lift, the geometry issues produced are not such a big deal, and certainly not much at all at the mid 400's and the old slow ramp cams. (Plus the stock rockers actually change ratio through the lift cycle in a way that somewhat
At .600", that is getting into another 'orbit' of forces and motions.... and it IS a big deal; faster cam ramps, higher RPM's, and higher ratios just pile on top of that. It is not just that 20% increase in lift..... it is a combination of motion changes if you get far 'out of whack' that significantly changes the accelerations and forces in various phases of the lift cycle. Those increases can make the springs vibrate more violently which adds force variations all through the cycle.
Here is a good way to start to appeciate this in the linked video below. You can see the internal spring vibrations going on and even see the individual coils smack into each other at times. Get the geometry set up poorly, and these types of internal vibrations can get more violent; hopefully, this makes it easier to see the resulting issues of lifter collapses and valve bounce on the seats, etc.
At .600", that is getting into another 'orbit' of forces and motions.... and it IS a big deal; faster cam ramps, higher RPM's, and higher ratios just pile on top of that. It is not just that 20% increase in lift..... it is a combination of motion changes if you get far 'out of whack' that significantly changes the accelerations and forces in various phases of the lift cycle. Those increases can make the springs vibrate more violently which adds force variations all through the cycle.
Here is a good way to start to appeciate this in the linked video below. You can see the internal spring vibrations going on and even see the individual coils smack into each other at times. Get the geometry set up poorly, and these types of internal vibrations can get more violent; hopefully, this makes it easier to see the resulting issues of lifter collapses and valve bounce on the seats, etc.
yellow rose
Overnight Sensation
I get it. But the OP is running a roller wheel. It needs correction. May not be his issue, but his geometry is wrong just because of that.
That's my point. And I totally understand what you point is.
340Duster247
Well-Known Member
Hey guys, before this thread dies, what springs do you recommend will have me covered for this combo?
And yes I'm going to go over the geometry, and look into the B3 kit.
Thanks again!!
And yes I'm going to go over the geometry, and look into the B3 kit.
Thanks again!!
PRH
Well-Known Member
I guess there’s no point in me posting anything else.
I’m probably just not qualified enough or have the experience to make a valid recommendation.
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