BROKEN INTAKE VALVE SPRINGS?

sorry i havent been here for a while......i just dont get it.....i broke off the top of the intake stem and thank god i didnt bend the valve or damage the piston.....valve just went straight up and down....so i tore off the valve covers to see what going on and found 5 intake valve springs broken......just the intakes....
so here what i have.....its a 572 keith black aluminum block with stage v big valve heads....2.40 titanium intake and 1.94 stainless exh.....a bullet roller cam duration@50...intake 283/exh.284....lift int.696...exh.682....stage v roller rockers...isky ez roll solid rollers...comp cams elite race triple valve springs 750lb....scat crank/oliver race rods/diamond pistons 11.5 to 1 compression......so 10,000 miles ago we did a complete rebuild...all new valves/guides/pistons/bearings/cam/etc...need to dyno engine to set valve lash hot....couldnt do it in car fast enough to bet valves covers off.....so we lashed the intakes at .022 and exhaust at .024.....engine dynod at 877hp @ 7000rpm and torque was 753 @5300rpms on 93 octane which i was very happy with since i mostly drive it on the street......so i got it home and check the lash cold and the intakes was .003 and exhaust was .005.....so the engine grows .019
whats got me crazy is why did just the intake valve spring break and not the exhaust?,,,,,,and why did the break?.....should i run heavier springs....i called comp cams and they said i should run there elite race triple valve spring with a 950lb......i know roller cams with solid roller lifter aren't mainly for the street but i got 10,000 miles out of it

What did the engine builder say?

I would find it hard to belive that a
272/.696" cam with Ti valves requires 950lb open. I realise it's a Hemi with a 2.400 but that's a lot of spring. I have had Comp 996 tool steel springs shatter. Good pressure right up until they broke. Then it broke 6 inners, 2 outers. For comparison my wedge runs 2.25"/1.81"stainless valves. 305/800psi. Pac1224 spring. 285/292,.800" to 7100.
Doug

Same here pac 1224s for me also. I kept breaking K Motion Springs in mine. switched to Pac,s a year ago no more problems

The question is why did the break in the first place?? How often did you check the lash??? 10,000 miles on a roller on the street is a fair amount to be sure. I too have a car with a solid roller that we drive on the street mainly and I check the valves on a regular basis. From what I'm reading it almost sounds like they have not been checked since it was on the dyno 10,000 miles ago. If that's the case I would say they did pretty damn good and would guess when and if you check the pressure on the intake springs they will be way down from the installed pressures.

Knowledge is power
On the tip of the intake valve breaking off and the intake valve springs breaking only there is a reason for this
I would replace all the valve springs with a better brand
PACs work fine for me also

I guess it's all relative..... But IMO any solid roller cam combo with lifts in the .700 range should have the springs replaced looooooong before 10,000 miles.

As for why the intakes?
Usually the intake lobe is faster, and/or the rocker ratio is higher, along with the higher weight of the bigger intake valve, all add up to put more stress on the intake springs..... So they just don't last as long.

On most of the heads I freshen that have been run with a roller cam, when I test the spring pressures, the intakes usually have less pressure than the exhaust. This is the case even when it's a single pattern cam being run with the same RR on both valves.
When the intake lobe is faster and/or the intake ratio is higher, then there is usually an even greater difference in pressures between intake and exhaust springs.

I agree with Dwayne 100%..The intake spring will always give up before the exhaust side does barring any mechanical interference issues..

I broke 1-4 otter intake springs on every 1/4 mile pass with my KB hemi after about 5 passes with new springs. Set of titanium springs at the time cost a 1000 bucks a set, actually more like 1200 if I bought one set at a time. Some springs lasted 4 runs and some 10. 950 on the seat but at 9500RPMs.

10K miles I would be jumping for joy if my stuff lasted that long.

I'd like to know the part number of the springs used and the installed height of the OP's stuff.

Also....... Being a hemi and all....... I'd say it's a pretty safe bet that the rockers didn't get backed off for the winter storage.

i usually check the lash every 3-4000 miles....and they are generally very close....i haven"t really checked the spring pressure since they stopped making the tool to remove the springs while the heads are on.....had one years ago and should've kept it but sold it

i was there yesterday and asked him what he thought.....he was thinking the coil bind could"ve been from the engine growing .019....maybe the install height was just too close

i went thru comp cams master list and looked up solid roller cams for a hemi and they require these 950lb springs for all there solid roller cams.....part # 26082-16

like i said all the valves were replace with brand new and the intake valve broke off right below the keeper line....we will look at all the valves and will definitely replace all the springs.....what are the best springs i should use and what pound springs will take a beating....comp cams thinks i did have enough spring pressure and thats why they broke

The springs need to match the cam, and the intended application.
If you're running a SS/AH car and trying to turn it 9000rpm, or a TA/FC car running 10,000 rpm...... Then you might need 950lb springs.

Not every roller cammed hemi has that type of cam, or is being used in that application.
One of the more street driven hemi's that I'm familiar with on this board is Chip's 572 in his Cuda.
His motor(with a custom roller from Comp) seems to be living just fine with springs that are only 600lbs open pressure.
Although, even as mild as his cam is, I still don't think I'd try and stretch out the service life of the springs to 10,000 miles.

i never really looked at it that way.....that really makes sense

wow....thats some pricey valve springs.....my hemi starts to fall on its face right at 7 grand.....you are running some high rpms.....i guess i should be jumping for joy.....lol

i am going to call bullet cams tomorrow to see what he says recommends for this cam.....i will have to send Chips 572 a message to see his combo......thats his name here?

I'm not suggesting at all that you try and run spring pressures the same as Chip runs, I'm merely pointing out that roller cammed hemis don't "require" 95b springs to run well and live.
It's all about matching all the components.

Chips name here is "an8sec70cuda"

IMO, you just left the parts in the motor waaay too long, and they broke......simple as that in my mind.

With the kind of spring pressure you're running(750lbs open), I absolutely wouldn't be trying to get 10,000 miles out of the springs/retainers/locks or valves.
I would also have the valve covers off for inspection much more often than every 3-4000 miles with a set-up like that.
3-4000 miles is more along the lines of what I tell guys with mild flat tappet cams to do.

thank you everyone for your help......one last thing......who makes a great valve spring?

There is no magic brand of springs.
Isky, PAC, PSI, Manley........ There are tons of quality springs out there.
The key is using the correct one for your application.

I'll say it again....... IMO, you got excellent life out of the springs you were running.
You waited too long to replace them.
I wouldn't expect any other spring to last any longer in that application.

IMO just a "lack of maintenance" is what has caused your problems. I agree 950lbs on the nose is likely overkill for what you have. As for springs IMO Pac makes the best stuff out there. They are an OE manufacturer not to mention they make many of the springs in other companies boxes.

First off, if you have an all aluminum engine the COLD lash should be no more than about .004-.006. Of you are setting lash at .022 cold on the intake, you'll have at a minimum .035-.036 running, maybe a bit more.


Close the cold lash way way down. If it will start with .002 cold lash set it there.


I have measured blocks that grow .020 or more when hot and I suspect that in reality, you are running over .040 lash.


All that does is beat the hell out of the lifters and all the valve train. I believe it can set up harmonics that will break anything you put around your valve train.


That is where I'd start first. Also, I think it was Mr. Porter who was talking about how frequently you need to change out springs. I agree with that.


Start by getting the cold lash as tight as you can. If you can get the passenger side VC off quicker and easier, then set the lash at .004 cold, get the engine to temp and check 1-2 valves when hot. Adjust the hot to get as close to .020 running as you can, even if that means .002 cold lash.

FWIW on my Cuda the cold lash was almost not measurable(hard to squeeze a piece of tin foil). On cold days, IE below the upper 30's the car would not start as the valves were still open.

Here's the basic gist of what I do for street motor combos like this where a solid roller is going to be used, and relatively long service intervals are desired.
In my mind, this automatically means that some amount of power will be sacrificed for longevity.

I run really slow lobe profiles designed for high endurance applications, like marine or 24hr road racing. Something that will operate at a sufficiently high rpm(for the application) with a moderate spring pressure.
Then couple that with a high end endurance spring, set up so it ends up somewhere near .100-.150 from coil bind at full net lift.
While setting up the springs in this manner can cost a bit in terms of the upper rpm limit of the valvetrain, it's much less stressful on the springs, and they just last longer.

I would have selected lobes that would have operated to 7k with no more than 650lbs open pressure, and then used something like a PAC 1396 spring set up at 2".

And even like that, I wouldn't have told my customer it was "good to go" for 10,000 miles.

Pac has been good for me
Doug

Like Fast68 said, I think you just went wayyy too long without changing springs! Your cam must be a much more aggressive profile than the one that Fast68 spec'd for me b/c my springs are only 220# on the seat and 600# open.
I change mine out at freshen ups (usually in the 3-4k mile range) and never even check them. I don't want to be tempted to reuse them. I've sent my Isky Red Zone lifters back twice for a checkup and had them returned w/ a note saying no work needed. They are not the EZ Roll bushed lifters...those weren't available in 2006 when I built mine.

What's the rest of the combo if you don't mind me asking? Any timeslips?

i called John at bullet cams and he wanted to know valve spring install height and diameter......my engine builder had all my specs so i went and visited him......turns out my springs are comp cams 944-16...double spring...id.1.120...od.1.575...install height 1.950....seat load 190lbs@1.950....open 747lbs@1.200....coil bind 1.100....so i gave John the specs and he recommend PAC 1244 springs
Part# PAC-1244
Description High Frequencey High Lift Dual Spring for Roller
Mass (g) 142.0
Outer Spring I.D. (in) 1.120
Outer Spring O.D. (in) 1.570
Inside Spring I.D. (in) 0.780
Install Load (LB) 190
Install Height (in) 1.950
Open Load (LB) 710
Open Height (in) 1.250
Coil Bind Max (in) 1.035
Lift Max (in) 0.800
Frequency Outer (CPM) 32630
Frequency Inner (CPM) 32965

my engine builder set the lash cold at .006 intake and .008 exhaust.....then i brought to his sons place and we ran it up to 180 degrees....shut it down pulled the covers and set the lash at .022 intake and .024 exhaust.....we did some pulls and was happy with the results......got it home and the next day when it was ice cold i check the lash.....turns out the lash on the intake was .003 and the exhaust was .005.....so engine grows .019

wow....Al.....what are you running?.....whats your lash hot?

since i went with the roller cam i haven"t been to the track.....this rebuild is....

keith black aluminum 4.50 bore/4.50 stroke block/scat crank/oliver race streel rods/ diamond pistons..11.5 to 1 compression[ pump gas]/stage v heads 2.40 titanium intake/1.94 stainless valves with custom port and polish from tim banning[FHO]/stage v roller rockers/bullet roller cam duration @50 intake 283/exhaust 284/lift intake 696/exhaust 682/isky ez roll 904 dia solid roller lifters/smith .120 push rods/milodon gear drive/milodon 9 qt pan with dual line with swing gate pickup and hole for steering/tti 2 1/4 primary/4 inch collector headers/msd distrib and 6al-2 box/ray barton single plane 4500 manifold/pro-systems 11.50 dominator/built 727/PTC 3500 stall convertor/gear vendors/dana 60[was 4.30] now 3.73 gears/ss springs /pinion snubber/frame connectors/mini tubbed/20 gallon fuel cell/batt in trunk/8 point cage

first all new build ran 10.38@129....it had a solid cam[specs?] with schubeck composite lifters[which all failed and unglued]indy tunnel ram with two pro-systems 10.50 dominators[which washed all the cylinders down]/4500 stall convertor/4.30 gears/2 1/8 primary...3.5 collector tti headers....roadrunner weighs with me in it....3900lbs

The PAC 1244 and Comp 944 are the same spring.
At least they were when Comp first started marketing the PAC-aloy series of springs.
"PAC-aloy"....... Get it?
At some point they started getting some of the springs sourced from different vendors and stopped using the PAC-aloy name at that time since not all of them came from PAC(some were, some werent).
You say your motor has been together 10 years?
Those could be PAC springs, bought as Comp 944's.

And........ FWIW....... I've seen a fair number of broken 944's.

A few others were;

1243 / 943
1245 / 955
1246 / 946
1247 / 947
1248 / 948

my builder said that today but i didn't put two and two together PAC-aloy.....no my motor was rebuilt like April 2015....ran it for 10,000 miles before i dropped the valve.....when it was new it lasted 12,000 miles with a solid cam with comp 919 springs

so basically the comp springs and pacs are the same or the pacs are better then comp cams springs?

YOU RAN A 8.91@150......whats your combo if you don"t mind?

If you got 10,000 miles out of those springs you did real good....... I wouldn't blame the springs in that situation at all.

I would just change them out sooner this time....... Hopefully before one fails.

yep my fault/lack of maintenance....didn't realize....does anybody sell a valve spring compressor to pull the springs while the heads on.....years ago they did sell them......dont see them anymore

Not that I am aware of.

If anyone has something for a Hemi it's probably LSM.

But the pressure isn't the whole story.
They can retain nearly 100% pressure right up until the point of failure.

They need regular replacement....... Whether they still test good or not.

thats good to know.....thanks for that

George,I am amazed your valvetrain lasted that long!! My spring pressures are similar to chips.

572" KB block, 4.5" Callies crank, 7" Oliver steel rods, 11:1 Diamond pistons, pump gas
CNC ported MP aluminum heads by MCH
276°/284° at fifty, .672"/.651" lift, solid roller (spec'd by Fast68plymouth), PAC 1243 springs, DLI roller rockers, Manton .134" wall pushrods
Barton single 4500 manifold, 1200 cfm Pro Systems dominator
TTI 2.25" pri., 4" collector headers, 4" exhaust
727, 9" 5k stall, 4.10 gear Dana 60, Cal-Tracs, 295-65 drag radials

N/A it has run 9.54 at 140.4 mph, 1.320 sixty foot. That was on pump gas at about 3800 lbs.
On about a 225 hp hit of nitrous it went 8.91 at 150, 1.310 sixty foot (delaying the hit) at 3900 lbs.

Just something to look at. The 2 shaft rocker systems, even SV are hard pressed to keep oil on the intake springs at idle, and low rpm. Even reved there isn't much there. Heat is what I've seen break springs more than cycles,(save coil bind) and really high rpm stuff that would never be street driven anyway. Maybe consider a spray bar to help keep them cool.

My personal spring choice is PSI. PAC also makes a great spring. would only run these two spring makers period.

Dwayne I have a crane solid roller in my 426 with 200# closed 455# open lift in 587 ex 568. Calls for .020 lash hot set at .012 cold aluminum heads cast block. Street driven. How often should I change out the springs?

Thanks Mike

Wow thats awesome....looks like the 5k stall/caltracs and 1200cfm makes a big difference compared to mine....when i get it together i am dying to find out what mine will do......thanks

Your problem on a hemi depending on the car it is in is going to be removing exhaust springs on the car. LSM may make an on head tool as well as Buxton

http://www.buxtonengineering.com/on_head_valve_spring_compressor.php

FWIW when I ran a Hemi we had spray bars for just the reason DT is referring to. For what you are doing you wont find a set it and forget it option for sure. But would be nice.

I would run the PAC stuff personally. I could be biased as my brother in law is a big wig at Peterson Spring, the parent company But I do feel they make the best race springs out there, coil, valve, torsion bars and so on

My stuff was a KB block B1 head deal. Hot lash was .016 on both..My current Predator is a World block with about .003 cold and .022 hot. I have another KB B1 engine as well that has .028 hot and .012 cold.

is there a post to see how and where to buy spray bars....that makes sense......would like to do that
i am going with PAC....thanks

We made our own that were epoxied into the valve cover.

yeah i souldve never sold my spring compressor ..that buxton setup looks like a fine tool but not for tight quarters...the one i had bolted off the stands with 4 bolts and was tight on the exhaust but did work.....i dont know why they stopped making them....yep going with PAC.....thanks

Obviously there is no hard and fast rule for this, as a lot of it would depend on how the vehicle is used........ How many runs down the track per spring cycle, if it's run into valve float at all,
whether it's lots of high speed interstate driving, or mostly around town and back roads, etc....... Along with the quality of the springs being used.

Do you know what brand and part number springs are in the motor now?

Since it's so much "fun" to swap out valve springs on a hemi with the motor in the car, I would use a pretty tame set of street friendly lobes(like you have), and the best springs I could put in it, to extend the service interval as long as possible.

The Buxton and LSM spring compressors both bolt in to shaft bolt holes..Was yours an old MP deal? Would not be hard to make one really

no its all stage v....stands and roller rockers

Those both bolt to stands or shafts, IF they make one for that head. I would imagine Buxton does last I checked LSM did not but that was a few years ago. I have both and they are very good pieces, inner fenders are the issue Only way to find out is give them a call

ok....thanks ....my inner fenders are the problem.....this would be fine if i pulled the motor.....that looks like a stout beefy compressor.....this was the tool


[img:center]https://goo.gl/images/vPjieB[/img]

LSM SC330 says T&D rocker on a Hemi..

http://lsmproducts.com/lsm_products/valve_spring_compressors

thank you

Just another thought on the spring choice......
I would use the PAC 1344 instead of the 1244, especially in this application.

The 1344 is the nitrided, higher endurance version of the 1244.

i almost called John at Bullet Cams to order the 1244"s....glad you mentioned this.....thank you

Not sure on the springs The float on the cam is 8200 max power rpm 7600 I have the shift light at 6500 and rev limiter at 7200. It has plenty of pull left at 7200 but with a 4 speed I wanted to play it on the safe side. I try to keep it around the 6500 and most times it's only running 4500 tops.

I guess "if it were me", I'd probably pull a few intake springs off at around 4000 miles and test them for pressure, as well as look at the overall condition of the shims/retainers/locks to see if there are signs of "unhappiness", and make a decision on whether to replace the springs at that time based on what I saw.

To put the OP's situation into a little perspective........ Using very rough guesstimates.......
10,000 miles, at an average speed of 50mph is 200hrs.
If the average rpm over the entire 200hrs of use is 2500rpm, with the cam running at 1/2 speed(1250 cycles per min), 60 mins per hour(75,000 cycles per hour), for 200hrs...... That's 15,000,000 cycles.

Ok, don't want to highjack this post, but you guys have me worried! I have 5,477 miles on my strickly street HEMI. I run a Comp Cams street HEMI solid roller. Comp #24-000-9. 248/254 @ .050, gross lift .604/.591. The MSD has a chip of 6,400 rpm and I have never revved it past 6,200.
Springs are Comp #953-16. I have tried to find pressures, all I have been able to come up with is #162/#484. Do I need to worry about spring replacement?
This is a STREET roller, supposedly designed to live on the street. Isky Bushed lifters, oil fed, stock rockers and valves. Stock oil to the upper end.
With MP aluminum heads, I adjust the valves every 1,000 miles at .010/.012 cold, .016/.018 hot.
So do I need to change the springs, or are my low pressure/rpm good to go for another season of driving the car?

Might want to call Pac direct and see what they say

It seems those springs are working for you, but they definitely aren't what I would have used.
In the Comp catalog, looking through listings for their street roller cams, where the 953 is listed as the spring of choice........ It's listed as the base spring..... Not the premium option.
The premium option for the 953 is the 938.
The specs for the 938 are 204 @ 1.900/ 492 @ 1.300.
99% of the time, this will be the minimum pressures I like to see in a BB application with a mild roller cam.
My spring of preference when looking to meet those specs is the Isky 9315.
210 @ 1.900/500 @ 1.300, and .100 more distance from coil bind at 1.300 than the 938.

I guess my advice for you would be the same as the other poster above...... Pop a couple out, have them tested, look all the associated parts over and make a decision based on what you find.

A PAC alternative would be a 1227; 225 @ 1.900/525 @ 1.300.

If you are running that high of pressure then look at every aspect of your valve train,springs,locks,retainers and valves should be change at a schudled interval as well as guides and seats along with a fresh valve job.Hemis tend to be hard on valve train componants.

The first time I freshened up my hemi, the valve stems were worn out. Luckily, new valves tightened it right up and I ran it like that for a few more years. The next freshen up it needed new valves again as well as guides. I just had bronze liners installed in the original guides, instead of driving out the old ones and putting new ones in. Worked great.

This last time, I did not put valve seals on the exhaust valves. Thinking maybe that will help somewhat w/ oiling the stems. Still have em on the intake though.

yep.....did the same thing....all new valves/springs/pressed in bronze valve guides/seals and lapped in the valves