Valve spring lifespan

[1KWIK72]

I broke an inner spring (intake) last weekend they are Manley Nextecs pt# 221424 that came with the BMF 18* heads 2.180 steel intake valve 1.60 exhaust. I shift at 7500 and go thru at about 7200 Cam lobes are Intake Adv. 311, .050" 274 .200" 194, .782" lift with a 1.7 rocker Exh is adv 319 .050" 286 .200" 205, .736" lift with a 1.6 rocker. My Cyl head guy says he has seen a few of these failures of the inner springs (always the inners he said) and suggested I replace them this winter and as long as they check good for tension keep them for spares. I talked to my engine guy today and he pretty much said what I was thinking. That I had found the cycle life of these springs in this application and to replace them all right now to avoid breaking anything else. The springs have about 190 passes on them now I usually make about 250-300 passes a yr. I would like to find somthing that will live at least a season is that too much to ask? My engine guy likes the Isky tool room springs but it doesn't look like they have a direct replacment for whats in there. Any recomendations?

Thanks
Craig

[Jay Allen]

Manley Nextecs pt# 221424
2.180 steel intake valve
1.60 exhaust
shift at 7500
go thru at about 7200
311/274/194
.782" lift with a 1.7 rocker
319/286/205
.736" lift with a 1.6 rocker
The springs have about 190 passes on them now
I usually make about 250-300 passes a yr.
I would like to find somthing that will live at least a season is that too much to ask?

Any recomendations?

Craig this is a tough call.

Cycling the valve train 7800 RPM with a steel 2.180 intake valve is going to take its toll on anything. That to me is asking a lot. A tooled steel spring will not show much fatigue, until it breaks. When one breaks, they are all not very far behind. If it were me, I wouldn't even start it w/o changing them all. A chrome silicone spring will simply fatigue little by little. As long as you check them often, you'll catch a failure long before it happens.

If it were me, I'd be looking for some used titanium intake valves over the winter. Invest is some light weight titanium retainers (not just the std titanium stuff). I'll bet the Manleys will go the distance at that point.

I am NOT a Isky fan at all except for the red zone lifters. Past that I do not recommend any of it. I will also say that if you look at where Manley says to set that spring up, it calss for 2.000". You are at .782" w/o lash or .750" with lash and deflection. That means the spring is at 1.250". Coil bind is at 1.070" or .180" away. IMHO, you are not working the spring near hard enough. It very well could be some funky harmonics going on. Just as you can run a spring too hard, you can run them too soft. This would explain the broken inners.......

Tighten the I/H up.
Used titanium intake valves.
Light weight titanium retainers.
Keep the Manleys.

Good Luck To You!

[Chris Uratchko]

HHHmmmm that cam spec seems to end up on everyones stuff these days.... everytime I ask someone their specs I always here 274/286.... is that like the generic spec folks are handing out today or what?

[Ed-vancedEngines]

You could be killing your springs with spring suge with them that far from coil bind at full open. You are probably not doing a very good job of valve control with that either, I would guess.

To begin with, I hate any spring that is supplied on a head as bought, no matter who it is bought from including the most haRD CORE RACE HEAD SHOPS. Almost all of them are using the springs that they are buying in bulk lots, and one size or one spring does not fit and work well with all applications. I at least pull them and run them through tstings to see what I can set them up at. Most racers do not. They gladly accept the heads just like they come and run them.

I also hate valve springs supplied by major cam companies as part of their cam kits. They are usually the bare minimum that could work.

Do yourself a favor and begin a research into valve spring life and spring surge and valvetrain harmonics. You will be amazed at the dance and motion that all of your valvetrain goes through and what the springs have to live through with each revolution.

Look at the words of Jay very closely. Also be sure that your valve springs are being lubricated.

The Nextec spring name is starTING TO BECOME A BUZZWORD IN RACING CIRCLES.
All Nextec is is the word or name that Manley is now calling all of their valve springs. There is no Nextec Spring company.

By your words, I would immediately be buying and instalaing new springs and Try to get some springs better suited for your needs and then then installed by someone that can build a high rpm engine thaat can live. .180 off the coil bind is ridicoulas and geos way back in what was used to be done before we learned better.

Most valve springs used in the performance industry are made by one of four spring companies, no matter how many different names they stick on them.
Ed

[81 olds]

http://jarvisperformance.myriadfx.com/home.shtml
i know he has or can get used tit. valves if your looking into them

[1KWIK72]

I apreciate the replys at this point I am defenetly going to replace the springs Just with what and what installed height is the question. I have about 5 weekends worth of racing left before it all comes apart for freshening this winter. Interesting to note my engine guy thought about shimming the springs to gain some installed pressure because of the valve weight but I think we decided against it because of the open pressures. It would make more sense to get a spring more closley suited to the application wouldn't it? Any recomendations? my engine guy also uses Comps stuff is it any good? any particular part #s you guys would recommend. I will defenetly look into Ti valves for next season.

Thanks
Craig

[Jay Allen]

You need not fear the open pressure. It ain't that big.

The more and more I think about it, the added weight of the stainless valve and miles too far from coil bind is not good.

Listen to what you have been told. Trying to reinvent the wheel will lead to further frustration. Dude, you got 190 passes on the stuff as it sets. That isn't bad at all. I have customers that if they get 19 passes they are doing cartwheels. All you need are a few tweaks here and there. Don't do a wholesale changes.

[1KWIK72]

So you are saying for the time being get another set of the same springs and maybe shorten up the installed height some? Where would you set them up at?

Thanks
Craig

[Jay Allen]

I would set them up where I was .100" from c/b. And wherever that is, is.

[1KWIK72]

Interesting...... Tonight I pulled all the springs and added .060" shims under all the cups. That should bring the installed height to 1.940 I am going to verify that tommorow when my buddy who is getting me springs brings his height mic by. That will get me closer to the ideal open height. The interesting thing was I found 3 or 4 springs that the inner spring did not fit tight in the outer. A couple of them will actually fall out without any help. They all seem to be from the Intake side. I wonder could this be the early signs of the inner starting to fail? maybe due to the weird harmonics that have been suggested. Most of the other springs you have to push the inner out and it takes a pretty good amount of pressure to do so.

[Jay Allen]

I said earlier in this post. When a spring like these break, you need to change them all. If they are brand new and come apart in your hand, I would contact Manley. You are right, they need to fit snug. Not super tight, but snug.

[1KWIK72]

The springs that were loose were the old ones off the motor. The largest part of the broken inner also slides through the outer spring really easily. Must be they loosen up just before they break which means I had about 4 more ready to let loose. The new set of springs are going to be here today. The new ones all will be checked at the installed height for proper tension and to make sure they have a snug fit between the 2 springs before I assemble them.

[Ed-vancedEngines]

I suggest to make your installed ht to be that which is desired by you to be from coil bind plus max lift and add the amount of free spring travel desired as the margin of safety, instead of just blindly following the recommended installed ht that may not be what is correct for your particular engine. I also suggest that .100 between max lift and coil bind to be the farthest or loosest clearance it an be. I set them up much much closer but I also take a lot of time to get them exact in what I am wanting to achieve.

Like Jay said. If you got 190 runs before that is really good. You might not get more runs with new spring setup but you could get better valve and spring control.

AS long as your seat pressure does not exceed the capability of your lifter there is no negative to more seat pressure. You would not believe what I set up.
Ed

[1KWIK72]

Well I got the new springs they all checked out at 295-300lbs @ 1.940" The old ones we checked at the original installed height of 2.000" the used springs where the inner spring was still tight were all around 245lbs about 5lbs less than the "advertised" pressure. The springs where the inner was loose were a different story they were down to 225lbs. Also interesting there was a big sticker inside the box basically saying what was mentioned above. That running the spring at less than .050" of the listed open height (1.150" in this case) would cause spring surge. Well as the heads came set up I was at about 1.250" on the intake and 1.300" on the exhaust. That is quite a bit under the 1.200" minimum open they recommend. We put a .060" shim in across the board and measured the actual installed heights they came in from 1.935" to 1.945" That should put me inside the spec that came with the springs on the intake and a touch outside on the exhausts. The bad spring and the ones that were loose all came off the intake side probably due to the heavier valve. While still not optimal I should be able to finish out the season with this setup. This winter I plan on getting this where it needs to be and probably switch to Ti intake valves and maybe a cam swap seems how everyone except my engine guy think it would make more power with a different cam. Thanks for the input I dont want to make the same mistakes twice.

Craig

[Jay Allen]

I'm happy for you.

There is always a better cam. Feedback from an engine allows you to always go forward. Your engine guy should not be so closed minded. I make improvements to my junk all of the time because of the FEEDBACK I get.

Most guys only think that running a spring too hard will hurt them. Running them too soft is just as bad.

Lastly, please don't take offense to this. 190 runs with a 2.180" steel valve and .782" lift is awesome. I can understand to want more. But dude, those parts served you well!

I wish you well.

[Chris Uratchko]

And if you really want to get tight you could use your valvetrain compliancy as a factor in determining your spring setup.

In other words, calculations say your lift is .780, but in reality with compliancy, tolerancs, etc you end up .740 with the real valve spring.

[1KWIK72]

Yeah Chris I figured "real world" lift about .750 on the intake and .700 on the exhaust. Given advertised lift is .782 .736 and lash is .026 .028 and a bit for deflection. I know this stuff moves around but exactly how much? I know it has to be some because back when I put it together once we got it all set up with the "real" springs on it and the new pistons P to V ended up being alot more than we had thought we would have. And Jay yeah I realize that many passes is good on this stuff it just kind of sucks to have to do this so close to the end of racing season. This is by far the most radical engine I have owned so I am in uncharted waters as far as component life. The next question is how long will the lifters last....... DOhhhhhhhhhh!

[MRE]

A related question for you Jay. How do you suggest setting the installed heights in a situation where there is significantly more lift on the intake than exhaust. For instance, if there's .150 more lift on the intake and I set the intakes up .080 from coil bind, I'd have to have .150 worth of shims on the exhaust in order to be the same distance from bind. The exhaust seat pressure would be sky high. I'm thinking it's common to set the exhausts further from bind, is that right?

[383Malibu]

Yeah Chris I figured "real world" lift about .750 on the intake and .700 on the exhaust. Given advertised lift is .782 .736 and lash is .026 .028 and a bit for deflection. I know this stuff moves around but exactly how much? ...I can't say for sure with your stuff, but we spent significant time with our last engine trying to nail this down and determined that we had over .040" deflection at full lift (1200# springs and 7/16" x .168" wall pushrods). BTW, using the measured lift, we set these springs up at ~ .050" from coil bind. Without any deflection we would be <.010" from coil bind.

[Chris Uratchko]

A related question for you Jay. How do you suggest setting the installed heights in a situation where there is significantly more lift on the intake than exhaust. For instance, if there's .150 more lift on the intake and I set the intakes up .080 from coil bind, I'd have to have .150 worth of shims on the exhaust in order to be the same distance from bind. The exhaust seat pressure would be sky high. I'm thinking it's common to set the exhausts further from bind, is that right?


That's where you have to decide whether it's more important to have the springs setup the way you want them, or if you are shooting for a seat number.... I tend to ignore the seat numbers... in this regard.

[Jay Allen]

Sorry, I was away.
That's where you have to decide whether it's more important to have the springs setup the way you want them, or if you are shooting for a seat number.... I tend to ignore the seat numbers... in this regard.
This is a good answer to the question asked above.

-OR-

You buy 2 sets of springs. You use 8 of them on the intake out of set 1 and you use 8 of them out of set 2. You then have a spring change at your hands.

But typically, I just ignore the seat pressure on the exhaust.

[1KWIK72]

Jay & Chris on a note related somwhat to this thread. I run this car in both heads up and bracket race every weekend. I have been running it in Mid Michigans Real street class and Martins True Street class both 10.00 indexes with great success. The car usually runs 9.70- 9.80s depending on the air. I may be in a position to throw some more cash at it this winter. I contemplated moving up to Super street at Mid Michigan. Do you think its possible to get this thing to run low 9s maybe a high 8 in decent air? With that in mind will it be a valvetrain eating machine? At this point this thing isn't low buck by any means but I am not independently wealthy either so i cant afford to rebuild this thing every weekend. I thought about switching to Alchohol that would probably get me at least part way there. Jay is a cam designed differently to run Alky? I understand it makes a lot more tourqe than gasoline. This is a small tired stock suspension car so there are limits there too. How do you guys approch somthing like this? Build a motor/cam with it set on kill and work the chassis out later or do you work around the aplication even if you may be leaving somthing on the table? More or less I am looking for opinions on what direction to go with this car. I love running the heads up stuff but it either isn't competative or dosen't fit the rules to run alot of the races. I fill in bracket racing it on the off weekends which I enjoy but because the car is reasonably high powered and has stock suspension it isnt the most consistant car out there. Hell maybe I need to build another car lol

Craig

[Jay Allen]

The faster you go, the more money you'll spend.

To jump from 9.80's to say 9.10's a major step. Not a simple cam change and alcohol will do that. That's pretty serious. An alcohol cam will be totally different than a gas cam.

It has been my approach that you get the power. The engine. You make it what you are able to build (financially). Once you have the power, then you go to work on the car. I have seen far too many guys get the car right. It works awesome. Its hooks to beat all get out. Put a decent engine in and it spins for days. They then have to start over. So the money spent the first time was wasted.

I think you REALLY need to think about what you want to do!

Good Luck on your decision.

[1KWIK72]

Thanks Jay, the cam that is in there now was supposed to help the thing not blow the tires off as was the converter. It does the job and it doesn't seem to be lacking too bad in the power department. That said I am considering making changes to the motor that are not that kind of compramise. Then maybe I may just change the rear suspension on the car too. I don't know I am just kind of kicking ideas around right now I like to go into things with a "plan" so the budget doesn't get blown way over. I am just in info gathering mode now looking for ideas. I apreciate your input and if I nail down what I am doing I may give ya a call about a cam.

Thanks
Craig

[John Wilson]

Craig, if you don't mind, could you list the basics of the motor & car combo??

Thanks,

John.

[1KWIK72]

Sure,
Dart little M block 4.155" bore 9.000" Deck height (0.0" Deck height)
Custom Diamond pistons small dome, big valve reliefs lateraly gas ported .043 back cut top ring .043" second ring and 3mm low tension oil ring. 14:1 actual compression ratio, 6" Eagle H beam rods Cola 3.75" 4340 crank Comp Cams custom roller (lobe specs at the top of this post) ground on a 109 lobe sep installed @ 105.5 intake centerline. Comp roller lifters w ofset intake, Trend 3/8 pushrods BMF CNC ported 18* heads 268cc http://www.bmfracing.com/sbc_flow_268.htm
http://www.bmfracing.com/sbc_spec_268.htm
Heads were milled to 52cc chambers. Edelbrock/Glidden intake with dominator flange, 1050hp dominator Jesel shaft rockers 1.7 intake 1.6 exhaust 2" Hedman hustler headers w 3.5" collector

[John Wilson]

Craig, thanks for the info! I'm running a somewhat similar combo (4" stroke) with a 4150 intake. I have a Vic-Glid 4500 intake to try down the road. What's the race weight?

[1KWIK72]

Depending on the fuel load usually around 3180 car is a stock suspension (Cal Tracks) 72 Nova with a th400 and a 4.22 rear gear 28x10.5 slick