Fitted a XE262H today and one heads valve springs. Problem is, I got these parts from an engine reconditioner and I think they're the LT1 spring and not the comp cams recomended spring. Will they be ok to use?

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84 Trans Am HO L69 WS6
5 Speed manual
Vortech Cherrybomb no cat
Removed A/C A.I.R. Hdflap
H/made cld air induction
K&N
Otherwise STD
Currently painting

 

best thing to do is find out what you have and not guess at it because it can and does make a big differance. i always run the cam grinders recommended springs or a similar spring. you ought to be able to have the springs tested to find out what they are. considering the cost for new springs i ithnk i'd just buy a set for my cam.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

What he said...

For as cheap as they are, valve springs can cause an unbelievable amount of damage. If there's any one part not to try to cut corners on, valve springs would be it.

Get the right ones. Don't fool around with stock ones for any kind of engine; get the Comp ones they recommend, or ones for similar cams from Crane or Lunati. Stay away from cheaper substitutes like K-motion. The small price difference just isn't worth the trouble they can create.

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"So many Mustangs, so little time..."
ICON Motorsports

 

RB

What is this warning that I keep hearing now and then about the K-Motion's?

I have a set on an engine that I purchased before hearing this.

 

They're OK as long as you knock about .050" off their "rated" lift... knowing the major cam mfrs as I do (personally), none of whom own spring winding machines and therefore buy them from someone in the world at large who does, I am positive that if there were springs available that would actually survive and not wipe out cams at those lifts, Comp and Lunati and Ultradyne (to name some of the ones I am particularly familiar with) would long since have found the source and would be packaging and rating them the same as K-motion does. K-motion doesn't make cams, and doesn't warranty cams, so they'll tell you whatever they think you want to hear to get you to buy their springs instead of the others.

Notice how none (and I do mean exactly none, quantity zero) of the cam mfrs. spec a 1.25" spring for lifts above .500". Pay attention to people's problems when they say their motor just won't rev; usually that's a valve spring problem, and usually they're running no-name or GM springs when they have that trouble.

IMHO valve springs are one of the most important parts of making an engine run the best it can. For as cheap as they are, even good ones, and as much trouble and expense they cause when they fail, it's a really bad place to try to cheap out a couple of coins.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Thanks RB!

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91 RS 5.0 TBI....LT4 cam....Edelbrock headers....3"Dynomax exhaust....5spd.... 3.08.....Ultimate tbi....afpr...ZR 255-50's...Koni's

 

RB

While on the subject of springs; what would be better for an endurance type engine for running a couple hours a day at open track road racing type events where the rev's are kept up at a higher level for a longer period of time.

A larger diameter spring?

 

Yes.

Ever bent a coat hanger back and forth until it breaks? That's exactly what valve springs are doing. They're getting bent every time the valve opens, and just like the coat hanger, they generate heat. When they heat up they lose their temper, which means their effectiveness goes away; and it doesn't come back when they cool back down. The metal they are made out of is permanently altered. Some amount of loss of pressure is actually normal, and the cam mfrs will tell you what their springs should check after some nominal number if use cycles. Do the cheapies tell you that?

If you took 2 springs, otherwise identical except that one of them is 1.25" diameter and the other is 1.45" diameter (the usual next step up for SBC), the smaller spring flexes about 16% more per unit length of its material than the larger one. And, there's 16% less material to spread that heat over. So it heats up as the square of the difference in diameter, or about 35% more. But... it also has 16% less surface area for the heat to escape out of the spring than the larger one does. So the actual running temperature increase over ambient (already the hottest place in the engine, the top of the heads) of the spring decreases with the cube of the spring diameter. That means that the smaller (1.25") spring has 56% greater temperature rise over ambient than the seemingly only modestly larger 1.45" one.

Just something to think about while you wonder if one is going to break like an overstressed coat hanger and drop the valve into the cylinder at 6000 RPM... don't forget, valve fragments are, for all practical purposes, incompressible...

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"So many Mustangs, so little time..."
ICON Motorsports

 

Thanks again RB83L69. Don't know where I'd be without your help. I did ask for the correct springs but the local reconditioners who sourced all the parts for me must have had a communication problem with the suppliers. I will try to get the correct ones tomorrow. Shame that in my enthusiasm I have already fitted one side before asking the question. Still, its worth doing right so out they come.

 

Thanks for the info RB!

Like you said; cheap insurance for peace of mind. I know what a 10/32 button head bolt does in the combustion chamber and I sure would not want to deal with a valve in there.

Getting higher lift ratings for the springs just got eazier too!

 

Danger,

Nobody covers it better than RB. In short, the LT1 springs would probably WORK with that cam, but aren't the best choice.

If you are cash-strapped, GMPP LT4 springs are a better choice at $50.00 (US) per set, but still require seat machining and still arent the greatest choice. If you're going that far, you might as well get the Comp recommended springs for a few coins more.

Please let me know how that cam works for you. That is the Comp grind number I have selected as the next step for my lowly 305 TeePee Eye when the time is right. I'd like to have your impressions.

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Later,
Vader
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If you want to beat the World, it might reach up and pull you down...
Adobe Acrobat Reader

 

Well I was told today that they were an LT1 spring but a heavier one than std, about 5pds lighter than the comp spring which is unavailable for 2 weeks. I have little option but to use them now.
It will be awhile before I get to try this cam as I still have all the body work and paint ahead of me.
Now I have to get a transporter to take the car to the muffler shop to fabricate a Y pipe for my new headers. They didn't want to make them off the plan I created.

 

Vader

What year TPI do you have?