I've been looking at relatively low-cost performance mods recently. As some of you recall I had just posted about TPI Runners. I wanted to ask about valve springs now...since they arent too expensive(i think) and are relatively easy to install. I have a Crane Cams cam/lifter set(see sig for specs)....was wondering what springs I should get? Crane Cams makes valve springs, and was wondering if I should go with them or another company. I'd also like to know what kind o power increase I would see with the springs done and if I should do anything else like pushrods? I'd really like to avoid taking off the intake again.

Like i said....just want to venture into a couple more minor mods that will give me some extra kick from this 305...she's got 155k on her now, but all the mods listed in my sig were done over the summer, about 10k miles ago...including the timing chain. *NOTE* I plan to also put on a set of Hooker 2055's within the next couple months.

Suggestions?

 

You can call up Crane and ask their cam help dept what springs will go with that cam, or you can pick up a set of z28 springs. The crane springs/retainers will probably set you back at least $80. A set of z28 springs/retainers will run about half that. If you're running the stock springs in there now, I would at least pick up the z28 springs. Even though the cam in it has a pretty low lift (.401/.423) I wouldn't trust the stock springs, let alone stock springs with 155k on them. You don't really need pushrods, unless one is bent (unlikely). The stock ones are fine until you get to higher lift cams with more aggressive ramp rates that require strong springs. The valvesprings might gain you 15hp, so it's not going to be a SOTP difference, but new springs will be able to control the valve much better.

 

do Z28 springs require enlarging the spring seat?

how much lift are they good for?

 

Thanks, sounds good. I will call up Crane and ask them. But in all honest opinion, with my mods now and the mods comming(headers, siamesed runners) would these springs (aside from not trusting them stock ones) be worth the hp gain?

 

YOU WOULD ONLY REALIZE A GAIN IF YOU ARE SUFFERING FROM VALVE FLOAT, WHICH IS ENTIRELY POSSIBLE WITH HIGH MILEAGE, FACTORY SPRINGS. YOU SHOULD ALWAYS MATCH YOUR SPRINGS TO THE CAM YOU ARE RUNNING. ALSO, THE MONEY SPENT ON SPRINGS IS FAR LESS THAN THE EXPENSE YOU WILL INCUR IF YOU DROP A VALVE.

 

I agree with what you said in the last sentance. I just want to make sure that by doing this, I will see some sort of gain in hp/tq. All i'm looking is for a bit more power...reliability is also important but at the same time, so is power.

 

YOU WON'T SEE A GAIN FOR SURE...... VALVE SPRINGS DO NOT MAKE HORSEPOWER, BUT THEY CAN COST YOU POWER IF THEY FLOAT. I CAN APPRECIATE YOUR QUEST FOR MORE POWER, BUT THE ONLY WAY THAT NEW SPRINGS ARE GOING TO MAKE MORE POWER IS IF YOUR OLD ONES ARE NOT DOING THEIR JOB CORRECTLY.

 

In all honesty, is it worth changing them then? I mean, as far as i know, the springs in that 305 came with the 305. 155k later, still holding up(to the best of my knowledge). It it worth the investment? That is the final question. Thanks for the input.

*EDIT* - What does the "floating" of the valve springs mean? Pardon the uneducation on the term.

 

Valve float happens when the valvespring can no longer control the valve. Instead of following the countour of the cam lobe, the lifter actually jumps up off the cam and "floats" in mid air until the valvesprings finally regains control of the valve and pushes the lifter back to the cam lobe. This can happen with hydraulic lifters when they are run at too high of an rpm (new ones can be run to 6.5-7k until they float, assuming good springs of course), or it also happens when a valvespring is too weak, whether it be the tension was not correct (for the cam) when the springs were purchased, or from fatigue.

I think you're missing the point here. You NEED NEW SPRINGS! Period. The stock ones cannot be trusted, it is a fact. Your motor can be damaged easily without them, and the outcome would be much, much more exspensive than new springs/retainers. The stockers will eventually break, in which case you'll drop a valve and possibly ruin the whole motor. You can also have valve damage if it floats as well. If they float, they can hit the piston travelling up which in turn will bend the valve which screws up the seats which will put more stress on the whole valvetrain and eventually some part of the valvetrain will fail, which will take out something with it. Motor parts don't go by themselves, they generally take something else with it, and that part is usually exspensive.

So to sum it all up, for reliabilities sake you need new springs. Performance wise you might gain a few ponies by controlling the valve, but it won't be a noticeable difference. In a street motor like this, valvesprings don't make power. In a race motor it's a different story. They are one part of the package.

llvll4l2c91350, the z28 springs can be had in 2 different rates. One is good for .550" lift, the other is good to .600" lift (IIRC). The first ones are generally used with hydraulic flat tappet cams and small solid flat tappet cams. The bigger ones are used for solid cams or really big hydrualic ones. For the .550" ones, the spring pocket does not need to be enlarged. They will drop right in. I'm not sure about the .600" lift ones though, but I think they fit in the stock diameter.

I would like to say though, these are not high quality springs. I would not use them in a race motor. However, they work great in street motors. Race and serious street/strip cars should use a good spring from Comp, Crane, K-motion, or any of the other big name manufactuers.

 

I see the point now. Good thing i started asking about it NOW instead of later, b/c its my day off and I was just thinking what else I could upgrade on the 305 before i go and build a serious 350 maybe a year from now. Thanks for clearing it all up for me, I really appreciate it. I'm going to get in touch with Crane Cams and ask them what set of springs they reccomend. Thanks again.

*EDIT* -forgive the ignorance, but the springs and retainers come as ONE right? Not two seperate parts.

 

No problem. Springs and retainers are usually sold seperately unless they are sold in a kit, then it's usually springs, retainers and locks.

 

I just looked through a Jegs catalog of mine....they have the Crane Cams spring & retainers as a kit....I just need to call and find out which kit is for me. Thanks again.

 

One more quick question.....is it really difficult to replace the valve springs?

 

Nope, real easy to do. Pull the PCV and breathers off the valve covers, then pull the covers. Once they are off you'll have access to the springs. You'll need to get a stud mounted spring compressor and an air chuck to put in the spark plug hole to hold the valves up on the cylinder you're working on. Then you mount the compressor on the stud, compress the spring and pull the keepers out (handy to use a magnet to pull them out, also put rags around the oil drainback holes so they don't drop down there) then uncompress the spring, pull off the retainer, and pull the spring out. Installing them is just the opposite. Make sure to use the air chuck to hold the valves up, otherwise you could drop one down into the cylinder.

 

what about those spring compressors i see at sears that look like a long angled flat piece of metal. how do they work?

 

Thanks for the information, its a great help. I will print this so i can follow the procedure.

 

kfoley - Thanks for the info on swapping valve springs!

Phantom TPI - Definately take his advice on swapping springs. I learned the hard way on a prior cam swap. After changing the cam, a stock valvespring (130,000 miles) actually cracked, a piece broke off and was never found. It destroyed my new cam and lifter set! I lost out bigtime, 2 cam swaps, 2 sets of lifters and one new set of valve springs, not to mention the maintenance hours!!!

 

Yep, that's the kind you need.

If you would like more detailed, step by step instructions just let me know. I have the day off tomorrow so I could whip up a little tech article and snap some pics.

 

I am......I dont want to end up blowing anything up before I am ready to do my 350 buildup.

 

that would be good. im not ready to do anything with valves just yet but i do have a motor ready to come out and get disassembled. i can print your article and save it.

 

Alright, I'll work on it this weekend.