[ss3966]

My engine is in the machine shop, and the machinist asked me what I wanted to do with the valvesprings - he said he would of course them. The springs are Manley 22441-16 and have 2.5 seasons of bracket racing in the mid-10's car in the signature, and some street driving.

I had a custom set of pistons made (with Wolfplace's help) that only have a .060 valve pocket on the intake and had .050 clearance above the piston face, or a total of .110 clearance. The heads had to be milled .015, so no clearance is down to .095 piston/valve. I went with the small valve pocket avoid burning the edges of the piston again if my tune goes lean. The valve springs won't have more than 10 lbs of boost to hold back. The valve springs were set at 150 lbs last time, but I don't know the installed height.

The cam is a Comp Cams SFT 11-405-5 with .605/.612 255/266, 114 and am using the identical grind again. I woiuld like to know if these valve springs should be changed just due to their age/use or if they check out alright I can save the $200 on a full rebuild which promises to go to about $3500 assembling it myself. I upgraded to series 2000 rod bolts, etc.

The rest of the motor is fresh - does it need another $200; I'm not looking so forward to picking it up at the machine shop right now but sometimes you can't cheap out on important parts.

 

[Orr89rocz]

Do the springs still check out pressure wise when tested? Good insurance is to replace them..but if they still have good pressure they may still be ok

 

[Mike]

2.5 seasons of bracket racing in the mid-10's car

As your doing a refresh ,now would be a good time.

 

[ss3966]

Now is not the time to cheap out, even though cost estimates keep climbing and climbing, mostly due my strength and reliability upgrades. I spoke to the fellow who did the heads - Gary at Colorado Custom Cylinder Heads. He said the valve springs are usually done at 175 to 200 passes.

Ive run in two classes for 2.5 years with some success, lots of test and tunes and I"m sure there are hundreds of passes on the motor. I wasn't aware they just wore out. Years ago another machinist told me that OEM springs, anyway, just don't go bad. That was for a street motor though.

Maybe I"m dodging my next educational opportunity, so to speak. Thanks for the replies.

 

[camaroman7d]

I would replace them. It's a lot easier to do right now while the engine is apart. $200 is nothing when you add it into the rest of the costs.

 

[ss3966]

I'm going to replace the springs. As camaroman points out, there is no additional labor if its done now. I"ve never replaced my own valvesprings on the motor, and dont own a valve micrometer. The shallow valve pockets are also a consideration.

Just need to get the motor out of the machine shop before I think of something else it needs.

 

[forcd ind]

def time to replace them, on a FT cam, esp that one, you dont want the lifters bouncing off the cam (not that they would prob do that, lol)
i have used that cam before on a 671, curious if your gonna run EDM lifters on it when you replace it

 

[ss3966]

Yes, I am going to use the EDM lifters; I've been using these since getting away from the hydraulic blower cam/lifters that I kept having to pull pieces out of the oil pan of. There is something to be said for lifter valley screens.

I also have the edge below the lifter face (depending on how you view it) chamfered at the machine shop at they were cutting into the bronze bushings in the lifter bores. Costs $4 per lifter, but keeps the oil pressure from dropping and the lifters aren't stuck in the bores the next time.

The block is from an LS-6 crate motor from the late 80's, so I saved it by doing the bronze lifter bores. Think the lifter bore problem started after an overheating incident 10 years ago or so when I drove down an 11,000 ft. pass without anti-freeze when the radiator cap lifted just as I crested the pass and got no high temperature reading as there was no coolant to read. A long overflow hose helped the coolant to discharge without my even knowing it. Think the bronze bushings were $500 or so, but anti-freeze/water at the right time would have been alot cheaper.

 

[Tom Mobley]

you have about 3.75 sq in of valve area, so at 10lbs boost it would be like having a 37lb lighter spring than what you really have. Might want to bump up the spring a little if you're going to hitting it with 10lbs boost.

[EDIT] that's figuring a 2.19 valve, if you have a larger valve you can figure it by this formula: diameter x diameter x .7854 x boost in lbs per sq in. to get a general idea.

 

[ss3966]

Appreciate the comment on the additional pressure on the intake valves - they are 2.19 valves, and I do have the tighter piston to valve clearance now.

I can say this valve train worked the last few seasons with the 150 lbs, but the p/v clearance wasn't at tite as it is now, with the reduced valve pocket. I will mention this to the machinist - though he may be getting tired of my afterthoughts - but he does know its a blower mother.

I read him the 150 lb. spec off the workorder and Manley spring number from the different shop that did the heads in summer, 2008. He may not consider it beyond that spec as I provided it, and so much of this has become about fianancial liability. Thus it would be on me, as I provided the spec. I will ask him if 150lbs sounds sufficient, in light of the small valve pocket, and remind that its a blower motor.

Thanks for the heads up.

 

[forcd ind]

i ran a lot more boost than that on the same cam, i dont believe it affects the valves like some people think-now 25-30 lbs it might-i have had 20-25 blower cars, just have not seen problems with the valves/springs
if you go upping the spring pressure on a flat tappet, well, figure it out, lol

 

[ss3966]

I bounced the spring pressure past the machinist also - his belief is also that if the spring pressure is increased, I risk having a bad cam break-in, without removing the inner springs - which means going through the Jesel set up again.

As I have broken in this same cam grind with these springs at this spring pressure - with inner and outer springs, I think I'll leave it as it was and do the same again. Never had any valve float issues at my boost pressures.

Its only the tighter P/V clearance that makes me squeemish, and I'll just have to get over that. Some had said having just .050 P/V with no valve relief at all was enough, on the intake side. I had a relief cut .060 anyway for .110 total clearance, then the heads had to be milled .015, so back to .095. Need to double check it on assembly, but the compression height is the same 1.270 on the flattops.

Good to have other huffer operators on the forum, too.

 

[camaroman7d]

Pretty risky breaking in the cam with full spring pressure.

Why are you concerned with the reduced P-V clearance? You said you didn't have any valve control issues before. As long as all the parts are where they are supposed to be when they are supposed to be there no reason to worry.

 

[ss3966]

Probably not a point of pride - breaking cams in with full spring pressure and something I should likely keep to oneself to keep from influencing newbies. Would make an interesting thread - what percentage of people assemble their valvetrain twice at start-up? The cam manufactures probably have to assume the cams will get full spring pressure as they can't verify how it was broken in, yet get the customer complaints anyway.

I have broken in a dozen or so flat tappets that way and may have just been lucky. Use of Moly, EOS, etc. More radical cams would be a different animal.

The concern with P/V clearance is something like timing chain stretch, as I don't know how it affects clearance, on the intake side. The Cloyes double-rollers don't seem to stretch much, checked seasons later, though.
Just don't like the valve reliefs on BBC's that go nearly to the top compression ring and are a problem waiting to happen if you go lean on the tune as I did when the ground on my methanol injection failed, but the motor was tired and ready for refreshing. Now have a timing retard that activates if methanol flow falls off, but haven't tested it installed yet.

I haven't bought it in years, but think 110 is $10 gal now at the local track, and I do some street driving too.