Valve Spring Selection

[cr_bobcat]

I'm slowing getting into rebuilding this C9 head and want to upgrade the guts, so to speak. For right now, I'm going to stick with stock valves as it saves me the price of machining and lets me spend elsewhere until I decide whether or not I'll eventually migrate to the CI head. I was considering upgrading the springs though. I've been through the CI literature a few times, and because I'm an engineer (albeit electrical) I like to putz around with stuff.

I've been digging through the specs on the lifters that CI has listed, the stock springs, and playing around on ye olde interwebs. Now I have a copy of the da Falcon book, unfortunately it has disappeared as my wife is rearranging things since the baby is due in a few weeks.... Anyway, I know that some 289/302 springs have been used so I've looked at a number of different p/n for these. I also noticed that CI sells what I'm assuming to be a Toyota spring, this just a guess based upon what they call the part numbers. So that got me thinking to just head out to Summit and Jegs and dig around.

Based upon the CI spec information, I see that the OEM outer diameter is 1.355", free height of 1.795", open height 1.22", closed height 1.585" with the pressure being 52/152. I started looking for something that had a similar O.D. so that I could avoid having to machine the spring seats. The most interesting dual-spring that I found was this guy:

http://www.camshaftwarehouse.com/Produc ... 8-16-.aspx

This thing has in O.D. = 1.384", I.D. = 0.804", Seat Load 117lb@1.600", and Open Load 232@1.100". First issue I see is that there no clearance for a standard umbrella seal with an O.D. of 0.81". Minor issue as I should be able to find a narrower option there.

The thing I don't fully understand is whether or not this will blow a lobe on me because of pressure. I wasn't planning on replacing the camshaft right now, but my intention was to go with the split camshaft that CI sells (264/274, 110*). Am I in danger of blowing out the old cam? I'm not 100% sure that I don't already have a bad lifter on #3? I would check but it's a pain in the ass to get my valve cover off because of the Monte Carlo bar that I have installed between the shock towers.

I mostly tried to understand O.D., I.D., and seat pressure. I can calculate the seat pressure once I find out what the actual install height is and the same with the load pressure based upon the camshaft lift and associated valve train geometry. Right now I plan on re-using the standard 1.5 non-adjustable train that came off of the thing. Unless I find something on ebay or craigslist, the cost of an adjustable valve train is potentially more then what I would spend on headers, which I would like to get here in the nearterm as well.

And a final thought, can I get away with my old retainers? I assume retainers "should" be ok as long as they sufficiently mate with the springs. I'll probably have to measure that too...

So am I all whacked out on goofballs here? Is my understanding of how this works remotely close? Have I covered everything?

Prost!

 

[cr_bobcat]

Oh, if I do migrate to the aluminum head, I intend to re-use the springs I put on this guy. I'd rather not buy twice.

 

[CZLN6]

howdy Prost:

I always enjoy a mind adventure. I have a couple of thoughts for you. In general, don't use anymore spring pressure than required to control the valve train through it's complete range. For most street use with a stock to mild performance cam is to assess the stock springs with a plan to reuse. Stock springs in good condition, shimmed .030" and used along with retainers from a ford 4.0 V6 and an adjustable rocker arm assembly are adequate for most applications. the 4.0 retainers are lighter then stock, two piece retainers.

Buying high pressure springs that you might someday need doesn't make much sense to me. They will increase wear with no performance advantage. A stack of shims is a few dollars, the 4.0 retainers a few more and you could live with the Non-adjustable rocker assembly, but adjustability would allow you to get the most out of your stock cam. Keep an eye out in the classified sections and keep scouring the swap meets.

We've used the 302 exhaust valve springs as well with good results with a 260 performance cam. Be sure to check valve stem seals for clearance with any cam with composite lifts of .400" plus.

Keep us posted on your progress.

Adios, David

 

[cr_bobcat]

Thanks David, makes sense. I was wondering if the increase in seat pressure was worth it. I do want to try to pull a few more RPM out of this guy. And maybe 30 thou of shim will get me sufficient pressure for what is basically a cruiser. And saving the dough for later is attractive.

Out of curiosity, is it purely a metallurgy thing with the spring pressure? For 1, I'm not intending to install hardened seats, so keeping the seat pressure to a reasonable level would seem prudent. This is one big science experiment to me. I just wasn't sure what the tradeoff was between shimming springs vs. Replacing with something a little stouter.

My example of the dual spring was entirely because of my desire to go with the split profile cam in the future. I was trying to "future-proof" as much as makes sense. I don't really have the ambition to pull the radiator again since i went through that last winter. And since i managed to get the front of the engine done without causing any leaks (new chain, water pump, and dampener) I don't want to tempt fate and try to replace that cam. I also am halfway through rebuilding a hot-swap C4. So i have plenty on my plate.

I do need to purchase new springs as what i do have are tired. There are some very economical 5.0 springs out there, but i would like to avoid purchasing a valve spring seat cutter. But let's face it, the cutter is maybe $60 and if i end up doing another head (i have 3 so odds are good), it'll pay for itself. And given the chance, I'll blow my budget buying tools because that is just how i am....

Prost!

 

[CZLN6]

howdy:

Hummm. What makes you say that your stock springs are shot? You are right, heavier springs will hasten sinking the valve seats.

Tell me about the C4 you are building. What rear end ratio are you using?

Adios, David

 

[cr_bobcat]

I haven't checked the spring tension. I'm basing that assumption on the sorry state of the valves and pushrods out of the donor engine. The guy wanted $200 total for the 250 and mated C4. Looks like the previous owner rode it like a rented mule.

The C4 is a 24/26 spline. Was hoping for a 26/26 since the donor car was a 71 Mustang, but the casting number turned out to be a D0 Fluid was rather rancid but think all the internals are in pretty good shape. He did whack the side of it with the sawzall when cutting it out, but i think it's still ok. Was going to take the case to a shop in town and ask one of the techs what they think. Hoping they can run it through their cleaner too so that i can get it all painted up nice. Considering throwing a shift kit in there too but i have some time to figure that out. Valve goes in last anyway....

This is my first attempt to ever work on a transmission but everyone I've talked to has said the C4 is about à easy as they come so i figured I'd give it a go...

Not sure what my rear end ratio is. I've owned the car for 20 yrs and the speedo has always been ~20% low. Not sure if that is from the speedo gear, rear ratio, and/or tire size. I really just need to jack the rear end up spin the tires and count driveshaft rotation.

So yeah, I've read a lot, now it's time to execute

 

[CZLN6]

Howdy Back:

It's cheaper to check the springs for tension than it is to replace unnecessarily. The old springs may be worth something to someone else too, so consider.

What year is the 260? On the core 250 check the ball tips of the front pushrods. They are the last place to get oil and a poorly maintained engine sludges up in the rocker arm shaft quickly. IF the tip is not round and shiny it will have a knob or a mohawk worn into it. Will need to be replaced.

On the C4, I have no experience rebuilding. I farm that part out, but good luck. I like a shift kit in a C4 too. You will need to know your rear end ratio when it comes time to select a cam.

Adios, David

 

[cr_bobcat]

I managed to find everything for less than $80 for brand new gear. The only part I have run down yet are the lighter retainers. I assume I can utilize the same keepers...

I'll have to double check on the 250. That block is still at the previous owner's house as I haven't had time to round someone up to help me bring it home. I think it was a D0 but I can't find where I wrote that stuff all down.

This is what the valves looked like coming out of the worst case cylinder. I'd have to go look to see which cylinder it was again. I stabbed 'em through a piece of cardboard in the order they came out so I do at least have that information. As you can see, they're kind of nasty. This thing could not have been running very well when pulled....

http://i1361.photobucket.com/albums/r67 ... 1421594467

I hadn't thought about the cam selection and its relationship to the rear end ratio. Is there a magic formula or anything that will give you a guideline on where the sweet spot is?

 

[cr_bobcat]

I should mention that I do plan on doing the direct mount 2V conversion with this head as well. Just not quite ready for that mod to happen yet since I don't have the carb. Keeping my eye out for one. No point in buying the adapter plate until I know what I'm gettin...

 

[bubba22349]

From your pictures looks like you need to check if the valve guide clearance is excessive on exhaust. Good luck

 

[cr_bobcat]

Yeah. I premptively got some new valve guides. Good old RockAuto had some brass ones for $0.88 a piece on closeout. I bought the last 13 based on what I saw when I pulled those valves. I just have to figure out exactly how to measure the play in the existing ones.

I might be crazy for thinking I can pull and replace the guides on my own though. I watched this on how to pull them. I don't know about the way he inserts them.

http://www.youtube.com/watch?v=iod2WuV1iYM

I would think heating the head, cooling the guides, and using a press would be a better route. Might just be in my best interest to just have that done for me and if it gets boogered up it's on someone else's nickle to fix it...

 

[bubba22349]

Good score on the guides! Well it all depends if the guides are still the stock original ones or if they have been replaced before. The originals are cast as part of the head and are therefore not removable as in your posted video. If that is the case they would need to be setup and leveled (front to back and side to side) on good drill press or mill etc. and bored out with the proper size reamer to provide for a slight interference fit. Now if the guides have been replaced before, you could drive them out with an air hammer, use a press, or pull them as in the video and then you could press in the new liners. Good luck

 

[cr_bobcat]

I'm glad I didn't go and try and pull those out yet then. I would've been sorely disappointed! I just assumed they were replaceable. I guess I'll just have to talk to my local shops once I get an idea of they're bad or not. I may not even be able to tell myself. We shall see, I suppose...

 

[bubba22349]

You can tell by feel rocking the valve stem in the guide sideways after you have did them enough times you can quickly feel how loose they are. Or you could measure your valve stems with a Mic or caliper and use a snap gauge in the guide then figure the clearance or difference between the two.

 

[cr_bobcat]

Well, all of the parts came in. Only disappointing thing was that i only got 6 sets of keepers. I ordered "12" keepers thinking i would get 12 pairs not 12 singles. Would have never imagined they would not come as pairs.... think I'll be making a call anyway.

Now i guess it's time to make a few measurements and see where i am on those valve guides. Then I'll start port matching and polishing the exhaust.

Is there any benefit to polishing valve faces? I can see the machining swirls and was just cycurious. I'm sure it's not going to give me any more juice but it's not like running a polishing wheel with my dremmel is going to cost me anything.

I did get 2 new head gaskets. They are Rol but we're only $9.98/piece. not sure what their crush thickness is but I'm guessing i will still probably want 20 thou or so removed. I was going to cc the head just to see for sure where i sit.

Feel like a kid in a candy store right now....

 

[Econoline]

I believe the Rol is identical to the Cortico, one company bought the other. I picked up one of those from Rock Auto as well a while back, just b/c they were $10 I'm going to be using 300 springs on my head, Comp Cams #903-12. I'll let the machinist sort out the installed height and measure the actual pressures.

What locks did you go with? I got some cheap ones from Comp, #600-12(full set), I hope they're adequate. Using them with the one piece CI retainers.

 

[cr_bobcat]

I just got some rockauto specials. Sealed Power VK144. Bone stock. Springs are stock but i got some 30 thou shims. Valves were on closeout too. Just staying stock for now. I'm considering as a min of going with a 2 bbl conversion but haven't ruled out tripower just yet. No purchase made on that front so far.

Right now I'm sticking with the stock retainers but considering my options yet...