Need valve spring recommendations for a stock 428CJ

[ERA427]

I've got a snapped valve spring on my 428CJ and need suggestions for a replacement set of springs. The motor was rebuilt in 1995 by the previous owner, but I believe it to be totally stock from the rebuild sheet. FoMoCo block, heads and PI Manifold.

So any recommendations on what springs to buy?

I also have a bent pushrod so I'm going to change those out too. Is there anything specific worth looking for with those, or is it just about getting the length right? Any thoughts or experiences?

I have the stock rockers and stock hydraulic lifters. My 428 is 1969 or 70 (not 100% sure as the date code is.

Any opinions? Please?

[patrickt]

Originally Posted by ERA427

Any opinions? Please?

Do you just have a relatively stock hydraulic flat tappet cam in there? Those springs are not relatively stiff, and they don't commonly break for no reason. Were you doing anything unusual or did you hear any funny noises before it broke?

[ERA427]

I didn't specifically notice it when it happened. I was driving around town. I don't think I over-revved it, but that's the only idea I can come up with. I've heard others online say that the stock 428 springs were junk, but I don't know.

The engine still runs, abeit rougher. I believe the lifters and cam to be original to the engine.

I have a bent pusrod and broken spring on the the intake valve. I haven't pulled the heads but have done everything else I could to try to deduce that nothing else is damaged.

So... what could have broken the spring? I'm pretty stumped on this. I never heard a big clink or bang when driving. It was more as I pulled into my garage it occured to me that it didn't sound as smooth as when I left.

If you have any suggestions of what else to look for, please help. The valve itself seems to be okay. I pressurized the cylinder with an air compressor, and it seemed to seat properly and seal.

The engine has been rock solid for the 4 years I've had it.

[patrickt]

Well, if it were me, if the valve isn't bent then I'd just chalk it up to the spring being, maybe, damaged a little bit during installation and it shortened its life span somehow. I'd just replace the pushrod and replace that one spring with the same type as the others (probably single -- and don't be fooled by the damper inside the spring that looks like a second spring). I think the Comp numbers for that spring are 981-16, but maybe you have dual springs in there. But, regardless, you have to measure them to make sure they fit. A step up from the "only fix what is broke" method is to replace all 16, which is a PITA when the heads are still on there.

[blykins]

Are you running stock retainers as well?

[Ron61]

Your motor should have double valve springs in it if it is stock. My 1969 Cobra with the 428 SCJ had them and I ran it hard and for over 10 years with no spring trouble. If it is stock then you should be able to contact Ford and find out what springs you need. I have since changed my cam and springs as I tried to keep up with the crap they call gas out here. But the stock setup would push the car to well over the 120 mark.

Ron

[patrickt]

The problem is that "The motor was rebuilt in 1995 by the previous owner, but I believe it to be...." When somebody does that, unless you have the parts in your hand, you really have no idea what he put in there. It could have been single springs, dual, triple, beehive, or coiled up paper clips for all we know. But, presumably, the rocker shaft is now off, and rope, or something, is jammed in the cylinder through the spark plug hole so he can now easily, and safely, inspect the broken spring, and maybe post some pics. Blykins' eye might spot something funky on the picture that would tip him off as to why it fell apart. I would just take the spring off the other valve in that cylinder and measure it and I bet somebody on the FE forum will most likely just send him a matching spring. It wouldn't surprise me though if some nice sharp pics of the broken spring/retainer/rocker might not show something to the trained eyes we have around here. And, if it doesn't, well then, "it was just one of those things...."

[ERA427]

Here is a pic of the broken spring and you can see the hole where I pulled the pushrod.

[patrickt]

Originally Posted by ERA427

Here is a pic of the broken spring and you can see the hole where I pulled the pushrod.

Yep, the spring is broken and the pushrod is gone. I can not tell clearly from your picture, but the little shiny thing that is just above the broken coil looks to me more like the flat, "slinky-like" dampers that go in there, as opposed to a second spring. But I can't be sure.

[patrickt]

What is the little imperfection-looking-mark that my yellow arrow points to? What does it look like in real life? Is it just an optical illusion of some sort?

[ERA427]

Patrick - not sure what you are pointing to - your picture didn't come through. Interesting to know what you're seeing.

[ERA427]

BTW - on the 1995 rebuild. I spoke to the guy who did it, and he recalled that it was log mileage engine - from a car that had crashed years before (he didn't remember what). He said it was and original cobra jet (the codes all support this), and that he "didn't have to do much to it." I think it was just main bearings and some other small part - perhaps piston rings. I have a bit of documentation on it, but he never said anything about having changed the cam, lifters, valves, springs, seats, etc. (I don't know that he rebuilt it to run on unleaded gas).

[PeteF]

There are no adjustment nuts on the stock rockers? Not necessary with hydraulic cam? Could a worn cam lobe or the broken spring have allowed the pushrod to pop out enough to bind on the rocker and bend?

[ERA427]

Originally Posted by PeteF

There are no adjustment nuts on the stock rockers? Not necessary with hydraulic cam? Could a worn cam lobe or the broken spring have allowed the pushrod to pop out enough to bind on the rocker and bend?

I think it must have been something like that. Because i have a broken spring, I'm inclined to thing that this happened first, then released the pressure on the pushrod, which let it jump out of it's cup in the rocker and got bent.

there is no obvious damage to the rocker from my untrained eye.

[byron w]

ERA427, what I think you have is a outer spring with damper. You can get a new spring just about anywhere for that engine. As long as it installed at 1.82 height you will never notice a difference in spring pressure with a stock cam. The original ford number for the spring is C8AZ-6513-B if you are looking on e-bay but it is not a requirement to be a ford spring. As long as the engine is running fairly well I would just change the spring and push rod. Oh yes, change the oil and filter to help make sure nothing got in the pan.

[55312]

I was breaking valve springs in my 427 center oiler 10 years ago and talked to George Anderson at Gessford Machine. He had me send in the spring(s), retainer and the "spring cup". He looked it over and sent me a set of Comp springs and cups. They worked flawless until Keith Craft replaced everything when he rebuilt the engine a few years ago. Brent might help you out or call Gessford Machine. Being hydraulic rather than solid lifters should make the selection a lot easier.

Tim

[patrickt]

This looks like a lovely valve spring compressor.
Buxton Engineering, Inc. - On Head Valve Spring Compressor

[patrickt]

But since you've got stock rockers, this would do the trick quite nicely:

[Texasdoc]

Ahhh, yes. Mysterious broken spring.

If you are going to do it, make sure you get it right. See if you can get it in five pieces.

[ERA427]

Thanks everyone. I think this gives me the right plan:
- stuff cylinder with rope to keep from losing valve
- remove broken spring with tool I need to buy
- Inspect spring further for evidence of cause
- remove other spring on same cylinder to measure pushrod and buy replacement
- confirm new spring and rod are exact matches
- install
- change oil and filter
- cross fingers
- crank motor
- check compression
- look listen learn
- let it start