Technical Engine builders: Why is my new 322 breaking rockers?

I must have misunderstood. I don't see how you can check for coil bind using a test spring. Actual observation is the sure way to find the interference. IMHO.

 

I agree with a physical test, versus math or especially trying to figure in a supposed ratio.


But like I asked before: This cam shows more lift on exhaust, so why has it also broken an intake rocker, before breaking ALL the exhausts, "IF" the springs and retainers and stem lenghts are same on intake vs. exhaust? That part does not make sense to me, as far as guaranteeing that this breakage is "only" due to coil bind.

Any opinions on this train of thought?
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I think you did, the way I read it, hes suggesting using a test spring while confirming the rocker ratio, not to check for coil bind...
I think we are kind of getting astray here, several posts back, I suggested checking the spring in a vise for coil bind, as a way to eliminate lifter bleed-down as a factor. The OP mentioned that he wasn't sure whether the gross lift numbers he had were with a 1.5 rocker, or 1.6. That's how this last little tangent got started...

 

You can go to any hardware store & find a spring capable of holding a valve well enough to test with...that's what I used to check rocker arm geometry
dave

 

If OP is as you mentioned, not equipped ? (yet another theory) I'm only try to help. Because one doesn't need a lot of high dollar tools to find the problem. It's basic's of understanding and basic tooling that is only needed. Math is only a human tool to find answer's to the unsolvable. Over thinking is and can be the enemy.

 

Roadsir, did your new valve springs come to you in plain white boxes with no labeling or info?
If they did, this is very well your problem. (Offshore Junk)

 

If you don't have spring or valve guide issues you might check for pistons hitting the valves on overlap exhaust stroke usually it bends valves. with a domed piston it might hit the valve centered enough to brake the rocker first.

 

Springs between rockers...Great idea. You never cease to amaze, Rich. Perfect.

 

I use ford FE rocker springs. They fit the inner step on 1.55 retainers like they were made for them, and I have scads of them around here. The only thing I ever see in hardware stores is BBQ starters, ABS pipe and patio swings...

 

I helped a friend with the re-do of a blown 425 nailhead that was supposed to be built by a Buick guru, but..........by the time we were done one thing was very apparent - nailhead valvetrain geometry is very specific in terms of stem height / lift/rocker rotational position, etc. The interplay of stem height, rocker shaft centerline, retainer dimensions, etc. is fairly complex. By looking at the first picture you can see that the further the pushrod goes "up", the more load is transferred to the outside of the pushrod cup, and at least one of the failed rockers seems to have had that kind of failure. What we came up with was that while lift, rocker arm ratio, etc may change, the best bet seemed to be to try to stick to the same relationship of all these factors as the stock setup as closely as possible. We did end up using a billet rocker arm setup and beehive springs - the engine runs really well now, but it was no quick fix.

 

More replies than I can keep up with.
Adjustable lifters was a lead-time and convenience decision. A full set is not that expensive, and they are in-stock. Due to the funky BUICK geometry the adjusting nuts don't clear too well at the top, and when they are at the bottom you can easily get a wrench on them....and since they are hydraulic they should not need re-adjusting.

Even with the Sealed Power inner spring having one less turn I was a little concerned about the bind dimension. I went down to the shop last night and measured inner spring retainer to head pocket distance, against the bind dimension, and sent an email off to Sealed power tech. They rate the bind height at 1.14 on the inner and 1.03 on the outer. Mathematically, assuming a full 1.6 rocker yields a .480 at the valve I would coil bind at 1.082 on the inner and 1.05 on the outer.

I called Russ Martin today. He had a different inner at .864 bind height that gets me well into a safe zone (albeit a little stiffer), and outers that are little less than the 1.03, that he feels should work with my combo, but need to check installed height, and verify actual lift at the valve.

Got an email from Charlie Price. The cam was made by Crane, which make me feel better, and due to the vintage, and source feel the lifters should be USA. I have an email into Crane regarding the specs.

Had I known the early short valve springs were discontinued and made common with the later .100 taller spring height I could have went to the later, taller, valves and gained spring clearance.

If for some reason I can't get the new outer springs to work, I am not going to pull the heads to machine the spring pockets deeper, or install new valves, I'll concede to the God's of Speed and put the iron 1.5's in, give up 10 or 15hp. The Buick tranny input, and 40 ford axle keys will thank me later.

I still have a set of 1.5 adjustable Gotha's I was hesitant to run due to reported breakage, or backing off. Maybe I'll give them a try as well.

 

Early short valve springs?? Hold on a minute, are the valves you are running longer than the originals? keep in mind, I am not a nailhead guy...

 

That's one of the cool things about this place: decades' worth of experience right at your fingertips.
I can't add anything that hasn't already been covered, and as much as I love those vertical-valve V-8 Buicks I've never had one apart. Keep digging - I'm sure you'll get it figured out. Your deuce is way too cool to be garage-bound for very long!

 

No, The 364 valves are the same length as 322 just a 1/16 larger OD so you can get a little more breathign. 401 and I think 425 valves, and spring height are both .100 taller. MFG'ers only list one spring for all years supposed to work for 322 and larger engines (both closed heights). So on the early 53-56 motors your at .100 additional spring compression disadvantage, and you start to lose the effective working range.

I'm going back to small block Chev's after this, hell I might even try a flathead.....

 

"I'm going back to small block Chev's after this, hell I might even try a flathead....."

hang in there, you will get it sorted.

as far as the Chevy comment, versus flattie.....a boatload of flathead guys have taken much bigger hits with huge downtime and dollars, but you sure don't need to ask the hardcore guys why they hang in there.
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Good god man!! Anything but THAT!

 

On the choices of stock iron 1.5 vs Gotha, I believe the Buick Gotha might be like Gotha Olds, in that they came with cup type pushrod tips because the screws have a ball, rather than a cup.

I got rid of 1.5 and 1.8 Olds Gotha, in favor of McGurk 1.5. Partly for wanting stock type pushrods, but also getting away from the self-locking screws that get compromised a bit more each time you adjust one.

I have the feeling that the rest of your aluminum rockers have been stressed, and might be worth mocking up the GM 1.5's?

My NOS Crower cam; I bench tested it to get all the specs that Crower did not have on record. A Olds hamber that has passed away, gave me the "safe lift" spec for a stock Olds 324 that had unmilled heads or decking, and stock headgaskets. He said I was .007 from the end of the safe zone for valve to piston, if I had stayed with the original 324 1.8 ratio. My cam must have been made for the early 1.5 motor...because after talking with other Olds ex racers, they all told of cam grinders making cams for each ratio back then.

In my opinion, looking at all the many rocker oiling changes and shaft oil groove changes, as well as lobe width changes, lifter size, etc, throughout the rest of the 1950s, I got the sense that Olds messed up when they changed from 1.5 in 1952.
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No way !, that's to easy. Keep at it, you won't be sorry when it's all sorted out. Just take a break from the thread for a bit and let things sink in. You can do it.

 

After getting my 322 problems sorted out because of the builder, late last year, now pushing 5,000 miles on it this year, not a spec of a problem (my avatar). Stick with it Eric, just about got it. If you go to a Chevy or flattie, you're gonna get a spanking!!

 

hell I might even try a flathead.....
Good god man!! Anything but THAT!

Now Now Now .............

 

I too have never been on the inside of a nail head but it's good to see the folks that have, step up to the plate with real world specs and knowledge. Hang by your thumbs man, you got some good info to work with and you WILL get it !

 

Boooooooo Chevy/flathead .... booooo ! The spanking part is kinda' kinky ... but, I will stick my tongue out at you. I'm hoping the Buick wears the car out, once this tangled bunch of geometry gets figured. I got my fingers and toes out for ya'. Kinda' stinky tho'.

 

Correct me if I'm wrong but normally the only way a rocker arm can be broken is if the tip on the valve stem stops and the rear on the pushrod keeps going up. The only thing that can cause this to happen is if (1) the valve stem sticks in the guide (personal experience) or (2) there is so much lift the springs go into coil bind or the valve is hitting the piston.
#1 is hard to find sometimes. It can be caused by a slightly bent valve stem or not enough clearance in the guide when the engine warms up.
#2 should be reasonably easy to find. Find a friend with a Rimac valve spring tester and measure installed height and compressed height at max lift...then check for spring bind. If it's not the springs and it's not #1 then pull the head and check the piston tops for damage.

 

I have been watching this and all the scientific ways to check for coil bind. If the OP just did what I said, Dummy lifter, use your eyes and a feeler gauge and this deal would be long done. But noooooo. More science.

 

What the ?, lol. Shaft mounted rocker assemblies are more tricky than individually adjustable rocker's and this is the down fall, not that it's a Nail Head. My Son ran into the same issue's on a SBC with shaft mount rocker's. Instead of breaking rocker's, he'd pull the whole assembly off the head @ 7000 RPM due to extreme side load on the valve's because the geometry was off. But OP first issue at hand is interference most likely from bad geometry. So you see, that Nail Head isn't the problem.

 

Easy now, remember. Buddha found the secret to happiness by laughing at other people's suffering. I find all this very entertaining. By the way, agreed on your method of finding the problem.

 

Just remember, there is more than one way to skin a cat! So people have been discussing other ways to check it out, not that big a deal to follow along or choose not to!

 

When I started my rebuilt 322" the first time and broke the Cam in, all went well. First drive I heard metallic noises at idle from the top end. It was breaking the inner Springs. The Engine was rebuilt with stock parts, but I did have the 1.6 Aluminum rockers on the shafts. I removed all the Springs and replaced them with a set of Schneiders, all good after that. The springs that broke came in those unmarked white boxes, offshore junk. After going through the "birthing" pains of the Engine all was good. The 322" Nailhead is a great Engine, I hope you get it right and can enjoy your Buick Power.

 

But this cat is not yet skinned. People have a tendency to do things the hard way because the easy way looks to hard.

 

Obviously the retainer (1st pic) is hitting the rocker. It's not that it's not seated the retainer is being lifted by the rocker. Lots of good info above, however one thing you mentioned (voids) may be good and bad. Like so: Good because the rockers are junk and they are acting like a shear pin, Bad because the rockers are junk. Bottom line dude you need to regroup... before you have a"catsasstofree"