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

Everyone has said it all. Just going to see what becomes of this. One question, how much did you preload the lifters ?

 

yea, and this is just ONE MORE reason why I F*%$ing HATE juice lifters. Its all apart anyway, go back and measure the installed height accurately per my instructions in post #49, stick a valve spring in a vise, crank the vice down until you reach the installed height, then compress it further to the gross valve lift number, and check for coil bind.

 

Oh, and of course, cover the jaws of the vice with something to protect the ends of the valve springs, you don't want to create any stress risers on the ends of the spring. Honestly, I would be EXTREMELY suspect of the quality of springs from Falcon, I would probably prefer to use something else.

 

you have to look at this in terms of a systematic approach to eliminating the things that ARENT the cause, whats left will be the answer. and it may not just be one thing...

 

It appears that you may have to remove the rockers, pull one or more lifter that has broken a rocker. Make a dummy solid lifter for checking. Use an old lifter or make something that will work. Install the solid and rockers. Adjust the pushrod for 0 clearance. Observe what is happening. Repeat as necessary.

 

George,springs get a little tricky for these motors,installed ht is close to 1.800 and the diameter is a odd size,to clear the pushrod opening. Go larger and the pushrods will rub them,smaller they won't work with the factory retainers that you have to use with the original valves because the keeper groove is a odd type.
Next one I do it will be 5/16 stems with beehive stuff.
I had to buy two sets to swap innerspring and make spacers to get 140 on the seat for a mechanical ft setup.

 

I went trough a bored and stroked nailhead years ago. The cam was marked as an Isky E 4 grind, and was perfect. But, several of the lifters looked bad. I had not seen that before or since. It turns out Chev solid lifters are the same diameter, so I bought a set. Then I found that the Chev parts are .125 taller than the Buick parts. I bought a strip of 1 by 1/8 iron at the hardware store, and made spacers to lift the rocker shafts. Everything worked out great. All the geometry was good. Double check to differences between the aluminum and the steel rockers. Then call me.

 

Thanks Gary, I have no nailhead background, and no intention to change that in the future. You are reading between the lines and doing a good job. Normally, I would get my installed height, and ID/OD and comb the valvespring specifications page in several catalogs till I found something suitable. I take it that may not be so easy with a nailhead...

 

I used to routinely shim the rocker shafts on BBM's but when I did, I took some precautions against splitting the rocker stand bosses, I drill/tap them deeper, remove the top few threads, and use longer bolts.

 

I do not have the installed ht number handy,1.750 sounds familiar.
As long as the person doing the valve job is aware and within reason,geometry is good with a stand type rocker. Added lift divided by 2 should be the amount you sink the valve to maintain geometry.
Why the guides were not cut to .531 pc type is beyond me. That should be sop on any valve job,Clearence to retainer bottom and a better seal- no brainer.
Call gary from rocker arm specialties,he hard chromed and bushes rocker assemblies for the guru in califonia.
He is a sharp cat and will sell you a complete set if need be.
Do what George has mentioned as far as checking installed ht and travel. Your adjustable pushrods will make up any variance in milling of the heads or block.
Everything else is just paying attention to the details.
The picture that shows you holding the valve up shows the Travel of the valve stem to be a rather small amount.
Put the retainer on with the keepers and hold the valve up on the seat and measure the distance between the guide and the bottom of the retainrer. It should be at least the gross valve lift and a additional .060 with the seal installed.

 

do these take a rubber umbrella seal?

If so, I REALLY like those on street motors, more than the fancy pants .531 pc type seals. As long as I am running a cam that will work with a spring that will accommodate them, I prefer the big rubber seals.

 

I like to use the blue viton pc type from us seal.that's why that make different color jelly beans

 

Russ Martin is considered by many to be one of the best sources of info, history and hands on experience for the Nailhead. He supplied me my parts and offered guidance during the build. One thing that he was adamant about was that you never run a valve seal on the exhaust valves. This will quickly take out the valve guide. Buick did not run an intake seal originally either, they went to them at the end, later part of production on the 401's
I cannot remember off hand the seated valve spring pressure, but it is very low stock, 70 pounds? This is another puzzling part of the breakage, spring pressure surely is not to blame. Coil bind or some other mechanical interference problem for sure. You mentioned 364 Valves installed. Are the Piston Valve reliefs large enough on a stock 322" piston to accomodate the 364" Valves? Just something else to consider.

 

Hmmm. 70lbs on the seat? Bigger valves? Cheap shit valve springs? Loss of valvetrain control is initiated by the valve bouncing off the seat as it closes far more often than it is from the lifter lofting off the nose.
As a general rule, I try to avoid looking at more exotic solutions to a problem until I have exhausted the basics, but valve float could explain the damage we are seeing here, and with the above recipe, its plausible that it could be occurring at a much lower rpm than you might expect...

I would exhaust all the basics (spring bind, retainers hitting guides, valve/piston, wrong height lifters screwing up the geometry, ect) before I started thinking about this, but with an aftermarket cam with more aggressive closing ramps combined with bigger valves and cheap shit spring metallurgy, well it does send up a red flag...

 

Update! Today I went down and pulled the intake and valley pan to look at the pushrod lengths. First of all they were all tight. All are adjusted to about the same length, but I could see some lifters that had bled down. We cranked the engine and they pumped back up, but would bleed down pretty quick. More on this later. Here's a pic where you can see one bled down.


Installed height on the outer spring is 1.530.

Yesterday, the exhaust valve had both a broken inner and outer spring. I replaced both.

After removing both rocker assemblies, so all valves were seated, I could see three more broken inner spring on different cylinders. Comparing the Falcon inner springs to the sealed power replacement I bought we could see the springs have the same free height but the Falcon supplied have 10 turns and the sealed power have 9 turns. Naturally the 9 turn compress about .100 more. We confirmed this by clamping the springs in a vice.


Sealed power on the right, Falcon unknown part number on the left.


Bottom line is there was inner coil bind, and I think the inner coil breaking into three pieces, may have taken the one outer spring with it.

Out of curiosity we checked the Falcon outer spring in the vise. From installed height to .500 compression it had at least .025 clearance between coils.


But that made me want to check the sealed power. I had only bought 4 (thinking I would have three spares) and had already installed all four on the valves that had inner spring failures. In this picture you can clearly see the sealed power outer spring has less turns than Falcon outer spring.


The sealed power and falcon supplied ( I wish I could find my invoice) had the same free height, but more turns, therefore inner bind Falcons.

Back to the lifters. Do you think they are being pumped down ( in a matter of minutes) from excessive spring pressure? Or should I replace them to be safe?

 

Sounds like those Falcon springs need to be changed out for Sealed Power.

 

I'd say juice lifters only pump down when a spring is pushing on them due to what position the engine last stopped running - sorry, that's pretty basic stuff. But, when the spring is done pushing, the bleeding stops. I can't see a lifter bleeding down so far that a pushrod falls out of place. Besides, there's a spring inside a juice lifter that would keep the lash to zero.

 

Yes, Whatever brand Falcon uses would probably be OK on the 58 and later engines, but not the earlier. Sealed Power looks like they work much better on the early engines.

 

Did you ever check how much travel the outer springs have past full lift, You really need to know all the numbers !!!!!!!!!

 

Sounds like you have found the problem.

 

As DND says, don't stop checking now, get all the info to make sure. You possibly have the culprit but get all the info so you don't end up having to go thru this again while cussing a blue streak!

 

I need to run through this for both the inner spring and the outer spring.
What is confusing is the cam is listed as 1953 to 1956 and is rated at .435 lift at the intake, .450 on the exhaust. 56 is the first year that some engines came with the aluminum 1.6 rockers. Earlier had the cast iron 1.5's. Based on this my guess is I should be getting .464 lift at the intake and .480 on the exhaust. If I am getting .480 lift I think the inner spring from sealed power (even with .100 more compression) could still be marginal. There is plenty of clearance between the valve guide and retainer.

I'm also surprised at how stiff the inner springs feel, and how much of the work they do. Is this typical of dual spring set-ups?

 

Hey Roady

You are just chasing your tail unless you now the correct numbers

Bolt plate next to one spring and measure with your calipers from the top of the retainer down to the plate and write it down, turn the engine so you get full lift on that spring and measure it and deduct the numbers to find out what the heck your lift is

Put your spring back in your vise at the installed height, and zero the caliper and go to full lift and then to coil bind and find out how much travel your spring has to coil bind

If you don't do this you are just flying blind and will most likely break more parts, that is why custom engines get ' Blue Printed ' so all the parts will work and not fail like the rockers are doing on your engine

 

or you can just put a dial indicator on the edge of the lifter (not on the plunger) and measure the lobe lift, then multiply by 1.6.
If you go to coil bind, you should toss the spring you test, as it will lose seat pressure, and also become a prime candidate to break later. I recommend you take it to the full valve number, then check for .060 between the coils. Once a valve spring has been taken all the way to coil bind, it shouldn't be re-used.

 

That was my next step, to borrow a base and indicator from work this week. After looking at Schneider specs (which they spec assuming 1.6 rockers) Compared to the Charlie Price Cam specs his might be rated at 1.6. I have an email into him to verify, but getting the measurements will be easy.

 

While you have a indicator out ,put it on the retainer and check to see that they actually are 1.6, all rockers are not created equal.
Put a light spring( some call them checker springs) in place of the valve spring and see in fact if it correlates to the lifter measurement.
Many times I found a 1.6 rocker to be a little more or a little less.
It's the little more that pops its head out when you least expect it.
Looks like you found your demon,now drive it like you stole it.

 

Questions:

Does the nailhead require the adjustable pushrods to be installed upside down?

Since you're using hydraulic lifters, why use adjustable pushrods at all? Custom pushrods are usually less expensive and lighter.

jack vines

 

the rockers are probably somewhat less than 1.6, I cant ever remember testing an OEM rocker that came out higher than its rated ratio. Aftermarket rockers are another story, and often measure higher(Crane).

 

Just a note about using math only. It will only get you in the ball park at best. Because if the push rods are not of correct length (in this case not much you can do because of shaft mounted rockers are where they are. Other mod's would need to come into play) the geometry can be way off and cause more lift than the math will show. I'd remove the valve spring and use a test spring (very soft and won't bleed lifter down) then rotate engine by hand and watch the clearance thru the test spring. Also, while your doing this, bring engine around so cam is at max lift to see what the exact lift is at the valve. Then and only then you'll know if true coil bind is in play.

 

Your first sentence is correct. But the number generated using math, will error on the high side of actual lift if you are using OEM rockers, not the low, and for that reason, is valid for checking for coil bind.
If the OP has soft springs to use, that is the best method. But I am assuming he doesn't, based on the fact that he doesn't own telescoping gauges or a dial indicator. This indicates to me that he is not someone that does this very much, and so is unlikely to own a pair of soft springs.