mrtexas

My 63 327 broke a #5 exhaust pushrod the other day. Wow, made some noise! I motored into the nearest small town here near Houston, Devers 28 miles from home. While waiting for my wife to pick me up, 6+ bubbas in pickups attempted to be helpful. One guy said, oh ground out the plug for that cylinder and you can drive it home. I parked it at one nice bubbas house a few blocks off the highway and met the wrecker the next morning there.

I borrowed a friend's orthoscope and couldn't see any damage. Looks like the intake lifter is collapsed after looking a little closer. I couldn't tighten down the rocker after taking out the lash. No apparent damage to the block/valves/pistons. Here is a shot of what the valves look like after taking off the head:

Any motor doctors out there? Perhaps bad rings making all that crude under the valves? This is my first look inside a SBC!



I'm thinking of getting the heads worked and slapping her back together.

claf

My vote is for valve guides and / or seals. Oil is coming down not up. Bob

Westlotorn

Have to agree, time for valve stem seals for sure but get the seats checked while you are at it.

mrtexas

After taking off the heads and looking closely, I figured out what caused my engine trouble:



Bubba has been at it again. One rocker stud is too high so I couldn't properly adjust the valve lash. The other rocker stud has a groove worn in it. This is the one that broke the push rod. What an unlikely place to look for the cause of the problem.

Oh well. Off to the machine shop for a valve job and replacing a couple rocker studs!

vettsplit 63

Look closely at the left stud and you'll see that it pulled. See the ring where it was? That is why I run nothing but screw in studs.

AZDoug

Can't blame Bubba for that.

Doug

Chuck Gongloff

Yep, been there, done that myself.

I had my heads freshened up a number of years ago. The machine shop INSISITED that they replace all the original "press fit" studs.

They did so...with new "press fit" studs.

Didn't take long for the studs to start pulling out, one, then another, then another.

Ended up replacing all 16 of 'em with screw in studs.

I'll also bet that if you look at the rocker arm that came off the stud that is cut, you'll see that the rocker arm itself has "issues".

Chuck

65tripleblack

You don't need a "valve job", and you don't need new valve seals either. What you show there is normal for a dirty, old, non computer controlled engine. You should see what that picture would look like if you had a high overlap cam installed!!

If I were you, first thing I'd do is check to see what your valve spring rate(s) are. It's very unusual to pull a stud if your heads are set up with the OEM, or equivalent marshmallow springs, unless a valve spring has experienced coil bind. If you find anything more than 80-100 pounds pressure on the seats (@ 1.700" height), then someone has replaced the original springs with less compliant (stiffer) ones. Once you see that, then it's time to see just what you have in there for a camshaft.

If you still have the original, or equivalent cam installed, then buy and install all 16 new Sealed Power VS677 springs. Might as well install new seals while you're at it (although there's nuttin' wrong with your old ones). Have the springs shimmed to 1.700 installed height.

As far as the studs are concerned, if you run the OEM cam/springs, then save your money and press in a new stud. Have them all pinned. Screw in studs are not needed if you are running marshmallow springs.

MikeM

Cutting a stud on the side like that is fairly common but it's been awhile since I've seen one. I had it happen to me, way back when. I chalked it up to running the valves too loose but I do know that on at least one incident, the rocker arm was cracked across the ball seat and letting the rocker ****. I think another one was a weak rocker that was flexing on just one side, letting the rocker **** when it opened the valve. Been too long ago, can't remember.

As far as replacing the stock press in studs, I'd never touch them if they were straight, not cut and not pulled. I've run a lot of SBC's pretty hard/fast but I've never pulled a stud. Never used anything but stock valve springs though.

If that was my engine, I'd knock that pulled stud back in the head. If it apppeared to be pretty tight, I'd set it to the right height and then pin it. The cut stud, I wouldn't worry about.

I'd investigate why you seem to have all that muck in the intake ports. Just because it has a carb is no reason for it to look like that.

Kerrmudgeon

Check the pushrod from the valve with the worn stud, you may find it a little bent. Possible form a backfire, and then the rocker wouldn't run true and caused wear to the stud.

63split63

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If that was my engine, I'd knock that pulled stud back in the head. If it apppeared to be pretty tight, I'd set it to the right height and then pin it. The cut stud, I wouldn't worry about.

Don't worry about the cut stud ?

If you have already pulled 1 stud, broke a pushrod and lifter and found another stud cut like that it is time to get the heads off and out to a component engine rebuild shop at the verry least .
I don't know how manny miles are on that engine but I would be recomending that it would be wise to pull it out for a rebuild now .
Do it right the first time, it is usually the cheapest way to go in the long run unless you are a used car guy and planning to flip it asap.

JMO Bill

MikeM

Did I look like I was kidding?

I've seen cut studs run ten of thousands of miles once the root cause of the cut was corrected without any problem. Some, I have seen half cut in two.

If I hadn't done what I was quoted above, I wouldn't be posting it here.

Whether you know it or not, if you let a shop replace any or all the studs, if they don't ream the hole to the proper oversize and use the proper oversize stud, they'll pull out again, just like mentioned above by Chuck.

63split63

I say again, you must be kidding !

Westlotorn

I never saw what 327 this is, stock or high HP.
Stock demands are much different from high HP.
The demand on the stock pressed in studs goes up dramatically if you increase lift and spring pressures as noted above. Stock 327's lived for decades without pulling studs.
Put a big cam in the same engine and guys pulled the studs in a weekend.
We all know they pull if you add more cam and springs to the engine.
No need to argue that point. Pin them or go threaded if running large cams with extra spring pressure is what you wish to do.
On the stud with the slice in it, once you cut a stud the strength is compromised quite a bit. OEM's have a pretty large safety net built into most parts, many are over engineered but I would replace that stud rather than worry about it snapping, it has certainly been compromised from design.

Vega$Vette

Note to Self

Never buy a car from MikeM

MikeM

Can't say as I blame ya'. Anybody that has to write in and ask how to get six bolts out of a hood to take it off should be very leery of buying anything he doesn't understand!

And you're a "project manager"? Does that mean "injuneer"?

Vega$Vette

Silly me I should have just knocked it off with a hammer

Yes Project Manager=one who thinks a project through by using knowledge, experience and research to determine the best course of action to achieve the desired goal most efficiently. And in a situation like this to take the reasonable steps to make sure it does not happen again.

In this case. The heads are off. He's already had a stud pull. Why not invest the couple extra bucks in either screw in studs (my personal choice for about $25) or pinning them?

He's already be broke down once. How could he ever feel comfortable taking the car more then a few miles from home if he bubbas it?

MikeM

I really like the buzz words in your sentence above. Very popular phrase.

Cutting studs on SBC's has been going on for years. Could you give me a brief write-up on how to stop it or even what causes it? Do you really think pinning the studs will stop them from being cut? Using screw in studs? Do you really think if you knocked that stud back down and pinned it like I suggested that it will pull again if it's a tight fit like I advised?

If you give me a nice write-up, I'll think about selling you a car. Otherwise...........................

Do you really have any field experience with any of this stuff you're talking about to know what works and what don't?

Vega$Vette

Sorry man I missing the pinning part on your post. I would still have some concern over the cut stud. I'd replace and pin it if it was mine.

Lol. I gotta enough cars for now.

63split63

OK, I'll bite again !

How about you tell us where you got your expierence .

You show me yours and I'll show mine