geo65

went to adjust valves, look what I found. its near cut through.

I have to get this out, it appears pressed in and I will use a puller. I expect it to break and intend to heat the head a bit first (any problem?) When it breaks, I will drill it out. Then, I suppose I should tap for screw in stud? and replace rocker (see picture)

is a press in repair an option?

(exhaust location- 327/365)

note valve stem top rounded a bit- necessary to flatten?

all else appears ok, I suppose from improper valve adjustment, motor ran well before this

suggestions and tips welcomed- thanks

427Hotrod

You can use a stack of washers and pull it out by tightening nut. Good chance it will pull out. It's good if it pulls out hard...that way new one will be tight too. You can just install another pressed in stud with some red LocTite..or even the Green type. If it's not real tight you can drill through it and put a roll pin through it like was done many many years ago. Next alternative is to tap hole and install a screw in stud without a hex base on it. After that you're down to serious machine work and installing screw in studs with hex on the bottom, guideplates etc. No need for all of that. Try to just put a press in back in there.

Clean up valve the best you can so it doesn't cut up new rocker and check pushrod for wear too. If it's a Hyd lifter...check it closely to make sure the little wire retainer is still in place and not damaged from being run loose.

JIM

tentuna

Repaired one on my 66 327/350, first drop the water level in the radiator, jack the stud out with spacers (washers) and a nut, I forget the tap size but tap the head , use plenty of rags to catch the chips so you don't have them in the valve springs, by the way the cast iron taps beautifully, double nut the new stud and apply red lock tite to the threads, torque the stud to 50 ft-lbs wait for the loc tite to setup a few minutes break the double nut and you are in business.

plaidside

They used to have a .003" oversize stud, I probally still have one. I believe you had to use a reamer first.
If you look in your GM shop manual you will find the fix.
Also I would change that rocker/push rod and check all the other ones. The tip on the rocker is very worn.
Joe

67vetteal

Put a good coat of White Lube around the Stud Boss prior to starting the repair. It will catch any stray shards/chips from the machining. Also, one of those small Pick Up magnets wil help contain debris. Easy if not intimidating repair. Al W.

MikeM

The problem here is not the stud replacement, it's the valve stem end. If you leave that valve in there with the rounded stem, you'll be back inside that engine before long for the same repair or worse.

I like your push rods.

landshark 454

MikeM is right. That stem could be trouble. What you need to do is check that stem against one that shows no wear. If the height of the stem above the keeper is close to the good one, you should be OK. If that mushroomed stem is worn closer to the keeper by any appreciable amount, I would replace that valve and any others that show similar wear, as you are wearing past the hardened metal on the tip, and the wear will accelerate. I have a friend that ventilated an L88 because he left a valve like that in his engine.

If the wear is not that severe, you can continue to run the valve, but I would check it again in 1000 miles, or sooner. Change that rocker, and check all of the others. Check the pushrods for side wear where they go through the head.

BTW, this is not uncommon wear on a small block, and is not the result of misadjustment. The only thing that would prevent this is using true needle bearing rocker arms. Rich

knight37128

What kind of spring pressure are you running?

What kind of cam? lift? roller? flat tappet?

geo65

thanks for all your replies...I'm still not sure which way I will proceed. as always, there are a few preferences noted by members.



this statement bothers me a bit...
"BTW, this is not uncommon wear on a small block, and is not the result of misadjustment."


...this can't be the result of misadjustment?? there are no more than 10k on this engine but the valves were not checked or confirmed from start. others that I have checked appear fine, what would it most likely be?

also, you are indicating the valves are surface hardened..assuming this is the case, I see the problem with the tip should I flatten it.


----- it's a stock solid lifter motor, rebuilt about 20 years ago but used little.

mrruffhouser

Anyone want to mention oil? Flat tappet oil requirements? Should I ask what oil has been used since the EPA required the oil companies to change formulation? I know, we've been there. Just thought I'd ask.

wmf62

i would think that if oil was to blame, then the cam would be toast.
Bill

MikeM

I don't know if I'd agree with the comment that adjustment won't cause your cut stud problem. I think it will through a secondary means at least. If the rocker is run loose enough, long enough, it will eventually round off the end of the valve stem and then you go into a vicious circle. Once the stem gets rounded, it'll cup the rocker and shove the pushrod against the head. It'll also side load the rocker/ball and cause that to weaken or split. All of which causes more wear at the tip of the valve stem.

No, you can't flatten that valve stem by hand. Forget it. Also, as mentioned if that stem tip wears down too much, the rocker stands a good chance of hitting the retainer while it's opening the valve. If/when it gets into it far enough, it will unlatch the keepers and bye-bye engine.

Many years ago, this used to be kinda' common on SBCs. It had nothing to do with oil. I do know that.

You need to replace the rocker, ball, valve and stud. Save the push rod if you can. That's one of the good ones. Looks like an original SHP part. Check for valve stem guide wear while you have the head off.

I had a 265 years ago that did this. It had three studs in it that were cut. I saw a number of 283's that way during the same time frame that also had the problem. To the best of my knowledge, all the ones I saw were solid lifter engines but that doesn't mean the hydraulic lifter engines were immune from the problem.

geo65

thanks for posts...the wear on the valve tip is my sticking point now, I don't want to remove the head at this point if I can help it. I'm sure I can flatten this and it will not affect the retainer however the hardness issue remains in question. The other option would be to leave the valve and monitor it. In either case, while not ideal, at what point will it become an issue will be hard to determine.....in 1,000, 10,000 or 20,000 mi

I tried removing the stud today using washers. Seemed tight, so I stopped, want to get a thrust bearing type puller which will be less likely to snap it since it is weakened quite a bit. Found one at Summit but on back order..also found others but about double the cost- about $100. Anyone have a lead?

Also, are there matching rockers available. NOS or OEM?

landshark 454

I stand by my statement that this was not the result of misadjustment. The car is a solid lifter car, so if it was misadjusted, it would have had a loud single tap from that valve, which would have been obvious, and should have been attended to. I assume you did not drive your car around with it clacking loudly. It may have ended up making noise, but I bet it did not start out that loud.

I have a 365 hp car that tore up the rockers just like that, but hardly affected the valves. I can assure you that the valves were set right before this issue occured, as I have been lashing solid lifter chevys for 40 years, and haven't screwed one up yet.

The lash setting for a solid lifter C2 is .030, which is a rather loose setting, as far as most solid lifters. In fact, I know of no other solid cam that is set that loose. This loose setting certainly does not help valvetrain durability.

Like I said, this was and is a common problem, especially on solid lifter Chevy engines, both big and small block, and all of them could not have been set wrong. Even hydraulic lifter engines do this.

It is a result of the rocker design. The ball pivot allows the rocker to pivot in all directions, not just up and down. On a solid lifter, the gap allows the rocker to lean left and right. Combine that with the clearance in the head for the pushrod, and now the rockers can not only lean left and right but shift to the left and right. Now you are contacting the side of the tip, and at a slight angle. Do this a few thousand times a minute, for hours on end, and you get exactly the wear pattern that we are seeing here. That is why Chevy went to pushrod guide plates on the hi-perf engines, and those funky self aligning, notched rockers they use nowadays.

As stated before, the only sure cure for this is full needle bearing rockers, which only pivot up and down, and have a roller on the valve to lessen friction and wear.

To pull that stud, do as they said, and run the nut down on a stack of washers. It should be hard to pull out. Otherwise, the rocker would do it for you. Rich

devildog

I have repaired these on the car many times over the years. here is a picture of one I did for a friend a few weeks ago.

Same as yours, stud pulled out, he ran it a bit too long, cut the stud, wore the valve stem at an angle.

I pulled the stud as Jim 427 HOTROD says by simply putting a few washers or big nut as a spacer and then just run not down and jack the stud up...MUCH BETTER than a puller because all forces a straight up and less chance of the pulerl being off center.

Pull it with washers and big nut spacer...remember it may seem tight, and yes it has cut thru it. But, they tough as hell and it is already loose that is why you have the problem.

We replaced the stud several times, but it kept pulling (just a stock set-up springs and hydraulic lifter), Often when the shop rebuild the heads they cook off the old oil, etc and get them too hot and enlarge the press hole.

Just drill and roll pin it. In the pic, my roll pin was too short to get a good flare on the ends. I was afraid it may work out, so I put a loop of aircraft safety wire thru it (over kill).



The worn valve stem can be squared up just a bit with small stone on a drill or dremel to keep the rocker riding straight and square. Then put a lash cap on it, they are hard.

This will run long time, I have one with 10,000 miles on it.

Joe

landshark 454

GEO65, I just looked at your pictures. If that is the same valve in both pictures, you should be OK. That valve wear isn't too bad. But check all of your rockers and studs. Rich

geo65

"Same as yours, stud pulled out, he ran it a bit too long, cut the stud, wore the valve stem at an angle."

My stud has not pulled and is not loose, but it has worn away from the contact with the rocker. I believe a result of a combination of all factors mentioned above and excessive lash. In examining the design I can see how this happens especially looking at the rocker punched through hole and its close proximity to the stud.

I still would prefer to pull using the proper tool rather than using the spacers (only due to the fact it is only at perhaps 50% strength).

I really like the idea of the lash cap.

I"ll see if I can get my hands on a tool and try to remove it.

MikeM

[QUOTE=geo65;1569946426I"ll see if I can get my hands on a tool and try to remove it.[/QUOTE]

It may suprise you to know that the correct Kent-Moore tool, J-5802-1, is nothing more than a sleeve that fits over the stud. You then drop a flat washer over the stud, run a nut down on the stud and then crank the stud out by turning the nut with a wrench.

You can drop a socket down over the stud instead of the washers and have the "correct" tool.

The Service Manual then directs you to ream the stud hole oversize and install either a .003 or .013 os stud. Coat the stud with hypoid gear lube and drive the stud in with a stud driver and two pound hammer.

That's "sorta" the way I've done it on more than a few occasions.

One of them I took out was out of a late model 350 GM crate engine. It snapped off clean with the head. I drilled the stud and tapped it with a 5/16 coarse tap, ran a short piece of all thread in the stud, stuck a socket over the allthread, put a nut and washer on it and cranked it out.

Chuck Gongloff

I wouldn't use a press in stud. Use a standard screw in stud. Refer to these pictures.

About 10 years ago, I had my heads gone over. No problems with them, just a "look-see".

When I went to pick them up, the guy had replaced all 16 original press in studs with...............................NEW press in studs.

I was not happy, but it was a done deal.

First time I ran the car to 5000 RPM (at Cecil County Dragway, BTW), the motor stopped pulling and started ticking. I had pulled one stud. Fixed that one with a screw in stud.

Second time.....................pulled another stud.

SO.................I replaced the remaining 15 on the car with screw in studs. NEVER a problem since. Borrowed a stud replacement kit from a bud of mine in the auto biz. Bought the studs at my local auto parts store.

The pic shows the jig used to both pull the old stud, and align the tap to tap the boss of the stud to be replaced.

Chuck

MikeM

Not to contradict Chuck's post at all but I've never seen a factory installed stud pull out on a SBC unless stiffer than stock valve springs were used. That's talking about the OEM stud installation at the engine plant.

The exception is the really early '55 V-8's that pulled studs and they made the studs longer and pressed them in deeper.

The only problem with threaded studs is getting the holes bored and tapped straight so you don't throw the valve geometry off and start breaking parts. Maybe it's a small chance.