Lock nut for rockers so tight its breaking tools

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
So yeah..my lock nuts on my rockers were so tight i broke two drivers and bent an allen wrench trying to remove them. No locktight visible. Im thinking the last builder(local shop) just wrenched on them with all he had....is there a torque spec on them. Did i miss the meeting where we decided to go hulk on the rocker nuts or something?
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
10,451
Reaction score
15,105
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
Definitely shouldn't be that tight. Tight enough to hold the adjustment, but should turn with a little resistance when it comes time to adjust the valves.
 

nvrenuf

Full Access Member
Joined
Jul 30, 2010
Posts
1,751
Reaction score
2,011
Location
Mobile, Al.
First Name
John
Truck Year
1991
Truck Model
K5
Engine Size
454
I'm surprised they are that tight, I've overtightened poly locks before and the nut split (spiral). Couldn't you just put a wrench on the hex nut and break the whole thing loose? Then you could work with the set screw.
 

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
Definitely shouldn't be that tight. Tight enough to hold the adjustment, but should turn with a little resistance when it comes time to adjust the valves.

That was my understanding as well. Ive never given them more than a bit past snug and never had any back off. These I just removed had me second guessing myself and standing there looking like a jackass after the second driver bit broke and the head got stuck in the rocker nut. I cant believe how much force it took to get them off.
I had to sleeve an allen wrench with a hollow screwdriver shaft to keep it from bending more than it already had; and hit it with a deadblow.
 

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
I'm surprised they are that tight, I've overtightened poly locks before and the nut split (spiral). Couldn't you just put a wrench on the hex nut and break the whole thing loose? Then you could work with the set screw.

I hear ya. These are poly locks on 1.6 comp roller rockers .Im a little worried about these having been stressed so much. IM not sure if removing them with the set screw that tight would have been good unless I had new studs ready to go in also. Maybe it would have work out but i honestly dont know either way. I just assume the same force holding the nut on would be working against the stud somehow and booger it up, but again I do not know. Never ran across them this tight before,LOL
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,951
Reaction score
11,020
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
We had poly-locks on the race car, and usually just broke them loose with the hex. Before you break out the drill try a brass punch and blast it good with a BFH.
 

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
We had poly-locks on the race car, and usually just broke them loose with the hex. Before you break out the drill try a brass punch and blast it good with a BFH.
They were off before I posted this. After breaking two 3/16 hex drivers and bending an allen wrench I wised up and reinforced the allen with a sleeve of sorts...after that the deadblow did the trick. Ive just never seen poly locks so unnecessarily tight and wanted to see if it was as uncommon as i thought.
I would have been mad at myself if I put them back like I normally do and later find out I wasnt giving it enough umph.
There may or may not be video footage of me cursing like a sailor about whoever had hands on it last. I lost my temper a bit when the 2nd 3/16 snapped.:banghead::throw:
 

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
I've always snugged the allen down, then put some more torque on the nut. Loosening them is reverse order, break the nut loose first, then back off the allen a bit.
I tried that and it didnt seem to want to move down(tighter) at all. I was afraid to try any harder than I was. I thought it may help but just didnt give me any movement at all until I had the hex loose. I wasnt sure about hurting the threads on the studs so I may have been too gingerly with it; but I think it should have moved if it was gonna...I have it a few grunts thats for sure.
Im just happy in the end they came off and that I was able to get the 3/16 bit head out of the poly lock. It took me longer to retrieve the broken bit head than it did to tear down both heads
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,764
Reaction score
6,834
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
Propane torch or other means of heat on the nut for a minute or two and it will literally fall off the bone
 

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
Propane torch or other means of heat on the nut for a minute or two and it will literally fall off the bone
I didnt have my torches with me at the shop otherwise it would probably have come to that. I dont know why i didnt at least bring the handheld propane with me considering how many rusty exhaust bolts I have to remove...just didnt expect to need it today on the heads.
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,951
Reaction score
11,020
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
I've always snugged the allen down, then put some more torque on the nut. Loosening them is reverse order, break the nut loose first, then back off the allen a bit.

That's what I used to do also. There just isn't enough grip on the allen screw to get it tight enough, so we treated the allen like the height adjustment and the hex as the locknut.
 

legopnuematic

Licensed Junk Dealer
Supporting Member
Joined
Oct 27, 2016
Posts
1,784
Reaction score
3,855
Location
MO
First Name
Spencer
Truck Year
1971, 1̶9̶7̶4, 1976, 1979,1̶9̶8̶5, 2002
Truck Model
Dart Swinger, Sierra 10, C10 Cheyenne, C10 Big Ten, Silverado 10, Ram 2500
Engine Size
225/6, 350 c.i., 350 c.i., 5.9l Cummins
X3 on snug the lock and then nip down with the hex on the nut itself, reverse for disassembly.

Realistically even if overtightened the likelihood of damaging the threads on the stud/nut itself is quite low, unless if seriously corroded, cross threaded or the threads were damaged to begin with.

High quality hex keys really pay for themselves, Eklind, Bondhus, Wiha, Wera all make good quality keys.
 

Swearbody

Full Access Member
Joined
Nov 4, 2018
Posts
701
Reaction score
716
Location
Birmingham AL
First Name
Jeff
Truck Year
84
Truck Model
C1500
Engine Size
355 sbc
X3 on snug the lock and then nip down with the hex on the nut itself, reverse for disassembly.

Realistically even if overtightened the likelihood of damaging the threads on the stud/nut itself is quite low, unless if seriously corroded, cross threaded or the threads were damaged to begin with.

High quality hex keys really pay for themselves, Eklind, Bondhus, Wiha, Wera all make good quality keys.

So it does seem quite possible that the previous build was done this way as there are many who like this approach. I did in fact try to reverse this procedure to remove them but had no luck since I was worried about the stud.
I was using Eklind ball end hex keys and thats what eventually got them off with some reinforcement to the shaft. The 2 3/16 hex bits were both Pittsburg though...and both ball end, so no real shocker that they snapped the head off.
I am going today to see what brands at the local HomeDesperate are lifetime warrantied and pick up a set of straight(not ball end) hex bits. Im thinking that if they had been non ball tip they would have been able to do it considering they both snapped at the thinner turned down area. Considering the fact that almost every bolt going back on the engine is ss 3/8 hex drive or smaller ill need some good bits anyway.

Thank you everybody for jumping on this thread. I cant wait to show off my work once everything is completed.
 

legopnuematic

Licensed Junk Dealer
Supporting Member
Joined
Oct 27, 2016
Posts
1,784
Reaction score
3,855
Location
MO
First Name
Spencer
Truck Year
1971, 1̶9̶7̶4, 1976, 1979,1̶9̶8̶5, 2002
Truck Model
Dart Swinger, Sierra 10, C10 Cheyenne, C10 Big Ten, Silverado 10, Ram 2500
Engine Size
225/6, 350 c.i., 350 c.i., 5.9l Cummins
Ball ends on hex keys for 3/8 square drive's don't seem to last under torque at all. My friends dad has managed to break almost every ball end square drive allen with their m12 fuel ratchet. If you can find a set of hex drive bits that use a straight bit with a set screw rather than a necked down one, this way if you break them you can pull the broken one out and cut a new piece for it from a donor hex key.

Something like this
You must be registered for see images attach
 
Top