Rocker studs in Dove aluminum heads

Michael C Henry · #1 (**permalink**) 11-22-2002, 07:35 PM

While installing my rocker assys.The center two studs on both Dove aluminum heads pulled,Heli-coils and all. Just the center two the outside studs are fine . What is next? Where do I go from here?I hate to tear up new intake and head gaskets.It was just starting to look like something.

concobra · #2 (**permalink**) 11-22-2002, 08:10 PM

One suggestion is to use a Key-locking thread insert. These have a much larger OD.

Specs. Are:
9/16" x 12 od thread
1/2" long (through bore)
3/8" X 16 id thread
Black Finish Steel

They are available from Mc Master Carr. Tel. 562-692-5911
NOte; Mcmaster Carr usually sells to other companies but will sell to the general public.

Insert part: # 90245A034
Insert cost: $1.67 each

Installation Tool: # 92100A717
Tool Cost: $10.80

Good Luck

A Snake · #3 (**permalink**) 11-23-2002, 02:10 AM

that will work and you won't have to pull the heads. Just keep the metal out of the rest of the engine when you install.

If those studs pulled out, it sounds like one of two things happened. Either they got over torqued or, they may not have had enough thread in the head. Watch when you do the redo, that you get enough depth (without hitting water) that the depth is more than equal to the diameter of the bolt. i.e. if the bolt is 3/8, you need more than 3/8 depth. If it were me, I'd like to see at least 7/16 depth.

My Dove heads and rockers were done by my builder, so I don't know how deep the studs were drilled. they didn't pull out so they must have been deep enough.

What I just told you about depth comes from industrial experience, not Dove heads.

Al

Michael C Henry · #4 (**permalink**) 11-23-2002, 08:41 AM

If you remember I started last Feb 02..I removed the manifold to have some work done. Upon reassembly I had problems with the valve adjustments increasing.I found two lobes and lifters had gone bad.I had to advance all the rocker adjustments though three or four times over a weekend in June and twenty miles.The machine shop didn't notice anything.I didn't figure it out then either.The studs were pulling obvisously last June.Why only the center studs on both heads.The outer studs were never a problem .How tight do you go with a 3/8'nf stud anyway? I guessed 25 ftlbs.When it's my stuff I get ratteled. I had problems w/the first pushrod on right side. I removed the whole rocker assy and didn't notice that the two center studs came with the rocker shaft assy and weren't in the head anymore.Then I noticed I had almost no screw sticking above the lock nuts on the inner rockers on the left side.I looked and could see daylight under the two center stands on the left side. I disconected as normal.No studs turned.but those center studs also came up with the shaft assy.

A Snake · #5 (**permalink**) 11-23-2002, 11:44 AM

Mike,

Try a little reverse engineering. Take those studs without the rocker assy. and see if you can put them back in the pulled out holes. This is just to see how much thread you had holding them. If it is less than I mentioned above, that's probably what caused the problem.

I haven't looked at any of those studs, but I suspect that they are NF thread on the top and coarse (16 threads per inch) in the head. Am I right? If not, the NF is not a good choice for aluminum, even with helicoils.

Check out the amount of thread you had holding them in the head. Like I said if they are threaded shallow, they will undoubtedly pull out.

Al

ADR · #6 (**permalink**) 11-23-2002, 07:14 PM

Michael C.

I noticed your in Tacoma.....I don't know what machine shop you are using now, but one of the best FE guys in the country is in Puyallup. His name is John Haskell and his number is 253-848-1628. His company is Aire Reaserch Eng. Give him a call.
Dale

PS. If you have binding in the valve train ie. retainer to guide or spring coil bind or whatever, fixing the rocker shaft is going to be very short term......I would look further into this and see if there are other problems. It may be just a bad casting or it could be a mechanical thing.

Jeff Frigo · #7 (**permalink**) 11-23-2002, 11:09 PM

Dove heads are well known for pulling heli-coils out. The aluminum is too soft on some heads. My guess is that it is a matter of time bfore you see it happen on the other side. Call George at Guessford, he has many years of experiane with Dove heads.

As far as thread depth goes, in aluminum it should be 1.5 times length to diameter.

Michael C Henry · #8 (**permalink**) 11-23-2002, 11:46 PM

Rigth now I using Bud's machine shop on Pacific Hyway south.I've talked to John before and heads and intakes are his specialty. Bliss is down in his back. I now have an assembled engine w/four stripped out 3/8" NC heli-coil holes.Talking to George Anderson about inserts he frequently uses.I'm blocking everything off .Masking everything. I plan on hauling the whole thing to somebody that can do better than me free handing it in my garage.I want the holes tight, perpendicular, and right on the money depth and center.So far I've four inserts 3/8 x 16 inside and 9/16 x 12 outside with red stuff outdide and slotted for a screw driver to install from Tacoma Screw Products .The inserts are just over .515" tall. Know of any better stuff?

GEORGE ANDERSON · #9 (**permalink**) 11-24-2002, 11:24 PM

Michael, see ya found something to correct your problem. We use one that's of course 3/8-16.
Drill a .516 straight hole with a 33/64" drill, .687" deep (11/16") Self Taping, Self Locking 55/60RC
Glad you found something to fix the problem you're having on these heads...
george

RICK LAKE · #10 (**permalink**) 11-26-2002, 07:35 AM

George Anderson Hi George Nobody should have to go though these kind of problems with helicoils coming out of heads. If Mike didnot bind the springs with a huge cam or rockers that hit the spring plates, this is another case of DOVE crap. George Have a nice thanksgiving with your family.
Michael C Henry How big a cam is in your motor?? Do you have good rocker arm clearance though the whole movement?? Is it possible you have spring binding?? A poor machine job at Dove could have caused this problem too. The center 2 bolts take more stress than the otherside ones, the stands break on the outsides. Put a flat gauge across the mount holes and make sure the head machined flat, If the center 2 mounts are lower this will put added stress on the studs. Hope this helps. Rick Lake

Michael C Henry · #11 (**permalink**) 11-26-2002, 07:40 PM

Comp Cams .598" lift.But the problem must have started last June ,when I was reinstalling my intake manifold.The studs must have been ready to start pulling then as I was sure I hadn't tightened the rocker studs enough but after torqueing the clearances kept increasing. That was a Crower cam and had two lobes and lifters gone bad.

GEORGE ANDERSON · #12 (**permalink**) 11-26-2002, 07:49 PM

Hi Rick.....

Actually I've been sending these to people having the problem with Edelbrock heads and this was the first Dove I've experienced this problem on. I'm also of the opinion something else is the cause.
Regards, George

ADR · #13 (**permalink**) 11-27-2002, 12:58 AM

Yep 2 wiped out cam lobes kinda makes you wonder.....

Have any of you guys used the T&D shaft rocker system ?.....I'm setting up a set right now on some Edelbrock's and they are really nice. You have to machine off the rocker pedestals completely and use the head studs/bolts to clamp them down.
They are spendy but like I said, nice stuff.
Dale

GEORGE ANDERSON · #14 (**permalink**) 11-27-2002, 08:56 PM

You'll have more to do and buy than just the few things you mentioned on the T&D's.....
Seems like we have helped them with R&D this past year!
Please post some images of the setup...it would be most interesting!
Regards, George
T&D's on Shelby Heads...

http://www.gessford.com/projects/ima...to427-YY06.jpg

T&D's on Dove heads

http://www.gessford.com/projects/ima...kes427-W07.jpg

kountzecobra · #15 (**permalink**) 11-28-2002, 07:05 AM

Wow, T&D setup looks bullitproof!

wkooiman · #16 (**permalink**) 12-03-2002, 03:21 PM

George helped me fix them. The rockmounts are great.

I have to say the problem was probably installer error (me). I tried installing my rocker shafts with too short bolts. Most stands were okay, but the oiling stand didn't engage enough threads, so it popped out at about 10 ft/lbs. I got the correct length bolts, and replaced the heli-coils, and they were okay.

A few months later, I had the rockers off, and they pulled out again. This time I had everything right, but I guess I had already messed up the threads enough from my earlier snafu. George fixed it with a rockmount, and it is holding great.

Later one pulled out on the other head. I'm guessing I just over torqued it (about 35 ft/lb). It popped out at about 6,000 rpms. I fixed that one with the engine installed (67 Mustang). It is holding great.

I'm no master mechanic, but I'm no dummy either. I don't think I would have had problems if I had measured everything carefully, and torqued the studs to 25 ft/lbs. Still, the heli-coils pulled way sooner than I expected, and the Edel heads seem to be very high quality.

Michael C Henry · #17 (**permalink**) 12-07-2002, 09:39 AM

I now have three styles of inserts including the rock-mounts. I sacreficed the head gaskets and removed the heads so the machinist could use all his special tooling. I can't see doing this again .Hell!, the head gaskets cost me$32 ea plus shippingI'll let the machinist determine how deep he can go. The different inserts have different lengths .515" to .6" something on the rock mounts .Probably just replace the two center locations on both heads.The two outside studsw/ original coils were tested to 40 ftlbs and worked fine. Still can't see the differance between outside and inner stud sockets. Studs are the only way to pull springs down in alluminum.George says he never had to repair stripped Dove heads but has repaired Elderbrocks.So he couldn't say from experinace if The Dove heads would accomadate the Rock-Mounts.The wife thinks I'm doing all this on purpose.I am intimidated by the break-in procses.being cold rainy and no fan. I put several engines together as a youngster before I knew all that could go wrong.After reading all the threads on failures I'm causious.This engine alone has a history of cams haveing lobes going flat( different cams ,manufactures and lobes) after talking to original owner.Can you see the new neighbors w/ baby when I start it up?

wkooiman · #18 (**permalink**) 12-07-2002, 10:54 AM

If it were me, I'd replace all 4 heli-coils while the head is off. The rockmounts look like much better than heli-coils. If two have failed, the other two can't be too far behind. It'll be a lot cheaper and easier to just do all 4 while the head is off and at the shop.

ADR · #19 (**permalink**) 12-07-2002, 12:33 PM

Michael
If the lifter bores are out a wack ( not perpendicular to the camshaft) you will never get a cam to live in that block. You will have to have the lifter bores bushed but most important they will have to be rebored in the proper location.
Dale

PatBurke · #20 (**permalink**) 12-11-2002, 09:09 AM

Responding to the posts about the T&D rockers. The two knocks that I hear about the T&D set up is that the heads have to be modified to use them and you need to convert to pushrod oiling. They may be overkill for a street engine but if you're willing to go thru the effort you'll end up with the most durable FE rocker system available.

We use them on our FE race engines and they have been virtually bullet proof. My engine regularly see's 9500 rpm with over 1000 lb. valve spring open pressure and the lash stays rock solid run after run. They've even seen 10,400 rpm once (broken transmission) and lived to tell about it. No other FE setup that I've seen could survive that.

I have a set of customers Dove HR heads at the shop now that we are converting to T&D. We make a custom lower mount bar for the HR heads. He ran Dove rockers previously and ripped the top of one of the intake ports right off the head. This isn't a hit against the Dove rockers, they work great in most applications, but they do have their limitations and that's where the T&D's take over.



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