cylinder head studs

Discussion of the Aerovee kit engine.

cylinder head studs

Postby surfly » Tue Jan 05, 2016 9:00 am

I would like concrete information on the installation of the cylinder head studs into the case halves. I have searched my assembly manual that came with my kit which shows the different length locations with no installation instructions other to install them. In the video the assembler simply screws them in with his hand without mention of how far or any torque specs. It seems to me that they need a sealant on the threads to prevent oil from seeping through the threads.
Did I miss some data from somewhere ??
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Re: cylinder head studs

Postby surfly » Tue Jan 05, 2016 9:17 am

I just watched another video of rebuilding a v-dub engine and the mechanic pointed out that the case half inserts are blind.
"Onward through the fog".
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Re: cylinder head studs

Postby Klimek » Tue Jan 05, 2016 11:43 am

Surfly,
Being a retired VW tech, this is what I did.
The longest studs go on the bottom 4 locations on each side. The next longest on the top outer locations. The shortest studs screw into the two
inner inserts. The intake manifold is located here and these studs are the shortest of the 3 lengths. I installed with BLUE Loctite and just snug them down.
If you torque them probably 30 in/lb will do. Just double nut them. Be careful to not to over tighten and cause the steel insert to turn in the case. This could
cause contact with rotating parts in the engine. Notice some of the steel inserts have been ground and at an angle for clearance for the crank counterweights.
As far as leaks go, the inserts are closed off in locations where they extend into the block where oil is present, the others are in the case where they do not
extend into an area that has oil. They simply are bottomed out in a threaded hole.
Hope this helps.
Frank
ONEX 090
N1970T
~55 hours
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Re: cylinder head studs

Postby kmacht » Tue Jan 05, 2016 11:45 am

The inserts are blind and the torque is applied when you tighten down the heads. You are over thinking this step.

Keith
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Re: cylinder head studs

Postby surfly » Tue Jan 05, 2016 5:55 pm

I discovered shortly after the jubilance of watching a video which stated the inserts were blind I found that the ones in my AeroVee case are not. Fortunately my hangar partner, Walter Eisenman, who has built these engines came to my assistance by explaining basically what Frank had said and I am now on the right track.
Thanks to all,
Surfly
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Re: cylinder head studs

Postby mike.smith » Tue Jan 05, 2016 7:14 pm

Note that after you test fit the heads and the rocker arm assemblies you will almost certainly have to cut the ends of some of the studs or they will contact the rocker arm assembly. So make sure you do this work before you are putting everything together for the final time, since cutting the studs with a hacksaw or Dremel will create lots of metal dust. And take into account the torquing the heads will cause the rocker arm assemblies to get even closer to those stud ends, so make sure you cut off enough.
Mike Smith
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Re: cylinder head studs

Postby surfly » Sat Jan 09, 2016 9:59 am

The cylinder head stud inserts that came with my case halves ARE NOT BLIND. During the interior machining of my case halves the inner or blind end of the insert was completely cut off. This makes for a very difficult assessment of how far to thread the studs inward or outward. This condition also obviously calls for sealing the threads into the inserts. None of the directions for sealing these studs are mentioned in the AeroVee manual or video. I think that the machining was done improperly and the case halves are not usable.
Sherm
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Re: cylinder head studs

Postby Rynoth » Sat Jan 09, 2016 12:21 pm

It's quite easy to turn the inserts if you apply too much torque to the studs by double-nutting. However I found using only my fingers didn't engage enough threads on the stud before I couldn't turn them any more. So I would double-nut, and just try to get as many easy turns as you can without spinning the inserts. I'd say a good rule of thumb would be to engage as many threads into the insert as the top nut has (4-5?)
Ryan Roth
N197RR - Waiex #197 (Turbo Aerovee Taildragger)
Knoxville, TN (Hangar at KRKW)
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Time-lapse video of my build: https://www.youtube.com/watch?v=Q8QTd2HoyAM
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Re: cylinder head studs

Postby Sonerai13 » Sat Jan 09, 2016 4:46 pm

surfly wrote: I think that the machining was done improperly and the case halves are not usable.


Your cases are fine and perfectly usable. Just thread the studs in until they are fully engaged in the case saver threads. That's all the deeper they have to go. You don't want them protruding into the inner side of the case.
Joe Norris
Sonex N208GD (S/N 450)
Sonerai II N13NN (S/N 1206)
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Re: cylinder head studs

Postby surfly » Sun Jan 10, 2016 9:47 am

Joe, I see your point and have already considered it. What sealer would you recommend for the threads? If they are not sealed crankcase oil will then run out the threads like an Oklahoma oil well. I am still unconvinced that the inside of the case halves were not cut too deep during machining thereby cutting off the inside end of the inserts which are normally blind as they are in in automotive use. The crankshaft clearance does not look to be a factor. I am surprised that other builders have not brought this subject forward before now. If the head bolt rods are truly expected to be installed in the manner that you recommend then I suggest that Sonex makes note of this in the assembly manual as well as the video.

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