March 28, 2024, 11:26:27 PM

News:

For advertising inquiries or help with registration or other issues, you may contact us by email at help@harleytechtalk.com


Tap size

Started by Dan, March 25, 2019, 10:28:29 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Dan

I need to helicoil rocker assembly hole in twin cam heads. 1. What size helicoil will I need, 2. Will helicoil be sufficient for 20ft lbls. of torque? I have a drill press to enlarge the hole in the head. Thanks all!

rigidthumper

March 25, 2019, 10:34:02 AM #1 Last Edit: March 28, 2019, 10:28:38 PM by FSG
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

Norton Commando

Quote from: Dan on March 25, 2019, 10:28:29 AM
I need to helicoil rocker assembly hole in twin cam heads. 1. What size helicoil will I need, 2. Will helicoil be sufficient for 20ft lbls. of torque? I have a drill press to enlarge the hole in the head. Thanks all!

The helicoil repair will easily handle 20ft-lbs of torque.

Jason
Remember, you can sleep in your car, but you can't drive your house.

Armin

The tap size  for the rocker support plate is 5/16-18 and my favourite thread repair system is Timesert, I secure the inserts with JB Weld, it's rocketproof.
If you use timesert you'll need longer inserts, measure the depth of the threaded hole and make your choice accordingly.
Check their website: http://www.timesert.com/html/inchsert.html

Armin.
Nothing can ruin a Man's day faster than an Almost-Takeoff!

92flhtcu

Need a bigger garage

Ajayrk

Quote from: Armin on March 25, 2019, 11:58:54 AM
The tap size  for the rocker support plate is 5/16-18 and my favourite thread repair system is Timesert, I secure the inserts with JB Weld, it's rocketproof.
If you use timesert you'll need longer inserts, measure the depth of the threaded hole and make your choice accordingly.
Check their website: http://www.timesert.com/html/inchsert.html

Armin.

:agree:
AJ

Dan

Thank you gents for your quick replies and knowledge! I appreciate your help!

Mattbastard

FYI, it's pretty imperative that you drill and tap perfectly perpendicular to the surface.  I learned the hard way if you don't use a drill press or a mill to direct the drill and start the tap and assume you're straight that the ensuing bolt will rub against the rocker box as you drive it in.  Fingering the bolt in and out isn't possible. 

Dan

I'm going to pull tbe head and do this on my drill press. Swapping out the lifters while I have them off. Thank you for the heads up! Much appreciated😊

Hillside Motorcycle

Properly installed Heli-Coil brand thread repairs, work great.
When doing machine work for the once McDonnell-Douglas Aircraft Company, while living in the St. Louis metro area, the Mil-Spec drawings stated the use of Heli-Coils at the initial point of manufacture in certain aluminum parts.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Dan


Mattbastard

When you think about it, threaded inserts make a LOT of sense when driving a steel bolt into an aluminum hole.   :koolaid:

Rsw

Caterpillar has used helicoil inserts for years in aluminum parts

Norton Commando

Quote from: Rsw on March 28, 2019, 09:50:20 AM
Caterpillar has used helicoil inserts for years in aluminum parts

The axial capacity of a bolted connection in aluminum is stronger with a Helicoil than without it.
Remember, you can sleep in your car, but you can't drive your house.

BB Stacker

I was an F-14 Ordnanceman in the Navy. All AIM-9, AIM-7 and AIM-54 A and B station launchers were attached and had helicoils for strength and ease of O level repairs of damaged threads. 500 pound missile plus launcher held on a supersonic fighter jet with helicoils. I am a big fan of that product. But I do understand that there are places where timeserts are much better suited to the application.

FSG

QuoteBut I do understand that there are places where timeserts are much better suited to the application.

:agree:

  jackrocks fixin pulled threads

[attach=0,msg1289570]

[attach=1,msg1289570]

[attach=2,msg1289570]

[attach=3,msg1289570]

Hillside Motorcycle

Full-Torque Permanent Thread Repair Inserts
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

vtwinjim

Helicoils are designed in from day one in aluminum on our designs. They allow higher torques than a plain aluminum thread.

Stainless and aluminum don't get along when it comes to galvanic corrosion. We typically install helicoils with a special 'paint' to prevent the aluminum from being attacked. This is probably not a problem in oiled cavities.

Our inserts also have a dry lube coating to prevent galling if using stainless steel fasteners. Chrome against stainless also can gall. Cadmium plating on bolts is a good lubricant, so galling may not be a concern.

Just some information to consider.

doubletrouble

On a twin cam - Would the .620 length time sert be the correct length sert for the 5/16-18 retainer bolts for the rocker support retainer bolts ?

rigidthumper

That would be 2D (2 times the diameter), so it should be adequate, as long as the parent material is OK.
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

ΚĜΗΟŜΤ

I do Rochester Quadrajets from time to time for my friends muscle car Chevelle's.
7/8-20 helicoil tap $70.00 threaded insert for fuel inlet $2.00....................priceless!
Member since 2004