Header bolt

Curious that the heli coil would not go in , but the time sert did .
Missing some facts .
Im Thinking the second hole was never taped for a heli coil .
 
Timeserts are good but I have used helicoils in multiples of engines with no problem and still holding up well. The solution is an insert then a stud then a coupling nut as they are long enough to drill for safety wire.
 
10 -4 I have heli coil kits so until I need something else I may try a time sert then .
I guess i'll have to get a time sert and see if it fits a heli coil thread .
 
jjchat said:
Time-serts require a counter bore (which is the second step referred to) prior to threading the hole for the insert. I don't it woul work if a heli-coil had already been inserted and then removed. Might be able to be cleaned up with a thread chaser well enough to put in the insert.
Click to expand...
On my engine, I had been able to get a heli coil threaded into one of the holes. We took that coil out, used the time sert tools, and were able to cleanly get the time sert into the hole. Took only 5 minutes, and worked great.
 
jjchat said:
Installing a stud in place of the head bolt would not be legal under Briggs 206 rules.
Click to expand...

That is 100% incorrect.



34. Exhaust Header


a. Header must be RLV Model 5507 or 5506 for all classes.

b. Header length:

a. 5507 will measure 18.75” +/- .25” along the short side using a 0.250”

wide tape measure.

b. 5506 will measure 17.50” +/-.25” along the short side using a 0.250” wide

tape measure.

c. Gasket and/or silicone are allowed to seal header to head. (One gasket

maximum)

d. Studs or bolts are permitted to fasten header to head. Bolts or nuts must be

safety wired.

e. Helicoiling of the exhaust is allowed.

f. Supplied header support brace is mandatory. The addition of a mechanical

support bracket (no welding involved) is allowed provided that there are no

alterations to the shape or dimensions of the exhaust configuration.

g. Any modification for or use of an O2, EGT, CO2 sensor is prohibited.
 
I think my post was the first to indicate a stud, but I assumed we were still talking about the header, not sure where the confusion came from.
 
fatboy1dh said:
Wow... in a 2 page thread about header bolts, I guess your post is technically correct, but irrelevant. I, too, assumed we were still talking header bolts and studs.
Click to expand...

My apologies, I misread the thread title.

FWIW, when doing an engine for clients, I replace the header bolts with studs and use coupling nuts. I also ditch the cometic gasket and use a copper gasket with sealent. I have yet to have a thread failure when using this procedure. I believe the copper gasket is the key component as with some movement, the cometic gasket breaks down and lets the pipe begin to move. From there, it doesn't take very long to destroy the threads.
 
The front brace has solved most of the problems, before that you were lucky to get one race before it broke around the bolt on the rear brace , if you didn't notice the header followed soon after. Fix that all up solid then it pulled the threads.
 
It depends on the brand of insert you get as well.
Each has their own tap/thread/pitch it seems.
I generally start out with a Heli-Coil if the hole is not too large already, then I have two different diameter inserts that I can go with (if needed.)
The larger insert barely fits and if you get too heavy with the installation tool, will deform the port a bit (= nokey-dokey in the tech barn,) so be careful.
We've offered this service for 30 years (going back to the early flathead days) just that few want it done until after it becomes a problem. ;)


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?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
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