Date: Tue, 18 Mar 2008 18:55:58 -0700
Reply-To: aatransaxle <daryl@AATRANSAXLE.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: aatransaxle <daryl@AATRANSAXLE.COM>
Subject: Re: Exhaust stud replacement on heads
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Its a real PITA to get them drilled straight..Even after 30 yrs of cussing
the job, I still don't always get it right..
Some machine shops have whats called an EDM which eats out the stud or tap
or drill electrically, but is only good if the head is off. My neighborhood
machine shop has one when taps break during CNC machining. Otherwise..
Getting a flat surface is critical to center punch and start a small drill.
I file or grind a flat if there is a bit sticking out above the head to
start it centered. If its below grade, just try to punch a flat spot and
center punch it so a small bit can be started in center. I have a larger
punch that I made to fit into an 8mm hole and ground the tip into a center
punch, so the hole trys to help keep the center punch straight. Drill bits
wander a bit, so you need to be very careful to keep on top of it..Try
tilting the drill to re center if need be..By all means, do not push the
drill bit very hard in the beginning or it will break off...Just a starting
hole will do so you can continue with a larger bit...Many times you will end
up crooked or off center no matter how careful you were.
In that case, just get rid of the existing stud and try to get it
straightend out after with the larger bit and do the timesert or helicoil.
Patience is key...Beer is not a necessity, but may help in
moderation...Oh...and good luck...you will need it.
Daryl of AA Transaxle
(425) 788-4070
aatransaxle.com
----- Original Message -----
From: "craig cowan" <phishman068@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, March 18, 2008 9:19 AM
Subject: Re: Exhaust stud replacement on heads
> how do the professional shops do this?
> especially lining up the drill/press to drill a proper hole
>
> I know of at least one "professional" shop here in PA that i'd recogmend
> whole heartily against! They did this repair in the van.....and broke off
> a
> drill bit in my head....
> Lets just say they never "Fully repaired" it. Now it's getting the
> attention
> it needs : )
>
> -Craig
> '85GL
>
> On Tue, Mar 18, 2008 at 11:15 AM, thomas LaPointe <vanagonmail@gmail.com>
> wrote:
>
>> Good Morning all...
>>
>> I have been searching the archives, but have not found any repair advice
>> on
>> replacing the exhaust studs on the waterleaker heads. we need to rebuild
>> a
>> set I have and have done one with helicoil, but wondered if there is a
>> more
>> proper/better way to do this. how do the professional shops do this?
>> especially lining up the drill/press to drill a proper hole. also, how
>> deep
>> can you go before striking water!
>> thanks, Thomas
>>
>>
>> --
>> 1985 Full Westy "Rustfalia"
>> 1982 Full Westy "dead engine"
>> 1991 GL
>> 1972 Honda Z600 2 cyl
>>
|