Does anyone sell a fixture for drilling broken exhaust studs

[Joeaksa]

Christian,

Beautiful work, please let us know when they are available!

JoeA

[A Quiet Boom]

First prototype in steel I completed just a few minutes ago. I'm off on one dimension slighty (metric to english conversion) and I need to clean up the code a touch. I made this one from 3/4" steel plate because I didn't have a chance to pick up my 5/8" plat today. I figure by monday I can take orders, since I'll want to fine tune things over the weekend.

I'll post a pic when I get home.

[A Quiet Boom]

Well here are some pics of the prototype, I apologize for the photo quality, my camera is old. This is the 41.6mm version with 17/64 x 1" drill bushing.

[Shuie]

Christian, this is great. Thanks for taking on this project! Do you need anything from me or did someone already give you the measurement of the port for a 2.4T?

[A Quiet Boom]

Sherman,

It would be great if someone could get me the port sizes for each engine. Sure would make things much easier. I've got a little code to clean up and I can make parts on Monday night. I'm thinking $100 each and probably $200 for a set of all three sizes. Removable bushings would add $15 to each tool plus the cost of the bushings. Hope that sounds fair. I'll have about two hours into each part when I add in finish work, pressing the bushing, and packaging for shipment. I need to get the weight to give an idea on shipping costs. I prefer to use fedex and paypal.

[Joeaksa]

Christian,

Looks great and am interested in one for a 3.6 engine.

Thanks,

Joe

[Shuie]

I'll get it first thing tomorrow morning and post it here.

The price is definitely fair since you have done all of the work. This place is unbelievable. I dont think there is anywhere else in the world I could ask a similar question and get a response like this.

edit: huge thanks to John Walker and everyone else who has helped out here

[john walker's workshop]

now we need a jig to drill the oil bypass in the engine case. one for drilling dilivars that break off flush, hmmmm, let me think.....

[jpahemi]

I'll take one for a 3.2 port. How close is the port size tolerance between heads? Will the tool disc be a tight fit?
Thank you,
J.P.

[john walker's workshop]

a problem with the 3.6 heads is the somewhat rough/irregular section of the port below the ceramic liner. keying off the exhaust gasket groove might work better. either that or expect to have to dress the port a bit to accept the tool. the port on this 993 head varies from 37.90 to 38.20. not good for getting the drill guide dead center over the stud.

[A Quiet Boom]

Originally posted by jpahemi
I'll take one for a 3.2 port. How close is the port size tolerance between heads? Will the tool disc be a tight fit?
Thank you,
J.P.

I'm working on getting a list of which engines have which sized ports. The plan is for a tight fit so that the drill centers directly over the stud.

Edit, should have read the post thoroughly. I don't know the head to head tolerance. I would think a touch up with a die grinder or file on any high spots would allow the tool to seat nicely and give the added benefit of matching your ports more closely. Having said that, 911 ports are some of the smoothest I've seen on a production car and I would think they are much more even than say a Ford. The tool won't work properly unless it seats tightly so you can drill just the center of the stud.

[A Quiet Boom]

Originally posted by john walker's workshop
a problem with the 3.6 heads is the somewhat rough/irregular section of the port below the ceramic liner. keying off the exhaust gasket groove might work better. either that or expect to have to dress the port a bit to accept the tool. the port on this 993 head varies from 37.90 to 38.20. not good for getting the drill guide dead center over the stud.

JW, keying of the groove would be simple, it's only 6 additional lines of code. Check your pm.

[jpahemi]

Christian:
Thanks for the reply. I was checking McMaster; what type of drill bushings will you be using? "H" type (shoulder) or the "P, PM and PC" type? I guess the will be the wear item of the tool, yes?
Regards,
J.P.
Ps. ID of the bushing: .2656(6.746 mm), .3125 or .316"?

[A Quiet Boom]

Originally posted by jpahemi
Christian:
Thanks for the reply. I was checking McMaster; what type of drill bushings will you be using? "H" type (shoulder) or the "P, PM and PC" type? I guess the will be the wear item of the tool, yes?
Regards,
J.P.
Ps. ID of the bushing: .2656(6.746 mm), .3125 or .316"?

I'm using the headless P type. They don't have a carbide PC type in 17/64" that john walker recommends. I can supply the tool with any bushing the customer wants at an additional charge. I can also supply with removeable bushing for $15.00 additional plus the extra bushing sizes if needed. Standard ID is 0.2656"

[jpahemi]

I apoloigize if this question is a bit off topic; in an ideal situation, if all the studs could removed, would it be feasible to replace the studs with an A4 stainless alloy? I recall seeing these advertised in Excellence a few issues back.
Regards,
J.P.

[jpahemi]

Christian:
Removeable bushing would be with set screw?
Regards,
J.P.

[A Quiet Boom]

J.P.

I would think stainless would be OK, but I'm not an expert on these cars. With this tool you could remove all the studs by doing one at a time. I'd be more tempted to just use a quality anti-seize on the threads as I've done on many other cars with great success. PermaTex makes a good one.

[A Quiet Boom]

Originally posted by jpahemi
Christian:
Removeable bushing would be with set screw?
Regards,
J.P.

Yes, and a flat ground on the bushing so it doesn't spin.

[jpahemi]

Christian:
Sent you a PM.
J.P.

[5axis]

Originally posted by john walker's workshop
a problem with the 3.6 heads is the somewhat rough/irregular section of the port below the ceramic liner. keying off the exhaust gasket groove might work better. either that or expect to have to dress the port a bit to accept the tool. the port on this 993 head varies from 37.90 to 38.20. not good for getting the drill guide dead center over the stud.

My suggestion for "keying" the groove would be to pop in 3 dowel pins of the appropriate size to locate in the groove. This reduces the chance that some crud or other stuff in the goove could interfere with the locating function. The pins do not need to match the width of the groove. The pins could be any common size smaller than the groove width. They would need to be located tangent to the ID or OD. Time to brush up on your trig, and a good excuse to buy that +/- reamer set I told you about previously.



Hand fitting cr@p under a microscope gets old, leave yourself a thou or two per side. It will still be more accurate than the holes themselves.


Keep up the good work and keep it fun!
david