Does anyone sell a fixture for drilling broken exhaust studs

[K.B.]

The best part of this tool is dealing with Christian. Great guy to deal with. I bought one and it did the trick. I bought a new drill bit, and everything went smooth. I then ran a tap thru the hole. It was slow going. I kept turning it a 1/16 of a turn and backing it out I tried wd-40 for cutting oil, then I tried penetrating oil. I finally found MMO (Mystery Marvel Oil) and it gave the easiest turning. I'm not sure if I was threading thru aluminum or the remnants of the stud. I was worried I was going to break off the cheap tap I was using. I spent an hour running the tap in and out. Maybe there is a better cutting oil out there. There is probably a better tap to use. Maybe Christian wil include a drill and a tap in a "KIT"

Anyway what a relief to have it done. Next time I will use the torch on all the nuts (exhaust that is)

[john walker's workshop]

you're not really supposed to run a tap in there. the object of the game is to drill out the shaft of the stud, leaving the threads. the threads are then picked out using a hammer on a small, sharp punch and sharp pointy needlenose pliers. work the end of the thread out enough to grab it with the pliers and twist counter-clockwise to uncoil the threads. some come out fairly whole, like a helicoil, and some in smaller sections. if they break, start again. using a tap in a hole like that, which still has the threads loose around the outside can do some serious damage as the threads break into bits and chew up the aluminum. use a thread chaser to clean up, only after removing the remaining threads.

[TimT]

Word... JW says the shizzle

[A Quiet Boom]

Thanks for the kind words Ken and the advice JW. I'm going to offer a kit that includes a high quality carbide bit and some cutting fluid. I agree on the tap, use it only after removing the threads.

I finished my first blank for the professional kit today. It will have a circular pocket to accept inserts that fit various ports. The base kit will include the three most common insert sizes. A second kit will have a second tool with the proper bushing to drill the hole for a timecert. I will offer all necessary insert sizes on a per order basis. This is the kit I will be sending to JW for his opinion.

I really appreciate everyone's input on this project so far and I'm glad I can help the hobbiests and pros alike.

[K.B.]

Thanks JW. I fiddled for an hour with dental pick type tools trying to do the uncoil thing, didn't get anywhere. Gave up and went for the tap. Figured the next step would be to drill for oversize stud or helicoil so what did I have to lose?

[john walker's workshop]

you gotta use a small punch ground to a pencil point and a hammer to get behind and pry out the end of the thread. if you can't figure out where the end is, just get the first coil started. sometimes you end up with a small groove down one side of the threads, from the hammer, pry and twist procedure. it doesn't hurt anything as long as all the punch work is in the same groove, instead of all over the place. i ground down the outside of some needlenose pliers a bit to allow them to get to the bottom of the hole. designated thread grabbers.

[Shuie]

Originally posted by K.B.
The best part of this tool is dealing with Christian. Great guy to deal with.

I couldnt agree more. Chris is first class.

I still have not drilled mine out to 21/64 for the helicoil tap yet. I'll try JW's method of removing the thread so I can get some pics of what I did. I know I didnt ruin all the thread, maybe theres actually enough left for a stud to thread into.

[A Quiet Boom]

I was working on the final production prototype of the professional version and it got me thinking, there where a few posters who where interested bet we still needed measurements of the exhaust ports. Did anyone ever get the dimensions of a 3.6 exhaust?

BTW JW your tool should be on the way sometime next week.

[Jeff Alton]

I should have one here shortly, email me at pacwestperformce@telus.net and once it arrives I will get what you need.

I am also in the market for your tools, when available.

Thanks, Jeff

[A Quiet Boom]

Tools are now available, I brought some to Hershey but left early do to the weather and lack of sleep the nights before. Presently I have sets with eight disks, still waiting on 3.6 measurements. I can be reached directly at rsr911@neo.rr.com which I check several times a day. I'm also still making the integral disc tool which is usable for only one port size. All tools include a hardened drill bushing and the pro-tool has the option of removeable bushings to drill just the center out of the stud or the entire stud, extra bushings are $10. I'd love to sell these cheaper but unfortunately it's 3 setups on the CNC plus a setup on the manual mill for each tool then I have to verify all measurments and press in the bushing so it's a time consuming endeavor. I highly recommend the pro tool with one disk since any decent machinist could whip up a disk in another size for a different engine or I can usually ship next day, for the extra money you get a tool you could share amongst friends etc.

These are precision pieces, several pelican members saw them at the show and I think the response was rather good. I've also sent a tool to John Walker and am waiting for him to get a chance to use it so I can get his input although he did mention via PM that the tool looked good. I'll post some pics of the tools tommorrow after I get some rest from the long drive back today.

[Nine9six]

I would think alum would suffice with the harended inserts. Alum would certainly quicken the machining time, along with lessening end mill tool wear.

[A Quiet Boom]

Originally posted by Nine9six
I would think alum would suffice with the harended inserts. Alum would certainly quicken the machining time, along with lessening end mill tool wear.

Had this dicussion with John Walker and he prefered steel. Remember many of these tools will go to mechanics and need to last a long time. Aside from that the extra cost for alum vs. steel makes up for the endmill wear and machining time somewhat. Alum doesn't necessarily machine that much faster since chip removal is more difficult. The big time consumer is all the setups on the machines, if I make a ton of tools in one shot it's no big deal but when I'm only making one or two the time really adds up. I'd also be concerned about wear when replacing the disk inserts for different port sizes, it's critical they are a tight fit to insure proper alignment over the center of the stud. Figure 0.001" clearance for the tool to disk and 0.001-0.002" for the disk to port, an alum disk and tool will wear faster and these tolerances will build up and not allow proper centering.

[drophit]

So this is for the 87 3.2 carrera motor also?

[A Quiet Boom]

Yes the tool works for a 3.2 as well. I still need measurements for a 3.6 and a few rare engines but with 8 disk sizes I've got most 911's pretty well covered.

[drophit]

Is there a cheaper one-use version? I only need it for one stud and $150 is a little steep for my needs.

[john walker's workshop]

yeah, a drill bit and an eyball. good luck, it might work.

[drophit]

WOW! Reason i asked was i noticed some earlier versions in this thread that show a simpler tool, without the extras and wondered if you'd sell those for the home mechanic.

[A Quiet Boom]

The single use tool sells for $110. I prefer an exact measurement of your port prior to making the tool though. For $150 you get the pro tool with one disc, you can use it and through it in your tool box. If you ever get another car or a buddy needs help I can send other discs or a local machinist can fix you up.

I want to stress that I don't make much money on these, after purchasing materials, machine setup, etc. I make less than I do at my regular job. Given the alternative (removing the motor and head and taking it to a machine shop for repair) this tool is really a bargain and it works really well. I tested it on some scrap heads sent to me by another member and was impressed at how accurate the setup works.

[drophit]

Hum so the cost is $110 for a one use setup?

I may be coming back to this thread with a solution for the home mechanic, i dont see why this can not be done for under $35.

I mean couldn't a simple aluminum piece simular to the one pictured on the first page of this thread be used? And then the cost is MUCH lower? Then the guides etc from the mc people

Z

[A Quiet Boom]

So for $35 you're going to mill a piece of aluminum, accurately bore three holes, bore a concentric pocket, ream the drill insert hole 0.001" undersize, fire up the lathe and make a disc with two precise diameters on it and intall a $9.00 bushing. Have at it, I'll keep making a tool that I know functions well and that I've quality checked every measurement before shipping that's made of steel to hold up to repeated use.

As John Walker stated earlier in the thread, it's critical that the drill line up dead center on the broken stud and that type of accuracy takes time and therefore money.