help with pyro tap

[HomerDog]

I have trans, boost, and pyro guages/lights all installed on the a-pillar and my last step is to drill for the pyro. I've read as many threads as I can but I've never done this so I have some questions. The DIS instructions call for a 7/16 hole and 1/4" tap. The TST instructions call for 5/16 hole and 1/8" tap. I bought a 1/8-27 NPT tap as it looks close to my temp fitting and the autometer instructions say it's 1/8" NPT. My guages are autometer ultra lites and it looks like the size of the temp sender. How far do I turn the tap into the drilled hole? I plan on not removing the turbo. Sorry for the long questions but I've never done this and I don't want to mess up. Any and all comments are appreciated.

 

[Rob Thomas]

Homer,



I did it by running the tap in a few turns and takin' it out, then check how deep it goes. (by putting the thermocouple in)I can't remember the depth,but the instructions should say that. The tap is tapered, so don't go to deep,better to go a couple of turns and check it. Do that 'till it comes out to the right depth. Hope that helps.



Rob

 

[BFC]

I have Autometer Z's and if memory serve me right tap is 1/8. Tap your hole just the thickness of the manifold, so the fitting won't extend into it. I tape up the tap at the proper dept to make sure I wouldn't go too deep.



If you don't remove the turbo, put some grease on the drill bit and on the tap to catck the fillings. Then use a magnet to get those who fell into the manifold. Make sure you get all of them, you don't want any going through your turbo.



Glenn

 

['956Wheel]

Start the tap and go about 3/16" deep and back it out, try the probe in the hole... . repeat this till you have about 3/4s of the threads (on the probe) in the hole, be sure the hole is real clean before each try. This is a tapered pipe thread so DO NOT go too far as sealing will not be possible.



It is one of those things that is easier done than said... yes done than said. Be certain to start the tap straight. Anti seize is a good tap lube and will catch most chips.



Mike

 

[KFaulk]

I just yesterday installed an Autometer pyrometer without unbolting the turbo. Use a 1/8 inch bit for a pilot hole making sure it is vertical in all directions. The small diameter pilot hole is quuicker to drill so you are less likely to get out of plumb. Use an 11/32 inch bit to drill the hole for the 1/8 NPT tap. Use bearing grease on the drill bits to catch the metal shavings. While drilling the hole, drill until the grease picks up a bunch of shaving, stop driliing, back out the bit and wipe it off, put more grease on the tip and drill some more. Keep doing this until you are almost through the manifold casting. By stopping the drilling and backing out of the hole you can see when the drill is approaching the full depth of the manifold. When the hole is right near the bottom, measure the depth of the hole. Then use this depth to mark on the 1/8 NPT fitting how far into the hole to screw the fitting. The bottom of the fitting should be even with the bottom of the hole, not protruding beyond the bottom. My manifold was very close to 1/4 inch thick. When you screw the fitting so that its bottom is flus with the bottom of the hole, there will be about 4 threads left above the manifold, if your fitting is the same length as mine. Be careful to start the tap straight, use grease on the tip to catch shavings, remove it after 3 or 4 turns, wipe it off, insert the fitting to check the depth, remove the fitting, put grease on the tap and repeat until you have tapped to the correct depth. Don't forget to use a mechanic's magnet (Sears has one that is about 1/4 inch in diameter) to fish the metal shavings out of the hole. I did this each time I removed the drill bit or the tap (overkill for sure. ) Coat the 1/8 NPT fitting with anit-seize compound before installing and tighten the fitting. Two final things - Read the instructions from Diesel Injection Service and TST Products about WHERE and how to install the thermocoupling AND measure the location three times. The only thing you can do wrong that would be a big problem is to drill the hole in the wrong place.

Send an email if you have questions.

 

[WestTN]

temp probe drilling

I didn't remove my turbo either. What I did do was loosen the four bolts that hold it to the exhaust manifold and let it drop away about a quarter of an inch. Then I cut a small piece from an old raingutter to the exact width of the space between mounting studs. I slid the aluminum piece into place between the manifold and turbo and drilled with NO lube at all. The chips were not sticky and slid right out onto the aluminum piece and fell onto the driveway as I drilled and tapped the hole. A careful puff with the air hose ( you can used the canned sprays available at Walmart in the computer stuff ) and I was ready to install the probe. Follow the suggestion above about tapping a little at a time and checking the fit.



Good luck!

 

[Boost]

To be safe I unbolted the downpipe and turbo. I did not remove the oil lines but pulled the turbo towards the front of the truck. I plugged the inlet holes to the turbo and drilled. It took about 20 minutes to get the turbo out of the way and 15 to get it back. In my opinion it was 35 minutes well spent to be 100% sure that there would be no shavings going through my turbo. I dont think that a few shavings going through your turbo at start up would hurt anything, but I would rather it not happen.



Rob

 

[LSMITH]

KFaulk, that is as good as I have seen this explained, great post.



Homer, take a look at ^^^^ and you are in good shape.

 

[nevinst]

KFaulk, that is as good as I have seen this explained, great post.

I agree. Great explaination! I completed mine this past week and did it basically the same but installed a piece of cardboard like WesTN did with the cut aluminum. I used the grease but I suppose leaving everything dry would work as well as long as the shavings were allowed to fall out.



I was afraid to start on the Pyro probe install so I had my guages sitting in the pillar for a week before I dug in to start the job. After it was all said and done, it took less than an hour and a half!



Anyone who is ready to do this should go to this site:



... ... ... http://www.showmestate.org/stltdr/how-tos/EGT_how_to.shtml .....



where there are pictures and great step-by-step instructions. I t really helped me.