View Full Version : Drill Guide for Head Bolt Inserts

07-01-08, 05:38 PM
Hi guys,

I have my N* and torn down and am ready to start drilling for installing Norm's Inserts, but I am weary about doing it freehand.

I remember seeing where someone modified the Tap Block that Norm provides in his kit but I have been searching for the past couple of days and have been unable to find it again.

Can anyone help with a link? I know that a lot of you have freehanded this with good results but I prefer to be a little more on the safe side - but I am also not interested in spending lots for a timesert kit for the drill guide.

07-01-08, 06:12 PM
All you really need to do is use the tap block as a guide and check for square in both directions (N-S and E-W) several times - especially when starting out. To answer your question, what someone did, I think, was to drill through the tap block with the drill, thereby making a guide to get the hole started. Just be sure the hole is at 90 degrees, or every hole you drill will automatically be off.

I I know you said you prefer to be safe, but you really don't need a guide. What you really DO need is a helper. I would agree that without a helper, it will be pretty hard to get the holes correct without a guide of some sort.

You will know how you did when you get to the bottom of the hole. If it is perfect, the outer portion of the bottom of the hole will be shiny, and the center, where the bit has been ground down to prevent drilling too deep, will still be dirty looking, since it was not touched by the bit. Don't fret if you are a little off - I was on a few holes and it bolted up just fine.

07-01-08, 08:45 PM
Thanks for the vote of confidence Richard - I guess I am just being a bit anal, and afraid - I want to make sure I don't mess things up.

I have pics of the teardown - as soon as I get them off the camera I will post links to them.

07-01-08, 10:47 PM

07-01-08, 11:00 PM
Two minutes with a drill press and a hardwood block will produce a servicable drill guide.

07-02-08, 01:48 PM
Jeff - call me at work to discuss if you want - 877-992-2766 X516. Maybe I can give you some advice that will make you feel more confident. Or look at my thread:


I covered the entire deck, including the timing chan cavity, with clear package sealing tape, and then cut out the tape from each cylinder head bolt hole with an Xacto knife. I must say this worked really well at completely sealing off the engine from all the metal and trash generated by the drilling and tapping operation. Overall, I am very pleased with Norm's kit. The only tricky part is starting the hole straight. I had a helper that held the supplied tap block to be sure I was square to the head. I would start and drill maybe around 1/8" and then stop and recheck with the tap block to be sure I was going square and make any needed adjustments. I checked again at maybe around 1/4", just to be sure, but I was always OK at that point. From that point to the bottom of the hole, about 3" deep, there was smooth sailing. It was easy to tell the bad holes by the type of trash thrown off by the drilling operation. The end of the drill bit is ground to prevent going too deep, so the very center of the hole is left untouched. It was apparent by the shape of the untouched aluminum that all off the holes had been drilled straight and square. I used a little flexible head mini flashlight to see inside each hole, and it worked great

Once the hole is drilled out, the next step is to use the tap block and a supplied tap with a tapered end, then repeat the process with a bottoming tap with a square end. Pretty standard stuff here - no challenges or surprises. The supplied tap oil is designed specifically for aluminum and works very well. I am leaving the final steps of cleaning and degreasing the inserts and holes and installation of the inserts with the supllied Loktite until the re-assembly stage, so I won't have to worry about keeping the holes clean.

QUOTE=jeffrsmith;1564279]Thanks for the vote of confidence Richard - I guess I am just being a bit anal, and afraid - I want to make sure I don't mess things up.

I have pics of the teardown - as soon as I get them off the camera I will post links to them.[/QUOTE]

07-02-08, 04:02 PM
Richard - thanks for the offer, I know that I can do it . I will have my neighbor over to help and I will take my time. Just being a bit over cautious I guess.

I have a roll of masking tape and intend to cover the whole works after I get the old gasket material cleaned off. I have a long weekend with the holiday, hopefully I will find time to get the inserts in and get the heads back on - I am really getting excited about getting it back together. Unfortunately there are more delays on the horizon - I have to do some travel to Ohio for my job end of next week so after this weekend it's going to be another three before I can do any further work on the car.

07-02-08, 07:33 PM

I messed up and forgot to quote this.

I agree. Norms inserts are a great product.... except for the lack of a drill jig. I modified the tapping jig, which he supplies, to double as a drill jig. I also added a piece of angle iron to the side and drilled it so you can bolt it down to an adjacent head bolt hole for stability. workes very well now.


07-02-08, 08:38 PM
AJ - that is exactly the picture that I was looking for.