[240/260Z]

I am attempting to clean out the head bolt threads in my 260 block with a new
10 mm X 1.5 tap. How much resistance should I have while screwing in the tap by hand (without the "T" shaped handle)? I bought a new 10 mm X 1.5 nut to test it and it screws in about 2 or 3 full threads and stops. The nut screws on the bolts very easily/perfectly. Should I use oil while cleaning the threads? I thank you for your help. Ernest, Las Vegas

 

[FlameZZZ]

Deffinetly use a light weight oil,and if you want a cool little secret,take a round speaker magnet and put it around the hole that your tapping,this will pick up most if not all pieces that you break free,and yes there should be some resistance in every hole but once you finish the tap try running a new bolt down the hole and see
if it feels right,good luck.

 

[GrahamBCZ]

Another tip

Get some wide masking tape and completely cover the top end of your engine with it. You will have to clean and de grease it for the tape to stick. Just tap the holes through the masking tape. It will prevent stuff from going down the bore and into the water jackets. Compressed air helps to blow out the holes if you have it. The magnet trick works too. Also, coat the tap in grease, it will help lubricate it and the metal filings if any, will stick to the grease.

 

[alan240zt]

Machinest trick

When the tap starts getting tight, back it off a half turn or so until its free, then go forward another turn, then repeat the above until you hit bottom. This allows the filing/rust/etc to lay in the grooves of the tap and be removed when you are done. The other tips given above should also be done. After blowing out with with air the head bolts should be oiled and screw all the way in easily by hand. Check it before putting on the head.

 

[240/260Z]

Re: Machinest trick

Thanks guys; your information is going to keep me out of a lot of trouble. Ernest