Datsun Roadster Forum-311s.org

So I'm a big dummy and stripped the threads on my 1600 aluminum head for my temperature sensor. Well some threads are still there but not enough! What's the best way to repair this? Helicoil? If so does anyone know the correct size? Can it be done without removing the head?

Thanks in advance for any advice or input.

I have used Helicoils on a lot of different repairs, and have never been disappointed. I have probably a dozen kits but have never done one in Al but I don't know why it wouldn't work. Some dis-assembly would be involved in order to get to it.

Thanks for the reply. I've done helicoiled in aluminum before. Problem is the tab on the back side of the helicoil will be in the way of the temp sensor. Somone else mentioned a Time - Sert insert. Looks similar to a helicoil but may not have the tab on the back side.

I think that the tab is supposed to be broken off and removed

I've done the brass adapter on senders if you can cut more pipe threads on the aluminum
Napa had them ....thread tape it

redroadster - I could retap the threads a size larger. Could you explain the brass adapter? Part number? Thanks.

Spl310 - Just checked and you are right about the tang being broken off. Guess I'd need to pull the head to do it so I don't get metal shaving in the cooling system.

I was thinking pipe thread ...this is the cartridge and cap right that alumaweld brazing rod and then cut same threads should work

mblue97 wrote: ↑Fri Dec 25, 2020 10:48 pm Spl310 - Just checked and you are right about the tang being broken off. Guess I'd need to pull the head to do it so I don't get metal shaving in the cooling system.

mblue, don't worry for a second about a few bits of aluminum in your coolant. It is not part of your lubrication system and in the operating life time cooling systems carry plenty of particles of all kind of stuff.

C.Costine wrote: ↑Sat Dec 26, 2020 8:09 am

mblue97 wrote: ↑Fri Dec 25, 2020 10:48 pm Spl310 - Just checked and you are right about the tang being broken off. Guess I'd need to pull the head to do it so I don't get metal shaving in the cooling system.

mblue, don't worry for a second about a few bits of aluminum in your coolant. It is not part of your lubrication system and in the operating life time cooling systems carry plenty of particles of all kind of stuff.

Yep, I thought pulling the head was a bit extreme as well. Worst case I would think you could turn the heater core by-pass valve on, drop the radiator hoses and do a quick flush. That's not even really necessary.

Put grease on the tap. It will catch most of the cuttings

Make sure you leave the shoulder in the hole or the head will be shot

You are not going to be able to thread insert “heilcoil” the hole. 2 Problems 1 the insert needs parallel threads so you would need to drill through the sealing seat which would make it impossible to put the sender back in. 2 I’m I do believe that it’s a metric parallel pipe thread and I don’t think that they make a insert kit in that thread. I think you are better off pulling the head and see if someone could repair it or just replace the head with a good head. There are a lot of R16 engines laying around from converting to SR and KA engines. Might be the easiest way out.

When I discovered the temp sender was stuck on my car, I was advised about a method to “ burn out” the sender which a certain company in my area did.I did not do it because the head had to be removed for this to be done. Could anything like this process be done to remove remaining material and prepare for further work?
I think I would take the head to a machine shop for a fix beyond the above idea. Can’t risk messing up the head.
I wound up leaving the temp sensor alone and going to a mechanical temp sensor , which does the job OK
Linda

Before pulling the head, I’d see if there is some kind of epoxy or heat tolerant sealant. That sensor is not under a ton of pressure( maybe 9-10 psi when hot) so if you have at least some threads to grab onto, an epoxy might get you wheee you need to be. At least until you find a more permanent solution.