Penetrating the water jacket of the head

[SKW 4084]

A tale of caution whilst trying to improve rocker rocker cover threads. So I was using a Timesert 1/4 thread insert, I managed to penetrate into the water jacket of the head. I drilled out the new size hole taking into account the depth of the existing hole. I threaded the hole for the insert, then proceeded to run the insert in with the given tool but that's when my problems started. The insert becomes tighter whilst running into new position this is as the last few threads that are not completely machined in production expand and lock the insert into position. Trouble for me is that I ran the tool a fraction too deep and appear to have penetrated the water jacket, although the particular hole does sit close to a core plug. So I know have a convenient hot water source on the top of my engine. Any ideas, I'm thinking new head.

[Keith]

What's the actual problem Stephen? You can put in the thread insert and then fit a stud with some thread sealing compound.

The exhaust manifold studs are the same, they go straight into the water jacket, but it's not a problem, the studs seal it off.

[SKW 4084]

Hi Keith
Wouldn't the hot water find it's way past the threadlock. But I see where your coming from. Ok so reduce water in engine so hole dries out then install insert with stud rather Rather than insert tool and leave it in place .hmmm it could work I'm sure.
Steve

[Chris_R]

What's the actual problem Stephen? You can put in the thread insert and then fit a stud with some thread sealing compound.

The exhaust manifold studs are the same, they go straight into the water jacket, but it's not a problem, the studs seal it off.

Exactly so and I can confirm I've done this on the exhaust. One thread for one of the studs was useless so I drilled it out, fitted the insert coated with thread sealing compound and then inserted the stud. Used thread sealing compound on the stud as well. No leaks. I may not have needed the thread sealing compound on the insert but I wanted to be sure nothing would seep past the insert.

[SKW 4084]

I'll give it a go in the morning. The thread was not the best even after drilling out with larger size drilling and tapping.First experience of trying to tap out cast iron and it wasn't good. Considered the possibility of hot water under an amount of pressure finding its way into the oil system very high.

[Chris_R]

Bit late now then I guess, but a good technique I've found for tapping is to go slow and carefully and to lubricate. Turn a little bit to cut and then reverse the turn. Repeat a little bit more each time. Remove from time to time and clear out any swarf. And use the correct sequence of taps. Start with the taper, then use the second and then finally the plug or bottom tap.

[cannonball]

like others have said, make sure to drain the water down. make sure all is perfectly dry and clean have the required stud reay at correct length etc, i would you use a good brand of metal set , and use that on the stud screw it in nice and snug and leave for a good few days when fitting valve covers there is no need to tighten hard so all will be fine.............. so long as your insert is good...

[AndrewP]

Steve,

You could always fit a little grub screw first (covered in the recommended sealant goop), then make sure the rocker cover bolt is shorter so as to not bottom out.
If you were desperate for mm, then you could always grind the grub screw down a bit.
Thinking outside the box a little....what about a high level coolant bleed? Perhaps Pirtek/Enzed may do something? Something hollow in the middle, threaded on the outside (to tighten the rocker cover down) and a bleed screw in the top?

Know anyone with a lathe in their garage?

[SKW 4084]

Hi Andrew
Thanks for the suggestions. I have decided to use the timesert insert and a moroso valve cover stud. I will use the valve cover stud to drive the insert home after I have half filled the hole and covered the insert and valve cover stud in Loctite metal which appears the strongest epoxy available. My only concern is that its rated too 150 degrees C. I think there is another epoxy rated at higher temperature but I'm not sure of its strength