**** me Ant, how do you manage to bring some humour when its so bad. Your better than me I can tell you, my toys would have been well and truly thrown out of the pram
Whats the next move......engine out I would suspect. After all your hard work, what a fooking ****....really sorry to hear this matey.

 

I forget if you are putting in studs or bolts. But in the one hole you should put in a stud. Most importantly when you tap this hole get a slightly smaller tap that is used for an interference fit or a slightly larger stud and use a thread locker or sealant. You'll be fine.

 

Thanks Nick, as ever I think you're right
I don't think it's all that bad now I've had time to assess the situation

My plan is to tap the hole and put a bolt in it
I'll then grind the head off and just drill it again

Once I've ground the head off the bolt I'm basically be back to where I was to begin with - No great shakes

What I can't decide is this:
I have some spare (longer) stainless bolts
I can't make my mind up whether to use one of these as the 'plug' or whether to get a length of aluminium and use that after threading it

What do you think?
Any difference between using stainless steel or aluminium here?


I've spoken with my father too
He used to work as an engineer for Rolls Royce many moons ago
He told me things like this would happen from time to time

Apparently they would simply inspect the item to check if it's performance or properties had been compromised

As long the item would still perform correctly, it would be fixed rather than replaced/scrapped, and used as was

So, I'm thinking I'll be alright with plugging and sealing it

 

Here's a picture to highlight what I've drilled

Doesn't look serious at all
Just plug it and start again

 

I'd use aluminum as it will have close to the same expansion rate as the head and also be easier to drill through. You will first have to thread the hole and most likely thread an aluminum rod to fill the hole, use a thread lock or it may leak under pressure. Did you just go too deep and punch into the jacket?

The only problem with plugging the hole and redrilling and rethreading is that you will most likely remove most of the plug leaving small fragments with little integrety causing more issues. This is unless your plug is only say 1/4" or less in length and fits only into the very bottom of the hole. In this instance you would want a tapered plug with pipe thread that will wedge in and not fall into the jacket. This plug would have to smaller in diameter than the original bolt hole to work properly.

I'd just leave it as is, thread it for a stud with an interference fit. Easy and effective There may be other options. It's easier seeing the problem in the flesh to find a viable solution. GL, let us know how you address the issue.

 

Thanks, I was thinking the same about using aluminium

I got a cobalt drill bit today - It was the first time I've used one of them
It drilled through the stud without much of a problem, and once it got into the aluminium head itself !!BANG!! It went through it instantly

I can't believe how vicious these cobalt bits are


That was my first thought, but since the manifold is held to the turbo with studs you can only remove the manifold (if I ever needed to in the future) by moving it down and sideways - Something I couldn't do with a stud in the head

It looks like it needs to be a bold in there
Can you tell me a bit more about what you meant about possibly having problems with putting a 'plug' in it?

From what I can make I think the total thickness of the casting is around 40mm

Of this, 30mm needs to be threaded for the bolt, and the remaining 10mm needs plugging up

 

The hole I've drilled is 5.5mm

I can buy aluminium rod is either 8mm or 10mm diameters

The cylinder head should have a M8 thread for the fixing bolt

What size bar should I plug the head with?

 

First off you need to plug the hole so it won't leak any coolant under pressure and hold for the rest of the life of the motor. I think it would be difficult to do just with a threaded aluminum made stud. You need something like a 1/16 NPT plug that you can tighten into the bottom of the hole that will seal by using a wedge effect on the threads. This will require tapping a 1/16 NPT tapered hole. Problem is the tap is too short and too fat to fit inside the threaded 8 mm hole. You will have to research this and if you think it will work, you will have to modify the tap to fit by grinding down the largest part of the OD while allowing it to still cut thread as needed. You'll also have to braze an extension for the drive. If unfamiliar with using NPT plugs, they are tapered and you will have to determine how to match the depth of hole threads with where you want the plug to tighten. I think it will work just fine, I do this stuff all the time. Here's a link to the plug dims:
http://www.alphathreadgage.com/refsheets/REFnptpipe.htm

 

Hadn't seen those tapered threads before

My thinking is that the hole is too deep to use this method - I might be completely wrong though as I'm only just starting to find out about them

My initial idea was to use the aluminium bar with a thread sealer on it
I think as long as it had a thread sealer in place I'd be ok??

If that isn't a option would something like the picture below work?
It's an NPT Allen head plug

Could I fit this to the bottom of the hole (with a sealer) and then carry on as before?
Not sure if I can use a plug like this, or if they're meant to remain surface mounted
I know they're used for blocking oil ways and water ways on engine blocks

 

That's exactly what I was talking about. You'll need the smallest one commonly available, 1/16 NPT, steel, aluminum or brass, doesn't matter. Follow my directions in a previous post.

 

Thanks Nick

I've checked the catalogue at my local fasteners place

They only have standard metric thread sizings
Is it a difference in threads which causes them to seal?

I've attached the catalogue below

They're called 'grub screws' and are located at the bottom of page 101
(page 11 out of 20)

http://www.fixings-directcentral.co.uk/Section%207.pdf

Are they any use, or no good to me?

 

Whenever I do any plumbing jobs I tend to use Laco Slic-Tite Paste

Do you think this'd be good to use here too?

http://www.jbind.com/products/produc...aspx?SKU=42019

 

OK, you don't want a grub screw. They are for securing a pulley on a shaft, a fastener of sorts. We don't want a fastener, we want a plug, to plug a hole. The only thing that will do is a 1/16 NPT with an allen (internal hex) head. NPT stands for National Pipe Thread. In a 1/16 size it has 27 TPI, Threads Per Inch. The 1/16" size is actually about .31" OD for a length of 1/16" pipe. Pipe sizes are measured by it ID, Tube sizes by OD. You can google 1/16 NPT, add tap and plug to learn more.

Again, as you learn more, reread my previous posts about modding the taps. They will make sense.

 

Thanks again Nick

I can't begin to tell you and everyone else that's helped so far how useful you've all been

I think I'd have admitted defeat if It weren't for everybody replying to my stupid questions

I'll keep reading and learning, and will refer back to your posts for pointers
I'm sure with more reading it'll begin to make sense

Again, thank you for all your help so far Nick