Need some advice on the repair (or not ) a small crack in the cylinder head between the water and a bolt hole.
What I al willing to do is drill a 4mm hole in the crack, half way between the bolt and the water jacket. Make a 5mm tread in the hole and put a 5mm bolt with locktide in the hole. Grind it all flat to finish the job.
On the photo the crack is hard to see but it is there.
Go to Lock N Stitch web site. Send them your picture and question. They should be able to help you. Dan
I wouldn't do a thing. Looks like it doesn't penetrate nor run. May have been there a very long time. Nothing to worry about.
Do nothing. I agree with Richard.
I do see it. Not sure if I would do anything though.
This is also a reason I use teflon sealer on my bolts to keep any residual coolant from seeping in the block threads and rusting the threads or worse rusting the bolts into the block.
I do like your idea of drilling and tapping a screw into the crack--essentially a lock stitch.
Using a regular screw thread will cause the crack to get wider due to the design of the thread. So while it may seal the crack, the crack itself will tend to get wider. The potential for future problems are obvious.
I recommend you use the specially designed screws from Locknstitch. The design of their thread actually pulls the metal together, reducing the potential for future problems.
You can see a sample of the thread and how effective they are on the the thread on my resurrection of a 1909 Model t. :-)
I just fill with block sealer and run
Read Tony's post. Lock N stitch threads are not just screw threads. If you have not used or seen their product, you should take time and look them up. Dan
Mill the head and see if the crack still exists.
I'm going to commit blashempy here an suggest you squish some "right Stuff" in the crack, or some JB Weld--this is just to help seal the crack so water will not be as likely to find it's way to the bolt hole. I've not tried it, but you could even put some of the Right Stuff on that bolt just before you put it in to help insure that you might be able to withdraw the bolt at some future time, yet seal it from the water jacket.
Otherwise, I'd just ignore it!
It may have been posted here at one point. Jay Leno, I believe, sent a fire truck engine to lock n' stitch in which a piece of the block was blown out. I watched that video, learnt a lot, and if some thing catastrophic happens to an engine of mine I would not hesitate contacting them. They will send you a kit, so as, to do it yourself if I can remember right.
The high heads are easy to find for a small price. I would just leave as is and perhaps seal the threads of the bolt so that if any coolant gets around the bolt it won't rust the threads. If it starts to leak a great amount, then consider replacing the head.
If it is a low head, they are harder to find and in that case considering repair. But as posted above, using a bolt could widen the crack and make it worse.
Those kind of cracks or imperfections sometime show up when cleaning up blocks or heads. I have a feeling that small crack has been there from near the beginning the head was originally cast and milled.
I would use some good sealer and use the head.
The closer you look at these old engines the more you might see! Especially when you look closely at transmission drums.
I dare to say there are a lot of T's running around with those kind of 'cracks' that aren't' known about.
You could "stop drill" it........same technique used in the aircraft industry. Center punch the end of the crack and drill a SMALL hole, the depth of the crack then fill it with something like JBWeld. The drilled hole relieves any stress and prevents further cracking.
As advised, I wouldn't just tap it and put in a bolt.
I did not know about the different threads. Is it the pitch? Of course they wouldn't be tapered.
I would follow Dave's suggestion and use the Right Stuff or even Ultra Black if you don't need the quick curing time. It's better than JB Weld in this application because of the flexibility.
The problem with stop drilling in something thick is that you don't know where the crack really ends. Below the visible surface it could be longer. If you don't catch it all, removing the stress riser and replacing it with the hole's smooth circumference, stop drilling will accomplish nothing.
Here is a link to an idea.
I found the Lock-N-Stitch pages already and I will order what I need to do this and some other repairs.
Andre: Look at the link I posted, that thing will be just one hole to drill and tap. It may cost a lot, but if you can not find a new head, what to do. I use their stuff to fix blocks all the time (got to do a Model A block today), so if I can help, PM me. Good luck Dan.
Do nothing. Use as-is.