excaleagle42

a friend bought a used boat that had a head gasket leak (454 gen 4) after removing the head, he found a heli coil in the center hole, 7/16 14. apparently it started to corrode and came loose. block threads aren't good anymore. it probably needs to be drilled again but what is the maximum until you hit the water jacket or not enough meat for a strong torque. he said he didn't want to pull the engine because it costs too much ( boat has to be hauled out) and it will get new engines next winter anyway. if we can't drill it bigger, i suggested a custom stud. there is enough room to get your finger through the water passage and get two skinny nuts on the backside with locktight and use industrial strenght titanium putty around stud for support and seal the water off.
1. where could he get a strong custom stud made?
2. can we forget about a custom stud and drill bigger for another heli coil?
3. is there any other gadgets or tricks or doo-hickeys that are stong and easily done that we haven't considered besides putting in a new block?
thanks in advance, Fran

Intolerant1

There is a thing called time-sert ( not sure on exact spelling) that is a threaded plug you insert into the hole. It has a threaded hole in the center where you install your original size bolt. They require a larger hole than a heli coil though. Ill see if I can find some info for you.

Intolerant1

Here ya go.

http://www.timesert.com/

Ive used these a couple times and they work much nicer than heli coils. They never back out as heli's can.

Ted G

All the Caddi Northstar motors are pulling the head bolt threads and the time-serts are the only thing they are using to fix them. They seem to work well if used correctly.

Iggy

Looks like a good product.
Perfect of that application.
Just make sure you use a good sealant/locking adhesive to make sure it doesn't leak or come loose.
Don't forget to use anti-seize compound on the bolt to prevent the threads from galling and jamming.

We use and insert here caled a Keensert. Similar product but it uses two to four locking pins to prevent the insert from backing out. It's mainly used in situations where disassembly and reassembly is constant.

DanL

what has been the best fix for me in the past was to have a machine shop take a piece of hardened steel stock and cut the stock to a few thousanths oversize on the threads for the head. then, they sized and threaded the other end for a nut. now you have a head stud that you can thread into the block finger tight and put a nut and torque the nut against the head instead of stressing the block. Thats why ARP head studs work so well. The clamping force is transferred to the top of the head where it belongs. Threaded inserts are only as strong as the material they're made of and can come loose.

Smitty

excaleagle42,
Get the time-sert and then get a set of ARP studs. I also stripped the threads out on my 454 Gen 5 and had it helicoiled and then used studs. I have a supercharged application and at 65+ hrs it is fine. Also make sure to spend the bucks for the best head gskts you can get--you won't be sorry.

Dave