broken valve cover bolt

[jordan]

I had leaking valve cover seals with a set of cast aluminum valve covers.  I bought new seals and have a set of stock stamped steel covers.  When I switch them out, I didn't take into account the length of the bolt, which is longer for the cast covers, and broke off one bolt in the bottom left hole of the passenger head.  I removed my A/C lines to get access.  The bolt is stainless, and I drilled it with a cobalt bit.  The threads were screwed up enough the new bolt wouldn't torque down.  I tried a tap, but it wouldn't go in far enough into the blind hole.  Not knowing how deep the hole is, I drilled into the water jacket!!  My question is can I tap the hole in the cast head, and is there a helicoil with a blind hole to fill the leak?  Or am I screwed, and have to get a new head? 

[Mike70]

I would think that you could tap the hole easily enough, then put some sealer on the bolt when you install it. Some exhaust bolts go into the water jacket, and this is how they are sealed. Just have to remember to seal the bolt every time you remove it.

Mike

[7Dcuda]

Do you know if the most forward exhaust bolt on the drivers side head on a 440 is one that goes into a water jacket?  Reason I ask is that was the first bolt I took out during the process of installing some ARP SS bolts and when I removed it a good bit of coolant came draining out.  Was worried that the head may be cracked between the water jacket and bolt hole.   

I would think that you could tap the hole easily enough, then put some sealer on the bolt when you install it. Some exhaust bolts go into the water jacket, and this is how they are sealed. Just have to remember to seal the bolt every time you remove it.

Mike

[MEK-Dangerfield]

All exhaust bolts on a 440 go into the water jackets.

[Chryco Psycho]

using a helicoil into the water jacket rarely works , the coolant leaks out the helicoil unless you can get thread sealant behind the thread insert

[Killer_Mopar]

I would just tap it to the next larger size, metric or standard. I think the stock bolts are 1/4-20, so go up to 5/16 or 8mm (maybe 7 ). My old set of heads had one hole tapped to the next larger size and it never gave me a problem, albeit I didn't have it going through to a water jacket. Use some sealant on the threads and it should take of the leaking.

[acudanut]

Am I missing something here. He said broken valve cover bolt and now we are talking exhaust manifold studs ??

[OxfordMotorSports]

I would just tap it to the next larger size, metric or standard. I think the stock bolts are 1/4-20, so go up to 5/16 or 8mm (maybe 7 ). My old set of heads had one hole tapped to the next larger size and it never gave me a problem, albeit I didn't have it going through to a water jacket. Use some sealant on the threads and it should take of the leaking.

 

Todd

[Moparal]

I think once you tap the hole out, you should use a stud in the hole and leave it sealed in there. On the 60's valve covers the bottom lower outside holoes came with studs and nuts, then the 4 middle holes were screws.  I have had the same problem happen before a few times over the years.  You don't need to replace the head.  Kind of a pain to work on the back bolt tho.

[jordan]

I think I like this last idea best.  Using a stud wont have antifreeze leaking when I remove the valve cover.  I can use the valve cover as a guide when drilling my over sized hole for better alignment.  I will try to get a few hours this week to work on it and let you guys know how it goes.   

[jordan]

After waiting a few weeks to cool off after being mad at myself for screwing up, a buddy came over with a time-sert set.  We tapped the hole larger, cut a small lip into the surface of the head for the insert to seat, and finished tapping the insert to seat it.  I sealed it with locktite red, and repaired the defect around the hole with some j-b weld to seal the leak into the water jacket if there was any.  I then studded the hole with the correct size 1/4 /20 and used more red locktite.  The  stock type stamped steel valve cover fits good, and no oil leaks.  My other valve cover leaked some, so that one is a do over.  I have not put any miles on the cuda yet, so I can't tell if the stud is leaking water into the head yet by checking the oil for gooey contaminated water/oil.  I guess I will be leary for a while until I know nothing leaks.  Thanks for the opinions on how to fix this.  Hopefully I can start cruising and hit a few shows yet this summer.