Busted manifold stud

[joe_db]

WARNING WARNING WARNING

I eventually had to replace my engine because of exactly this issue
Water will seep around the manifold studs and slowly erode the holes bigger and bigger as well as feed water into the manifold and cause no end of problems.
I tried a few things and it never worked for long. Helicoils = bad joke at best for getting a steel stud into an iron block. The slinky-spring things are by far the weakest part of the setup and come back out. Repair bushings are better IF done right. The local machine shop that did mine didn't do a good job and maybe didn't realize there was water on the other side. Two of them had water get around them eventually
I would take the engine out and have a GOOD machine shop do the repairs and make SURE it is all sealed water-tight. You also might look into brass nuts on the studs. They at least won't corrode onto the studs and refuse to ever come off again.

[ndutton]

Shawn,

Before you decide you might give Ken or even Don a call. They offer thread repair inserts in their catalog and I cannot imagine they'd offer anything that wasn't top shelf, thoroughly tested and endorsed by them.

While you're on the phone, ask about the potential for coolant leaks like Joe mentioned. This can't be foreign to them. For example, Chevy small block head bolts also thread into the water jacket and it's normal practice to seal the threads with Permatex before installation.

[edwardc]

Joe,

I agree, repair bushings are a much better choice where the water jacket is involved. Don makes the same recommendation for head studs.

Helicoils are simply a spiral of steel with a square cross section that forms the inner and outer threads. They provide little sealing on their own.

Repair bushings, on the other hand, are made from a solid cylinder of material, with threads cut on the inside and outside. Much less prone to leak, especially if the threads get sealed properly, with adhesive on the outside and permatex on the inside.

[sastanley]

joe, that was my first thought

Joe, when I started to realize the magnitude of this problem, that is the first thing that went thru my head.."uh oh, time for a new block". The only thing that helps alleviate the pain (other than $$) is the fact the Moyer is manufacturing them, so there is no pressing search for an old block in good condition.

Ed, Thanks for the explanation on the other stuff too..I'll stop using the terms helicoil & repair bushing interchangeably.

Neil, A call to Ken is exactly what I plan to do. I am currently going thru a mental checklist to try and get the rest of my order together as well. Although I have enough spares to cover all gaskets needed for re-assembly, some of my supply will be depleted after this current exercise. I also plan to replace the throttle bracket which is starting to look a little suspect, and it had to be removed as well..Since I have the manifold off, I will replace all the studs, shift to studs on the valve cover and determine if I have any broken valve springs..which is another reason I was doing this dis-assembly project...I have a funny tinging sound at low RPM, which I thought might be a couple pieces of valve spring clacking together & it's been two years since I've had the valve cover off.

Can we assume that brass nuts will be strong enough to hold on the manifold? That is an interesting idea. I use them with stainless studs in the water jacket side plate, that they aren't holding on a 20+ lbs. hunk of metal hanging off the side of the block. My other thought was to use something like Noalox.

Ajax, yes...I'll cobble something together...maybe just tabbing a piece of PVC board or something in there. Now that I physically have that tank in there, I can also start getting the hoses & wires up out of the way more permanently. I had mostly just taped that stuff up out of the way since I wasn't quite sure how this project would go. The forward end of the tank will be up against the 1.5" thru-hull as well..I don't want the tank bashing into that either.

[edwardc]

I would think the brass nuts would hold fine, as the studs are holding all the weight, and the torque spec on those nuts are quite low, NOT like the head studs!

[joe_db]

It took me awhile to figure out why the hot section of my exhaust would rust through - water was being injected into the exhaust from the manifold leak

[sastanley]

As you can see in the picture on post #1, there is definitely a leak out of that stud. I do not have any noticeable water injection into the manifold yet (no signs of water in the hot section), but I think this thing was on the ragged edge of being completely blown open due to stud failure. It looks like corroded stud in the block was really the only thing slowing down the leak.

[67c&ccorv]

I like these for my repairs on motorcycle and other hi-stress applications - note that when fully cured the threads are sealed to liquids and gases up to 6000psi;

http://www.threadtoolsupply.com/m12x175-id-m16x2-od-heavy-duty-stainless-steel-e-z-lok-thread-inserts.html

[Mo]

good find.

67,

That can't help but work...good find.

[Ajax]

I like these for my repairs on motorcycle and other hi-stress applications - note that when fully cured the threads are sealed to liquids and gases up to 6000psi;



http://www.threadtoolsupply.com/m12x...d-inserts.html

Wow, thanks for posting that. I'm certain that I'll find all sorts of uses for these.

[sastanley]

67...those look awesome...too bad Moyer doesn't sell these..they look more reliable than a helicoil style repair to me. I have some type of threads I can feel with the pick in the stud hole. I just need to get in there with couple different bolts or thread chasers and see what fits, so I can maybe find one of their inserts.

[ndutton]

Here's what Moyer offers:

http://www.moyermarine.com/cgi-bin/shopper.cgi?preadd=action&key=OBLK_09_114

[Mo]

Geez...as i sit here and look at that picture, I realize what a wreck the poor boat is..

Shawn,
It's a boat and boats are always in varyious stages of repair and or use...no kidding, there is always something. The boat looks fine, and once everything goes back together a cleaning will spiffy her up.

People that use their boat rarely have them pristine all the time. There may be a few neat pics of mine around but I can assure you that after a sail in a stiff breeze it looks like a bomb hit it. Sometimes I come back and am just too tired to clean the interior prior to heading home.

When I'm heading in I put the boat away on the way in....main dropped and stowed, jack lines back to the mast, cover on. Furl jib, secure sheets etc...then to dock and tie on. It is at this point I may do a clean up inside if time and energy permits. So don't be worrying about how the boat looks...it's a boat.

Now, back to the subject at hand. Hanley mentioned that it might be worth a try to tap the existing hole and put in a new stud with sealant...I have to agree. I love the idea of the http://www.threadtoolsupply.com/m12x...d-inserts.html but it may be better to try as Hanley suggested first...you can always move up to C&C 67's idea if the tap doesn't work.

[sastanley]

Other than the pretty pictures, I have zero experience or familiararity with either type of product. I certainly try to patronize Moyer's store when I can do so, but I'd like some additional opinions..I also would like confidence in my repair, so opinions and stories are always appreciated.

I already will be using Moyer for the studs/gaskets, etc..I KNOW those are the right parts for their application..we are just talking about a single part at this time...and I don't mind sourcing from multiple vendors if more than one sells a better part than other for a specific application. Hell, if the insert doesn't fix it, I may be buying a new block!

67's mention of high stress motorcycle applications (think about all the vibration in those things!) is certainly a compelling case for the stainless inserts at this time.

[joe_db]

I did use those thread repair bushings in the link. I think I got mine from McMaster-Carr. They did - sort of - work, but I was quite handicapped by doing the job with the engine in place and almost no room to work. I did the drilling and tapping BY HAND The holes were eroded in varying amounts and I think I used more than one size of bushing. It held long enough to finish out the season and then the engine came out. The sealant is fairly useless if the metal is wet and oily.

The point is the engine needs to come out or you need to do a REALLY good job drilling and tapping in place for these to succeed long-term.