Busted manifold stud

[sastanley]

Sometimes, preventative maintenance is a good thing...or maybe I am lucky I stumbled across this in the off season when I had ulterior motives....

Two things I have not had off the motor since I've had the boat is the manifold and the head. I see no reason to pull the head (yet), but while doing the FWC upgrade, & needing to clean the water jacket....I was thinking a couple of nuts off the manifold studs and off comes the manifold for an in-home cleaning & it seemed like a good idea to me.

(Full disclosure) The C-30 engine is in the middle of the boat. Some C-30's later than mine came with a tank on the port side. I bought a matching tank from Ronco, and I want to install it to add some more fresh water to the boat. The issue is the tank won't currently fit without me cutting up the boat, which I suspect means the water tank was installed before the engine, or the settee cutouts were different/bigger in later boats. I thought maybe I could squeeze the tank by the engine if I removed the hot-stack (which needed inspection after 4 seasons) and then I was removing the fittings on the manifold, and well, the manifold is only 3 more nuts/studs, & I've never had it off, so why not??

This manifold removal will also give me good access to the valve chamber. A fellow motorhead heard the same funny tinging at low RPM that I've heard and thought maybe I had a broken valve spring. - It's been two years since I've seen the valves...OK, one more more reason to check everything and make it all accessible.

Well...here's where I am getting at...the two forward manifold stud nuts came off no problem..the third aft/bottom one immediately gave me trouble. At first glance, it appeared to have sheared off in the block. After settling down in the car on the way home, on the way to pre-holiday dinner with family and some rational discussion with myself, checking out the crappy phone pictures and some mental pictures.....I think (hope)...maybe the stud just disintegrated when I tried to remove the manifold. There are two pictures...one of the hole in the block where the stud goes...(notice the coolant leaking out & running down the valve cover)..I think that is a good sign the stud's integrity was no good, and also the 2nd pic which is the manifold (in a milk crate in the garage)...the stud sticking out of the manifold is completely worn out I think. The manifold is upside down...the shiny studs go to the hot section & the rusty part is the aft end of the manifold on the bottom...so the broken stud is the dark nubby sticking out above the white rag.

So, my current theory is the stud was intact just enough to keep coolant in the block, until I disturbed it. Put a wrench on it, and it fell apart. The coolant leak I think means the stud threads in the block are corroded/compromised/gone (good news) - I did not get a good visual on the block status, except for the pic.. the family holiday bruncheon called and it was time to go.

Until I get a better look, opinions of anyone that has 'been there done that' are welcome.

Next trip to the boat, I'll go dig into the block with a small pick and ascertain the status. Looking at the pic it is entirely possible I've been having a coolant leak in the area of that stud for some time, just based on the odd corrosion I am seeing just above the valve cover/under the bad stud.

[Al Schober]

The end of the stud may just have corroded away. See:
http://www.moyermarine.com/forums/showthread.php?t=6973

[lat 64]

Hey Shawn,
I was talking to Ed about a leak issue that I have somewhere inside my manifold. That was the morning of the epic Crab Pot Slalom, Knockabout, Tip it Back and Drain it, Slackwater Jack cruise.
I may have the same issue you have. I am trying to figure out how I get antifreeze in the air horn each time I leave the boat sit for about a month or more. Maybe my manifold stud is leaking through the exhaust gasket and into the manifold?
I will probably do the same surgery next spring.

Happy days to you all,
Russ

[sastanley]

Al, I am thinking the same thing..I think it just corroded away. I have had a small coolant leak since I've installed the FWC..it is entirely possible I had a RWC leak as well...it may explain the inexplicable trace of water I was always seeing under the engine, outside of the motor mounts, that is now green since the FWC conversion.

I also have a slight leak in one of the fittings related to the HX as well, which I was assuming was why I had to add a few ounces of coolant every time I used the boat this summer...now I think it may have been a combination.

Both the manifold & HX are home, so they will get a thorough work-over this winter.

We were invited to a favorite friends' house for New Years today..they asked if we might come by boat..I chuckled and said, "sorry guys, we'll have to drive...half the boat's engine is in the garage.

[hanleyclifford]

Shawn, Looks like all you have to do is run a tap into the block and buy a new stud. If the tap won't go in easily you might have to do a little precision drilling.

[sastanley]

Hanley, I sure hope so & right now I agree with you. I will bring the better camera and do a more thorough inspection hopefully in a few days. After these pics were taken, I did a little prodding with a pick and the coolant suddenly started flowing pretty freely out of the stud hole..I am hoping a little clean out and a new stud is all I need..one more thing to add to my post-Christmas Moyer list.

here's a couple of pics of the boat's 'status'...this was pre-manifold removal...One of the goals is to get that water tank into the port settee..The galley is currently in the v-berth!

The 'arrival mat' was a present from the Mother-in-law..

Mo, I also finished the oil change yesterday...notice the 15w-40 Rotella?

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

[sastanley]

By the way..Merry Christmas, Happy Chanukah, or whatever holiday you celebrate to all my fellow A4 enthusiasts on the Moyer forum...

Who'd have thought four years ago, I'd be tackling & renovating something like this 30' hole in the water?

[sastanley]

Made it to the boat this weekend...

The good news is after a week of PB Blaster soaking, I was able to get the other two studs out of the block without too much trouble & after a little prodding with a pick, there seems to be no signs of residual stud in the aft most hole in the block that secured the manifold. This also gave me enough clearance to get the water tank into the port settee.

The bad news is the aft stud hole is ALREADY oversized. A normal stud just slides right thru it & doesn't grip any threads.

I dunno if the P.O. JB Welded the stud in there, or what the deal was. It does not appear to be a Moyer repair stud...however, I do not have the old bad stud & the two good studs together yet to compare. I put the good studs in a bag and labeled them, and conveniently left them on the boat, while the manifold with the bad stud still stuck in it is at home.

I am hoping there is enough material in the block that a Moyer repair stud will work. There appear to be some threads in the block, but I dunno if they are cut for a repair stud or not. - it looks like the repair stud offered in the catalog will work in this application.

In other news, I decided this was the opportunity to properly clean out the water jacket, so off came the alternator, starter & side plate. There is certainly plenty of Chesapeake muck inside.
So, since I have the sideplate off (again), and I have converted to FWC, I am thinking about blocking off the by-pass to the t-stat housing completely, and forcing all cooling water from the HX thru the sideplate/block and up thru the t-stat (or possibly removing it as well). I have pretty much had the by-pass valve closed off since I went to FWC anyway...this would simplify the hardware and hoses & stuff hanging off the sideplate. Anyone see any issue with this? My understanding of the by-pass system is that its job is to get cooling water to the exhaust system..this is taken care of now with a salt-water pump. Removing the cumbersome 'tee' set up at the sideplate & putting a plug in the t-stat inlet would simplify the FWC loop quite a bit.

[Al Schober]

Shawn,
Any issue in running without the bypass hose? I'll let you know when I get it fired up. Your mod should look something like this:

[sastanley]

Al..real nice & clean..That is exactly my plan. I just don't see a need for it any longer!

Y'all don't want to see any pictures of my engine right now..

[romantic comedy]

Al, nice water jacket cover!! I bet that hose clamp says stainless.

I have FWC, and keep the thermostat. I do have a valve in the bypass loop, in case it runs hot. It runs at 180.

[edwardc]

Originally Posted by sastanley

...I am hoping there is enough material in the block that a Moyer repair stud will work. There appear to be some threads in the block, but I dunno if they are cut for a repair stud or not. - it looks like the repair stud offered in the catalog will work in this application. ...

Shawn,

Rather than a repair stud, consider inserting a helicoil or repair bushing. This would allow you to remain with standard studs, and pretty much eliminate any possibility of ever cross-threading the block, as the inserts are much harder than the block.

[sastanley]

Ed, thanks...so if I understand correctly, are you suggesting I just pick up an insert from Moyer and install 3 of the 'proper' sized studs instead? I assume I'd JB weld that bad boy in place and then the insert is threaded for a standard stud?? I've never used one of those before so I dunno the procedure.

I think I see where you are getting at...the block material is softer than the helicoil/thread bushing insert...so it would be more resilient to abuse in the future, whereas if I drill out & tap the block itself for a bigger stud I am possibly inviting the same problem to reappear a few years down the road..

Part # OBLK_09_114 ??

[sastanley]

by the way - part of this exercise was to get the damn water tank in to the settee. I did finally manage to stuff it past the motor with the manifold & studs & other port side paraphernalia removed...

[Ajax]

Wow dude. That you managed to get that tank in there without any structural cutting is amazing. Are you going to mount some blocks or something to ensure that it doesn't slide around in that space?

I like the Helicoil idea better than tapping the block, but will there be any issues of galvanic corrosion with dissimilar metals, or is it all steel? Will you be using stainless fasteners or something else?

[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, 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/m12x...d-inserts.html

[Mo]

67,

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

[Ajax]

Originally Posted by 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/m12x...d-inserts.html

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