For anyone who cares to remember I submitted a thread a few weeks ago lamenting that my freshly re-built flathead leaked water out the exhaust manifold on the right side. After taking the head off, a high heliocoil was found. This was carefully shaved down, and the head was reinstalled and torqued, but it still leaks at the exhaust manifold. All the sparkplugs are dry, so I don't think the heliocoil is the issue. A new manifold was installed, and it's not backwards. I'm fed-up!!! I am so depressed I feel like dumping the whole project into the ocean. Could my block be cracked by the exhaust manifold? When you fill it with water, everything is fine until it is about 3/4 full, then it starts pouring out. The engine has never been fired up, so it's not an expansion thing. If the head were cracked wouldn't the problem only manifest itself when the engine were hot? Any ideas???? This was supposed to be fun.......but it's NOT!!!! Tomorrow we will take off the right water pump to look for anything obvious, but I'm not feeling very optimistic right now. This really s___ks!!!

 

have you tried leaving the manifold off and filling it, to see if its coming from a certain area?...check for cracks on the head around the mounting holes for the exhaust manifold... if the head has cracked for some reason, it might have cracked deep enough to hit the water passage....... just some thoughts.....

 

Is the water literally coming from inside the exhaust manifold? Not on the outside? If so, it sounds like there is a crack (must be big) in the exhaust passage inside the block. Do try filling it with the manifold off, if it's a tube that's cracked it will come out one of the exhaust ports.

I hope that's not it! Let us know!

Here is a cutaway flathead that shows how the exhaust tubes run in the water jackets.

 

Sorry to hear that Joe, hang in there - it'll be worth it in the end.

Is this engine in the truck or out? Finding the problem will be a lot easier if the engine is on the shop floor.

Pull the exhaust manifold on that side, find which port is leaking and work your way upstream until you find the source.

I'm not sure why you would pull a waterpump?? I doubt you'll be able to see much. Good luck - Tim

 

Yea, unfortunately the motor is in the truck. It arrived on a pallet from the re-builder all clean and painted; there was no reason to think it was defective (at least not to this extent). When I called the re-builder I was told they went out of business in November! I wonder why? I do have another old block that I picked up for cheap, but who knows if it's any good either. Well there's not much I can do except try to determine what's going on and figure out how to make it good. Thanks again for all your help.

 

Joe -

I'm no flathead expert and I know they are notorious for cracks, BUT in my experience, water does not POUR OUT of a crack. I think this is wrong/reversed gasket or such. Maybe your look at the water pump attachment will solve this riddle.

If you don't discover the problem soon, I would pull the motor back out to investigate it further. It may be time to become a flathead rebuild expert.

 

I agree with what Randy just said.

You didn't mention how you reinstalled the head and gasket after you pulled them off. Did you just put the head gasket back the way it came off? If I remember from your previous thread Tim mentioned that a head gasket installed backwards would cause a major water leak as you describe.

Might be worth looking into

Bobby

 

I'm no expert by any means - I've only been messing with flatheads since '99 but I've managed to keep mine running as a daily driver since '01. I haven't heard of a single flathead cracking from overheating in the past 9 years. I believe most cracks were a result of the cast iron 'settling-in'.

I heat my home with wood and can't count the times I've dumped cold water into a cast iron kettle that sits on the woodstove. It gets hot enough that the water evaporates instantly as it's poured in and we're still using the same humidifier/kettle that we bought 13 years ago. Flathead castings have to be better quality iron than those stovetop pots.

Point of all this related to your problem? Not sure.... The rebuilder should have done a pressure test after the machining was done. No way to tell now if he did, but it's doubtful. I agree with Randy, water won't pour out of a crack. There's a hole somewhere.

After messing with a bare block out in the shop, here's what I suspect:
Either a gasket is wrong,
OR the builder cranked a too-long bolt down into one of the exhaust tubes and broke out a chunk of the casting. You could tell if this is the case by looking up into the exhaust ports as the front, back and center columns of bolts can all contact the exhaust ports.
OR a chunk of casting broke away farther upstream - say in one of the valve pockets,

No matter what it is, it will be a lot easier to troubleshoot if the engine is out of the truck. I wish you luck.

 

I just came back from the shop, and the water comes out the front exhaust tube on the right side (the one directly behind the water pump). All the spark plugs are bone dry even after it was cranked a few times, so that would eliminate a gasget problem, right???? It only starts to leak when the water jacket is full, like there is a hole on the top of the exhaust tube. I like the theory of the too long head bolt being cranked down and puncturing the exhaust tube. I mean this engine rebuilder said that they pressure test and magnaflux before they use a head, so in my nieve thought process, I don't think they would intentionally use a bad block. (Anybody want to sell me a used car??) I guess I just like to think that your average person is basically honest. Regardless, whether the head bolt was the reason or not, is the defect in a place where we can get at it to fix. There's no extreme pressure in the water jacket, so couldn't we have it welded or even use epoxy??? I'm getting way ahead of myself...we have to see where the water is coming from first.

 

I don't believe the head bolts tie into the exhaust tubes; they would grow too much with heat to be useful for gasketing. (Look at the cutaway engine) I think unless you can see the crack or hole from the exhaust port, you'll have to pull the head and that exhaust valve, look inside from that end. You can also see the top side of the tube with the head off.

Any chance this engine has been ported (passages ground to smooth the casting)?

 

What about the wrong gasket behind the water pump? I have heard that there are ports behind the pumps that the gasket covers. Given the symptom, is that possible? I would hope so.

 

I didn't say the bolts tie into the exhaust tubes - just that they break out into the water jacket above or beside them.......if someone tried to torque down a bolt that was in contact with the exhaust tube??........

 

Tim,
Ah, yeah, OK, I see what you are saying

jreilly57,
what about the head gasket? did you put it back on exaclty as it came off? and if so are you sure it was installed correctly. If was installed wrong to begin with (causing your problem) and you reinstalled in the same way....well.......

It would definately be easier to mess with out of the truck, but you might still be able to figure it out in place. I forsee some major contortionist acts, streams of curse words, and several well palced mirrors.

Bobby

 

Water pump gasket??? Did they make different ones? We'll have to look.

 

A brand new head gasket was installed on the right side. In order for it to be installed upside down, wouldn't it have had to be the left side gasket? Does everything line up on either side if the correct gasket were upside down? I only bought the right hand side to replace. Anyway, I'll check, but if it were the gasket wouldn't there be water in the cylinders and spark plugs especially after you crank it? Wow, would that be sweet if it were simply the water pump gasket. For some reason I don't think I'll be that lucky!!!