valve seat nightmare
 

NEW NEWS! I took the block and had it pressure checked, and both sleeves the machine shop put are leaking and can't be fixed. Now fighting with the machine shop. After having $800 worth of machine work on my 37-38 21 stud flathead V8, (block prep, 2 sleeves, bore .060,) I assembled the engine with new parts, pistons, rings, bearings. I started the engine and it filled the crank case with water. Thought it was a head gasket problem, no way. After taking the engine out, and taking it apart, we found that at some time someone cut in new valve seats and must have cut into the water jackets. I tried K W block seal twice, no go. Is there any way to seal these up, or is the block junk? The way things have been going with this block, I am not feeling very positive! Thanks for reading this post. Any ideas greatly appreciated. Thanks Ron
P.S. We put air in the radiator and we could see the water coming in through the valves, looking in the spark plug holes.

Re: valve seat nightmare
 

Boy it would take a lot of valve seat cutting to go into a water passage. Check the 4 freeze plugs on the pan rail [about 3/4" diam] common for them to rot out. ken ct.

Re: valve seat nightmare
 

There was likely a crack there that went undetected unless they were trying to put too big a seat in there. The block can be pinned as long as the crack doesn't go too deep into the valve pocket. A person should always do a pressure test on these blocks before putting them together so as to avoid this type of problem.

Re: valve seat nightmare
 

Like Ken, I doubt that cutting for new seats could cause that problem. It's somewhere else.
Have it pressure tested and find it.
I had a similar problem. There was a crack in the lifter valley area between the lifters. Lots of water

Re: valve seat nightmare
 

It could be a freeze crack from an engine that sat upside down exposed to the elements. I recently had the misfortune of finding just that. When I got the block it was sitting outside and upside down. There is a crack in the intake runner which magnaflux didn't find. I'm now sold on the pressure testing requirement.

Re: valve seat nightmare
 

Wasn't there a post a while back of bolt protruding into exhaust port causing a water leak ? Zeke

Re: valve seat nightmare
 

At this stage of the game you'll have to pull the head and remove the valve and see if you can see where it's leaking. Chances are the crack goes down the port some. I've cut in 100's of seats in every brand of engine you can think of. If you have to install a larger seat for some reason I've cut into the water before. If it's just a little cut usually green lock tight and drive the seat in will seal it. Let us know how you make out. Walt

Re: valve seat nightmare
 

Hi ron, you're really going to have to strip it down for a decent evaluation? Not good news, but it's the "right" way!

I've posted about this issue numerous times before, and it's mentioned above here also, but whoever is doing the machining should be pressure testing the casting. You want to test it before you do ANY machining, unless there's an obvious crack, for example a cylinder, where the sleeve would need to be put in before a pressure-test is even possible, and if there's any previous sleeve work, seat installation's, crack stitching, etc., ANY operation that MAY come into contact with the water jackets, you test it again.

When machining these units it's not uncommon to test them more than twice, it comes with the territory! I've tested some 3 times before they leave. The customer pays ONLY once. At the point we do the work, sleeve, seat, whatever, we need to stand behind it.

Having said all that, if it turns out to be behind the seat area we've had excellent results with (aircraft-type) epoxy BEHIND the seat, before the seat is reinstalled. It must set up for a day and then be remachined for the seat. Not necessarily machining any larger/deeper, but basically to "clean-up" the epoxy.

This confirms again why "magging" the casting isn't 100% positive, they've GOT to be pressure tested.

Thanks, Gary in N.Y.

P.S. I know of 2 builds out with this procedure, "cracks" behind the seats, and they've been out for some time. If it's a "very minor" leak it will eventually close itself up. It all depends on the type of leak. These casting's are so "thin" in certain areas that stitching isn't always an option.

Re: valve seat nightmare
 

Thanks for all your help! The engine is torn down and we maged it again with no cracks. The shop guys said all they could come up with was the valve seats are leaking. With the heads off the only way to pressure test it is to make a test plate, $250 plus. The shop has done many flatheads. I really don't want to scrap it and my $800, I am lost. Thanks Ron

Re: valve seat nightmare
 

Guides are leaking???

R

Re: valve seat nightmare
 

Don't see any real reason a used head cannot be substituted for a plate by blocking-off the water outlet. You're only going to apply pressure to one side of the block at a time, anyway. Hoping for the best for ya. DD

Re: valve seat nightmare
 

If they have done many flatheads why don't they have the equipment like block off plates?

Re: valve seat nightmare
 

I don't see the connection that a flat head valve guide would have any thing to do with a coolant leak?

Re: valve seat nightmare
 

I believe he meant to say valve "seats". DD

Re: valve seat nightmare
 

With the block all stripped , just install the head with the gasket and torque it down. Make a plate to cover the water pump hole. block off the head where the top hose goes. Accually you can fill that side of the block with water then cap the head where the hose goes. Turn the engine over and look down cyl and see if you can see any water coming around the seat area. That won't cost nothing. Walt

Re: valve seat nightmare
 

Ship that block down to La Cresenta, CA. and have h&h check it for you. Mike Herman,
is the proprieter, and they do excellent work.