I finally got the engine out and on my stand today. I got the left bank head off and everything looked fine. I got the right bank head off and uh-oh...I have a crack from cylinder #4 to the intake valve seat. The crack descends into the cylinder wall about 3/4". How fatal is this? Would modern welding techniques and equipment be able to repair this? I've got that sinking feeling.

The oil was like mud in the pan and the valve galley is really sludged up, too.

 

Anything can be fixed, I would call a local machine shop and have them look at it.

 

I seen worse than that. As long as the valve seat isnt cracked then of
course that has to be replaced. That area is kind of thick. Back in the
day when Flatheads dominated oval racing, is was a common belief not
to run thermostats. the master builders beleived the cold rush of water
cracked them every time. True or not kind of makes sense. I ran one
for years with cracks and ran good even with a couple of Chevy valves
in it because its not a high compression engine. As far as valves, we
never went by the book, we take the timiming gear off and turn the
cam by hand you get a better feel for adjustment. Being correct while
running you should only hear the fanbelts. Very irratating to assemble
to find one or two loud valves then take it apart again. One more note
setting the clearance on each valve, you must put the (spring) keeper
in, a pain but you have to and the books dont say that. The valve has
to be loaded. Adjustables expensive but the way to go.

 

Best way to find out how bad it is would be to find a machine shop with a set of block off plates and get a pressure test done to see if the crack goes into water .If it does not then just have the crack pinned and a hardened seat ( All 16 would be best) along with any other machining that is required .

 

A Flathead block is difficult to weld - It can be done but the block needs to be slow heated to the proper temp and then a specific alloy stick used to weld the area - It may take several heating cycles of the block to get the whole crack welded.
Pinning and sleeving the block just requires who knows HOW to pin metal.

 

Mine has a similar crack. Somewhere along the line someone sleeved cylinder and I've never a problem with it.

 

There are too many good blocks around to mess with that one. Clean it up (that is the worst sludge I've ever seen!), and stick it out behind the garage for the days when they are so hard to find that someone is willing to pay to fix that. PM sent.

 

Thanks for the replies guys. I'm gonna look for a 8BA block and go from there. Both thermostat housings didn't have thermostats in them. I've got to save up some $$ to move forward with the engine build. I guess I'll complete the many little jobs i have parts for now while I save up for the motor stuff.

 

Give H&H Automotive a call, there up in La cresenta. They are the flat head guru's in So Cal. They speak flat head. bill

 

Now for sale $500, if interested, contact me by PM or email from the FTE. Thx folks.

 

What's the plan going forward?

BTW your ad says "3-sp crashbox" -- appears to be a 4-sp

 

Making space in the garage...was going to rebuild this one, but I'd like to build a turbo motor for my 74 BMW. Putting my F3 truck up for sale as well.
I thought it was a 3 sped, thx for the info.