History Nailhead help

I recently had the heads done on my 56 buick, The shop put harden seats in which i thought nothing about, I was told now i could run "todays" type of gas with no problems. Well I have about 700 miles on the rebuilt engine, recently i noticed whit some when starting and wind up the engine, but not at idle. Which I thought was odd. I called the engine builder who told me the rings still need to seat which could take a few thousand miles.He built the lower half of the engine and just put everything back together. Well i spoke with another nailhead guru he told me the hardend seat are blocking the water passages.
When they cut your heads for hard seats they went into the cooling passages and that is where your white smoke is coming from, there is a 50% chance you will ruin heads when seats are installed.

What do you guys think?

 

they're not blocking the water packages, they cut into them. in a word they ruined your heads. This is pretty common. The biggest thing is that the Nailheads have relatively low spring pressure and high nickel content in the castings, there is no reason to put in hardened seats. Anyone that says different does not know Nailheads and shouldn't work on them.

 

Absolutely true and, by the way, the Nailhead engines have a very high nickel content which helps prevent any valve recessetation (sp?). In other words, you don't need hardened seats and the water passages are too close for installing them.

 

You will need to pressure test the cooling system for starters with the plugs removed.

We've got some experience with the "Nails" and can tell you this, it takes some real "finesse" to get seats installed correctly. We recommend to most customers to "pass" on this procedure! Much safer and in the long run and we've found the heads/valves work fine even on todays fuels!

Not sure about the seats "blocking" the passages, but the heads are very "thin" on one side and it's easy to machine through the casting into the water jackets!

(Add) The seat time on the rings if the block is done correctly should be minimal. Most of our own builds "seat" the rings by the time they're off the dyno!

Thanks, Gary in N.Y.

P.S. There are certain heads, the early Hemi's come to mind, that are better left "seatless"!! The ONLY way to have "hardened" seats done on many of these older type heads is to radius-cut the seat area and lay a "nickel" bead in there, usually done by a very experienced welder using "gas", not electric.

 

so should i pull the heads off and look for another set? I don't want to damage the rest of the engine, so far the heads seem to be fine, there is no coolant in the oil. any advise?

 

and would this be the cause of the white smoke?

 

so say i missunderstood the guy, and he put new seats in not hardend, any thoughts on what else could cause the white smoke?

 

If he put in new seats he cut your heads. If he only did a valve job, that is a different story.