Has anyone ever hit water, or had a head crack after installing hard seats in 67 1.60 valve 915 heads. I think the book said a 1.78 hard seat is safe, any issues? These heads sonic checked .240 or better when they were 1.60 valve, machine shop installed 1.74 valve and you guessed it set them to deep. Valve stems are too high, ferrea only allows .010-.015 max stem machining, so need another answer.t

hi

if the inserts are large enough can you install 1.81 valve to raise them in the chamber ??

1.81 normaly has a thicker margin .

i had some installed in the 915 pair under my bench to use 1.81 valves , cant seem to get time to finish them ?

Might be smart to buy one 1.81 and see if that would raise it enough.

What are you using for valves, and how much extra tip height do you have?

FWIW, I’ve seen the valves sunk pretty far before........ sometimes from just being used up, sometimes to gain v/p clearance.......and those heads never caused any other problems as a result of it.

If you really want a thick margin 1.74 valve, take a 1.81 and turn it down to 1.74.
The margin will be very thick, and you’d likely be able to reface the valve back to a margin thickness that would correct your tip height......... unless they’re just way way off...... in which case cutting the seats out and installing new ones is probably the better option.

I started with new ferrea 2.08-1.74 5000 series valves, the heads were 2.08.-1.60 67 heads, the intakes are in near perfect and within .005 of each other in height as they are still the factory seats. Exhausts are buried about .060 farther, guess he did not notice the thicker margin, other problem is they are in at different heights, vary by .027, guy is usually spot on , don't know what happened here. He has already cut the stems, how much I do not know yet, but ferrea says .010 max, never more than .015. So are you saying I could take a 1.81 valve and turn it down and move the stem in towards the chamber, or smarter to just put a 1.81 in and cut new seats (not this guy), on a serdi, already plan on all new valves, pretty sure some are stemmed too much. I know shoulda bought source heads and painted them orange.

Oh by the way not real worried about sunk exhaust valves, using exhaust manifolds anyway, just need to solve the stem height issue and I am good. It has ross flatops so no issue with valve clearance moving valves out.

Are you saying the new ferrea 5000 1.74’s have about a .060” higher tip height than a ferrea 5000 2.08?

If so, I don’t know that you’ll be able to correct it that much by using a 1.81 valve...... either as a 1.81 on a 1.81 seat or as cut down to a 1.74 with a thick margin.

That’s a lot to make up.

If that’s how far off they are, I’d just cut the seats out and start over.
Not really that big of a deal........unless they installed the super hard seats(Those are a b-yotch to cut out).
Normal “hardened” seats machine easily.

Yes, about .060 higher tip on the worst exhaust, and in varying amounts by .027. Ferrea says the overall length of the 1.74 and 1.81 is .035 longer, due to the thicker margin, guess he missed that. The good is no hard seats in them yet so guess that is the fix. Back to the original question, has anyone hit water putting hard seats in original 1.60 valve heads, or had them crack later?

There would be no difference in the castings whether they got 1.74’s or 1.60’s.

Ok thanks.