Hot Rod Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
210 Posts
Discussion Starter · #1 ·
I have a set of 351w D0OE heads that the pervious owner claims has hardened exhaust seats.

I could pay the $60 or so and have them replaced to be sure but I'd rather keep my money if possible.

Is there anything I should know about the original castings exh seats that might help me know whether they have been replaced or not....I am aware they were not hardened form the factory....is there any way short of destroying the seats to find out?

I did notice there were seat inserts on the exh side as well as intake but someone mentioned they would have them on the pre72 castings, were the later castings did not have exh inserts.

Any thoughts appreciated
 

·
Hotrodders.com Moderator
Joined
·
1,642 Posts
If the heads have inserts in the seat area, it's a hard seat. The factory generally used induction hardening which was a heat treating process to a certain depth, which involved the as-cast iron in the head.

Rebuilders cut a pocket and install an insert to get the job done.

Generally on a road engine of any kind, hard seat inserts usually won't hardly wear at all. If the head has inserts in it now, and the valve stem height is correct, I wouldn't mess with them. Just do your valve job and go on.

Brian
 

·
Registered
Joined
·
210 Posts
Discussion Starter · #3 ·
Thats what I wasn't clear on, I asked someone and they made the comment, inserts were used before 72 and induction hardening the casting and not using inserts was done after. So with that in mind, I thought finding out how to tell the difference might be difficult.



Lemme clarify one more time, just to be certain, I can be thick sometimes.

So your saying ford never used seat inserts from the factory on any sbf head, they only used a inducton hardening (72 and later) or nothing on the earlier castings (72 and earlier)?

The seats look good as they are and the valves seemed to seal real well.
 

·
Hotrodders.com Moderator
Joined
·
1,642 Posts
I can't say they never used inserts. I'm not a Ford expert, but all of the automotive castings (non-industrial or heavy duty truck), I have seen from the factory used as-cast seats, where the early heads were not induction hardened on the exhaust, and the later model ones were.

If your heads have inserts in them, they are hard enough for unleaded fuel.


Brian
 

·
Registered
Joined
·
2,384 Posts
hardened valve seats

Ive seen both ground in valve seats and replaceable valve seats in winsors, but the hardened valve seats for use with unleaded gas didnt come into fashion til the 73 model year. Some of the heavy duty or truck versions had them earlier due to the more strenious wear and tear, higher exhaust temps etc. If in doubt, look down into the valve seat, and about a 1/4 inch or so inside the bowl from the seat, if you see a line around the throat of the valve seat, then you have replaceable valve seats. The others, in order to install the hardened seats, require having them machined out for it. If these are for the D0 castings we discussed previously, its doubtful they had press in valve seats.

Since your valve seats are looking good, I wouldnt recommend messing with them. Just get your good 3 angle valve job, and do some good porting on them and have a ball.
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top