Hardened seats or Stainless valves?

[rang-a-stang]

I dropped my heads off at the machinist today for rebuilding/blueprinting (babywag gets to laugh because he warned me this was going to happen).

I am building my engine to last about 150k miles so the machinist recommended installing EITHER hardened seats (on the exhaust) or stainless exhaust valves. In another thread SC/397 recommended these stainless valves to someone else:
Ebay, 16 Stainless valves

The also sell just the exhaust valves
Ebay, 8 Stainless exhuast valves

I think it would be cheapest to just order this set and have the machinist install them on the standard iron seats. If that's the case, should i spring the extra money and do all stainless or just the exhuast ones?

[joe]

79 motor? Are your seats showing obvious signs of regression? Shouldn't cause by 79 the seats should already be unleaded compatible. If were mine I'd have a proper refurbish done on the intakes and spring for new exhaust valves. Your call if you think you need "new" intake valves? Whether brand new motor or rebuild you can expect at some point in the next 150,000 miles to do a valve job. For optimum performance occasional valve jobs are normal maint.

[rang-a-stang]

My truck is a 79 but the heads are not. My heads have casting number 3216090-1 which google said is a 1973 casting. I have not had them disassembled yet but I had decent compression when my engine was still together and passed CA smog just before tear down so I assume they were decent.

[joe]

Don't fret the 73 heads unless valve seat regression is obvious. IMHO the 1974(?) Chicken Little the sky is falling and all our motors are going to blow up w/o lead in the gas turned out to be a major crock of chit rumor promoted by machine shops. That's regarding normal use street cars/trucks, not race motors. Freshen up your existing heads to spec and go drive...

[440sixpack]

If you want maximum engine life hard seats are required. the factory didn't go with hard seats because they needed to get rid of unwanted cash they did it because they're required. VSR is very real and not just some marketing scam . I've seen it too many times.

On low performance engines not used hard you can get by for a long time without them. especially if you use a higher grade fuel and set your timing correctly. does this mean you don't need hard seats ? that depends entirely on your expectations. most experts say figure 60k rather than 100k as a rule. do you feel lucky ? you decide.


Stainless valves will not compensate for soft seats. but they're better than doing nothing.


Anything worth doing is worth doing right. hard seats are doing it right. if you're just trying to get the last gasp out of a POS then I can see not spending a few extra bucks but that's about it.

[wiley-moeracing]

or save up a few more bucks and by the aluminum Edelbrock heads and be done.

[SC/397]

The valve seats were induction hardened from the factory after about '72. Even in 1966 the heads and block were made out of casting with a higher nickel content. It would be rare if a seat or two was wore enough to justify new seats. Your machinist should be more worried about the guides being wore out.

[babywag]

My truck is a 79 but the heads are not. My heads have casting number 3216090-1 which google said is a 1973 casting. I have not had them disassembled yet but I had decent compression when my engine was still together and passed CA smog just before tear down so I assume they were decent.

It's always best to tear down & inspect before you bring them in.
Some shops aggressively push the "full monte" and want to spend a lot of your $$...many times it just isn't needed on a mild street build.

[fsj454]

Heads

What I did to my stock 1990 heads. 4 exhaust valves and guides and seats .New springs and seals .resurface head .Machine shop fee total out the door 350.00

[rang-a-stang]

It's always best to tear down & inspect before you bring them in.
Some shops aggressively push the "full monte" and want to spend a lot of your $$...many times it just isn't needed on a mild street build.

Totally. good info. I called him and asked him to tear them down, send them through the cleaner, then call me and I will head out there and check them out with him. I wouldn't say he is "pushing"; he just knows I want this motor to last a long time so he says "should" alot. Kind of the same thing 440sixpack is saying. my problem is i'm tapped out. I want to do it right but can't really afford it.

[babywag]

Just because you don’t do everything brand new doesn’t mean it’s not “right”.
Nothing wrong with reusing valves to keep some $ in your pocket.

[Ristow]

if the valves are not pocketed now i wouldn't bother with hardened seats.


you're gonna need exhaust valves,almost surely. the intakes should be fine. go with stainless on replacements. cast iron guides and positive seals. and call it done.



tell the machinist to grind the new valves. they are not always ground true. been there,done that,took it back apart and did it again.....



i'd go all new myself.



as far as long lasting,lets get real here. very few here will put 100K on their fsj.

[rang-a-stang]

All good stuff. Thank you, everyone. I found this thread today and the OP pretty NAILED everything I am reading.
Ford Muscle discussion on hardened seats
I am going to see how the seats look once they are opened and cleaned. if they need replacing, they will get replaced but I am not going to replace seats that can be serviced.

as far as long lasting,lets get real here. very few here will put 100K on their fsj.

Very true. Honestly, I might, though. I am building this one with the intent of road tripping it often. When we move to Boise (hopefully next summer), I will be 6 hours from my brothers in law (Portland), 6 hours from my parents (Reno), and 6 hours from my son in Utah. I expect my oldest son and his family (my first grand baby) to move to Utah in the next couple years, too. I would rather drive my Cherokee to go visit my family than my Mazda because it is MUCH comfier. If I add a 4 speed auto and gears it should get better MPG than our Pathfinder (~16 mpg highway) and not much worse than my Mazda (about 24 mpg highway).

[Ristow]

Very true. Honestly, I might, though. I am building this one with the intent of road tripping it often.

take it from a guy thats been in alot of these motors,and daily drove one for years for a 104 mile round trip......if you do put alot of miles on it won't be the valves/seats that start giving you trouble. they'll be the least of your problems come 150K miles later. i really doubt you will be running seat pressures or a cam thats gonna be hammering the seats.

if the valves and seats can be cut without pocketing a valve,than do so.

[rang-a-stang]

Haha! Good point! I love it when reality smacks you (well, actually me) in face!