Are hardened valve seats necessary?

[767Jockey]

I'm about to have a set of Cleveland 4V heads redone. The engine will be a 408" stroker Cleveland, with about 10.5 compression ratio, run on 93 octane. The car won't be driven more than about 4000 miles per year, and while I'd like to do more I don't anticipate more than one track day a year, if that. Here's the question, the guy redoing the heads wants to put in hardened exhaust valve seats. I know that it certainly wouldn't hurt to do so, but all things considered I'd rather not do them if I don't need to. Once I start adding up all that CAN be done, rather than what NEEDS to be done, I'm starting to get into that very annoying territory where you find yourself saying ......."for just a little bit more, I can get these awesome CHI aluminum heads"...... I would really like to keep these low cost, but well performing. I don't want to screw things up and do it on the cheap, but I don't want to pay for things I really don't need either. Any ideas on this?

[Snakebit]

Don't skimp on your engine. Like the Fram commercial you can pay me a little now, or a lot later. With unleaded gas, stainless valves and hardened seats are the way to go.

[RACER X #99]

Pretty sure you need the hardened seats for unleaded gas. Almost all the head manufacturers advertise (hardened seats).
RD

[J Persons]

If you are only going to use the car for your stated mileage, the non hardened iron seats will last you about 5 or 6 years. The problem is that unleaded gas doesn't have lead, and one of the benefits of leaded gas is that it is easy on valve seats. The unleaded gas will tend to erode the seats over time. But the key word here is time. If it's going to be a daily driver, get the hardened seats installed.

[brobehr]

With the myriad of variables associated with driving and engines ,hardened exhaust seats are never a bad idea.

brobehr

[BigGuy]

I had to use lead substitute in my Corvette without the hardened seats for unleaded gas. When I rebuilt the engine I went with the hardened seats.

Hardened seats are worth it, for the protection. Lead substitute coats the car with black "exahaust dust". If you want some lead sub. I can give you some, just stop by .

.

[Jac Mac]

I would give those CHI heads some more thought for some NOT so normal reasons.
The std 351c 4v heads have 1.71" dia exhaust valves, when you install hardened seats to accomodate these the O.D. of the new exh seat starts to encroach into the intake seat area in an area which already has very little metal due to the large valve dia's. By going back to the 2v exh size of 1.625" you can help this situation a bit, but then your up for new valves etc as well.
In years to come your current 4v heads will appreciate in value to collectors with race cars etc who would probably prefer them unseated for use with race fuel ( you may even be able to get more for them in Australia than the USA )
When you take all that into consideration the CHI heads may be the way to fly. I have built one motor for a circuit car with them fitted and there is absolutely no way we could have acheived the same performance on iron 4v heads that this car has. ( And the owner had a set when we initially started the build ) The increase in bottom end torque without any penalty at high RPM, plus the weight loss in regard to handling made it all worthwhile.

Jac Mac

[767Jockey]

JacMac -
I agree that with $ removed from the equation the CHI's or AFD's are a no brainer. I'm a bit tight on cash now, so the plan is to use these 4V's for a season or two, then swap over to the Aussie Aluminum CHI's or AFD's later. The only way I would keep the iron heads is if performance is sufficient. Then again, the plan is for about 550 - 600 HP with the iron heads, so they may be lasting a bit longer than I thought!

I've gotten a lot of good advice here. If the seats were cheap it would be a no brainer, but they're going to be over $300, which isn't exactly cheap in the big picture of building these heads. They are the single biggest cost of the head build. Given the low use and possible temporary nature of these heads I'm very tempted to skip the seats, especially after what you just told me about reducing the valve area.

Is anyone out there actually running without the hardened seats, and have you seen an adverse effect? I doubt that it would actually have to be a Cleveland, I would think cast iron Windsor's or FE's would be affected by this as well. Anyone?

[jwd]

Never mind. I guess it wasn't important.

[Excaliber]

I totally understand the delima of what CAN be done vs what really NEEDS to be done. Here on Club Cobra the advice almost always leans toward what CAN be done, spare no expense etc. There is a place for that, but not all of us are on a limited budget.

Heres why I would NOT worry about hardened valve seats:
When unleaded gas first came on the scene virtually a 100% of the industry recommended hardened seats, solid advice, but not needed for everyone. Turns out the valve seats are at risk when your driving a LOT of miles in a SINGLE journey. Keeping the temps up over a period of time is what kills the seats. Shorter trips, lower mileage are not so much of a problem. I would think that also applies to limited track use, run some laps, pit, run some more. Running it HARD and LONG? Use a lead additive in the tank for such conditions.

[Jac Mac]

Originally Posted by Excaliber

I totally understand the delima of what CAN be done vs what really NEEDS to be done. Here on Club Cobra the advice almost always leans toward what CAN be done, spare no expense etc. There is a place for that, but not all of us are on a limited budget.

Heres why I would NOT worry about hardened valve seats:
When unleaded gas first came on the scene virtually a 100% of the industry recommended hardened seats, solid advice, but not needed for everyone. Turns out the valve seats are at risk when your driving a LOT of miles in a SINGLE journey. Keeping the temps up over a period of time is what kills the seats. Shorter trips, lower mileage are not so much of a problem. I would think that also applies to limited track use, run some laps, pit, run some more. Running it HARD and LONG? Use a lead additive in the tank for such conditions.

767 Jockey,

There is a lot of merit in what Ernie states above. Quite frankly if I were in your position I would not use them if the car was not going to be a daily-longer trip driver. Fit the stainless exh valves and single groove retainers( DO NOT use the std 3 groove type that promote/allow valve rotation), Choose a cam profile that use's a 'tight lash' setting to ease the seating , this helps a bit and get a few gallons of av gas to put about 10% mix in for longer trips. On shorter runs there seems to be enough lube from cold starts & stem oil to prevent rapid wear.Ensure that you use good valve springs/retainers to eliminate any valve rotation & therefore the tendency for the valve to try and weld itself to the seat when closing which is the real cause of the seat erosion. I have been in the auto repair business for the last 40 years thru all this BS and saw seat erosion big time in jet boats used in tourism in Queenstown NZ. These run all day @ around 4000 rpm. While the decreasing lead values were part of the problem, the biggest single factor was getting the correct valve spring package and cam profile to eliminate any spring surge etc. We could kill a set of standard exh valve seats in around 450 hrs if the wrong combo was fitted.
I know this flys in the face of what some PC folk will tell you, but when Im paying & or doing the maintainance, what works for me is what gets done!

Should have mentioned the boats were powered by Clevelands!

Jac Mac

[CHANMADD]

I agree that hardened seats are not necessary for the use that Cobra's get. Those 4V heads ,for the money are hard to beat. I've got a pair that I am going to use an a small block and I am not contemplating changing the seats.

[767Jockey]

Thanks, JM, Chan and Ernie-
I'm probably going to have a whole custom roller cam made up and source the lifters, springs and everything else from the some guy at the same time so everything works well together.

[eschaider]

767 Jockey,

I think most anything worth commenting on leaded/nonleaded/hard seat/soft seat has been already said in this thread but you might want to do one more check before deciding what to do.

What year are your heads? Were they produced by Ford for early unleaded use? If they were chances are dollars to donuts that the seats are already hardened by Ford. Of course depending on the year of manufacture and whether or not the car was built for leaded fuel it may also mean your seats are not hardened.

Redearch it a little, check some Ford sites, call FRPP maybe same some money.


Ed

[767Jockey]

FRPP? What's that, I'm not familiar. I don't know the year the heads were made. I'll look into it. They are closed chamber and those are the earlier ones. Once the whole smog thing hit they went to the open chamber low compression heads. I'm not hopeful, but what you say is a good point. I'll look into it - thanks.

[Excaliber]

Wouldn't that be ironic, to replace the seats only to find out later it DID have hardened seats to begin with!

Jac Mac, interesting observation on valve rotation.

[767Jockey]

That's about par for the course for me lately, Ernie......

[Jac Mac]

Induction Hardened seats were on 'Open Chamber' CJ heads only--- Not on closed chamber versions. Since its 'depth' was limited by the time the seats have had a light grind or cut its likely any 'hardened' material has been removed.
Jac Mac

[olddog]

I worked for Clark Oil from 1974 through 1978. Clark wanted to sell Premium, leaded regular, and unleaded. However they only had pumps and tanks to carry two fuels. Since they were required to carry unleaded by law, they decided to make the unleaded a Premium 93 octane unleaded. They claimed it would not hurt the valves in the older cars. I was told that it was the 87 octane that caused more problems than the lack of lead, but I do not know for sure if their 93 octane unleaded had anything in it that is not in todays premium unleaded fuel (we may not be talking the same fuel - today verses then).

During those years I put about 24K miles on my 68 Dodge Charger using the 93 octane unleaded. Those were extreamly hard miles on a big block mopar. I never had any problems. I also ran it in a 327 chevy, a 350 chevy, and something else that I am forgetting. I never had any valve problems.

Although I would not suggest using the old seats for something I wanted to last 100K miles, I think they would last 20K. Trueth is the old seats didn't last much over 100K with leaded fuel either.

[olddog]

I think the 4V Clevland was made from 69 to 73 give or take a year. Unleaded fuel was required in the 1975 model year cars. Additionally the 4V 351C were all high compression engines. When the 87 octane unleaded hit, the compression was dropped to 8.5:1. I do not think any 4V heads would have been built to run unleaded. So I doubt any had hardened seats.

I also fuzzily remember that the manufactures did not realize that the unleaded fuel was going to eat the seats up until after the public found out the hard way. Seems like this was't discovered until the cars were on the road about a year. But I don't remember this clearly, so it could be wrong.