Mostly just a lurker here, but I have a some questions that other people here might be able to answer and that might help others.

Long story (kinda) short, I have a pair of C6AE-R heads that saw about 12,000 street miles (on a 428 short block that gave up a rod bearing) that I am having freshened up to go on a new short block. Heads have a decent homeport and are set up with CJ sized stainless valves (2.09 intake, 1.66 exhaust). Old combo had 9.8:1 compression, fairly mild hydraulic cam, never rpm'd past 6K. Valve springs had 120# on the seat when assembled, an I ran adjustable rocker arms. When I had the heads machined, I chose not to install hardened seats because of that 'void' on the outside of the port under the seat. I was afraid there might not be enough meat to hold the inserts in, figured if I ran some Marvel Mystery Oil or other lead additive with pump gas, erosion wouldn't be a problem. Heads were virgin Pick-A-Part pieces off an LTD when I started.

Dropped the heads off with my machinist to clean 'em up, figured that all they might need was a surface on the decks, lap in the valves again, new springs, ready to roll. Turns out that the exhaust seats have already taken a fair amount of abuse, even in the short amount of time they were run. Talked to my machinist today about inserts, he found some in his book listed for a 428CJ with a 7/32" thickness, so he is going to see if there is enough meat to anchor them in.

So, my questions are:

1) Has anybody else experienced rapid seat erosion running heads without hardened seat inserts on unleaded pump gas? Wondering if the oxygenated gas we get in California is more prone to this condition, or if this is normal?

2) What kind of luck have people had running hardened seat inserts on heads with the early style exhaust port with the 'void' under the valve seat?

I have a fair amount of time and money in these heads and would hate to have to write them off as a loss.

Thanks in advance, Brett



'65 F-100 SWB Stepside 2WD Frankentruck
'67 Fairlane/'69 Falcon Frankenwagon

on a 428 with a solid roller cam. It was my everyday driver for years. I have had very good luck with harden seats. I'm sure I have put more miles on that then any one else has......No problems!

"The Poor Mans 427"
http://www.fordification.com/poormans427.htm

"The F.E. Wiki Home"
http://fordfe.wetpaint.com/


Wes Adams FORD428CJ
Built Ford Tuff With Good Ford Stuff
03 F-250 Crew Cab 4x4 6.0 and 35's
64 Falcon X-Ram 428
55 FORD Truck 4-link Rides on air with X-Ram 428
2000 Yamaha V-MAX VMOA#4277
2000 Yamaha 700 Mountain Max
2001 Polaris 600 Edge X
2001 Polaris 500 SP

Yes, we have run hardened seats in the c6ae-r heads (the c8ae-h is ok with seats as it has meat all around, the c6ae-r and earlier are tricky, they do not)

Yes, we dropped a seat, this in an F-250 that works hard and runs kinda warm, stock 390-4v, iron log exhaust, 203-156 valves. But only one seat, and this was after maybe 50,000 miles. Replaced it and no problems since. Maybe a fluke but scary enough.

No, I don't think it is the gas. The truck above is back in the USA, but here in Callie, no problems running unleaded on non-hardened seats in early heads, Galaxies with mostly light duty but some strip duty, again iron manifolds, log and 406-style.

I've always figured it was load related and maybe temperature too ie keep the engine cool, 180F-190F, and the chambers cool ie don't jet too lean at cruise or full throttle. Just some hunches.

Are you running headers? Carb / jetting? Engine temp?

I am running headers, Hooker Super Comps with 1 3/4" primaries. Carb is a 1000 HP vacuum secondary (glorified 850) with annular boosters, forget what the jetting is, but not far off stock was where is was happy. I'm using the stock temp guage, but the needle always rode on the left side of the dial. Thermostat was 180*.



This was in the F-100, not a work truck, rarely hauled a heavy load. 3.89 rear gear and a 2400 stall converter, so it wasn't laboring too hard against itself.

'65 F-100 SWB Stepside 2WD Frankentruck

'67 Fairlane/'69 Falcon Frankenwagon

A good machine shop, should be able to fit them properly.

When California changed over to unleaded gas (check the archives for further information) there was a contentious discussion on whether or not hardened seat were necessary. The general opinion, at the time, centered around the fact that since most engines had been using leaded gasoline most of their life, it was not immediately necessary. Lead acts/acted as a lubricant to prevent heat and impact from 'welding' the valve to the seat, which ~ more or less is the root cause for recession.

Leaded gasoline has been outlawed (for general passenger car use) for quite some time. My personal opinion assumes that the remedial benefit of prior leaded gas use is no longer the insurance it was, if it ever was that good in the first place. Certianly, if you have cut into or are cutting into the valve seat, at some point you need to address the issue.

I had mine iron heads done many years ago, there have been no leaks or odd problems in all that time. The only real issue is finding someone that knows what the heck he's doing! People have been installing replacment seats long before unleaded gas was madatory, its not like this is/was a new thing.

 

I run hardened seats in all my trucks I work them pretty hard and have found the stock seats will erode very quickly if hardened seats are not installed. I have run stock seats in the galaxie and no problems. IMO it has to do with how hot they get. I pull a 11k gooseneck horse trailer with the 69 F250 it sunk all 8 exhaust valves in less than 10k miles with a stock set of C8EA-H heads
Richard

68 F250 2wd 390
69 F250 4wd 390
72 F250 2wd 390
76 F250 4wd 428
92 F350 4wd CC 460
65 Galaxie 2dr HT 352 for now

posts that may be helpful.

http://www.network54.com/Forum/74182/thread/1216439275/Question+for+the+engine+builders

See WerbyFord's post on no seats in early FE heads.....no support!

I'm still sticking to my post in the above-mentioned thread: unless one is planning on pulling trailers and/or using the engine in a heavy or heavily loaded truck, adding hardened seats isn't necessary. This is especially true for the intakes as the low heat load protects the valve and seat (one can and should cut for new seats and install new seats in later FE heads if the old ones are shot....but I would not do so merely to gain hardened seats otherwise if they are still in good shape).

Many others have noticed this too as running today's unleaded gas in lighly loaded street cars or even drag cars (short run time here) doesn't affect the exhaust valves or seats. It's engines that are constantly heavily loaded and run those exhaust valves near red hot for long periods that DO need hardened exhaust seats!

Thanks Bob (and everybody else for that matter),



Sounds like there just isn't enough meat there to support the seats, like the problem Moose had with his CJ heads and Werby noted in the referenced post. Just what I feared. Damn.

'65 F-100 SWB Stepside 2WD Frankentruck

'67 Fairlane/'69 Falcon Frankenwagon

... the original machine shop ground the seats so much the valves fell into the port...go figure.. I took them to a Friend of mine who had just opened a shop.
He installed all of the seats over 40,000 miles ago and they seem to be ok, He has done a lot of FE heads.

I will know when I pull the heads...

I will say, it looks unsupported under the inserts looking into the bowls, not a lot of iron holding them up...

Also, he doesnt use real hard inserts either.



Richard.

heads are c4ae-c on a stock 390 tbird engine. Just a weekend cruiser with limited x-way driving. Should I bother with a lead substitute?

below is one I found elsewhere some time ago but I do agree with his premise (see section on daily drivers, etc.). Unless you are heating those exhaust valves regularly by towing a heavy trailer up the sides of mountains, IMHO you could skip the use of a lead additive or, for peace of mind, use it but only every 3rd or 4th tankful. No need to tear down an engine just to replace the as-cast seats with hardened inserts. Also, it's a great idea to use hardened seats if the heads do show excessive wear and need some serious seat work. Still, unless they are rare FE heads or have had serious porting work, a replacement set may be a better idea.

If you have been following our original poster's question, the real problem I think he's encountered is the extremely thin metal behind the seats in certain early FE heads. Adding (insert type) seats leave a good portion of the new seat's perimeter hanging and unsupported by the surrounding cast iron. That unsupported section turns into a hot spot (microwelding the valve to the seat) as it cannot transfer exhaust heat into the mass of the head.

And I'm sure others here will have varying opinions on the used of seats and lead additives!

*****************************************************************************

How old is "old"? Since 1972, all motor vehicle engines sold in the US have been required to be mechanically tolerant of no-lead gasoline.

And, largely, to no consequence for old vehicles.

With an unhardened (pre-1972) exhaust valve and seat, the valve and seat can micro-weld to each other if they get hot enough. Lead acts as a buffer to prevent this happening. The important thing is that exhaust valve and seat recession ONLY takes place when the valve gets hot enough to undergo localised welding. Then, when the valve opens next, the metal pulls apart like taffy. This roughens the meeting surfaces, and they become quite abrasive. The pounding/turning of a valve with such "pulled" metal on it creates a nice grinding wheel effect on the seat. In addition, the roughened surfaces no longer seal against each other properly, which eventually allows still-burning combustion gases to flow through the "closed" valve, causing a blowtorch effect on the poor valve and depriving it of any prayer of a chance to cool while it's on the seat. The blowtorch effect rapidly deteriorates the seal further, snowballing the seat recession.

The main thing to remember is that this bad stuff cannot happen If the valve never reaches the crucial temperature. Whether the valve reaches the crucial temperature depends mainly on how the car is driven and used (Towing, drag racing or pedal-on-the-floor hauling WILL heat the valves--driving down the highway at a constant 70 won't, and neither will hopping from traffic light to traffic light in the city or running down to the local grocery for a carton of ice cream.) Other factors in the margin of safety include the size of the exhaust valve, its material, and the efficiency of valve seat cooling in that particular engine design.

Very VERY little lead is required to prevent the localised welding and

"taffy pull apart" effect that leads to the abrasive surface which, through incidental or positive rotation of the valve, eventually grinds-down an unhardened seat. I'll emphasize that again: VERY LITTLE

LEAD. The remainder was in the fuel as an octane booster, that's all. It was widely used because it was a very cheap and very effective octane booster. When unleaded fuels were first widely introduced (which introduction was brought about by legislation) , there was generally only one grade of unleaded available, and the octane was quite low--less than that of leaded regular.

We all know that when you use a fuel of insufficient octane, your engine pings (detonation, pinking, pinging, spark knock--call it what you will.)

This phenomenon creates tremendous heat in the combustion chamber--certainly enough heat to push the exhaust valves to the crucial temperature. Because for quite a while only unleaded fuel of subregular octane was available, plenty of people experienced these effects from using unleaded. While a fraction of those engines that suffered under this low-octane unleaded really DID need the lead (high load and/or high-RPM engines), the vast majority of the failures were due to the low octane increasing combustion chamber temperatures (see above). And so the myth was born that old cars' engines "WILL DIE" if run on unleaded.

These days we have universal availability of high-octane unleaded fuels, which obviate the insufficient-octane cause of valve heating and subsequent localized welding.

if you have an old car that is a low-stress application , used in daily-driver service, then you need have no qualms about using whichever octane grade of lead-free fuel your car runs well on and drive it for a

Loooooooonnnnnng time with nary a valve or seat problem. Many domestic 6 and 8 cylinder engines fall into this category in normal daily driving service. The way to eliminate even the possibility of valve heating causing localized welding and subsequent seat recession is to install hardened exhaust valve seat inserts and exhaust valves of upgraded material (typically 21-4N stainless instead of 21-2N). This is utterly standard practice in the rebuilding of cylinder heads, and has been for years.

Hard seats and valves are readily available for just about anything you want to put them in. It's a very common operation and a competent machine shop can handle it. But the main thing here is that there's absolutely no reason to tear into the engine solely to install hard seats. There is no collateral damage from seat recession. Drive and enjoy! You likely won't experience any problems for a LONG time, if ever. If you ever do, have a head job done.

The additives available on shelves vary widely in what they do. Some of them use a sodium salt and claim to duplicate the buffer effect of lead.

Some of them use "MMT" (methylcyclopentadienyl manganese tricarbonyl), which is not a very nice substance at all and is of questionable benefit in buffering exhaust valves. Regardless of whether or not any human-health or environmental risk is posed by MMT, the stuff causes hard red deposits on your spark plugs that will cause you to need to replace them more often. Other additives are simply octane boosters of varying effectiveness and varying side effects.

It's worth noting that on the East Coast of the US, Amoco marketed unleaded high-octane gasoline for decades before the EPA decided to
"unlead" the country's fuel by regulation. That Amoco high-test unleaded was widely regarded as quite a fine fuel indeed.

Another poster in this thread claimed that lead-substitute additives will "give you peace of mind". That's about all the good they'll do.
They're expensive, messy to work with, often hazardous to store in your trunk, are a hassle, and--in the vast majority of cars driven on the street--just aren't necessary.

Of greater concern to you should be the growing use of "reformulated" and
"oxygenated" fuels in many areas of the country, either year round or seasonally. These fuels can attack and degrade some parts of your fuel system and can cause driveability problems. There's a lot you can do for very little money and effort to proof your old car against these new fuel formulations.

what I thought. Although I don't have a history on the car, it appears to be original with 97k on the clock. I had the heads off this spring to replace bad gaskets, and pulled and re-sealed the valves at the time. Things in general looked good. I drove the car some this year to get a feel for what I had before tearing into it. Next spring the engine comes out, and the plan is to keep things original ( no hot-rod stuff). I'm sure lots of those miles were made using unleaded fuel. Thanks for the info, I read everything on this forum and the knowledge as well as the bantering can make my day. Although this car won't get any performance mods the next one might, Thanks again, Bob C