428 PI, Hardened Exhaust Valve Seats or Not?

[8T03S1425]

I was reading a discussion started by a guy who was seeking advice on disassembling and rebuilding or reassembling a '66 HiPo 289. The discussion turned to the topic of the need for hardened exhaust seats in his engine. Randy weighed in and stated:

   Steve,
      The reason not to do it is there is no reason to do it in the first place. IF the heads suffer from seat recession , then by all means have exhaust seats installed. If they do not , you don't have a problem to fix in the first place. Replacement seats have been known to "fall out" if installed with "too little" press fit , and crack the head under the seat if installed with "too much" press fit. Much paranoia was created in '72 when Ford cast a bunch of "junk" 351C 2V heads that had seat recession and horrible guide wear. As I mentioned gas formulations have been improved to reduce seat recession and it rarely happens now days.
   Randy

I recently had the original, to my GT500, C8AE-H FE heads rebuilt to stock specs. Except for the mention of the '72 351 2V heads, my engine builder's advice pretty much paralleled Randy's advice. Because I remember a time when using hardened exhaust valve seats were commonly recommended, I pressed him for the reason why he didn't think I needed them.

He told me that they're not needed for today's pump gas, especially if the car will be used for typical recreational and spirited driving. He also added that putting hardened exhaust valve seats in 390 GT or 428 CJ heads is a bit challenging due to how close the intake and exhaust valves are to one another. With that said, he told me that if I wanted the hardened exhaust valve seats he'd be able to add them, but their cost and installation would increase my cost of the rebuild. I opted against their use. If I was going to use the car for cross country highway trips or repeated and regular drag racing, he recommended I use a lead additive, otherwise I should be fine without fuel additives.

I open this topic in a new thread for 428 engines to solicit comments, pro and con, for hardened exhaust valve seats. I'd also like to hear from those who have had the hardened seats installed on 390 GT or 428 heads. Has it been a good decision or were there unexpected outcomes.

Steve

[shelbydoug]

You don't  do seat inserts unless the heads are already damaged and the seats need to be repaired.

The FE's all have issues to begin with in the valve pockets. The castings are very thin there and it is very common to find cracks between the seats of the valves leaking into the water jackets.

Unless you are going to use the stellite inserts used in the aluminum 427 heads it's likely that your builder is going to use the cast iron inserts used in the current run of aluminum aftermarket heads.

From experience, if you can find some, those stellites are so hard that they tend to crack the casting when you press them in.


The cast iron inserts are actually SOFTER then the cast iron in the heads themselves. There is NO benefit to them, only drawbacks.

You ONLY use inserts if the valve seats are cut so deeply the valves are recessed or the seats need to be repaired.

Any shop "highly recommending" them is just looking for more work and I would question their knowlwdge and competency with Fords? Let them stick with Chevys.



Once the heads start cracking they are on the way out. They can be welded but that has not proven to be dependable and is only a temporary reprieve to the scrap pile.

Even just putting bigger valves in the heads can  be risky.

The big 427 valves in fact were taken out of the aluminum GT40 heads in favor of the CJ valves. This all had to do with dependable longevity.

Leave the heads alone. They were never designed for inserts.

[Royce Peterson]

+1 Agree.

You don't  do seat inserts unless the heads are already damaged and the seats need to be repaired.

The FE's all have issues to begin with in the valve pockets. The castings are very thin there and it is very common to find cracks between the seats of the valves leaking into the water jackets.

Unless you are going to use the stellite inserts used in the aluminum 427 heads it's likely that your builder is going to use the cast iron inserts used in the current run of aluminum aftermarket heads.

From experience, those are so hard that they tend to crack the casting when you press them in.


The cast iron inserts are actually SOFTER then the cast iron in the heads themselves. There is NO benefit to them, only drawbacks.

You ONLY use inserts if the valve seats are cut so deeply the valves are recessed or the seats need to be repaired.

Any shop "highly recommending" them is just looking for more work and I would question their knowlwdge and competency with Fords? Let them stick with Chevys.



Once the heads start cracking they are on the way out. They can be welded but that has not proven to be dependable and is only a temporary reprieve to the scrap pile.

Even just putting bigger valves in the heads can  be risky.

The big 427 valves in fact were taken out of the aluminum GT40 heads in favor of the CJ valves. This all had to do with dependable longevity.

Leave the heads alone. They were never designed for inserts.

[Greg]

That is exactly what I have been told, no need for hardened seats.  I think that mode of thinking carried over from the late 70's, 80's. when everyone was worried about putting unleaded in leaded fuel cars.

[shelbydoug]

That is exactly what I have been told, no need for hardened seats.  I think that mode of thinking carried over from the late 70's, 80's. when everyone was worried about putting unleaded in leaded fuel cars.

There is some circumstantial evidence that indicates it was a "campaign of misinformation instituted by the oil industry itself".

There is some value to using inserts with GM products since they use a much softer alloy of cast iron then Ford does.

Ford's alloy approaches the hardness of nodular iron if not in fact being nodular iron itself.

As Randy pointed out, Ford has experimented with using the cheaper and softer iron in production at times and it just came back to shoot them in the foot since it also effects the durability of the cast in valve guides.

NONE of the Ford cast iron heads do well with inserts. They are all too thin under the valve and even when you do them, you need to use a thinner insert to avoid from cutting too deeply into the valve pocket.

With casting variations from head to head, that is very risky unless you x-ray each and every casting at every intended cut.

Unfortunately Ford iron castings have lots of drop outs the size of a BB and often are on the inside of the casting that you can't see.

Ask the head porters about that. In the '60s many would destroy two heads for every one that they ported successfully. They would also tell you that you can hole through at any point and that a "race ported head" is just a "temporary head".

[gt350hr]

  Steve,
       After 54 years the cast iron seats are "work hardened", LOL . As I said no need to spend the money. Nice to see others share my opinion/experience.
    Randy

[8T03S1425]

Thanks guys! I highly respect your opinions and experiences.

My engine builder is Doug Meyers of Automotive Machine Services. When I was looking for someone to build my engine, his name came up repeatedly. He was highly recommended by other HiPo Ford owners I talked with at local shows, especially the FE crowd. He does lots of race engines which means that there is no such thing as a short turn around, unless yours is a race engine he built, you broke something, and you have a race coming up. New comers and stock rebuilds for restorations require advance planning and longer lead times. My heads were in his queue for about 6 weeks. When it came time to work on my heads, we talked about cam selection so he could select the valve springs best matched for my intended build. He also pointed out an anomaly that needed to be addressed.

He told me that my C8AE-H heads had CJ valves and wanted to know if I wanted the valve seats opened up accordingly or if he was to replace the valves with 390 GT valves. I can only guess how the CJ valves got in there, but considering the sketchy history my car carried, and some of the other things I had to fix, I wasn't surprised. I opted to use the 390 GT valves to keep things stock.

Have you guys heard of CJ valves being successfully used in C8AE-H heads without the seats being opened up to match? I can't imagine there not being a compression leakage problem with the CJ valves being used.

I hope this discussion helps others who have similar concerns during their restorations.

Steve

[1967 eight barrel]

Yes. Just about anyone who wants a bit of performance runs the 2.09 1.65 valves. If they were in the seat it was already cut for them. However, what he probably meant is unshrouding the valve. The chambers are usually cut slightly for clearances.
Look at my Edelbrock head. Look at the chamber portion where the red dye is absent next to the exhaust valve. That was unshrouded. These heads utilize the 2.25 1.75 valves. The same relief/unshrouding is required in stock heads for the larger valves. It helps them breathe.
                                                                         -Keith

[shelbydoug]

Steve, You want the CJ valves. No big deal to install them. There is very little unshrouding work to do with them if at all since you already had cj valves in the heads.

The intakes only go from 2.02 to 2.08 so it isn't a drastic change like going to 2.25 like in Keiths Edelbrock heads.

Those are tunnel port size valves. Bigger then the 2.19 427 MR intakes.


He may actually be refering to the dimensions of the ports under the valves. Normally when you put a bigger valve in you also open up that port proportionally. The flow is controlled by the size of the opening.

It sounds like he sees no evidence of the enlargement of the ports with the larger valves?



Keith, did you need to notch the block to use that Edelbrock head with those valves?

As I recall, the 427 blocks do have clearance notches for the big 2.19 intake valves.

[1967 eight barrel]

Doug:
The Edelbrocks will clear with no issue on bores larger than 4.150. The valve angles are different than Ford geometry.  Keith Black did the heads on the new motor.
With the factory MR and TP heads they required block notching. It's also good to unshroud the valve. The small difference in the 2.09 Vs 2.03 and 1.65 Vs. 1.56 valves didn't require pocket work on the C6AE-R heads I ran initially, but the bowl needed to be unshrouded like the Edelbrocks in the picture. The C8AE-H head is a non-performing low-flow head. Anything to help with breathing helps. I guess he doesn't have a CJ, but the 68 PI heads. I would have put the swirl polished 2.09 1.65 valves in them.
Alexparts is a great place to get valves and springs. I have dealt with him for years.
https://www.alexsparts.com/
                                                                 -Keith

[Royce Peterson]

CJ valves fit fine in the low performance C8AE H heads. In a 428 bore they will help performance a bit. It is also a great thing to use to avoid tricky / expensive installation of repair seats in the heads.

Going back to 390 sized (all of them are the same regardless of GT or not) valves will force the machinist to install hardened seats and reduce performance at the same time. Extra money and work for reduced performance? Not what I would want.

He told me that my C8AE-H heads had CJ valves and wanted to know if I wanted the valve seats opened up accordingly or if he was to replace the valves with 390 GT valves. I can only guess how the CJ valves got in there, but considering the sketchy history my car carried, and some of the other things I had to fix, I wasn't surprised. I opted to use the 390 GT valves to keep things stock.

Have you guys heard of CJ valves being successfully used in C8AE-H heads without the seats being opened up to match? I can't imagine there not being a compression leakage problem with the CJ valves being used.

I hope this discussion helps others who have similar concerns during their restorations.

Steve

[gt350hr]

  You should also ask if the machine shop has the ability to do a valve job with a torque plate in place. This has a dramatic effect on the distortion of the end exhaust seats as it simulates the head being bolted onto the block to eliminate that problem. If they can't you will probably have leaky exhaust valves on all four ends.
   Randy

[1967 eight barrel]

  You should also ask if the machine shop has the ability to do a valve job with a torque plate in place. This has a dramatic effect on the distortion of the end exhaust seats as it simulates the head being bolted onto the block to eliminate that problem. If they can't you will probably have leaky exhaust valves on all four ends.

Randy:
I was surprised when I went into Charles Machine and saw the torque plate on the head.  I had never heard or seen that done before. He surfaced them first as well. I don't think many use the plates.     -Keith
                                       

[8T03S1425]

When the 428 PI was built at the factory, did the C8AE-H heads come with 390 valves, or did they receive the larger CJ valves and any unshrouding work that would be required for their use? My goal is to have the engine built as it was delivered to the first buyer.

The valve seats were not damaged, nor were hardened seats installed. If CJ valves were installed at the factory, I may be going back to Doug and asking him to replace the 390 valves with CJ valves. (Ugh, if only I knew then what I know now.)



I'm also not understanding how two different sized valves could fit into the same size hole and deliver different performance results. I understand the opening between valve seat and the valve has a flared shape. In my way of thinking, a cross section of the valve opening would have the larger CJ valves making a different sealing contact surface than the smaller 390 valves. The larger valves would have a sealing contact surface closer to the piston, but the air/fuel mixture, or exhaust gases are still passing through the same size cross section of the valve openings, assuming the same cam is used for either setup.

What am I missing on the performance upgrade of using CJ valves over the 390 valves?

Steve

[1967 eight barrel]

The valve seats are cut larger for the 2.09 1.65 CJ valves. This is why he mentioned replacing the seats if you went back to the smaller valves. FEs use 2.03 1.56 for most standard applications.  I wouldn't use the springs that are on the heads either if they're original springs and stay away from the "umbrella" valve stem seals and go with the positive seals.
                                                                          -Keith