Valve Stem Seal Problems

[TennTechMan]

UPDATE: Valve Stem Seal Problems: Anyone with Dual Springs, Please Read

About two years ago, I rebuilt my '94 Explorer's OHV engine. I rebuilt the bottom to stock, bought new 95TM heads from Alabama Cylinder Head, 422 cam and double valve springs, and reused the stock rockers, push rods, valve spring retainers (Crane had them on back-order), and no machining on the heads for the valve spring seats. Less than 18 months (~15,000 miles) after the build, the engine had started smoking at idle and would blow a large puff of smoke the first time you push the throttle after a long idle. I suspected something was up with the valve stem seals.

6 months after this all started, I finally pulled the engine to check it all out. What I found was something I had not seen before. More than half of the valve stem seals had seperated from the head and were riding at the top of the valve stem. The seals are still intact and appear undamaged. It looks like they just popped off the head.

Anyone else had this issue? Any way to keep it from happening again? If I put the new valve stem seals on, and it happens again in another 15,000 miles, I probably wouldn't mind too much. I would hate it though if they only last 5,000 miles this time. And if I can keep it from happening ever again, that would be ideal.

The other thing I want to do while the motor is out, is to put in the correct length pushrods and a set of Delta's rocker arms. Ever since I rebuilt the engine, it tapped a lot. I tried to email them this morning, but the email was rejected. I'll try to call them Monday. Anyone else had trouble getting a hold of them? Are they still selling the rocker arms and pushrods?

For anyone looking for more history on this truck, search for my posts created under my name. I've got a pretty good write-up of the motor build with some video too.

 

[Anime]

Did you get the heads bare or they came with the valves and seals from ACH? If they were on the heads when you bought them, you should probably call them about it. If the seals were pressed in after, you're probably best off buying all new seals.

I called Delta Cam earlier this week, using their 800 number is a lot faster, their server or web host is incredibly flaky. You might consider using Smith Bros. pushrods, they're about ~$80 a set, but they are 4130 Cro-Mo shafts (Delta Cam's are steel with hardened tips), and you can get them in a custom length to go with either new stock rockers or slightly longer for Delta's.

 

[TennTechMan]

The heads were fully assembled. I'll be sure to give them a call to find out if they've had the problem with any others. I really don't want to remove the heads if I don't have to, so I'm going to try to avoid having them swapped under their advertised lifetime warranty.

Smith Bros. sells the rockers too? I may have to look into that.

 

[Anime]

You can swap out the valve stem seals without taking off the heads? I thought for sure they could only be pressed in with the heads off. Sounds to me like something involving sending them back to ACH for new seals to be pressed in, but if you can put in new ones and save yourself the time and hassle of head removal, it's probably worth it.

Smith Bros. only sells the pushrods as far as I know.

I've heard Ford sells revised rockers in response to the wear issue. FPN has these rocker assemblies for $103 ea, so I'm thinking I'll go with two of those and Smith Bros rods for an all-new $300 setup, rather than the Delta Cam deal of rebuilt rockers and hardened aftermarket rods for $200.

Delta Cam does offer to rebuild your original rockers for the same kit price though, if you can afford the downtime and swapping out your worn rockers for rebuilts doesn't sound as good.


Personally I would go with the Cro-Mo Smith Bros. rods with that 422 cam. They quoted me $7 each for Cro-Mo with hardened tips and $8.50 each for a hardened Cro-Mo rod with hardened tips.

The proper length pushrod seems to be different between using the factory rockers and the rebuilt Delta Cam rockers, so you may need to measure or do some thread searching to find what works.

 

[TennTechMan]

I think you might be confusing the valve stem seals with the valve guides. I haven't taken the valve springs off yet, but when I do, I'll make sure there's no excessive play in the guides.

I'm a little worried that if the heads' mating tolerance of the valve stem seals are incorrect, the same thing will happen again. Maybe I'll figure out a little more when I start to pull the valve springs off.

 

[TennTechMan]

UPDATE:

I just received my new rockers and pushrods from Delta. The stuff looks great out of the box. Hopefully it will perform as well as it looks.

I swapped all the valve stem seals out last night. No problem doing it with the heads still on the engine. It just took some compressed air to hold the valves shut while I swapped them. The problem is a result of a poor combination of parts. The design of the valve stem seals that I removed had a pretty large lip on the OD of the seal. This lip apparently was catching on the relatively small ID of the dual valve springs. The new valve stem seals have a much smaller OD, and look like there is no chance of interference with the springs.

When I put the dual valve springs on, I had no machining done to the heads for the springs to seat well onto. I also used stock valve spring retainers because Crane discontinued the retainers about the time that I was building the engine. I'm guessing several others have also used the dual springs with stock heads and retainers. Anyone else seen anything like this? Better location of the springs might have saved all of this work.

For those that have had the propper machining done to the heads before using dual valve springs, what was the cost? I design aftermarket automotive parts for a living, so I've got some experience designing parts and bringing them to market. I'm considering designing up some spring seats that will basicly be spring shims with the correct locating diameters for the dual valve springs that most people have used with the 422 cam. These shims would slide over the valve stem and guide, and locate the bottom of the spring. I am also considering designing up some valve spring retainers to locate the top of the spring. This combination of parts would guarantee the end user that they don't end up with the same problem I did.

I'd like to get some feedback from you guys as to whether or not this is something you guys think is needed. I have no idea on price yet, and I won't know until I make some drawings and get some quotes from my suppliers. I'm not wanting to make much of anything off of this, but it doesn't make sense for me to do it if I'm going to lose money. For the relatively low quantities that these will be, I'm guessing I could sell the kit of shims and retainers for $250 or so. Does this seem reasonable? If I get any possitive feedback, I'll start making some drawings and getting prices. Then I can follow up with a more definite price to see if you guys are still interested.

I appreciate any feedback.

 

[Anime]

Which valve stem seals did you go with?

Stock retainers with the dual springs? I guess thats all you can do if the Crane ones are no longer available, that's the first I've heard about them being discontinued, though. Did you just hear that from one place or you can't order them anywhere? The hot setup seems to be new heads with the 410 or 422 cam, dual springs, and the Crane retainers. Doesn't make a whole lot of sense to discontinue the one part in that setup.

There seems to be some debate on whether the head machining for the dual springs is necessary. Some say the springs won't go on without machining, others say they fit just perfect on stock heads. Perhaps they sit just fine on the 95TM/98TM heads but not the 90TM/93TM, or the other way around?

At a price of $250, it might just be easier to have the work done when swapping heads.

Spring seats/shims that would make a cam and pushrod/rocker swap a drop-in deal would probably be worth it to some people.

 

[TennTechMan]

Which valve stem seals did you go with?

Stock retainers with the dual springs? I guess thats all you can do if the Crane ones are no longer available, that's the first I've heard about them being discontinued, though. Did you just hear that from one place or you can't order them anywhere? The hot setup seems to be new heads with the 410 or 422 cam, dual springs, and the Crane retainers. Doesn't make a whole lot of sense to discontinue the one part in that setup.

The valve stem seals with the smaller outside diameter are out of a Fel-Pro gasket set. The ones that caused the problem were what came on the 95TM Alabama Cylinder heads.

At the time I was building the engine, I ordered the spring retainers from Jegs. After waiting two months for them because they were on backorder, Jegs told me that Crane had decided to discontinue them. I haven't looked for any since. If no one else is making them, I'm thinking that's a hole in the spring retainer market. At least for Ranger/Explorer guys with 4.0L OHV engines. After some talk with one of my suppliers earlier today, I think I may be able to get that price lower. I'll find out in a few days for sure. The $250 that I mentioned would be retainers and shims together, not $250 each.