Anyone else have problem's with stealth heads

[Musicman]

When I was talking to machine shop about getting heads with long block rebuild, he said he would only warranty the engine build if he bought the heads and inspected and made any corrections and fixed any found problems first.   This was in reference to eddy heads back then, last summer?  anyways, he said the last 3 pairs of eddy rpm heads he had built an engine with needed some sort of small fix up on the springs or retainers or something, can't remember.   So, seems that bolt on from either company is at your own risk without an expert or semi expert double checking factory assembly/parts.   

  Always check them out first, regardless of manufacture.

[AKcharger]

...In Bill's case, the very end of the spring appears to be sticking out a bit, so it may be the spring itself that is or is not at fault. Perhaps the very end of the spring where it was cut and re-curved to sit flat got sprung a little during manufacture. A couple of quick measurements taken in place with a set of calipers would reveal that answer.

Copy, I plan to pop the rockers off tomorrow and double check everything, will keep everyone posted...great info, thanks to all!

[frederick]

Just checked one of my heads.
One one occasion the retainer is hitting the stock stamped rocker, some other ones are very close.

I've got 10degree retainers and locks from compcams.  (613-16 an 748-16)
On assembling them I did notice the installed height increased by aprox. 0.040' so added shims under the springs to compensate.

Frederick

[Chatt69chgr]

I called 440 Source to discuss this issue.  I have a set of the Stealth heads but have not installed them  They say that you have to shim up the rocker arms to get appropriate clearance between the rocker and the valve retainer.  They said that these shims are available from Mancini or others.  They don't sell studs to use for attachement of the rocker arms.  I havn't called ARP to see if they have them.  Also have not called Edelbrock about whether they have the studs and shims.  440 Source said that as long as you only tightened to 25 ft pounds that bolts will work fine and won't strip out the aluminum (when attaching rocker arms).  I think I would still like to find studs.  I have not had time to try to identify the recommended shims yet.  But if this solution works then that would be good as you wouldn't have to change out the springs.  Note that I am going to be running a Engle K56 cam.  They said it is a good idea to go to the 10 degree locks and retainers.  I bought these from Comp Cams already.  They did say that the clearance between the retainer and the rocker should be at least 50 or 60 thousands.  Would be interested in what others think about these recommended solutions.  I plan on having my heads torn down and checked for valve sealing, valve stem clearance, and rocker to valve retainer clearance when I have the new retainers and locks installed.

[General_01]

It is almost starting to sound like the way to go with these heads is to by them bare and get the right parts and have a builder put them together for you.

[Musicman]

They say that you can shim up the rocker arms to get appropriate clearance between the rocker and the valve retainer.  They said that these shims are available from Mancini or others.

I personally don't like the idea of putting shims under the arms to gain clearance. Those shims were designed for guys that had the heads shaved and needed to compensate for the loss. You could use shims, but now you will have to compensate for the loss at the other end.
In a case like this, I would look for a new set of retainers as Ron suggested... ones that would grab the locks a little sooner. Grabbing the locks earlier (lower on the stem) would give you the clearance required without changing the geometry. Unfortunately there is no way to tell which ones will do the job without trying them first. Spec's like that aren't given in most cases... product experience is the key there. To bad they don't make conical tapered shims that you could just drop in the hole between the lock & retainer. Forget it, that would be to easy...

They said it is a good idea to go to the 10 degree locks and retainers.

Agreed... most of us qualify for this upgrade anyway.

They did say that the clearance between the retainer and the rocker should be at least 50 or 60 thousands.

That is pretty much what I have now... I am switching over to 10 degree locks & keepers however, so we will have to see what happens there. Hopefully I will find a set that grabs the locks sooner than later.

[Chatt69chgr]

I just got off the phone with Edelbrock and was asking them about their performer rpm heads for 440 application.  They said they recommend a adjustable rocker assembly.  They don't recommend using their head with the stock stamped rockers.  They don't recommend shims.  They don't sell any shim kits or shims.  They supply two studs for the shallow rocker mtg holes.  You are to use bolts on the other three.  I'am wondering if the crane adjustable rockers and the appropriate push rods along with the 10 degree locks and retainers would effectively solve the problem.  I realize that the adjustable's are not cheap.  I think Summit sells the Crane set for $324.  Doesn't include the push rods either.  I havn't looked to see what Harland Sharp, Comp Cams, or Hughes has yet.  So we may be barking up a tree trying to use stock stamped steel rockers since, apparently, the Stealth heads are more or less clones of the Edelbrocks.

[firefighter3931]

Stock stamped rockers work fine with the edelbrock heads....of course those come set up properly while the "source" heads are hit or miss. I've said this several times on here ; upgrade the locks and retainers and you won't have any issues. There are 2 types of locks.....stamped and machined. The stamped stuff is low grade and guess what the stealth heads come with ? Wanna guess what you get with the E-heads ? 


Look guys, these heads are very reasonably priced and there is some compromises made in the hardware.....that much is evident.    If you really want to run these heads have them inspected and corrected.....it's that simple.

I personally don't like the idea of putting shims under the arms to gain clearance. Those shims were designed for guys that had the heads shaved and needed to compensate for the loss. You could use shims, but now you will have to compensate for the loss at the other end.
In a case like this, I would look for a new set of retainers as Ron suggested... ones that would grab the locks a little sooner. Grabbing the locks earlier (lower on the stem) would give you the clearance required without changing the geometry. Unfortunately there is no way to tell which ones will do the job without trying them first. Spec's like that aren't given in most cases... product experience is the key there. To bad they don't make conical tapered shims that you could just drop in the hole between the lock & retainer. Forget it, that would be to easy...

I have to agree with Mike here....shimming the rocker shafts is a mickey mouse solution. You will need longer pushrods most likely and the rocker sweep across the valvetip will be compromised. Bandaiding one problem creates larger headaches. Bottom line, fix it right and sleep better at night. 



Ron

[RD]

needless to say, i believe that after hearing from others, 440source needs to change their statement regarding the usage of stamped rockers with their heads.  obviously, stock stamped rockers cannot be the recommended or viable product to use with the heads due to the clearance issues.

i still dont think the purchaser of the heads should HAVE to tear them apart and put them back together with new locks.  440source should do this, even if costs a little more (one less thing to worry about purchasing).

i dont go to a store (any store) and buy an appliance just to take it to a repair man to see if everything is okay inside.  I buy the product based upon the businesses description and warranty/guarantee and go from there.  440source needs to back up what they claim and make it right. i do disagree with ron though on one aspect... I do not believe that if I want these heads to run i should have to pay to have them corrected.  They SHOULD be corrected prior to purchase.  It is not my responsibility, it is the companies.  Afterall, if the belt on your dryer was substandard, would you go buy a new belt and replace it, or would you go back to sears and have them fix it? (yes, i believe this to be apples to apples).

i am not arguing the fact that you all are stating:

1. new locks should be installed
2. shims are not the answer

[Musicman]

I disagree with Ron though on one aspect... I do not believe that if I want these heads to run I should have to pay to have them corrected.  They SHOULD be corrected prior to purchase. 

I understand your feelings on the matter, but the facts still remain... Manufactures are selling you a set of heads complete with their components, at a price which is less than if you purchased the items separately. However, you are not paying for the proper machine work that goes into correctly fitting these components to the heads. Yes, it sucks, but it is a fact of life common to ALL  manufactures of engine heads. I do believe manufactures could do a little better with their advertising practices however. For instance 440 source says the "Heads are assembled and ready to bolt on the engine"... true enough, but certainly not the whole truth to be sure. Don't get me wrong, some manufactures make no claims at all about fully assembled heads other than the fact that they come fully assembled. Missleading perhaps, but a little more truthful...
It's an area that needs work to be sure... it's not just engine heads either you know, look around... There's misleading information everywhere in the aftermarket automotive performance industry.

[Musicman]

Chatt69chgr... Thanks for taking the extra steps, making some phone calls and posting your findings   I'm sure many folks here appreciate your efforts. Good information, straight from the horses mouth...

[Ghoste]

It's an area that needs work to be sure... it's not just engine heads either you know, look around... There's misleading information everywhere in the aftermarket automotive performance industry.

It'd also be fair to say that sometimes you get what you pay for too.

[frederick]

Noticed another thing:
The rockertip is right on the edge of the valvestem when the valve is closed. Not good geometry.
So I will need the rockershaft shims to to correct this.

Frederick

[Chatt69chgr]

I've about decided to go with the Crane ductile iron adjustable rockers, P/N 64770-16.   They are OK for valve spring dia up to 1.565.  They want you to use their rocker shaft too.  It's about $100.  I called them and they said to put the head on the block and use a checking pushrod to get the proper length then call them and they can supply whatever that length turns out to be.  The pushrods are ball/cup and are 3/8 inch dia.  The rockers are made to fit standard offset, ie, stock.  I tried to call 440 Source to make absolutely sure that these will be OK---that is, that the Stealths are std offset--- and I will do that monday but I think they are.  The other rockers I looked at were the Comp Cams P/N 1321-16.  They are investment cast steel and are a little higher tech as they use pin bearings on the rocker shaft and have a roller tip plus are adjustable.  They would probably work fine.  They are for max valve spring dia of 1.54.  They cost $500 for the rockers, shaft, and hold down bolts/fittings.  That was from Summit.  Somebody else may sell them cheaper.  But I kind of like the Crane pieces.  They should yield more spacing between the valve spring keeper and the underside of the rocker and from what I have read are just about indestructable.  If I was building a higher rpm engine, the Comp Cams pieces might be a better choice.  My machinist says that he put a set of the Comp Cams rockers on a 440 a year ago and they worked out real nice.
I will note that when I read frederick's post below about "the rockertip is right on the edge of the valvestem when the valve is closed" has given me a bit of concern.  I wonder if the rockertip of the Crane ductile iron rockers will be like that?  Has anyone used the Crane ductile iron rockers and if so can they report on their experience.
As I mentioned in an earlier post, I will be changing out the locks and keepers for new 10 degee pieces from Comp Cams.  From everything I have read, I think the springs that were supplied on the Stealth heads should be OK.  May not have mentioned before but bought lifters from comp cams and cam is a Engle K56.
When I get the heads worked over I will report back as to whether the valves needed any seat work or not as well as if the guides had proper clearance.

[AKcharger]

Well I popped off my rockers, marked the valve tips with magic marker, put the rockers back on and turned it over. After pulling the rockers again they were hitting square, except for 2, but even those didn't cause me any concern. I put everything together again and drive it 250 mile to a show, so I'm comfortable with my set up.

You guys have scared me into changing out my valve keepers this winter however.

[Steve P.]

WHY WAIT?? 

[Chatt69chgr]

I'am having second thoughts about using the Crane ductile iron rockers.  They don't have any bushings.  So you will be running cast iron on steel which can result in galling.  You can have them bushed at rocker arm specialists for $125 for a set.  That would make these a total of $425.  Shaft is extra.  Same with comp cams adjustable lifter which are made out of stainless steel.  Those cost $500 for set plus shaft is included here--but they can only handle valve spring dia of 1.540 which is not good enough as the Stealths are valve spring dia of 1.550.  I looked on the Hughes Engines website and they have a roller rocker that is asjustable.  It's their model 1510S-16 for $460.  There are several good things about this one.  They make their own shafts which are the same dia as stock but thicker walls than stock or the other vendors.  They also do what they call a bananna cut to the oil holes ensuring a good oil supply for the rockers.  And they supply shims to go between the rockers also helping with the rocker oiling.  They don't use bearings as they say the aluminum doesn't require one.  Say that if they put a bronze bearing in that it would reduce the strength on the valve side where you are narrow to allow larger valve spring size.  I found out that they can handle up to 1.625 valve spring dia.  They said that these are used all day long on Edelbrock Performer RPM heads which are more or less identical to the Stealths particularly in valve spring size and installed height (and virtually everything else).  And their rockers are for std offset which is what the Edelbrock Performer RPM is.  The adjuster has a ball end so you will be using a ball/cup pushrod--3/8 inch.  Ball and cup are 5/16 dia.  On request, they will send you a P/N 8100 checker lifter (for hydraulic applications) and a P/N 8214 checking pushrod.  You pay a total $100 deposit on these and get your money back when you send them back in.  They will make the pushrods to your measured length.  Cost about $165.  They also have a complete hold down set for these which costs $85 and it uses studs and twelve point nuts.  Also, the hold downs are machined instead of stamped.  I found that Mancini Racing sells Hughes stuff for a few % discount---not much though.  They get $445 for the rocker/shaft set and $75 for the stud hold down kit.  I assume they can supply the checking pushrod and checking lifter.  Don't know yet.  I will also be substituting the new comp cams 10 degree locks and retainers as well as their valve guide seals.  Will keep the Stealth springs.  Using the Engle K56 HYD I will have a total valve action (1.5:1 rockers) of .504 inches.  The Stealth heads say they are OK for up to .600 lift.  Comments appreciated.

There is one other way that I thought of that might allow one to use the stamped steel rockers.  That would be to use a beehive spring.  I have no idea if one is available.  I am wondering even if one was, since the Stealth heads are machined for the steel cup that the current spring sits in, that if you put a spring in with a smaller dia. on the foot, that the cup it sat in would dance around and that wouldn't be good.  I was going to ask Comp Cams about such a spring and it's application but have never been able to get through to their tech persons.  But even if you did figure the spring part out, you would still be using the stamped steel rockers and I think Ron pointed out that these rarely ever are 1.5:1 rocker ratio.  They are less and vary all over the place.  At least with good (expensive) rockers, you will be getting the true 1.5:1.  Now whether this makes any difference in how much power the engine makes I have no idea.  I have run across some posts where guys had 1.5:1 rockers and put in 1.6:1 rockers and found that their ET at the track was about the same.  Might have improved a few hundredths of a second.  So this factor may not be all that important.  I don't have the experience to say.   

[Runner]

I'am having second thoughts about using the Crane ductile iron rockers.  They don't have any bushings.  So you will be running cast iron on steel which can result in galling.  You can have them bushed at rocker arm specialists for $125 for a set.  That would make these a total of $425.  Shaft is extra.  Same with comp cams adjustable lifter which are made out of stainless steel.  Those cost $500 for set plus shaft is included here--but they can only handle valve spring dia of 1.540 which is not good enough as the Stealths are valve spring dia of 1.550.  I looked on the Hughes Engines website and they have a roller rocker that is asjustable.  It's their model 1510S-16 for $460.  There are several good things about this one.  They make their own shafts which are the same dia as stock but thicker walls than stock or the other vendors.  They also do what they call a bananna cut to the oil holes ensuring a good oil supply for the rockers.  And they supply shims to go between the rockers also helping with the rocker oiling.  They don't use bearings as they say the aluminum doesn't require one.  Say that if they put a bronze bearing in that it would reduce the strength on the valve side where you are narrow to allow larger valve spring size.  I found out that they can handle up to 1.625 valve spring dia.  They said that these are used all day long on Edelbrock Performer RPM heads which are more or less identical to the Stealths particularly in valve spring size and installed height (and virtually everything else).  And their rockers are for std offset which is what the Edelbrock Performer RPM is.  The adjuster has a ball end so you will be using a ball/cup pushrod--3/8 inch.  Ball and cup are 5/16 dia.  On request, they will send you a P/N 8100 checker lifter (for hydraulic applications) and a P/N 8214 checking pushrod.  You pay a total $100 deposit on these and get your money back when you send them back in.  They will make the pushrods to your measured length.  Cost about $165.  They also have a complete hold down set for these which costs $85 and it uses studs and twelve point nuts.  Also, the hold downs are machined instead of stamped.  I found that Mancini Racing sells Hughes stuff for a few % discount---not much though.  They get $445 for the rocker/shaft set and $75 for the stud hold down kit.  I assume they can supply the checking pushrod and checking lifter.  Don't know yet.  I will also be substituting the new comp cams 10 degree locks and retainers as well as their valve guide seals.  Will keep the Stealth springs.  Using the Engle K56 HYD I will have a total valve action (1.5:1 rockers) of .504 inches.  The Stealth heads say they are OK for up to .600 lift.  Comments appreciated.

There is one other way that I thought of that might allow one to use the stamped steel rockers.  That would be to use a beehive spring.  I have no idea if one is available.  I am wondering even if one was, since the Stealth heads are machined for the steel cup that the current spring sits in, that if you put a spring in with a smaller dia. on the foot, that the cup it sat in would dance around and that wouldn't be good.  I was going to ask Comp Cams about such a spring and it's application but have never been able to get through to their tech persons.  But even if you did figure the spring part out, you would still be using the stamped steel rockers and I think Ron pointed out that these rarely ever are 1.5:1 rocker ratio.  They are less and vary all over the place.  At least with good (expensive) rockers, you will be getting the true 1.5:1.  Now whether this makes any difference in how much power the engine makes I have no idea.  I have run across some posts where guys had 1.5:1 rockers and put in 1.6:1 rockers and found that their ET at the track was about the same.  Might have improved a few hundredths of a second.  So this factor may not be all that important.  I don't have the experience to say.   

    un bushed iron rockers on steal shafts are just fine. mopar sent lots of cars out the door stock this way. crane and isky iron rockers have been used successfully for years on mopars and fe fords.   however, use what ever rocker you feel best about.    if i was in your shoes id get my heads set up to accept the rockers that i wanted to use.

[firefighter3931]

    un bushed iron rockers on steal shafts are just fine. mopar sent lots of cars out the door stock this way. crane and isky iron rockers have been used successfully for years on mopars and fe fords.   however, use what ever rocker you feel best about.    if i was in your shoes id get my heads set up to accept the rockers that i wanted to use.

Good solid advice ! 

These heads should be able to run a stock stamped steel rocker. If the valve spring and retainer diameters are too large just swap out something better. This will be much cheaper in the long run. The Comp #911 valvespring works fine with the correct installed height on a stock head with the matching retainer so there's no reason it won't work on the Stealth heads. Throwing several hundred dollars into an adjustable valvetrain to "fix" an incorrect hardware issue seems like the wrong way to go.

Mike (MFR426) is running stock rockers/shafts with his stealth headed 505 stroker and these issues were not present upon inspection at Barton's shop. Obviously all Stealth heads are not equal and it seems like there's a mish/mash of parts bolted onto these wherever they're being assembled.



Ron

[Musicman]

Obviously all Stealth heads are not equal and it seems like there's a mish/mash of parts bolted onto these wherever they're being assembled.

It's like I done told ya... they just pick parts out of an old rusty bucket at the factory 

[Mfr426]

   

Mike (MFR426) is running stock rockers/shafts with his stealth headed 505 stroker and these issues were not present upon inspection at Barton's shop. Obviously all Stealth heads are not equal and it seems like there's a mish/mash of parts bolted onto these wherever they're being assembled.


Ron

Yep...so far so good with my "out of the box" Stealth heads and new Mopar stock stamped rockers. We did pull the valve covers after some pulls on the dyno too at Bartons. All valves and components appeared to be in good shape. 

[jerry]

i don't know what the big deal is. i mean replacing engine or half of it because of really bad parts [heads] that 6 months ago were the best thing to come down the pike because they were so cheap.well $3000.00 later to replace blocks or parts ,labor. pretty expensive set of heads. i am just repeating what i read above.

[RD]

jerry... did your heads fail also in the same fashion?

[jerry]

no,i have MP made by edelbrock.no problems out of the box.

[Mfr426]

So, looking back now how many folks who purchased Stealth heads have actually had failures causing damage to their engines???

?