I recently completed a build that used a combination of a Dart Big M block and AFR 335 CNC heads that are both considered to be high quality components.
However after we fired the motor up and it started to get warm a real racket started up in the top. After running the motor with the valve covers off it was noted that there was insufficient clearance between the head and the 3/8 120 wall push rod. The 3/8 push rod is a "standard stock" size for any BB and this happened despite there being sufficient anticipated clearance for when the heads expanded with heat. That does not excuse the problem not being caught during assembly but it is also the result of poor planning by AFR
Where the problem is that AFR despite their claim of their heads being "ready to assemble", when they are used with the Big M's extra tall lifters AFR heads do not provide the extra needed room because of the geometry change in the pushrod travel.
The tall lifers used in the Big M block cause a vertical movement beyond that of the normal lifter to rocker relationship thus taking up more space in the angled head passages of the head than a factory block with "normal' lifters would require.
There is room for the passages to be drilled out and would have been caught during assembly had we anticipated or noted the change in the pushrod geometry.
This was not the only shortcoming noted with the AFR head. All of the tapped holes needed to be chased as well as the header bolt pattern is not exactly the same as stock heads are. This made headers that would work on other heads have to have their bolt holes enlarged in order to mate up to the AFR head.......... or have your headers made expressly for AFR heads only
Also the standard rectangular port Fel Pro head gasket is not a good match and if someone was to port match their intake to the Fel Pro gasket they would be very disappointed with the results. (that is noted in the AFR literature) What is needed is to only use the AFR "cardboard gasket" and then do your port matching with that.
Finally because of the relationship of the rocker bases to the ports within the AFR head the corresponding shaft rockers for AFR are about 40% more expensive than they would be for the heads of other manufactures. That fact adds several hundred dollars to the cost of using AFR heads.
Hindsight being what it is I wished I had stuck to my first choice that was using Dart Pro One Heads that were approximately the same price and performance level but would not have had any of the problems noted above. Unfortunately I followed the advice of a company that designs motors that I had contracted to design my valvetrain instead of keeping everything in-shop like I should have.
On the plus side maybe AFR will take note of this and improve their heads as needed to be compatible with other tried and proven high performance manufactures products.
One more note........ AFR lists the Brodix 2000 as one of the compatible intakes to their head. It can be but it takes a lot of work...... like a 1/4" off one side and an 1/8" off the bottom of every port.
Hate too see this man. I put a dart 540 ci BB WITH DART PORTED 335 HEADS IN THE 57 CHEV 2DR H/T WITH THE BIG PUSH RODS WITH A SET OF J&D ROCKER SHAFTS ON THEM AND HAD NO PROBLEMS. AGAIN HATE THIS ISSUE ON YOUR PART..
It is the same BS with AFR heads for small blocks. Poor design for oil return causes problems with your new motor smoking within a few thousand miles because the oil level is above the valve seals. The high oil level also means that the valve cover gasket is below the oil level and sealing is a problem and when you remove the valve cover the oil runs down the side of your motor.
The spark plugs run into the headers on a couple of cylinders. So you have to dent the primary pipe to even have plug wire clearance
Just things that should have been corrected 10 years ago and they just keep screwing up even with the new heads.
Hate too see this man. I put a dart 540 ci BB WITH DART PORTED 335 HEADS IN THE 57 CHEV 2DR H/T WITH THE BIG PUSH RODS WITH A SET OF J&D ROCKER SHAFTS ON THEM AND HAD NO PROBLEMS. AGAIN HATE THIS ISSUE ON YOUR PART..
I had heard of some of the problems associated with SB AFR heads and I had been advised by one member here that in his last 540 build he found that Dart Pro One 335's are considerably better all around heads than AFR 335 heads are....... now with the reduced price of Dart it is (should have been for me) a no brainer to go with the Dart Pro One heads over the AFR head.
I have really chastised myself for hiring an "expert" who unfortunately throughout all of our business relationship continually chose in the better interest of his suppliers over what would have been better for me.
Hopefully his choice of cam lobes is better than his other recommendations were.
Anyway we plan to put it back on the stand today with the passages considerably enlarged............ heck I could even put 7/16 push rods in there now
Did anyone bother mockign this up before torquing down? With an aftermarket block theres almost always something that needs to be worked.
On the sbc problem where are you getting your info from?
Well for one see post # 3 concerning AFR's and small blocks then do a search here on CF.com where you will find more complaints about AFR SB heads.
As far as the mock up goes if you would take the time to read all of my post you will notice that I have accepted responsibility for not noting the interference before the assembly ....... the price of that was several hours of added labor over and above drilling the heads out. That does not excuse AFR from not at least giving a heads up as they have about Fel Pro intake gaskets not being the best choice for this particular head. However in all reality with a $3000 head the push rod passages and the header bolt holes should have both been correctly drilled prior to them being shipped to me......... especially when the competition does it right
The full story concerning that part is that during the mock-up it was noted that there was not enough room for the 7/16 push rods that were originally planned for. So I contacted the hired designer and he said that the 7/16 were really unnecessary and to go ahead and use 120 wall 3/8 push rods that would be "no problem at all" because he had "built many of them" quote/unquote......... obviously I should have not allowed him to influence me and especially as by this time he had already designed one cam that would have only 40 thousand clearance and then got very insulting as to who I thought I was to question him when I turned it down......... so I guess you could blame me twice as I have myself.
However the purpose of the thread is to give a big heads up to others before they purchase AFR 335 CNC heads. It is not to either excuse my responsibility or have a rant about a "professional engine designer" otherwise I would be posting their name.
Location: Mississauga, Ontario I know all the answers it's the questions I don't understand
I have the new 227 Eliminators on my 427ci small block and there is an oil return problem they have known about since day one that has not been fixed. My theory is that is how they are getting good flow rates, the intake runner is high up in the head and they don't want to cut into it with a proper oil return path, I could be wrong on this though, just a theory.
I am sorry for the troubles you are having. When I build a motor and when it gets to past the short block and into the heads I buy the heads bare and put the parts on them I want on them.
The heads are checked and assembled by a race shop near me. Even my new 227's out of the box had to have a few things done to them. I am not saying you did this but no one should bolt a set of heads on right out of the box, you are asking for trouble.
Next thing is to check piston to valve clearance and then valve train geometry. This has to be done very meticulously as there are many points of contact that could show up as well as the simple things like the contact patch on the valve tip.
If you ( I don't mean the op ) aren't mocking the motor up and putting the heads on and off a dozen times ( I am talking HP custom motor here ) then you very well could miss something that comes back to bite you.
I hope the OP gets everything straitened out, I know how frustrating this is
__________________ 1980 Corvette, 427ci Motown SBC 465RWHP N/A so far,500 is the goal, AFR 227 Eliminators
T&D Shaft Rockers,Vic Jr, XR286R solid roller,248/254 dur .640" lift 10.6:1 Mahle pistons
Eagle stroker rods, 4 in. Callies DragonSlayer crank, 825 Drag Race Demon, 3 in exhaust Paint by Dream Car Garage
I dont have alot of time right now but I will quickly break down your laundry list of issues....
Quote:
Originally Posted by Shurshot
I recently completed a build that used a combination of a Dart Big M block and AFR 335 CNC heads that are both considered to be high quality components.
However after we fired the motor up and it started to get warm a real racket started up in the top. After running the motor with the valve covers off it was noted that there was insufficient clearance between the head and the 3/8 120 wall push rod. The 3/8 push rod is a "standard stock" size for any BB and this happened despite there being sufficient anticipated clearance for when the heads expanded with heat. That does not excuse the problem not being caught during assembly but it is also the result of poor planning by AFR
This seems more of an issue with proper assembly (clearance) issues, than your choice of AFR heads. Our heads are turn key with 3/8 pushrods and stock style studmount rockers....larger pushrods and/or shaftrockers throw a huge monkey wrench in the mix and nine our of ten installs must have additional clearance ground by hand....some manufacturers shaftmount set-ups require less clearance than others. This is standard issue stuff when building a racing engine with parts from various manufacturers....your not bolting together a $3000 SBC with all stock internals....fitting and additional time to insure everything works well with one another is par for the course. Ultimately the extra power from the entire effort more than justifies the bumps in the road these types of projects usually present and it doesn't matter who's name or three letters are on the end-pad of the head.
Quote:
Originally Posted by Shurshot
Where the problem is that AFR despite their claim of their heads being "ready to assemble", when they are used with the Big M's extra tall lifters AFR heads do not provide the extra needed room because of the geometry change in the pushrod travel.
The tall lifers used in the Big M block cause a vertical movement beyond that of the normal lifter to rocker relationship thus taking up more space in the angled head passages of the head than a factory block with "normal' lifters would require.
I think you answered your own question with what you stated above....we design our product to work with typical standard lifters and other components that are similar in design....as soon as you introduce a variable you need to be prepared to potentially modify other parts. Its impossible for any head manufacturer to design a product around every single situation, and in fact have to design it around the bread and butter common components if we are to chose one direction over another regarding geometry and fitment.
Quote:
Originally Posted by Shurshot
This was not the only shortcoming noted with the AFR head. All of the tapped holes needed to be chased as well as the header bolt pattern is not exactly the same as stock heads are. This made headers that would work on other heads have to have their bolt holes enlarged in order to mate up to the AFR head.......... or have your headers made expressly for AFR heads only
We have not had any complaints regarding our holes not being tapped properly....I would have liked to see the head to see potentially what our QC department may have missed. Obviously if there was an issue it shouldn't have left AFR that way, but once again we have shipped hundreds of these heads and that isn't a complaint I think I have seen even once. Regarding our header bolt/exhaust flange holes once again, never really got any negative feedback their either and as far as I know, they are exactly in the GM factory location. Perhaps your header flange was off a tiny bit and your making the assumption the bolt holes are in the wrong place? Once again, without seeing the head its not easy to confirm or deny that situation.
Quote:
Originally Posted by Shurshot
Also the standard rectangular port Fel Pro head gasket is not a good match and if someone was to port match their intake to the Fel Pro gasket they would be very disappointed with the results. (that is noted in the AFR literature) What is needed is to only use the AFR "cardboard gasket" and then do your port matching with that.
Yes....thats exactly right. We don't let a gasket manufacturer tie our hands when it comes to a more efficient cylinder head....the sharp corners in the Felpro gasket are not conducive to flow and efficiency and we have a gasket in house that is a high quality material with a print-o-seal type bead around the intake ports that we recommend if you want a perfect fitting gasket that you could also use for port matching. With the fact you knew that already as its clearly stated in our literature how does that become a problem or fault with the product?? Our choice to do so makes it a better product.....
Quote:
Originally Posted by Shurshot
Finally because of the relationship of the rocker bases to the ports within the AFR head the corresponding shaft rockers for AFR are about 40% more expensive than they would be for the heads of other manufactures. That fact adds several hundred dollars to the cost of using AFR heads.
I am 95% sure if you call Jesel or T&D and ask for a shaftmount system for either our head, a DART head, a Brodix head, etc., you will be quoted the same price. When I return to the office on Monday I will verify that statement is an accurate one.
Quote:
Originally Posted by Shurshot
Hindsight being what it is I wished I had stuck to my first choice that was using Dart Pro One Heads that were approximately the same price and performance level but would not have had any of the problems noted above. Unfortunately I followed the advice of a company that designs motors that I had contracted to design my valvetrain instead of keeping everything in-shop like I should have.
On the plus side maybe AFR will take note of this and improve their heads as needed to be compatible with other tried and proven high performance manufactures products.
One more note........ AFR lists the Brodix 2000 as one of the compatible intakes to their head. It can be but it takes a lot of work...... like a 1/4" off one side and an 1/8" off the bottom of every port.
Doug
I'm sorry your AFR install didn't go a bit smoother but my guess is no aftermarket head would have provided the seamless install is seems you expected. Once you have built a handful of race engines you will come to expect everything doesn't fit and be surprised and happy when it does. We do our best to provide a turn key solution that can generate big power with stock type rockers and components but as soon as you start throwing a bunch of aftermarket items that stray from stock, some of what we do to help out the guy with standard components has to be modified....it just unfortunately goes with the territory.
I would also advise anyone that has what they believe to be issues with our product to contact AFR directly or reach out and contact me. Then we can better determine if the problem you are having is really a problem or something more common with the components you have chosen (like having to clearance for a shaftrocker or 7/16 pushrod install).
I think when you get a chance to experience the power they will help you generate you will long forget about the couple of issues you encountered with the install....they really are an extremely efficient high flowing piece and the power they are capable of generating is impressive if the combination is chosen wisely.
You must type fast as you have written a long post for someone with only a little time.
Have you noticed that we have accepted the responsibility for missing the clearance issue on the pushrods. It is not like there was not any clearance tests done...... especially when you are using 230 valves with only 70 thousands on piston valve clearances on a mostly street cam with a healthy dose of duration built on a 108 LSA....... my builder does do pretty well on the strip against the other builders around here and as more time goes by I see more of their customers coming to him.
However you have missed my point concerning your gasket. I have no problem with your intake gasket and have now used them twice for install and once for port matching. My point is that when you are selling a gasket you are quick to point out the shortcomings of other gaskets but when you are not selling something you are not taking the same time to give your customers a courtesy heads up to problems with pushrod clearance that by your own words have been known to exist with your heads for some time now.
Quote:
Our heads are turn key with 3/8 pushrods and stock style studmount rockers....larger pushrods and/or shaftrockers throw a huge monkey wrench in the mix and nine our of ten installs must have additional clearance ground by hand
Since when did shaft rockers throw a huge monkey wrench into the equation ?.......... As far as I have ever found out for myself is that shaft rockers remove the monkey wrench from an equation as that is their purpose. Also I do believe that the manufactures of shaft rockers would agree with me on that.
Why should I expect a problem using brand new T&D shaft rockers on your heads when I have used T&D shafts on other manufactures heads with absolutely no problem?.......is there something else you need to add here?. What I can tell you is that the same person who sells T&D shaft rockers for your heads also sells them for Dart Pro One 335 CNC heads. Unfortunately for AFR heads they cost an additional $325 over the cost for the ones for Dart and according to him it is because of complex geometry associated with your heads........
Anyway what difference do retail prices make in todays tight economy? Even if the retail prices are the same it is what the actual cost versus the performance that matter to me. To be quite frank with you IMO your heads do not measure up to Dart heads in either user friendliness or performance that are now available for roughly the same amount of money....... and I might add "my opinion" on this is not alone
What did throw a monkey wrench into mine were the tall lifters that between either AFR or the person who sold them to me who is one your dealers should have given me a heads up as to when there is already a well known problem using your heads....... let alone say for us to go ahead and run them as they are sure through their experience that there will be no problem.
Sorry if I sound hard to get along with but in my book giving someone a heads up is basic common courtesy let alone also being good business sense. Guys like me who have bought new motors at least every 5 years for the last thirty with several different manufactures heads are worth keeping....... at least some folks feel that way.
Anyway I am not a fast typer but I am late for a date so I need to scoot......
Sorry to hear about all the *fun* you're having...but I can guarantee you when it's done the AFR's WILL make plenty of power and put a grin on your face!
I've usually had to do a little grinding here and there with 3/8" pushrods on them even with stock type rockers and non-tall lifter blocks. Just depends on how things stack up.
The port shape/angle of the AFR's is a little different than most others so even matching the intake is a little trickier. The Vic Jr comes pretty close but needs a little epoxy or welding if you don't want to mess with the port opening in heads.
Rocker arm geometry/pattern has been a sticky point with the AFR's for awhile on the intakes. They did make some changes on the later heads that apparently helped, but you still hear some stories. Previously you needed to cut guideplates or use adjustable pretty often. Shaft stuff made it easier usually, but still has to be checked closely. Other methods have been to use *backset* rockers on the intakes.
I did recently use some Dart 335's and everything went pretty easily. I even used 7/16" pushrods with 3 different cam combos (3 different pushrod lengths) and only had to dust off two little spots to clear. This was with the tall lifter Dart block. This was using Jesel Sportsman shaft rockers. Had to shim intake stands a little, but nothing dramatic.
Again, as you've noted, it's all part of building these things, but when you're done you'll have a killer motor and will be very happy!
I just ordered an engine from Shafiroff and they use AFR heads on the 427. Should I tell them to change to Dart Pro 1 heads or keep the AFR's? I am terrified about this engine swap and want everything to go perfectly--I sure am paying for it. I sure don't want an $11K oil burner. I keep hearing horror stories and I am getting a little scared about what I am getting into!!! Surely there is someone I can trust out in the engine world.
Sorry to hear about all the *fun* you're having...but I can guarantee you when it's done the AFR's WILL make plenty of power and put a grin on your face!
I've usually had to do a little grinding here and there with 3/8" pushrods on them even with stock type rockers and non-tall lifter blocks. Just depends on how things stack up.
The port shape/angle of the AFR's is a little different than most others so even matching the intake is a little trickier. The Vic Jr comes pretty close but needs a little epoxy or welding if you don't want to mess with the port opening in heads.
Rocker arm geometry/pattern has been a sticky point with the AFR's for awhile on the intakes. They did make some changes on the later heads that apparently helped, but you still hear some stories. Previously you needed to cut guideplates or use adjustable pretty often. Shaft stuff made it easier usually, but still has to be checked closely. Other methods have been to use *backset* rockers on the intakes.
I did recently use some Dart 335's and everything went pretty easily. I even used 7/16" pushrods with 3 different cam combos (3 different pushrod lengths) and only had to dust off two little spots to clear. This was with the tall lifter Dart block. This was using Jesel Sportsman shaft rockers. Had to shim intake stands a little, but nothing dramatic.
Again, as you've noted, it's all part of building these things, but when you're done you'll have a killer motor and will be very happy!
Good luck!
JIM
Hi Jim
For sure your AFR's are getting the job done right
While there have been a fair amount of inconveniences with the AFR heads the fact they they do produce good power is the silver lining and the light at the end of the tunnel. AFR could make the experience with their heads a lot better with a more accurate flow of information coming through both their dealers and their tech line.
For example when I first went to get some plugs I found out that the ones that AFR recommends on their website are out of production. Then their tech line recommends plugs that neither Summit, Spark plug.com, Advance or Auto Zone show in their data banks......... Finally by calling the NGK tech line I find out from them the plugs I need to use for the AFR heads....... go figure
Still putting all that aside I am not convinced that the push rod clearance is the sum total of the problem. Simply put I am not happy with the small amount of oil getting to the shaft rockers. I have excellent oil pressure (standard volume pump) and the rockers have the spring oiling option but we could sit there and run the motor with the valve covers off without oil going everywhere........... I have never seen a top end run as dry as this one does and that makes me wonder about the 120 wall on the 3/8 rod ...........
Maybe I should run 7/16 as I had originally planned and I would get more oil that way.......
Hmmnn.....my motor has Brodix on it!! Ancient ones at that!!
The AFR's weren't available when I did mine. Otherwise they would have likely been the choice. These days I'm very happy with the Dart CNC heads too.
You don't have any restrictors in that block do you? You should have no added oil restrictors. None are needed, especially for a street motor. Mine floods the top with a good bit of oil.
I don't think the pushrod will hurt anything either way, it's plenty big enough internally unless you got some of the restrictor type ones. Which lifters do you have? What oil pressure at idle?
Hmmnn.....my motor has Brodix on it!! Ancient ones at that!!
The AFR's weren't available when I did mine. Otherwise they would have likely been the choice. These days I'm very happy with the Dart CNC heads too.
You don't have any restrictors in that block do you? You should have no added oil restrictors. None are needed, especially for a street motor. Mine floods the top with a good bit of oil.
I don't think the pushrod will hurt anything either way, it's plenty big enough internally unless you got some of the restrictor type ones. Which lifters do you have? What oil pressure at idle?
JIM
Not sure what to say........... not that nothing matters because it does.
Anyway the motor blew and it blew real bad. A brand new L 19 bolt is twisted and you know the corresponding damage (rod & crank etc )that goes along with that.
I am certainly not blaming the heads for this and whenever I do get the funds to rebuild I will but right now it is out of the question.
Just not sure when it will happen and who will do it......... certainly not the same team that was involved in this one and that applies to both the shop that designed as well as the one that built it.
This is a response I sent to another member here who sent a PM of condolences as well as a suggestion to spend some time on the chevelle forum
This issue with the L19 bolts coming loose might be be one more story of a tech line giving out bad info
I was there when Scott torqued the rod caps and measured the stretch on each one.
This was Scott's first time with using L19 bolts and only chose them because they are suppose to be better than one he normally uses for HP builds ...... the ARP 2000.
The issues on the heads seem well known it is just that my friend Scott had only installed one set of AFR's before and they were for an SB drag motor.
Still it falls on him even though ****** had said what I posted about just go ahead a "run the 3/8 120 wall with no problem". However it always falls back on the builder and for the sake of the customers as well as the pride of the builder it should.
However the catastrophic failure was caused by the ARP L19 rod cap bolts that are suppose to be the best all loosing their torque. They were all at different degrees of coming loose with one having fallen out. Of course the remaining bolt and rod cap on that one then snapped throwing one rod against another and then hitting the crank as well as putting a hole through the side of the oil pan. Fortunately the block is OK
I was there when Scott talked to the ARP tech and got both the torque #s as well as the stretch #s I saw everyone of them set accordingly and assembly lube was used as per the tech instructions
So what caused the torque on the bolts to fail ?????? I have no idea but tomorrow I will go to ARP site and check out their tech #s against what their website calls for......... seems like more and more I am finding tech folks that do not know their left hand from their right.
Anyway Scott accepts all the responsibility and has already ordered the new crank (4.5 stroke though) If new pistons are needed because of the length of the new rods then the new motor will be somewhere around 588 to 605 or so. Then we will have to see about the cam #s....... actually they may work better because ***** had messed up on the original compression so the cylinders were not getting filled as they should have been....... cranking compression was only 165 and should be 180-185 for max HP and still run pump gas
I know when Scott was checking them he was measuring the stretch on each rod because I was standing there watching him. According to Scott he cares most about the stretch # no matter the torque it takes to get the right #. That night the measured torque to get the stretch mentioned by the tech rep was 65 pounds with lube
However when I look on their site all of the 200-6200 L series bolts are 75 pounds with lube.
I think what happened is apparent but the truth is we have all had enough bad experiences with bad tech reps to know better than to count on them for something as critical as a rod cap bolt torque and stretch #s being repeated correctly on the phone...... if they are printed wrong at least you have something you can blame the manufacture for.
Even at Scott's cost it will still run him two grand for an Eagle Crank and rods plus Morrel pistons along with all the gaskets etc by the time he is done. Plus that figure has nothing to do with all the extra hours it will take him when he is already behind in his work. Consequently I doubt if he will make that mistake again but to be honest with you I am at the end of my rope with reasons, excuses or anything in between. At this point anything less than good results is all to me
Corvette Store
Heads up on Dart BB w/ AFR heads
Surely there is someone I can trust out in the engine world.
........... 
to me
