Tom's 'roller rockers'

Discussion in ''Da Nailhead' started by DualQuad55, Dec 18, 2006.

  1. yacster

    yacster Lv the gun tk the Canolis

    Tom - it will be great if you make it down the 22nd. If you want to come the night before and need a place to stay you're more then welcome to stay at my house. I know you have friends in Baldwin, but the offer is there all the same. :beers2:

    PS - I should have the dual Quad set up on by then. :Brow:
     
  2. DualQuad55

    DualQuad55 Well-Known Member

    Walt, I installed them with stock pushrods which put my adjusters almost exactly halfway through the range. Tom figures this is about a 1.70-1.75 ratio there. I didn't figure it that high, this was where my mistake came.
    anyhow, I will try ot figure out exactly how much if any damage occured tonight.
    I am not sure what the next step is with the pushrod length until I can see what I have for valve to piston clearance.
    I will work through it though, I'll keep everyone posted.
     
  3. telriv

    telriv Founders Club Member

    Everyone, I cannot stress this enough. It's stated in the instructions at least 5-6 times YOU MUST CHECK CLEARANCES. Also as stated, you will get a lift at the valve over & above whatever the cam card says. I DON'T CARE WHAT THE CAM CARD SAYS!!!!!!! YOU GOTTA CHECK YOUR CLEARANCES!!!!!! I'm sorry Joe & Ryan have had problems & I will do whatever I can to help the situation, but like I said, any deviations from stock are YOUR RESPONSIBILITY!!!!!!! Even stock you gotta check clearances. This is just basic engine assembly 101. I don't want ANYBODY having problems!!!! Having to do it over again "Sucks".
     
  4. GOSFAST

    GOSFAST Well-Known Member

    Fooling With Valve Lengths!!!!

    Listen up guys!

    You can't simply put longer valves in these units. It's not that easy. I've been there most recently!

    1-You are working with a "stationary" (fixed) rocker arm location. Namely the rocker shafts!

    2-You are very limited with respect to the space that the pushrods have to function. This is the reason if you look very closely at the "stock" pushrods they are approximately .250" on the stem and have extremely large radii on the ends.

    3-You are going to encounter both "geometry", with the shafts, and the "arc" that the rocker and pushrod has to be able to travel through, and keep all the components from contacting the casting at every point through the opening and closing of the valve.

    4-You also have to pay close attention to the retainer to rocker clearances.

    The last unit I did the machining on used a set of Ross slugs and I've got to tell you, they've got the valve notches in the wrong locations. Especially with the fact I used different diameter valves. Ross was notified immediately and
    given a recommendation for a cure. Whether or not they paid attention, I don't know!

    These are not simple units to build correctly, they require some extra scrutiny for sure, once you get off the path of the original design. I know Tom had some insight into the "engineering" area, and like I said, I haven't seen the rockers yet, but I know some serious thought went into the design! It had to!

    Thanks, Gary in N.Y.

    P.S. I do understand Tom's rockers are an excellent piece, I haven't had the pleasure of handling them yet, my only concern would be the installation "in-the-field"!
     
  5. nailheadina67

    nailheadina67 Official Nailheader

    In the factory manual........it clearly states that the spec for the distance between the end of the valve stem and the rocker arm surface of the heads (1.540? ) and the stems are supposed to NOT exceed .050" from that spec. I don't think the engineers were kidding with that information........exceeding that would throw off the geometry.

    Perhaps with a high lift cam you may want be closer to 1.590 to make up for the added lift? :idea2:
     
  6. DualQuad55

    DualQuad55 Well-Known Member

    I am NOT blaming anyone but Myself for the issues I have right now. Tom has been more than helpful and understanding. He has been more helpful than could be expected. I am not trying to make it sound like his rockers are the cause of my problem, I am the cause of my problem. I was only trying to inform everyone that if you don't follow the instructions (as I did-not) you may run into this situation. Even though Tom personnally told me on more than one occasion that I need to check clearences, my brain shut down as I was in a 'big hurry' to get them on. Well, we know how far that got me.
    I am perfectly confident that once I get the motor geometry/valve clearance set up properly these things will really help out. This was what I was trying to hint towards in the other post where I stated that these REALLY add to valve lift. I think perhaps a good setup would be the 'early' 401 cam with these rockers on most street applications, some of the other guys (such as Tom, Gary, etc...) who know the cam specs better may have more info about this. I really think/know I will be happy with these rockers as soon as I get the clearances set.

    Gary, If running longer stems is not really an option, how hard is it to cut the valve seat pockets to accomodate higher lift cams/rockers so I can avoid coil bind up/stacking? This was my big reason for the 'Chevy' valves- to use the longer stems to avoid this.
     
  7. GOSFAST

    GOSFAST Well-Known Member

    Hi Joe, my main problem here is when I did the last Nailhead I knew Tom's rockers were not far behind, BUT, I didn't have them here for that build. It might have made the world of difference to me and the customer.

    You have very minimal clearances "up & down" with respect to the spring seat location and the very tip of the valve. You cannot use the "inner" seat spring area, that must be "filled" with shims to brought level to the height of the "outer" spring seat. In other words, you want a flat seat area where the dual spring sits even at the BOTTOM of the spring. You do not want the inner coil sitting down in that well. If you go back and look again at the pushrod clearance holes you will notice they actually pass under part of the spring seat location!

    When you start "jockeying" these dimensions about, you have to remember you need an existing valve spring to handle the job. You are very limited in that respect. You need a dual spring to make the pressure, the installed height, the diameter, the total lift number, AND clear a valve seal at least on the intakes. If you now go to a brand new set of lift numbers from Tom's rockers, you now MAY need to make room for those add'l lift numbers. I can't answer this part of the equation, as I said, because I didn't have a set here on my build!

    As of tonight that particular unit only has approximatley .070" intake P/V and .080" exhaust P/V. This is with a 234*/244* @ .050 x .323" lobe lift. To get the valve lift you would multiply the .323" x the rocker ratio, example:
    .323" x 1.6 = .517" lift @ the valve. If Tom's rockers end up at 1.7/1.75 you should still be able to make that setup work with those cam dimensions. The only part the equation I would need to figure out is what effect the additional ratio would have ONLY on the duration. The lift would PROBABLY go without any additional piston flycutting, it's only an increased duration that affects the distance between the pistons and valves while the valves are in the overlap position. Simply put, the lift isn't near as critical as the duration!

    Those clearances above is with me doing add'l flycutting on those "custom" Ross pistons I mentioned previously. This was the reason I had immediately contacted the guy's at Ross and warned them about the valve notch locations AND their own pocket depths. Their "prints" are wrong. Now having said that, they WILL work in a "standard" Nailhead overhaul, one where the lifts may only see some .400"/.450". The next set (?) we order will have NO valve pockets from them, we will put these pockets where we want them exactly and as deep as we need to make possibly up past .700" lifts. We would only go to the required depth to accomodate the build and possibly leave some extra room for later!

    Thanks, Gary in N.Y.

    P.S. Joe, I said it here before, most of the problems you encounter is due the fact you are working with 45* unit! It's the only one I know of, design-wise, in existence. It's one tough unit to make happen, NOT impossible, but tough!
    As I was building the last unit here I had spoke about such a simple task as "tapping" all the pressed-in oil plugs and was told by some high-end shops around here not attempt it, "the block will end up junk". We do the SB Chevies all the time. And I did my customers Nailhead, there's not 1 pressed-in plug in his block today. Like I said, you just got to pay attention and be careful! It's that simple.
     
  8. yacster

    yacster Lv the gun tk the Canolis

    Sorry Guys but whoa - Tom I am glad you installed mine. I am the kind of person with a photogenic memory, but I have to see what you guys are talking about to really grasp it. I hope when the re-build is done next winter I can assist Tom and watch so I can learn. This is just out of my realm. Don't mean to upset anyone but I have to let you know you lost the backyard mechanics. However I really am getting the knowledge (theory-wise) I just need to see it.:Dou: :TU:
     
  9. Poppaluv

    Poppaluv I CALL WINNERS!!!

    I was just thinkin' that when I read this. I can change oil....:laugh: You're lucky to be able to see Tom in person. I'd give a FEMA check to help/watch my Nailhead come together.
    Wouldn't that be a great thing to document for the board!!!!!:TU:
     
  10. Mentalkase

    Mentalkase Desert Coonass

    Don't feel bad Jason,I am much more than a backyard mechanic,and reading this thread has me a bit breathless.I was thinking about buying a set myself.I may have to get my friend who works for John Force to come visit when I make my decision.

    The more I read this thread,the more I drool at the idea of buying them.:3gears:
     
  11. yacster

    yacster Lv the gun tk the Canolis

    Poppa- I hope to photo document the build. It would be great for us oil changers to actually see the whole process.:beer
     
  12. telriv

    telriv Founders Club Member

    Everything Gary from GOSFAST said is correct. This 45* angle set-up is all by itself. With that said there are a few comments. Like all machinists Gary measures the lobe lift to figure "Advertised" valve lift. Advertised is the key word here. In Buddy's case .323"x1.6 theoretical rocker ratio =.517". In actuality Buddy had the old "Export" rockers. So .323x1.5=.485". When installed a solid lifter & actually checked it at the valve it was closer to .425". On Yackster's worn cam, original lift was .385". Now these were rebuilt iron rockers that someone installed & I believe were actually 1.5's. After I installed "My Rockers" with the adjustments backed all the way out for the most ratio he now had .495". This was barely enough clearances wise all the way around, right on the outside of the limits for a stock, never torn apart engine. I'm sure I warned you Tony, but don't over rev the engine!!!!! You won't need to go as high RPM wise to make the power now. On my car I actually shift at 500RPM's lower & go faster.
    Now as far as valve length goes. We have been using the longer valves in Bob's "Nail" for the last 7-8 years. I feel the advantages out weigh the disadvantages by a long shot. By using them there are many more options now open as far as cost, parts availability, etc. I'm not going to give away all the secrets because we have been working on this soooooooo lonnngggg!!!!! As Gary can attest, it all takes mucho time & time =$$$$$$$$$$$, many $$$$$$$$$$$$!!!!!!! Especially when you are experimenting & don't know if the results will work, never mind the amount of $$$$$$ that come into play. In total, if we had to pay for this playin' with heads, valves, etc. Shipping pieces of heads to Germany, etc. to an "Expert" for some constructive criticism & ideas. Taking time off from work & travelin' 6-8 hrs. one way for ideas. I'm sure you would be looking at the high side of 10K+. Who on this site is willing to spend that kind of $$$$$ to go faster on just a set of heads?????? Yea, we know geometry isn't exactly correct, but it gains 20+HP every time they are added. Like Rich said (the engine dyno operator) who cares they added 20HP!!!! What this all means is that for every application there would have to be a different set of rocker arms made. That of course is not possible. Who in their right mind would spend 20-25K to design something just for their engine. Most of us on these sites are just average working people. We are trying to gleam as much info as possible from others experiences & knowledge to help us with the decisions & options that we have or may come to be available to us.
    Again, I can't stress this enough, YA' GOTTA' CHECK ALL YOUR CLEARANCES!!!!! Gary, I'll get a "Rocker" to you when this next batch is ready. Do you want a whole completed set for testing???? I may have enough "Extra" parts to accomplish this.
    The heads are where the power is mostly. Get the air in & the engine will make some surprising HP. It's been held back for years, but not anymore. It now has the capability to breath a little better. In most cases over & above a cam swap & all the assorted hassles & while I'm at it's that come into play.
    I've been at Island Dragway all day & I'm hittin' the sack. Good night.

    Tom T.
     
  13. Poppaluv

    Poppaluv I CALL WINNERS!!!

    YIPEEEE!!!!!:pp
     
  14. 66gsconv

    66gsconv nailhead apprentice

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    Have been working on the engine this winter, its starting to look good with toms rockers on top
    Bob
     
  15. 66gsconv

    66gsconv nailhead apprentice

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  16. 66gsconv

    66gsconv nailhead apprentice

  17. GOSFAST

    GOSFAST Well-Known Member

    Hi Tom, let me just expand slightly on the highlighted section above, just to keep the
    "record" straight!

    I never measured the lobe lift from Schneider's cam initially, I wasn't concerned about it until AFTER I had degreed the cam AND checked the P/V dimension. If you follow the procedure you'll see why I take this route. (I had numerous issues with both TA Performance AND Schneider over this cam, wasn't a "happy camper" with either vendor!)

    It's extremely difficult to get to this dimension with a "hydraulic" lifter due to the plunger trying to "collapse". The P/V is done with a pair of .842" Chevy solid lifters and a pair of adjustable pushrods ONLY to establish whether or not the pistons had to be flycut. Upon determining they would indeed have to be cut, I now can go back and set the 2 hydraulic lifters in position, with BOTH valves on the seats, and reset the adjustable pushrod lengths for the ass'y! This gives me the "final" pushrod length to be ordered. I proceed to add to that measurement the depth I want the plungers to function. When all is done the lifter plungers are now "down" about .015"/.020" from the retainer (lock ring), where they will end up running.

    There IS one factor that I should mention, not doing the final ass'y I only picked out 2 of the best appearing rockers and did all the checking with them. Follow me where I'm heading here, it'll be to your advantage. I would have to say it's highly likely that there was probably some major differences between the 16 rockers I was supplied. Now with that last sentence down, it sure would be nice if all 16, back then, were exactly identical, you know, like a set of some "custom" roller rockers maybe!!!

    The part of the equation that I have trouble with is this. If the unit had only .425" lift, it doesn't ring true that the custom pistons from Ross, as "bad" as they were, would have to have been clearanced. In short, it stands to reason that a lift of .425" average, due to possible "stock" rocker variation, and a duration of 234 @ .050" should have "gone" easily with not a single issue with respect to P/V! Those pistons HAD to be cut!

    Tom, whatever you decide about your rocker's with respect to installation in the field, DO NOT give up, I believe they are a good product even not being familiar with them yet.

    On a final note, I'm literally "buried" with units to build and as much as I'd really like to "fool-around" with your rocker, I couldn't begin to find the time anywhere in the short term. Trust me, I do appreciate the rocker offer, I mean it! It's a little ironic, but when your 20 years old you have "hours" of spare time, when you "age" it seems like you don't have even "seconds" to spare.

    Thanks, Gary in N.Y.

    P.S. The part above about discrepancies in the "stock" rockers makes all the more reason to use a "custom" piece, it leads that much closer to a "perfect" build. Tom, if possible I sure would like to just have a copy of the installation instructions for your rockers, no rush! Thanks again, Gary.

    Double P.S. I want add a note here about "Melling", I got some tremendous "back-door" help from George Richmond out there and he helped solve a major dilemma for this particular unit being a "stroker". Not sure what I would have done without him!!! Thanks George!
     
  18. DualQuad55

    DualQuad55 Well-Known Member

    Well, back to my car....
    Looks like I got lucky, no bent valves or other damage to the heads etc...
    I think the issue I was running into may have been coilbind/stacking on the valve springs. I was able to get the car fired on the old rockers, and after I get it tuned, I am planning on setting up for the roller tip rockers.
    I am sure the results will be what I am looking for, I probably could do all the mesuring now and get them set up, but I will wait until I know everything else is running correctly.

    A big thanks to Tom for all the 'coaching' he has been giving me. Hopefully I can return some of the favor by helping to prove how well these work.
     
  19. OutlawJD

    OutlawJD Active Member

    I have a Poston NH 400 Cam, Would this Cam work well with Tom's R/Rocker setup in my 66 Riv GS ?

    Thanks
    Jim
     
  20. 87GN@Tahoe

    87GN@Tahoe Well-Known Member

    these rockers wake everything up!... you just have to make sure you have enough piston-to-valve clearence:beers2:

    wes
     

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