Rocker arm selection

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    Author Topic: Rocker arm selection  (Read 2104 times)

    Offline Imlearning

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    Rocker arm selection
    « on: December 19, 2005 - 08:03:38 PM »
    Hety guys. This is my first post on this site. I was a regular on the old "Dodge-Charger" under the name Young Gun. That name really no longer applies as I'm now 22 but I am still learning so I think my name fits. Its nice to see alot of familier names like Cryco and Firefighter ect.
    Any way, I consulted many of you on my engine build about two years ago. Its a 440 with ported906 heads, Hughes cam, six pack pistons, 1 3/4 headers, Street dominator intake and so on. The cam "we" chose was a hughes (HEH 2832 BL) with about .524 lift intake and .540 exh. and 228 degrees intake and 232 degrees exh. Since I put it together, it has alway run pretty weak. I think my 75' 318 that I pulled out would probably beat it. It has alway made some sort of ticking or knocking noise but I could never tell where it came from. Just surfing the internet now I see that my Valve springs have a outer diameter of 1.540". I used the mopar performance brand stamped rock arms (cheap) and now notice that they have a maximum spring diameter of 1.490". I don't know how I missed this?
    What could this do to my engine? Could this explain my utter lack of power?
    Thanks for all the help. And its nice to see a lot of familier internet faces.   :biggrin:
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    Offline Chryco Psycho

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    Re: Rocker arm selection
    « Reply #1 on: December 20, 2005 - 12:47:25 AM »
    Welcome YG
      the outer diameter of the spring could touch under the rocker arms depending which retainers were used
     & no it will not explain the lack of power
     I have not used Hughes Cams , Engle used to make them but do not do so anymore , I have stuck with the Engle grinds Not the Hughes grinds , Engle is Far better to deal with
     I also have a customer with  hughes cam in his 340 & it is not performing well either & is contiously breaking Rocker arms which can be caused by the opening ramp on the cam
    there could be a thousand things causing the lack of power poor cam is often the cause , was it degreed when it was installed , the timing can be a problem & if the   the dist has a siezed advance mech that can kill power , the port work could ba a problem as well , I have seen ported heads that lose power from untouched heads , porting is very personal & a give npersons ideas can make heads awesome or Junk , my heads have been proven both on the track & dyno & do work . Poor machine work can make a huge differenc ein power , attention to detail is a must . Other factors like a very poor converter choice in an auto can make a powerful car feel dog slow or a a bad trans build could be robbing a lot of power
     So many variables when I am not there to feel or diagnose ti
    « Last Edit: December 20, 2005 - 09:56:10 PM by Chryco Psycho »
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    Offline Imlearning

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    Re: Rocker arm selection
    « Reply #2 on: December 20, 2005 - 05:37:58 PM »
    Thanks for the responce. I guess I'll probably have to look around else where for the power, but I gota get new rockers now that I know this. Ignition is the next place I'm going to start looking. Lets put it this way, in gear on the road I can't get the rpms past 4200. I once checked to see if it would rev higher with out a load, and in neutral it would only rev to about 4900.
    As far as rocker selection, I know cryco really likes the Crane Cast adjustables. But I don't thik they come with shafts and mine are pretty well shot, I think they might even be "crushed from some one tourquing them down too much. The Crane Race Gold roller rockers are even cheaper than the iron ones if you factor in new shafts. Which one do you think would work better for a car that wont really see more than 3000-6000 miles per years.

    Thanks for all the help :thumbsup:
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    Offline Chryco Psycho

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    Re: Rocker arm selection
    « Reply #3 on: December 20, 2005 - 09:59:01 PM »
    weird , here the Iron rockers with shafts are just over 1/2 the cost of Gold rockers & yes I have to order the shafts separatly
     WHat size carb are you using ?
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    Offline Imlearning

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    Re: Rocker arm selection
    « Reply #4 on: December 20, 2005 - 10:33:06 PM »
    I am not saying that the Gold Race rockers are neccesarily the same price. They are 349.95 usd through summit and they come with hardened shafts. The iron rockers are 209.98 and then the shafts would be 98.99 for  a pair from Crane. Altogether I guess I'm looking at about a difference of 40.98 usd. I was just wondering if the Gold Roller rocker set would give me any improvments over the iron rockers for that 40 bucks? :dunno:

    As for your question, i see where you're going with this. I would have guesed that it was to small too by what I posted ealier. I am running a Demon 850 with 3/8" line from tank to carb and pumped by a Carter Strip pump. I had to put a regulator inbetween the pump and the carb because I was getting like 15 psi (I can't really tell as the gage was maxed at 15). It is pretty much strait out the box, I even tried a friends 750 Holley to no avail.
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    Offline Chryco Psycho

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    Re: Rocker arm selection
    « Reply #5 on: December 21, 2005 - 12:04:25 AM »
    Hmmm pricing is high for the shafts , check around
     could be an ign problem limiting the rpm fo rsure 
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    kudakidd

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    Re: Rocker arm selection
    « Reply #6 on: December 21, 2005 - 10:51:17 AM »
    Check this out:
    http://store.summitracing.com/default.asp?Ntt=mechanical+fuel+pump&searchinresults=false&Ntk=KeywordSearch&DDS=1&N=115&target=egnsearch.asp&x=45&y=12

    I have a feeling you may have a fuel restriction problem. Why? Cause even the strip pump only produces 8 psi. How could you get 15+ psi? Also, you stated that your friend's 750 made no difference. I would check the fuel line from the pick up in the tank to the carb. If it's not the prob, I agree with CP, then it must be ignition. KK
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    Offline Imlearning

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    Re: Rocker arm selection
    « Reply #7 on: December 21, 2005 - 04:27:11 PM »
    I was thinking that it is some sort of fuel restriction too. I was really suprised to see the 15psi reading as it is only a 8 psi pump. I am using a guage that is about 3 inches away from my carb and I changed it twice thinking that the guage was broken. Nothing changed.
    What could cause a 8 psi mechanical pump to put out 15 psi?
    The really wierd part is that it stays in the 7 psi range with the regulator adjusted but slowly goes down to 0psi as the engine warms up. Obviously this is wrong, but the engine runs the same weather I have it adjusted to 5psi at startup or 12 psi. In writing this I have come to distrust my second fuel pressure guage, I think I'll get another.
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    Offline matt63

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    Re: Rocker arm selection
    « Reply #8 on: December 21, 2005 - 06:23:49 PM »
    Quote from: Imlearning on December 21, 2005 - 04:27:11 PM
    I was thinking that it is some sort of fuel restriction too. I was really suprised to see the 15psi reading as it is only a 8 psi pump. I am using a guage that is about 3 inches away from my carb and I changed it twice thinking that the guage was broken. Nothing changed.
    What could cause a 8 psi mechanical pump to put out 15 psi?
    The really wierd part is that it stays in the 7 psi range with the regulator adjusted but slowly goes down to 0psi as the engine warms up. Obviously this is wrong, but the engine runs the same weather I have it adjusted to 5psi at startup or 12 psi. In writing this I have come to distrust my second fuel pressure guage, I think I'll get another.

    My last car, a 383 Demon,had the same problem.  The fuel pump had too much pressure and a regulator was needed.  the biggest problem was at idle and it was very sensitive to float levels.
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    Matt in Edmonton

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    Offline firefighter3931

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    Re: Rocker arm selection
    « Reply #9 on: December 23, 2005 - 02:04:46 PM »
    Quote from: Imlearning on December 20, 2005 - 05:37:58 PM
    . Lets put it this way, in gear on the road I can't get the rpms past 4200. I once checked to see if it would rev higher with out a load, and in neutral it would only rev to about 4900.


    Check to see that your throttle is opening all they way. I've seen misadjusted throttle linkage cause the problems you describe. Mancini Racing sells hardened shafts for $25.00 each. I also like the ductile iron rockers for street applications on a budget. They are also available in a 1.6 ratio if you so desire. Like Chryco said, there are a lot of things that can cause the issues you're describing....start with ignition and carb. Get a timing light on it and make sure the distributor is advancing. Check the base timing...it should be at least 15* at idle.

    FWIW, the carter "strip" mechanical pump will deliver 13-15psi and needs a regulator. The 120gpm "street" pump is 6-8 psi....no regulator needed.

    Ron

    Ps. here's the link to the hardened shafts:

    http://store.yahoo.com/chucker54/manbrbharchr.html
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