Well, SOB. That'll teach me to listen to your advice about this stuff. I remember you telling me to use stock rockers with this build...now I know why. I diverted from your advice about the rockers because I wanted the adjustability in the valvetrain without adjustable pushrods. oops. Would it not be a wise choice to switch to a solid cam/lifter combo? ...and retain 1.6 rollers?
Sure, you can run solid lifters on the 413, just give them about .010 hot lash.. If you have alum heads make sure you lash them hot, they grow.. Don't get me wrong here, folks, I am not telling you not to run a 413 cam. In fact, I am pretty sure that TA is having someone else grind that cam these days, with different masters, and there very well could be no issue at all anymore. All the info I have on that cam is at least 5 years old, I have not seen one since. All I am saying is if your having an issue with your build nosing over at rpm, and have high ratio rollers, bolt on a set of stock rockers, and see what happens. Regardless of what/whose cam your using. That, and everyone that is thinking about going to roller rockers, with a hydraulic cam, should be buying TA's 1.55 ratio. I have no info on the E heads, with their Chev style rocker, other than this phenomenon is not only limited to Buicks. It does happen on motors that have stud type rockers.
Jim, I have 1.6 TA Roller Rockers. Absolutely no issues at all with revving to at least 6000 RPM. The KB118 cam I know is described as being easy on the valve train, so I am sure the valve opening rates are low enough so as not to cause this type of problem. How does this figure into my future build with the hydraulic roller? Doesn't a roller profile open the valves really fast?
Larry, That's a good question, and no one will know until they strap one to a dyno. A roller is a different deal, while the overall valve speed is faster, it's not so abrupt coming off the base circle. That being said, I do know engine builders that run solid roller lifters on hyd roller cams.. Cliff Ruggles does that, with his Pontiacs. That's why I want to do the testing, against a 413 cam.. to study the lastest version of that cam with the rollers, and then since it's the closest flat tappet cam to your roller, we can get a good idea of what the power increase will be. You can bet I will have a set of stock rockers on hand, during the testing. As you know, I don't take anything for granted. JW
Shaft mount roller rockers , particularly those with a roller fulcrum like the TAs, will be inherently more stable than any stock, stamped steel rocker arm. The roller fulcrum requires minimal clearance and small amounts of oil to operate extremely well. The stamped steel rocker arms require more clearance and good oil flow to operate satisfactorily. By their very nature, the rockers with roller fulcrums will be more stable at RPM. If a stamped steel rocker arm allows the engine to RPM better, there is most likely something wrong with the camshaft that the slack (clearance) in the stock rocker arms is compensating for. Imperfections in the profile, base circle runout, harmonics, damage from shipping, etc could all be factors. Running a solid lifter with lash should have the same effect and allow the engine to RPM fine as long as the appropriate spring pressures are used. SB
... associated with 1.6 and higher ratio Roller Rockers, but whether or not the same problem is exhibited with TA 1.55 RR's has yet to be determined
Everyone knows the answer you JackAzz 42 !! <object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/YRFVqRXCvOI?fs=1&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/YRFVqRXCvOI?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
Now you guys have me worried. The 462 im currently putting together is using the 288-92H and im using Edelbrock heads and had planned on on 1.65 roller rockers from Gessler Head Porting. Has anybody experienced similer problems (not pulling above 5000 rpms) with the eddy heads and this (or a similar i.e. TA413) cam?? I know Jim mentioned in an earlier post that he didnt have direct experience with the Eddy heads in this situation. Or should I just bite the bullet and go with 1.55 rockers to be safe??o No:
While the adjustable fulcrum point of a stud rocker is less prone to this issue than the fixed point of a shaft setup, I would still recommend the lower ratio rockers, with a hydraulic cam. The difference here is about .025 in lift, on your standard .320 lobe cam, and you would be hard pressed to see a couple more ponies from that. And the higher ratio rocker is considerably harder on the valvetrain as a whole, from the rocker studs on up. JW
no problems. I have a fresh .040 BBB with same Eddy heads, same cam, 1.6 Comp stainless steel roller rockers, GM delphi lifters all form Gessler. On the dyno sheet it looks like it was run all the way to 5800rpm. In the car it revs up VERY fast and will pull to 6000rpm with ease (have rev limiter). peak hp is 5300 rpm and peak torq is at 4600 rpm
Thats makes me feel worlds better!! Jim, I was really hoping youd chime in because your knowledge is priceless in these matters IMO. Thanks sooo much!! And Kick71, based on what you said, I just stole your valve train setup (im copying that to a "t"!!:beer Thanks for sharing!! What kind of power did you make with your combo??
Bolted on the rockers last night. Haven't got to run it yet... waiting for my header to come back from machine shop... But the quality in the TA roller rockers is insane after you see the stock rocker setup. TA makes some nice pieces (TD is the manufacturer, I believe).
