Cam bushings

Well....

joefarmer said:
NASCAR is a bunch of toothless rednecks, not unlike sledpullers. The theory of turn-em loose jimbo boogity booogity boogity applies.
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I fail to see how that applies to your claim of, "too much drag over 8k rpm." And actually, Nascar is more businessmen than you would believe. Name a toothless redneck involved in the sport.
 
roller cam bearings. . . . . all the way for me! seen in on the dyno. proven to free up power.

back when i started racing,i was in a 4cylender chevy chevette,looked all summer for the bearings,found them put them in. seat of the paints feel was wow! shoudl have done this much sooner! but the bad thing was,didnt have a hardened cam,so the cam wouldnt live.

then when i moved up to late models run a steel block chevy for a season with cam bushings "cam bearsing" they were almost gone by the end of the season,then put rollers in,and again WOW!

but this is my 2 cents!!

any time you can free up the motor you will make more power!!

o i for get what its called,its a tool that you can check drag on a bearing etc and check it!
and as far as nascar goes,man if it wasnt for them,NO motorsport would,have a chance,because no one woudl build parts,push for the next big thing,you wouldnt have stuff like bend tech pro,dyno,ross pistions,and all this other performance parts you like to build your motor with. but again this is my two cents,who know maybe im wrong,been down their for school."nascar tech" i know what them boys are just like everyone else,good old boys!!!
 
XLR8R said:
Cup teams & their efforts have generated a significant portion of our current knowledge base - and I know many of them who can speak the king's English.
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You're not exactly helping me...

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XLR8R said:
Mea culpa - difficult at times to separate trolls from tards...
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Sorry buddy! You always catch some dolphin when you're fishin' the tuna! :hehe:

BTW- I'm still getting the weight #'s on the Carrillos and I'll ship that crank off once I have all the weights.
 
Sounds good!
Judging from your time frame I figure you won't be using it for the Super Stock race... which is good, since I almost got in hot water for "cranking" out too much info. :hehe::rules:
 
ask racin wayne. To relieve potential stress and free up friction, a roller cam and tappets are the only way to go. my 2 cents
 
GMac said:
ask racin wayne. To relieve potential stress and free up friction, a roller cam and tappets are the only way to go. my 2 cents
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Roller is not always better for our particular applications. When you graph valve lift as a function of crank angle rollers don't always look as good. In a most instances unless you are going with some really high duration, high lift profiles, in my opinion flat tappets are superior.

Another thing to look at is just because you have a roller tip on the lifter does not equate to less friction in the valvetrain. Less friction on the lifter face yes, but when you look at the side loading of the lifter in it's bore in most instances there is greater overall friction in the system. A lot of that depends on how much the lifter comes out of the bore which is dependant on the size of the base circle. The more the lifter comes out of the lifter bore , the greater the fulcrum action, side loading of the lifter bore and tendency to mushroom the base of the lifter bore.

I was in a meeting with a bunch of motorsport engineers, many in the camshaft industry a month or so back. I heard story after story of increased oil temps when roller lifters were used. This can be explained by nothing other than increased friction due to lifter sideloading. Even with the decreased friction of the roller tip.

When sideloading, and slower initial ramp rates are factored in, rollers are not always the best choice.

Zach
 
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XLR8R said:
Sounds good!
Judging from your time frame I figure you won't be using it for the Super Stock race... which is good, since I almost got in hot water for "cranking" out too much info. :hehe::rules:
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Nah. That bottom end has been built for awhile and not about to come apart.
 
Nascar name calling aside, I finally found my notes on the topic. "roller bearings reduced friction greatly up to 8K rpm and the plain bearings reduced friction better above that rpm". Of course, you may want to note it came from notes taken on this app:
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1.5" CR mushroom tappets are the envy of many... BBC folks are thrilled to reach .98x".
Rollers aren't superior until well in excess of 25% L/D ratio, and increased oil temp from lifter bore friction is almost inevitable with a grind requiring roller ramps.
 
XLR8R said:
1.5" CR mushroom tappets are the envy of many... BBC folks are thrilled to reach .98x".
Rollers aren't superior until well in excess of 25% L/D ratio, and increased oil temp from lifter bore friction is almost inevitable with a grind requiring roller ramps.
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Why such envy of a larger tappet? Doesn't that equate to more moving mass which is not ideal for freeing up horsepower. I can see the benifit such as a wider contact patch.
 
The slight weight penalty of a large mushroom tappet on the good side of the rocker arm is insignificant in comparison to potential extra power production from additional vulva action in relation to crankshaft position.
 
XLR8R said:
The slight weight penalty of a large mushroom tappet on the good side of the rocker arm is insignificant in comparison to potential extra power production from additional vulva action in relation to crankshaft position.
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You said mushroom and vulva in the same post. LOL

Sorry i couldn't help myself. I'm fuggin bored.
 
:doh: The missus has been calling me to bed - guess I got distracted... time to go take care of business! :hump:
 
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