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#21
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#22
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well I can verify that 1991 CRANE lifters had the 2 groves...as I just threw mine away After my 400 death and all the "stuff" that I found in the pan I really did not want to go thru cleaning each of them. Figured I would just buy a new set...add another $150 to the already over budget ...budget build
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#23
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Thank you for verifying what I posted.
67Fbird, Send me a PM and we can work out a deal on another set of the good 1991 lifters. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#24
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Would those lifters be leak down siilar to the Rhoads lifters for Pontiac blocks?
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#25
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No, the lifters WOULD NOT LEAK DOWN THE SAME as the Rhoads Lifters WITHOUT the
Rhoads lifter modification of the internal lifter plunger. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#26
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around the lifters. Tom V. Reply from MIke : Is this were the "Lifter Debacle" in the late 1990s came from. By the way years ago I followed your post on Tri-power #'s from the info. you Published on this forum . It help confirm some of my past findings on the Rochester 2GC+V Carbs. |
#27
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My post was about this:
Johnson supplies Hydraulic Lifters for Rhoads Lifters MODIFICATION. Rhodes buys the lifters, takes them apart, removed the Piston in the center of the lifter, machines a very high quality GROOVE of a precise size for oil flow in a North/South direction on the piston. This causes the lifter to bleed down and the hydraulic piston to be lowered at idle and low rpm speeds. At higher rpm the piston cannot bleed down fast enough and you get full valve lift. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. Last edited by Tom Vaught; 08-28-2021 at 07:51 PM. Reason: fixed post |
#28
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around the lifters. Tom V. Reply from MIke : Is this were the "Lifter Debacle" in the late 1990s came from. By the way years ago I followed your post on Tri-power #'s from the info. you Published on this forum . It help confirm some of my past findings on the Rochester 2GC+V Carbs. |
#29
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#30
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Because the lifter is acting like a SPONGE at low rpm (low oil flow...low oil pressure) and therefore NOT transmitting the cam lobe movement EXACTLY. The lifter is moving slow enough that instead of transfering the "lift" directly to the pushrod per the cam....the cam pushes UP...the lifter pushes UP but the valve spring force causes the lifter's internal plunger to "BLEED OFF" some of its hydraulic support. Basically making the net valve movement LESS and the duration LESS than what the camshaft is sending. NOW...when rpm (oil flow and pressure, speed) INCREASE.....there is NO "bleed off" and everything is back to "normal"
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#31
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Lift has little effect on driveability. Duration and overlap have much a bigger influence. Rhoades modify their lifters to collapse (bleed down) much faster than a standard lifter. This cause the valves to close faster (sooner) and make the cam act as if it has less duration. When the intake valve closes sooner the engine builds more cylinder pressure. When the exhaust valve closes sooner the overlap is reduced. As engine RPM increases the time for the lifter to bleed down is reduced so the Rhoades lifter starts to act more like a normal lifter... In short.
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#32
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the cam pushes UP...the lifter pushes UP but the valve spring force causes the lifter's internal plunger to "BLEED OFF" some of its hydraulic support. Basically making the net valve movement LESS and the duration LESS than what the camshaft is sending. NOW...when rpm (oil flow and pressure, speed) INCREASE.....there is NO "bleed off" and everything is back to "normal" Mikes reply to this : Got "how it works", but now I would like to no "why it works" to gain performance please . Mike out.
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#33
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The Following User Says Thank You to TRADERMIKE 2012 For This Useful Post: | ||
#34
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Mikes answer to this : When the intake valve closes sooner the engine builds more cylinder pressure. "Is this why one would advance the cam in the first place , in that the result is more cylinder pressure equals a higher performance engine.
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#35
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You have one set of timing events that the valves see at low speeds and another set of timing events built into the camshaft design that adds more performance on the top end. Kind of like a "Lifter Turbocharger" soft on the bottom of the power range but at higher rpm your valve event "turbocharger" gives you the extra power to be happy at the higher engine speeds. It softens the low speed rpm camshaft events and makes the camshaft act like a smaller duration camshaft. Better low speed drive-ability but also a milder sounding engine. No PRO STOCK engine sound. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#36
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I jumped on a Kawasaki 900 in 1975 bored over to 1100 cc kit ,Turbo charged. Hard tail. I weighed 135 lb at the time.When the turbo kicked in( late) I was holding the throttle with one hand and the other grip with the other and almost came off the seat . Then the hard tail started to bonce due to "no" rear shocks. I am hanging on for my life and the rear end was jumping off the ground from side to side and almost threw me like a bucking bull. I let off the throttle and drove home slowly and gave the motorcycle back to the owner. Fastest vehicle I ever rode. The stained seat is a reminder not to get on something like that anymore. When the turbo spooled up and launched was the most thrilling experience I ever had. I won't experience anything like that with these Rhoad lifters, will I ? ps. I think the real question is Will I notice the difference between the Johnson vs Rhoads lifters, along with the cam timing advancement at 109 LSA that I plan to do after degreeing the cam?
Last edited by TRADERMIKE 2012; 08-29-2021 at 11:50 PM. |
#37
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no.
it's not like you are way overcammed already. Yes there will be a little bottom end torque increase but unless your booty dyno can tell +/- 30 ft/lbs ....nah. The ONLY advantage you MIGHT be able to pinpoint is a little softer idle (increase in vacuum) and the noisy tick tick tick... |
#38
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My booty dyno is calibrated to +/- 50 lbft so your rite. That is what I red , that one can hear the Rhoades lifters ,not into noise and I like the lope I have now . No Rhoades for me . Thank you for the Honest input . Mike
Last edited by TRADERMIKE 2012; 08-30-2021 at 03:07 PM. |
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