Swapping hydraulic for mechanical rollers, which ones 4 RB?
#2207156
12/03/16 09:09 PM
12/03/16 09:09 PM
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Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
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I'm changing my unbushed-lifter-bore, stock RB block from a hydraulic roller to a mechanical roller valvetrain.
I am leaning towards running the Isky 3672RHEZX EZ-ROLL X Solid Bushing Roller Lifters with the .125" higher pushrod seats, so I can run shorter, more ridged pushrods.
I have learned that virtually all mechanical roller lifters slightly uncover the lifter bore on the cam side of the lifter bore on unbushed lifter bore blocks. How much depends on the individual casting and machining characteristics of a given block. I would have bushed it, but I don't really want to tear down the short block to do it now.
Is there anything I should know or need to consider before pulling the trigger on these lifters or on not running a bushed bore for the lifters?
Thanks, guys.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: jbc426]
#2207164
12/03/16 09:17 PM
12/03/16 09:17 PM
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Joined: Feb 2011
Posts: 4,302 Nebraska
72Swinger
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Nebraska
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Those are really good lifters but I think you can also get them in solid body? MRL has some lifters available that he claims work fine in unbushed bores, might be worth a call to him.
Mopar to the bone!!!
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: 72Swinger]
#2207217
12/03/16 10:17 PM
12/03/16 10:17 PM
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Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
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Thanks. I was told that its the notch for the wheel that exposes the oil galley not the lifter body.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: jbc426]
#2207230
12/03/16 10:28 PM
12/03/16 10:28 PM
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Joined: Dec 2007
Posts: 12,588 Great Neck,LI,new york
hemi-itis
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I Live Here
Joined: Dec 2007
Posts: 12,588
Great Neck,LI,new york
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What kind of spring pressure?? I have had great luck with the comp 848 with under 700lbs over the nose.Also put restrictors in the PRs.
HEMI-ITIS has no cure. My condition is fully BLOWN!!
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: BSB67]
#2207260
12/03/16 10:57 PM
12/03/16 10:57 PM
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Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
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The cam specifics have not been decided yet, but it's on the small side for a mechanical roller. It should come in at or just over .600 lift with a 1.6 to 1 rocker.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: jbc426]
#2207301
12/03/16 11:58 PM
12/03/16 11:58 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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The cam specifics have not been decided yet, but it's on the small side for a mechanical roller. It should come in at or just over .600 lift with a 1.6 to 1 rocker. You could have it ground on a smaller base if needed.. you have to watch both the base and full lift... I have come real close(closer than I like on the base) on my SB stuff so look at the cam and what you want for lift EDIT Also those holes going to the axle are large so you will loose a lot of pressure with them... you have to figure that hole times 16.. I wasnt happy with the pressure loss on my SB
Last edited by MR_P_BODY; 12/04/16 12:05 AM.
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: MR_P_BODY]
#2207308
12/04/16 12:10 AM
12/04/16 12:10 AM
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Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
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Thank you for the insight. I hadn't considered grinding the cam on a smaller base the reduce the overall installed height of the lifters. I'll ask the guy going through and setting up the heads and spec'ing the cam about that.
FWIW I am not oiling the rockers through the pushrods.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: Swapping hydraulic for mechanical rollers, which ones 4 RB?
[Re: jbc426]
#2207314
12/04/16 12:19 AM
12/04/16 12:19 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
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Posts: 52,972
Romeo MI
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Thank you for the insight. I hadn't considered grinding the cam on a smaller base the reduce the overall installed height of the lifters. I'll ask the guy going through and setting up the heads and spec'ing the cam about that.
FWIW I am not oiling the rockers through the pushrods. Weather you PR oil or not.. the hole going to the axle and roller is always leaking.. if this is race only I would forget the axle oiler hole... JMO... the axle oiler is really more for low RPM like on the street... again JMO
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