for what it is worth, bushed vs needle roller lifters

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Re: for what it is worth, bushed vs needle roller lifters

Postby F-BIRD'88 » Sat Aug 12, 2017 4:01 pm

The automatic lash (compensation) mechanism need not be in the lifter... "hydraulic lifter"
In fact that is a bad place for it. It need not be hydraulic. It need not be in the lifter.

Hydraulic lifters were just a simple affordable adaption to existing OHV pushrod engines at the time for passenger cars. This works very well right up to the operation point where it does not.

There are better ways of doing this.

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Re: for what it is worth, bushed vs needle roller lifters

Postby F-BIRD'88 » Sat Aug 12, 2017 4:17 pm

If valvetrain separation at lash causes roller lifter bearing shock then the camshaft lobes should be designed to reduce that lash ramp shock (or lack of a lash ramp shock)
Valvetrain running noise level is a good indicator of the mechanical lash shock on the opening side. And the shock of the valve seating on the closing side.

If you want less shock, design it into the cam lobe lash ramp. (length of and rate of)
A longer lash ramp on the lobe allows for more lash setting variance caused by engine temp change.
If less shock is better then a quieter running valvetrain is better.

The needed slightly more extended seat to seat valve event duration for this as a cam lobe design parameter can be offset by a slightly higher engine compression ratio. The keyword is "slightly".

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Re: for what it is worth, bushed vs needle roller lifters

Postby MadBill » Sat Aug 12, 2017 5:11 pm

Warp Speed wrote:...At idle and low speed, what is the rpm of the roller wheel, and how much does this rpm change as it rolls around the lobe, assuming constant contact?..


If we assume a 0.800" roller, a 1.0" cam base circle, a 0.400" lobe lift and a 1,000 RPM idle (500 cam RPM) the roller speed on the BC would be 500 x 1.00/0.80 or 625 RPM. At the top of the lobe it would be 875 RPM. Sounds a lot less drastic that the high RPM case: 5,000 & 7,000 respectively @ 8,000 crank RPM... :-k
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Re: for what it is worth, bushed vs needle roller lifters

Postby The Radius Kid » Sat Aug 12, 2017 9:29 pm

turdwilly wrote:Perhaps the benefit of pressurized oiling through the needle bearings of the lifter is not so much from the standpoint of lubrication, but of cooling?


Correct.
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Re: for what it is worth, bushed vs needle roller lifters

Postby Geoff2 » Sun Aug 13, 2017 5:34 am

Warpspeed,
Lots of criticism of me by you, but no answers or objective opposing views. Just criticism. Any idiot can do that. There must be an agenda that I am missing...

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Re: for what it is worth, bushed vs needle roller lifters

Postby j-c-c » Sun Aug 13, 2017 1:18 pm

The Radius Kid wrote:
turdwilly wrote:Perhaps the benefit of pressurized oiling through the needle bearings of the lifter is not so much from the standpoint of lubrication, but of cooling?


Correct.


Based on what? We are starting to go in circles it seems (pun intended), many have made the case the main advantage of needles is less friction, less friction means less heat, the reason given for bushings as a poorer choice is they have more friction, but they require pressurized oil, to reduce friction with an oil wedge and therefore reduces heat, but still need "cooling"? I have not seen the case made needles need to be "cooled" by pressurized oil so much as that they need lubrication, which i am sure we all agree has to remove some heat regardless. Where the heat is actually generated locally to or by the roller, and greater by which roller, I believe is the concern.

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Re: for what it is worth, bushed vs needle roller lifters

Postby Belgian1979 » Sun Aug 13, 2017 4:04 pm

j-c-c wrote:
The Radius Kid wrote:
turdwilly wrote:Perhaps the benefit of pressurized oiling through the needle bearings of the lifter is not so much from the standpoint of lubrication, but of cooling?


Correct.


Based on what? We are starting to go in circles it seems (pun intended), many have made the case the main advantage of needles is less friction, less friction means less heat, the reason given for bushings as a poorer choice is they have more friction, but they require pressurized oil, to reduce friction with an oil wedge and therefore reduces heat, but still need "cooling"? I have not seen the case made needles need to be "cooled" by pressurized oil so much as that they need lubrication, which i am sure we all agree has to remove some heat regardless. Where the heat is actually generated locally to or by the roller, and greater by which roller, I believe is the concern.


With a needle you don't have a wedge forming as you have a very small contact patch. There is metal to metal contact, which is not there if bushing functions as intended. Therein lies the advantage of a bushing imo. However, I'm sceptical about a perfect oil wedge from being formed.

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Re: for what it is worth, bushed vs needle roller lifters

Postby cjperformance » Sun Aug 13, 2017 7:43 pm

Warp Speed wrote:
At idle and low speed, what is the rpm of the roller wheel, and how much does this rpm change as it rolls around the lobe, assuming constant contact?
At this rpm, with solid roller lash, is the inertia weight of the wheel itself enough to cause a rapid change above surface/lobe speed in the short time cam is on the base circle? Or are you saying the roller actually stops?
Is that what we're trying to cure with a rev kit or?


Thankfully Bill saved the me wheel speed the math in his post.
Im dont think the roller ever actually stops , as said in the other thread I moreso think that the slowing of the wheel on closing then the unloading of the wheel at lash allows the needles to "unload" and bunch up and upon reload at the start of opening the needles resettle and rattle/vibrate which damages them , the wheel and the axle. This leads (all else being well) to needle failure at which point the wheel could definetly stop, skid badly and the rest is history.
I think the rev kit simply 'helps' keep everything more evenly loaded at low rpms which just helps to really slow down the damage when talking a lot of street type use.
Craig.

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Re: for what it is worth, bushed vs needle roller lifters

Postby Warp Speed » Mon Aug 14, 2017 8:16 am

Geoff2 wrote:Warpspeed,
Lots of criticism of me by you, but no answers or objective opposing views. Just criticism. Any idiot can do that. There must be an agenda that I am missing...


Not criticizing you, just your constant comparison of wheel bearings and u joints to roller lifter operation. They are similar as far as they both use roller bearings. But that is where the similarities end! IMO
Sure, you can use a little engine oil for lubrication of wheel bearings (been done in Nascar many times for super speedway qualifying) and I guess you could do something similar for a u joint. But unless they are ran for very short duration, or at very low speeds and loads, they will fail in a short period.
Both are typically greased, which imparts a stronger film than a little bit of 5-30 or whatever engine oil?
Which brings us back to the pressurized oiling being a marketing gimmick portion of the thread.
As with flat tappets (apples and oranges to rollers but..) roller lifter damage is agravated by low oiling during low speeds. At low rpm, oil flow and pressure is down, so the amount of oil getting thrown around to use for splash oiling is far less than at higher speeds. Same even when pressurized oiling to the wheel is used. The constant leak path of oem oiling design can lead to starvation/low flow even when pressurized. This starvation doesn't help the tiny needle bearing maintain its lubrication wedge (low surface speeds And flow). It is Amazing how many of these symptoms go away when correct oil paths and strategies are used.

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Re: for what it is worth, bushed vs needle roller lifters

Postby tjs44 » Mon Aug 14, 2017 9:39 am

OK,after 6 pages of this stuff,I talked to Danny at RCR,he said most cup teams run the Jesel lifter.So if you figure the engine is made to last 700 miles that is 2800 1/4 mile passes.This is the lifter they run and they are needle bearings.Tom
http://www.jesel.com/valvetrain/index.p ... ers/keyway

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Re: for what it is worth, bushed vs needle roller lifters

Postby MadBill » Mon Aug 14, 2017 10:42 am

Although the numbers are relatively small compared to needle designs, there are many thousands of bushed lifters in service on the street and in race apps. Can anyone provide details/pix of roller failures of same?
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Re: for what it is worth, bushed vs needle roller lifters

Postby Warp Speed » Mon Aug 14, 2017 11:09 am

tjs44 wrote:OK,after 6 pages of this stuff,I talked to Danny at RCR,he said most cup teams run the Jesel lifter.So if you figure the engine is made to last 700 miles that is 2800 1/4 mile passes.This is the lifter they run and they are needle bearings.Tom
http://www.jesel.com/valvetrain/index.p ... ers/keyway


Glad Danny cleared that up for us! :P

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Re: for what it is worth, bushed vs needle roller lifters

Postby nhrastocker » Mon Aug 14, 2017 12:57 pm

Warp Speed wrote:
tjs44 wrote:OK,after 6 pages of this stuff,I talked to Danny at RCR,he said most cup teams run the Jesel lifter.So if you figure the engine is made to last 700 miles that is 2800 1/4 mile passes.This is the lifter they run and they are needle bearings.Tom
http://www.jesel.com/valvetrain/index.p ... ers/keyway


Glad Danny cleared that up for us! :P


Jay, I just spilled my drink all over me... LMAO! :lol: :lol: :lol: :lol:

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Re: for what it is worth, bushed vs needle roller lifters

Postby DaveMcLain » Mon Aug 14, 2017 2:33 pm

tjs44 wrote:OK,after 6 pages of this stuff,I talked to Danny at RCR,he said most cup teams run the Jesel lifter.So if you figure the engine is made to last 700 miles that is 2800 1/4 mile passes.This is the lifter they run and they are needle bearings.Tom
http://www.jesel.com/valvetrain/index.p ... ers/keyway


Isn't it also true that NASCAR doesn't allow a bushing lifter to be used? Only the needle bearing type are legal.

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Re: for what it is worth, bushed vs needle roller lifters

Postby Warp Speed » Mon Aug 14, 2017 2:41 pm

DaveMcLain wrote:
tjs44 wrote:OK,after 6 pages of this stuff,I talked to Danny at RCR,he said most cup teams run the Jesel lifter.So if you figure the engine is made to last 700 miles that is 2800 1/4 mile passes.This is the lifter they run and they are needle bearings.Tom
http://www.jesel.com/valvetrain/index.p ... ers/keyway


Isn't it also true that NASCAR doesn't allow a bushing lifter to be used? Only the needle bearing type are legal.


Yep! LOL
Not all manufactures offer them so.........?


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