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Roller Rocker and Cam Replacement Interval.

Started by 838, November 21, 2023, 12:01:27 PM

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838

If the geometry is set correctly, with a .660" lift cam what would the expected lifespan of a set of roller rockers and cams be???

Old t-man 113" cvo kit (with tman headwork) with old 662-2 cams. I believe the kit used s&s rollers.


OldBogie

The most basic question is whether the heads show sufficient flow improvement with lift at .660 inch. So some flow bench data is needed. If the port can't feed lift above say .5 inch with increased flow then there is no point to pushing into more lift. More lift adds a lot of wear and tear on the valve train. So its use needs to be justified by the knowledge that the port can feed significantly improved flow at those high lifts. Otherwise you're better off trading more duration against more lift.

Bogie

Ohio HD

I think asking for a length of life is going to be a question that really can't be answered. How a motor is run, spring pressure, the lift (which you know) can all play a part in how long they last. That being said, S&S has a rebuild kit. Part number 90-4104.



wfolarry

Just as long as any other setup.
.660 lift in itself does not destroy parts. If it was ground for a street bike that's all figured into the lobe shape.
If you try running a race cam on the street you can expect more abuse to the valve train.

838

Quote from: wfolarry on December 02, 2023, 12:31:21 PMJust as long as any other setup.
.660 lift in itself does not destroy parts. If it was ground for a street bike that's all figured into the lobe shape.
If you try running a race cam on the street you can expect more abuse to the valve train.

I'd be interested to hear how you would come to that conclusion (street or race profile) based on how a cam is advertised and what the average joe can find out based on specs. Without having the ability to put each cam on a degree wheel/dial indicator to check lobe profile?

Quote from: Ohio HD on December 02, 2023, 11:59:27 AMI think asking for a length of life is going to be a question that really can't be answered. How a motor is run, spring pressure, the lift (which you know) can all play a part in how long they last. That being said, S&S has a rebuild kit. Part number 90-4104.




I saw these as well. Nice solution. Thank you.

wfolarry

Quote from: 838 on December 04, 2023, 09:59:52 AM
Quote from: wfolarry on December 02, 2023, 12:31:21 PMJust as long as any other setup.
.660 lift in itself does not destroy parts. If it was ground for a street bike that's all figured into the lobe shape.
If you try running a race cam on the street you can expect more abuse to the valve train.

I'd be interested to hear how you would come to that conclusion (street or race profile) based on how a cam is advertised and what the average joe can find out based on specs. Without having the ability to put each cam on a degree wheel/dial indicator to check lobe profile?

Quote from: Ohio HD on December 02, 2023, 11:59:27 AMI think asking for a length of life is going to be a question that really can't be answered. How a motor is run, spring pressure, the lift (which you know) can all play a part in how long they last. That being said, S&S has a rebuild kit. Part number 90-4104.




I saw these as well. Nice solution. Thank you.

Well if the cam manufacturer won't tell you then you'd have to find out for yourself.
I have a cam test stand  :teeth: