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Notching 16v cam bearings for more lift?

 
Old 11-28-2011, 08:38 PM
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danglerb
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Default Notching 16v cam bearings for more lift?

No plans to do it, no big reason to do it, just wondering if it might work.

.506 is the most lift that seems to fit through the cam bearings on a 16v motor. I'm wondering if the cam bearing would still work well if it had one or more "bumps" so a slightly larger nose on a cam lobe would fit through.
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Old 11-28-2011, 08:56 PM
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Loss of oil pressure?
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Old 11-28-2011, 08:59 PM
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That would cause a major loss of oil pressure. atb beat me to it

Last edited by ZEUS+; 11-28-2011 at 09:01 PM. Reason: atb there first
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Old 11-28-2011, 09:00 PM
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Originally Posted by ZEUS+ View Post
That would cause a major loss of oil pressure.
Well, oil does leave the bearing ALL the way around it..right? As long as this isnt where oil is inserted into the bearing..its not really leaving any faster there..is it?
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Old 11-28-2011, 09:05 PM
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Originally Posted by Speedtoys View Post
Well, oil does leave the bearing ALL the way around it..right? As long as this isnt where oil is inserted into the bearing..its not really leaving any faster there..is it?
Under pressure it would find the path of least resistance. The cam journal and bearing diameter is a calculated bleed. Also it would be difficult to determine where to notch.
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Old 11-28-2011, 09:08 PM
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Perfect...that's the context I lacked.
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Old 11-28-2011, 09:22 PM
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has anyone tried to use roller bearings for the 16 valve cam shaft?

http://www.hotrod.com/techarticles/b...rings_install/
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Old 11-28-2011, 10:29 PM
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Given the .506 fitting, even .600 wouldn't be much of a bump in the bearing, but I forgot about the whole sealed cam carrier arrangement. Kills any practicality without a redesign with an open cam area, then might as well make two piece bearings.
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Old 11-28-2011, 11:23 PM
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Airflow through the head would be a consideration, also.

Do the heads actaully have airflow at .500 lift?

How about at .600?
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Old 11-29-2011, 01:31 AM
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Shhhhhh we dont need any logical thought here GB.

Why dont you guys just cut the cam housing in half and then figure out how to hold it back together.....
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Old 11-29-2011, 01:51 AM
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Billet cam housing.
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Old 11-29-2011, 02:09 AM
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reduce the base circle of the cam / high installed valve stem height / costom retainers and valve springs. then fully port and polish the heads . Then check it all on a flow bench ... all 16 ports . Oh yea mod the lifter holes . search 16V performance Terry
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Old 11-29-2011, 06:13 AM
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On VW engines we could line bore the case and put in cam bearings. The VW engine like the 928 heads had no cam bearings. The VW case over time would wear and to rebuild the engine the case was bored and cam bearing put in. I think cams could be turned as well so there was an under and standard, but I could be wrong on that.

As I understand it at least on the 32 valve engines the cam can be bored and bearing fitted. I have never seen this so maybe it was just an idea. I suppose the 16 valve cam covers could be line bored too and bearings fitted. I suppose it is also possible to bore them off center to give more lift but since line bore set ups generally use the case as a guide it would take some pretty good planning and some specialized equipment to accomplish this. Then there is the issue of finding some bearings or more probably making some and then worrying about the closed clearance and not hitting the pistons.
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Old 11-29-2011, 07:00 AM
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I have a set of solid lifter cams with 0.550" lift, however 0.650" lift cam with a standard lifter or a bit more with say a 40 mm lifter. Depending on the port design, which there is several actually verified on a flow bench flow of 315 to 325. Cfm is achievable but not straight forward. A more radical port with proven design features may achieve over 350 cfm but again a lot of work and expense. However a lift of 0.550" with a 48 mm valve can achieve very good discharge co-efficients.
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Old 11-29-2011, 07:48 PM
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This is classic danglerb.
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