Bill Boudway Posted July 13, 2005 Share Posted July 13, 2005 Hi,What's an acceptable amount for the radial clearance on a roller tappet?Thanks for your help.Bill Boudway Link to comment Share on other sites More sharing options...
Guest imported_Joe Kieliszek Posted July 16, 2005 Share Posted July 16, 2005 Hi,I would not want any internal rolling/reciprocating clearances toexceed .005 thousands; also check for "flat spots" and rustpitting on the rollers..Thanks,Joe Kieliszek Link to comment Share on other sites More sharing options...
nearchoclatetown Posted July 16, 2005 Share Posted July 16, 2005 I've wondered about this for some time, was hoping someone that really knew the answer would respond. I think too,as has been suggested there is no clearance with a roller tappet. I think the tappet must be in constant contact for proper function. I think I even remember my neighbor's SB Corvette, with a roller, that has springs under the heads to keep the lifters in contact with the cam. Have you checked with the cam manufacturer? Link to comment Share on other sites More sharing options...
Guest imported_Joe Kieliszek Posted July 17, 2005 Share Posted July 17, 2005 Hi again,This is pretty much a guess on my part (maximum clearance). Acouple years back, I made replacement rollers for the lifters onmy 2 clinder Buick motor out of case hardened shafting (sometimescalled "Thomson shafting"). I bored out the soft center of theshafting to accept hardened drill guide bushings that I had purchasedfrom McMaster-Carr. Torrington needle bearings would also work well.I was also able to recondition my cam lobes by rigging up a pivotarm and counterbalance for the tool post grinder I use on the lathe.I still haven't fired up the motor though..Joe Link to comment Share on other sites More sharing options...
Guest Stllrng. Posted July 17, 2005 Share Posted July 17, 2005 I would agree that you need to be at around .005" of valve lash with the roller tappets. The only time you would have a zero lash type of a situation would be if you had hydraulic roller lifters. Any solid lifter cam, whether it is a roller style or flat tappet must have clearance. If you were to run with no lash whatsoever, you will have a loss of compression and burned valves. Is this as used on a twin six Packard? Link to comment Share on other sites More sharing options...
The Old Guy Posted July 17, 2005 Share Posted July 17, 2005 In the older Buicks, they ran .008 clearance. The roller tappet was held to the cam with a apring and the clearance was between the push rod and the rocker arm. Link to comment Share on other sites More sharing options...
Guest imported_Joe Kieliszek Posted July 17, 2005 Share Posted July 17, 2005 Hi again,I remember reading in a reprinted volume of the Model T repair manualthat the valve clearance should be set "to the thickness of athin dime". Boy, thats pretty exact!Joe Kieliszek Link to comment Share on other sites More sharing options...
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