Dual thrust cam bearings.

The thrust cam-bearings, have no tabs to prevent them from rotating in the case. Is a special trick needed create these tabs without destroying the bearings and case, or should I just punch them in position (in an old case) to bend them and create the tabs?

Bill, '67 bug.

Reply to
Bill Spiliotopoulos
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Bill, i have had different sources tell me different things...some say "don't worry about it, they can't go anywhere" and others say to use a chisel to kinda "peen" them into the slots in the case....maybe John C or Bob H. can speak up here and help us all out....

------------------- Chris Perdue

*All opinions are those of the author of this post* "Sometimes you're the windshield, sometimes you're the bug"
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reply take your PANTS off
Reply to
Chris Perdue

Dear Bill (and the Group),

I've not found any advantage to a full-circle thrust-flange on the #3 cam bearing unless the engine spends a significant amount of time above 5000 rpm OR the cam is being asked to transmit an unusual amount of power to the valve train (dual springs, high-lift, etc.)

If you want to form a tang on the cam bearing shell I suggest you carefully mark the BACK of the bearing shell then use a Swiss file (or similar) to cut a 'ramp' of suitable size in the STEEL shell. Then make up a swaging punch of suitable size (ie, NARROWER than the tang by the twice the thickness of pewter bearing material on the inside of the steel shell) and use a junked case as your die.

I've only seen a couple of engines where the #3 cam bearing has spun and they were always in conjunction with a catastrophic lubrication failure, after-market cam gear and so forth.

Keep in mind that the cam spins at half the speed of the crank, and that when the cam is properly fitted to its bearings, it will have quite a bit of clearance at normal operating temperature (assuming it is ground on a cast iron blank).

-Bob Hoover

Reply to
Veeduber

Thank you both for your answers. I'll be using a cam with higher lift than the stock cam, with a stock cam gear and with single HD valve springs , so the side thrust will be somewhat greater than that of a stock engine, and I want the dual thrust bearings just to be sure.

Bill, '67 bug.

Reply to
Bill Spiliotopoulos

I carefully file or grind off the tang off of ONE bearing shell (not both). Use this on the non-tanged side of the case. You can put the groove in the case, but this is how I do it.

John Aircooled.Net Inc.

Reply to
John Connolly

John seems to be describing the situation I usually find myself in: Dual thrust bearings where both sides have tangs but only one side of the case has a slot. John files off a tang, I file a new slot. Either works.

OTOH, the OP seems to be describing the opposite situation where NEITHER thrust bearing half has a tang. I've not seen this, and I'd worry a bit, too.

Which way are all the new double thrust cam bearings coming now, or does it vary according to the source?

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

The Kolbenschmidt set of dual thrust cam bearings (this is what is available in Europe and I can get easy locally) have two stock style #3 cam bearing shells without the tangs. They just replace the one shell without the thrust surface (which has the tang) with one with the thrust surface (which doesn't have the tang). These bearings are steel backed, and you cannot just bend them to create the tang. I'll try to cut the back first to be able to bend it a little and create a tang.

Bill, '67 bug.

Reply to
Bill Spiliotopoulos

Glue them in...

J.

Reply to
BergRace

all our DT cam bearings have a tang on each thrust bearing shell.

John Aircooled.Net Inc.

Reply to
John Connolly

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