Worn cams/Oil restrictor disc mystery in timing cover...

[gideonbok]

Hi there.
I had some badly worn cams in my twin, which I now have replacements for, and also ordered other replacement parts that looked worn in the timing case. I noticed that the holes in the new rubber washer/oil restrictor discs that fit into the timing case cover are much larger than the discs that were in the machine when I took it apart. The new ones are the size of a regular washer, with about a 1/4" hole. The old discs had tiny little pin holes in them. Someone told me the holes were supposed to be that small, but I was wondering perhaps this is why the cams wore out?

Any insight would be greatly appreciated, and I hope everyone has a glorious holiday.

 

[chankly bore]

Mystery

The restrictor discs were a fitting to lessen oil flow to the piston, not the camshaft spindle. These should have about a .025" hole in them and are usually made of .006" brass. The rubber washers should bear up against a Nyloc or Simmonds thin nut 5/16" B.S.F. part no. 98. A lot of 1970's cams and followers seemed to suffer wear and there has been a lot of debate as to the reason(s). P.E.I. used to say a lot more damage was caused by thick oil not getting where it was useful than by thin oil breaking down! Use only oil for pre 1985 vehicles, not one for Paralytic Perverter cars. The older oils are better at lubricating long flat surfaces. I recommed you buy "Know Thy Beast" and do a bit of homework on old car or motorcycle sites re lubrication. Cheers, F5AB/2A/7945 since 1970 P.S. another possible cause is wrong cams with wrong lower valve guides!!!!

 

[vibrac]

My summary:
No restrictors+no wear+lots of racing+clean hands=Castrol R

and nowadays check the relative prices of oil from beans against oil of dead prehistoric sea creatures - they are still growing beans

 

[Howard]

My summary:
No restrictors+no wear+lots of racing+clean hands=Castrol R

and nowadays check the relative prices of oil from beans against oil of dead prehistoric sea creatures - they are still growing beans

You do go on about R!

Do you use it on the road, or just track? Do you still have to remove all traces of dead sea creatures before you can use it?

Does it still smell as good?

H

 

[vince998]

Have you got restrictor wires in the rocker feed oil jets?
They´re sometimes left in to reduce oil consumption caused by worn lower valve guides.
Sort the guides, and remove the wires.
The more oil you can get going down the pushtod tubes, the better.
The lowest scavenge hole (bottom left of the timing chest) is blocked up with silicon on my twin (mod from my father)
This has the effect of keeping the lower quarter of the large idler in oil which lubes the rest of the timing chest through splash.

Hi there.
I had some badly worn cams in my twin, which I now have replacements for, and also ordered other replacement parts that looked worn in the timing case. I noticed that the holes in the new rubber washer/oil restrictor discs that fit into the timing case cover are much larger than the discs that were in the machine when I took it apart. The new ones are the size of a regular washer, with about a 1/4" hole. The old discs had tiny little pin holes in them. Someone told me the holes were supposed to be that small, but I was wondering perhaps this is why the cams wore out?

Any insight would be greatly appreciated, and I hope everyone has a glorious holiday.

 

[riptragle1953]

I highly recommend Mobil #1.

 

[Big Sid]

Sid here . The thin brass discs were used ONLY behind the two rearward rubber washers that fed oil to the rear piston thrust faces . Not those that fed the cams . And this ONLY if those cylinders are running oily , wet plugs . Never reduce the feeds to the cam spindles . Cams need all the oil they can get .
Also the metering wires Up top need only be fitted where that same over oiling is experianced . Both of these reduction measures were introduced to reduce complaints coming in about fouling plugs during town running . The wires need only go in the intake rocker feed . A 20 thou wire in the 30 thou hole .

 

[Big Sid]

Sid again . Flat followers need an oil carrying the ZDDP zinc anti friction oil additive package . But this helps prolong life through out the motor and I have used it for 50 years . First in DA Speed Sport oil developed for Offy motors and then went to Valvoline Racing .
Cam or follower replacement needs cease to be an issue . Spindles and bushes etc last seemingly forever also bearings etc , anyplace there is sliding friction . As a result there is cooler running too .

 

[vibrac]

I use it in the road twin and the racers I intend to recycle the old (racing oil is never over used) R in my scott two stroke I read somewhere that to clean oil all you need is two containers one high with the dirty oil in and a wick to a lower new container and presto clean oil! (never tried it yet, cant think of a good wick off hand) but I do know R doesnt easily wear out!

 

[riptragle1953]

From my point of view restricting the oil flow to the pistons with wire (if indeed this was the reason) to prevent oiled up combustion chambers and fouled plugs is no solution at all. Excellent oil control rings, sealed intake guides and a real
crankcase breathing system would keep things clean. Restricting wires indeed! Well, they are cheaper than doing it right.