rods and lancers on R25 / 2

Begonnen von Anto, 19 Februar 2019, 22:30:03

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Anto

 Hi, can anyone explain to me why on one of the two rocker arms on an R25 / 2 has a longitudinal cut? Thank you.

Anto


4Taktix

If you mean the little (radial) slot in the face-side - this is to spill some oil out and spread it. That side should point to the pushrod-end of the rocker-axle.
These Rockers are equipped with a fixed brass tube as a bearing with the matching axle.
There are also rockers without this slot, they were assembled with a two-piece floating steel-tube-bearing on a different rocker-axle and do have a little hole on top
to spread the spill-oil. attention: If this is a genuine /2-head, with the particular oil-supply via copper-tubing into the rocker-axle, you got to use the matching rockers.
Both above have different axles with different diameters and different end groves.
Or is it something else ? Never seen a rocker with a "longitudinal cut". Can you post a picture to clarify ?

Regards,
Sascha
Think outside the box !

Anto

Hi Sascha, I do not mean on the rocker but it's a very thin slit along a single control rod of one of the rockers. To understand each other better is the rod that rises parallel to the cylinder and connects the camshaft with the rocker arm. During the cleaning I realized that one of the two has a very thin longitudinal cut. Tomorrow night I go to the garage and take a picture. Hi Anto

Anto

This is the photo of the auction. The line does not communicate with the central hole. Strangely I also have a problem with the plate that touches the rocker of the new long-stem valves purchased by Mark Hugget CH. From him I bought the two valves, the latches and the plates. The outlet valve remains pointed and can not be adjusted. The previously fitted valves were a mix of long and short. I only had the valve seats sanding and the engine was fine first. What could have changed? A too strong abrasion I think can not compensate for a minimum of 2 mm of lack of play. Thank you

4Taktix

#4
Hello Anto,
the pushrod is a case for the bin. I wouldn't use it anymore.
Your valvetrain certainly is not OK, the valve-stems are too long. This could either be caused by regrinded seats, especially if they were grind the second or third time.
Or else by wrong valve-collets, and mayby wrong valve-plates. There were 3 different types of valvestems and collets. They mandatory have to match.
It is also possible that you have foreign pushrods, which are too long, but this is rather unlikely.
However, I'd measure the length and compare, they should have ~ 185mm
For a "quick & dirty" solution you could shim up the rockerblocks, but use grind shims of equal thickness.
But I wouldn't recommend this, as the rockerbosses are already the weak spot in the valvetrain, as they are not very stiff/rigid.
If you put shims between bosses and rockerblocks, they will lose even more stiffness.
Better you get the correct valves/collets/plates.
I attach the drawings with details and measures from the comparison-list.
Hope this helps.
By the way: Are you certain, that you have a R25, R25/2, R25/3 Cylinder ? I ask as it is possible to assemble the engine with a R26/27 Cylinder,
and these are 9,5mm shorter than the first 3 models. This could explain, why you have such a missmatch on top-end.

Regards,
Sascha
Think outside the box !

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