oil pressure by-pass valve question

[bluesman]

Hello all,
So, I'm changing the oil and filter on my '79 r100 and finally remember to check the ball in the relief valve and it doesn't move at all. After looking at pictures on the web I see that mine is screwed in way farther than it should. I screwed it out to almost flush and felt it tighten somewhat and now the ball moves freely. I read Snowbum's article on the subject and he say's to use blue thread locker but having read through articles here I see mention of spiking. It doesn't appear mine was ever spiked. Also, would the fact that it was screwed in so far and the ball not moving be the cause high pressure in the engine causing many of my seals to weep? Thank's for any help or recommendations.

Bluesman

[robert]

It has nothing to do with oil pressure to the engine. It just regulates differential pressure across the filter element.
High oil pressure would have nothing to do with the seals leaking.

[Rob Frankham]

Are we talking here about the oil pressure relief valve, which is bolted to the front cover above the crankshaft, or the oil filter bypass valve which is at the bottom of the oil filter housing? From your description, I would guess it is the latter... if so, I agree with Robert. it will not generally affect the overall oil pressure, it is simply there to allow oil to bypass a blocked filter. Mind you, if the filter were to become blocked and if the valve were locked closed, it would cause a lack of oil pressure at the bearings...

In any case, none of the oil seals are subject to oil at feed pressure so, even if the pressure were too high, it wouldn't cause the seals to weep.

Leaking oils seals can be attributed to a number of issues including:

• Worn out seals
• Wear to the sealing surface on the journal,
• High crankcase pressure due to a defective/blocked vent valve and/or excess blowby from one or both cylinders.
• The use of synthetic oil with old seals
• The list goes on...

But not excessive oil pressure in the oil distribution circuit.

Rob

[bluesman]

Yes I am talking about the oil filter by-pass valve.

[barryh]

The filter bypass valve spring has been known to break and small pieces pass through to the bearings which can wreck the crank. Your spring must have been fully compressed and coil bound. I wonder what effect that will have on it's life.

[bluesman]

So are you recommending I replace the spring?

[barryh]

Well I don't know enough about what would fatigue a spring to say for definite but it has been in an unusual state for some time so it might be a wise precaution to replace it. Perhaps someone else with specific knowledge about springs could comment. May be they should even be a regular service item given that it's not unknown for them to break in service. The cost vs consequence makes it a very cheap precaution.

Take a look at this thread where ME 109 had the spring break twice

http://forum.boxerworks.com/viewtopic. ... ass+spring

[bluesman]

Yes I agree, I'm going to order the parts tomorrow. Any tricks om how to install? Looks like it could be a bit tricky!

[bluesman]

Yes I agree, I'm going to order the parts tomorrow. Any tricks om how to install? Looks like it could be a bit tricky!

[Rob Frankham]

Yes I agree, I'm going to order the parts tomorrow. Any tricks om how to install? Looks like it could be a bit tricky!

A magnetic screwdriver will be your friend here... or possibly a big gob of grease on the end of a non magnetic one. Easier if the engine is on it's side but it can be done in situ.

Rob