Subject: Re: of valves, guides and liners
Author: Patrick Hayes
Date: May 3, 2005, 10:46 AM
Post ID: 1718806277
brian c wrote:
| an automotive machine shop that quoted $100 to ream 4 existing guides and install the liners and trim them. Anybody ever done this? Now, the other thing is that I don't know the history of this engine, but from the condition of the valve surfaces, this seems to be premature valve guide wear- which would lead me to believe there is a problem with the rocker aligment somewhere- or is it possible that poor valve clearance adjustment could cuase this as well? Or maybe someone just put in new valves with old guides last ime? |
Never heard of guide liners, but sounds doable. Why not just put in new
guides and use the existing valves? Guides aren't that expensive.
Yes, Guzzis do tend to eat valve guides. On older motors they seem to
last about 35K before they begin to ovalize. Once the damage starts, it
progresses rapidly. I doubt it would be an alignment issue as there is
nothing to change in the system. Could it be someone installed
aftermarket valves with stems a little too long? In such a case, the
rocker arms would impart a more significant amount of lateral force
vector in addition to the linear thrust vector. Even with correct
standard valves, the rocker arm ALWAYS adds lateral thrust to the valve
stem tip. It can only be reduced by use of roller tip rockers. It is
common for the guides go before the valve faces do. Newer Guzzis seem
to have better guide material and they last far longer. The damage to
the old valve guides might also be due to the loss of lead in fuel which
was a lubricant and cushion for most of the valve train bits.
Patrick Hayes
Fremont CA