Through the miracles of modern technology, this post was truncated prematurely. Should have read: > For some reason this rumor is endemic in the DeLorean community and > simply refuses to die (quite ironic when you consider DeLo usage > accounts for only .8% of total PRV production). There is no difference > in camshaft composition between various B27/B28 applications, nor to > my knowledge between various Peugeot, Renault, and Volvo aps. The only > TSB Volvo ever printed on the subject was to substitute 10W30 oil over > the previous 10W40 spec (retroactive to the beginning of PRV usage). > Thicker oil has a tendency to gum up camshaft/rocker arm orifices. > Note that the rocker arm orifices are located at the camshaft lobes, > not the valve stems -- probably the source of characteristic valve noise. > > Volvo's words Re: camshaft wear (circa 1985 -- after the TSB, > footnoted as a supplement to my particular manual): > "Damaged (worn) rocker arms and/or camshafts may be due to one or more > of the following causes: > - Incorrect quality or grade of oil. It is important that the correct > oil is used and that it is changed sufficiently often with regard to > driving conditions. > - Contaminated oil. May be caused by camshaft grindings, coolant, > fuel, etc. > - Insufficient oil supply to rocker arms." > > That last point is especially important if timing chain tensioners are > fully extended -- oil will simply flow past them back into the pan, > never reaching the camshafts. > > Consider this: If later production camshafts were so superior, why is > premature wear still a concern in 1985? > > Bill Robertson > #5939 > To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/