[DML] Re: Motor Tick (was Looking for a DMC (Ryan))

["content22207" <brobertson@xxxxxxxxxxxx>]

Bad connecting rod journals or pins don't really "tick" or "click" --
they "bang" and "knock".

Little noises are usually rocker arms tapping against valve stems. On
some engines, like the PRV, excessive lash can be adjusted out.

Note that valve tap can also be caused by the PRV's indirect
lubrication system. Oil does not wash over the rocker arm/valve stem
interfaces, but rather is slung against them by rotating camshaft
lobes. Viscosity problems, low oil pressure (caused by leakage after
the sending unit, such as timing chain tensioners), and gummed up
orifices will exacerbate the problem.

While we're on the subject: there's an urban legend about "soft" B27
camshafts, corrected in the B28. This is nonsense -- both are made of
the same hardened materials (were actually three different lobe
combinations). Volvo *NEVER* mentioned changes in camshaft
composition. What they *DID* mention in a 1984 Service Bulletin was to
discontinue use of grade SE oil in lieu of SF, and to substitute 10W30
oil for the 10W40 recommended in earlier owner's manuals. Basically
it's an attempt to overcome oiling weaknesses endemic to all PRV's
with increased detergents and lower viscosity. Some Volvo owners also
feel the oil return passages are too small (same size between B27 and
B28 BTW) and drill them larger.

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, Mike Substelny <msubstel@xxxx> wrote:
> When I first heard a motor tick from my DeLorean I thought it was a rod 
> problem, too.  It turned out to be just a leaky exhaust manifold 
> gasket.  Replacing them is not easy, but the job is much cheaper than 
> the engine rebuild I thought I needed.
> 
> The exhaust manifold gasket is a pretty common failure point in 
> DeLoreans, and to this day I am amazed at the awful sound made by any 
> DeLorean afflicted with this problem.  It really does sound like moving 
> engine parts smashing into each other in ways never intended by PRV.  
> You'd think the engine was tearing itself apart.
> 
> I might be wrong, but if I am right this DeLorean can be purring like a 
> kitten for $30 in parts and one day of hard work.
> 
> - Mike Substelny
> VIN 1280, 10 wonderful years
> 
> Wizard wrote:
> 
> >Ryan:
> >
> >I missed your previous e-mails.  I may be selling my 81 Delorean if
I an
> >successful at purchasing another one next week.  The reason I am
selling
> >it is because someone painted it red.  If runs o.k., has a loud tick,
> >probably the rods.  It has had quite a bit of work done to it and I was
> >going to used another one I have that is smashed as a donor car. 
Plus I
> >have an extra engine and block that I will sell with the red one.
> >Besides being red and the motor tick, the trans seems fine, new brakes,
> >etc.  Let me know if you are interested and I will keep you on my list.
> >Like I said, if I do not get this other car, which does not run and
> >needs an entire engine, then I will probably not sell.
> >
> >Jason
> >  
> >




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