Re: PSI on compression test

["Heikki Rinta-Koski" <hrk951@domain.elided>]

My budget is what I'm trying to determine here. What mods are the biggest 
bang for buck on Alfa 1962cc TwinCam engine with Weber's and seemingly bad 
piston rings.
Yes I'm going to do all the assembly and simple machining (matching 
manifolds, matching rod weights if necessary) myself in my garage. 
Everything which needs special tools or equipment (balancing 
clutch/flywheel/crankshaft assembly) I'd have to have done somewhere else. 
Any recommendations of shops in Atlanta area?
I've done similar things in past and I'm in not in a greatest of hurry.

Heikki Rinta-Koski



> From: webb.p@domain.elided
> To: "Heikki Rinta-Koski" <hrk951@domain.elided>
> Subject: Re: PSI on compression test
> Date: Wed, 09 Oct 2002 14:11:41 +0000
>
> What is your budget for this project.   Doing everything
> you mentioned would be an improvement.   It all depends
> on how much you have to spend.   Are you doing the work
> yourself?
>
> -Peter
> > Tested this -76 Spider yesterday.
> > Plugs on three first ones were black and seemed to have had oil, fourth 
> was
> > clean.
> > Compression was 90-150-150-180 psi. Not too good...:(
> > When we added oil in the first one it bounced up to 150. Head should 
> have
> > been refreshened 4 years and ~2000 miles ago. Car has been standing or 
> with
> > a little use for about a year, could piston rings have ceased and when
> > started again cracked?
> > What kind of time and money for parts am I looking for if I check the 
> engine
> > (seals, lower end bearings, piston rings minimum or sleeves and pistons 
> in
> > worse case)
> >
> > Anything else I should do "while I'm there"? Balancing rods and pistons,
> > lightening and balancing flywheel, new hotter cams, porting head and
> > increasing compression ratio, matching existing Weber manifold to head,
> > exhaust headers? Suggestions and experience would be appreciated in 
> helping
> > to determine the scale of rebuild.
> > Car is going to be Sunday and sometimes daily driver and autocross car 
> if it
> > is suitable for it. So I'm not planning to maximise everything but I'd 
> like
> > to do it once and right and take advantage of worthwhile modifications 
> for
> > this engine. Streetable 150 hp could be a target.
> >
> > Does anybody autocross these cars? I don't have to go on big track with
> > Spider that's covered with my daily driver already.
> >
> > Thank you
> > Heikki Rinta-Koski
> >
> > >From: AlfaNeely@domain.elided
> > >To: alfa@domain.elided, hrk951@domain.elided
> > >Subject: PSI on compression test
> > >Date: Tue, 08 Oct 2002 16:07:34 -0400
> > >
> > >      The results of compression testing depend on a number of factors, 
> so
> > >absolute numbers cannot be given.  For example, long duration camshafts 
> can
> > >make a healthy engine show very low numbers on a compression gauge.
> > >      As a rule of thumb, I figure any cylinder with less than 100 
> pounds
> > >is sick.  If compression is above 140 pounds and within 10% from 
> highest to
> > >lowest cylinder, then that is pretty good and the engine is probably
> > >healthy.  Compression around 160 and even between cylinders would be 
> even
> > >better.
> > >      If any cylinder is low, squirt motor oil down the spark plug 
> hole.
> > >If the compression comes up, then the rings are bad.  If compression 
> does
> > >not change with oil, then the valves are bad.
> > >      Do make sure you hold the throttle open while performing the
> > >compression test.  I also like to have all four spark plugs out so that 
> the
> > >engine turns faster during the test.
> > >      Make sure to record the cylinder readings in a permanent record.
> > >Then you can track the engine's wear over time.
> > >Ciao,
> > >Russ Neely
> > >Oklahoma City
> > >
> > >
> > >
> > >
> > >In a message dated Tue, 08 Oct 2002 19:36:43 +0000,
> > >owner-alfa-digest@domain.elided writes:
> > >
> > > > Date: Tue, 08 Oct 2002 14:28:47 -0400
> > > > From: "Heikki Rinta-Koski" <hrk951@domain.elided>
> > > > Subject: PSI on compression test
> > > >
> > > > Hi everyone,
> > > >
> > > > I'm a newbie on this list looking for Alfa as a project car/daily
> > >driver.
> > > >
> > > > What kind of readings should I expect from compression check when I 
> go
> > >and
> > > > see possible candidate for future toy.
> > > > The car is Alfa Spider -76 with reconditioned head and only
> > > > 56000 miles.
> > > > With weber conversion if that matters.
> > > > I believe compression ratio should be 9:1, am I correct?.
> > > >
> > > > Heikki Rinta-Koski
> > > > Atlanta
> >
> >
> >
> >
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