spider compression

[AlfaNeely@xxxxxxx]

In a message dated 4/6/2003 10:58:46 PM Central Daylight Time, 
owner-alfa-digest@domain.elided writes:

> Date: Sun, 6 Apr 2003 13:14:38 EDT
> From: Wiskas42@domain.elided
> Subject: spider compression
> 
> Hello,
> Im going to check the compression on my 91 spider.The engine starts quick 
> and 
> runs good.What is the correct compression range for a car with 50,000 
> miles. 
> Im also going to pull the valve cover and try to quiet down the valve or 
> timing chain clatter. Any suggestions would be appreciated.
> Tony
> 

       I am a bit behind in my response.  Compression should be even across 
all cylinders with no more than about 10% variation from highest to lowest.  
Make sure you hold the throttle open when you do the compression test so the 
engine gets some air to compress.
       I would expect a minimum of 150 pounds per cylinder from your Motronic 
engine.  I would hope for more like 170 to 180 on all.  Any engine with any 
cylinder under 100 needs an overhaul.  Squirt some oil down the offending 
cylinder and if compression comes up significantly, the rings are bad.  If 
not, it is probably the valves.
       Do not forget that long duration camshafts will kill static 
compression.  Not a problem on your 91, if it is stock.  But many race 
engines with really high compression will not show it on a compression check 
due to the camshafts.

       Make sure all valves are close to 0.017 inches intake and 0.019 
exhaust.  If they are way off, adjust them.  If they range from 0.015 to 0.21 
or so, I would not worry.  When I adjust valves I get them all to within 1/2 
of 0.001 inches, which is the limit to accuracy with a manual feeler gauge 
anyway.  But most people are not so picky (anal retentive) and most mechanics 
cannot afford to take the time to get them that close.  The allowable range 
per the book is 0.016 to 0.018 intake and 0.018 to 0.020 inches exhaust.
       I measure everything in inches as that is what my feeler gauge and 
micrometer are graduated in.
       On the timing chain, I have seen them so loose that they left rub 
marks inside the head and valve cover.  Just loosen the bolt on the front of 
the block and roll the car forward in third or fourth gear and tighten the 
bolt as you roll.  That should be plenty tight.  If you can deflect the chain 
between the two camshafts more than just a smidgen (technical term), it is 
probably too loose.  You do not want it overly tight either or it can be hard 
on bushings.
       While you have the valve cover off, make sure to get rid of the half 
quart of dirty oil.  I do that about every other oil change.  And I look at 
the timing chain about every other oil change.
       When I buy a different Alfa, I always drop the bottom off the bat wing 
oil pan.  I occasionally drop the pan on Alfas I have owned a while.  With 
all the baffles in there, grunge (another technical term) tends to accumulate 
in the corners.  Probably does not hurt much as long as it is not suspended 
in the oil, but I like to know my engine is clean inside.

Ciao,
Russ Neely
Oklahoma City
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