[Public-List] atomic 4 compression test

Mike Lehman sail_505 at hotmail.com
Sat Dec 1 13:55:38 PST 2012

Your compression is excellent...no need for a valve job or rings. Experts 
tell me that Atomic 4 will run with 40 psi although it will lack some power. 
I am in the process of rebuilding an atomic 4 (in fact 3 of them) myself. 
The important part of compression is that is close to equal on all 
cylinders. If your engine is running rough the first thing to check is the 
ignition system because it is the easiest to troubleshoot...good points with 
proper gap, good plugs properly gapped, good wires and proper timing. If 
that is all right then it is fuel system (harder to troubleshoot). First 
take clean carb, then fuel pump, then check (and replace fuel lines) with 
fuels lines that are A1 rated, make sure that you have a fuel supply that 
new or has been stabilized to prevent ethanol separation and that there is 
no water in the fuel supply. Good fuel, good ignition, good compression and 
she will run like a dream.

~~~_/)_/)~~ Mike Lehman ~~_/)~~~
-----Original Message----- 
From: Sandi & Mark Bisset
Sent: Saturday, December 01, 2012 11:27 AM
To: public-list at lists.alberg30.org
Subject: [Public-List] atomic 4 compression test

We are currently rebuilding an old Atomic 4 and trying to determine a 
baseline for compression. We were testing the engine when it was cold, using 
a battery, and got results in the 100-110 range. Adding oil increased 
compression to 115-125ish. The plugs are fouling very quickly in regular 
useage (black soot, not oily) and the engine is running rough at times with 
significant vibration. It has been suggested that it needs a ring and/or 
valve job. But the compression seems to be in the specified range.
Any thoughts would be much appreciated.

Mark Bisset
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