Universal Atomic Four Engine - Parts

Tune-up Parts and Common Spares

Many parts can often be purchased at an auto parts store if you know the right numbers to ask. Sometimes the store will know what parts fit the Atomic 4, but most know nothing about marine engines. The Annapolis NAPA Auto parts store is one of the exceptional ones; you can give them a call at (410) 263-2695. Cobe Marine (1-800-414-COBE) in Pasadena, MD tells me they've got a tune-up kit with points, condensor, cap and rotor (Sierra Products #18-5268) as well as other Atomic 4 parts.

I've compiled a list of part numbers over the years, some of which I've personally used and some of which I've gleaned from others. I'm no expert and I don't guarantee anything. It's best to take the old parts with you to compare. Remember that a lot could have changed since the boat was delivered. And please, let me know about any errors or additions.
Spark plugs:gap: 0.035 Hotter plugs
Champion J8C or RJ8C RJ12C
(now called Champion 14)
AC #R45 or #M45
Autolight 295 Autolight 308
Note: A reader reports "The NGK BR6S plugs fouled nearly immediately. When I put the old Champion RJ8C's back in the engine loved it. It was called to my attention that some plugs are shorter than the Champions and evidently that lack of reach into the cylinder hampers combustion. Just reporting my experience."
Belden 700708 (kit, put on your own ends)
Belden 700999 (custom wire set at Annapolis NAPA store)
Carol 32570 (82 Datsun)
Cooper Automotive "PowerPath" #700705 (longest wire is a slight stretch).
Pep Boys Auto Parts #1924 (for all 1974 Volvo 4 cyl. engines)

There are two distributors used. The older engines (serial numbers 71000 through 170507) had a Prestolite distributor which, I'm told, is the same as that used in a circa 1944 Willys Jeep. Newer engines (serial numbers 170508 and up) came with a Delco distributor. Verify which distributor is actually installed in your boat; don't just depend on the serial number of the engine.

For the Delco distributor, you'll do well at the local auto parts shop by telling them you've got a 1974 Chevy Vega (thanks to Gavin Peters for that suggestion). That gives a different condensor part number than I've got listed, but I guess that's OK.
Distributor cap: Delco Distributor Prestolite Distributor
Standard Motor Products DR-437 Standard Motor Products AL-25
Borg Warner C167 Echlin AL91
Delco D322R
GM 1962446
Echlin RR181
Standard Motor Products DR-314 Standard Motor Products AL-102
Delco 423R Echlin AL-58 or AL-32
GM 800056
GP DR106 (maybe)
Borg Warner D152P
Echlin RR182R
Standard (Blue Streak) DR-90X Standard (Blue Streak) AL-106
Borg Warner G126 Echlin AL-38 or AL-116
Delco D203
GM 1928111
Echlin RR176
Points: timing: just starting to open at TDC
gap: 0.025 0.018 - 0.020
dwell: 31 to 34 degrees38 degrees
Standard (Blue Streak) DR-2240XStandard (Blue Streak) AL5661X
Delco D108P Echlin CS-709
GM 1954557
Borg Warner A109V
GP DR695
Echlin CS788P
A number of water pumps have been used over the years. For raw-water-cooled engines, the most recent (and the replacement for previous models) is the Oberdorfer M202-3. The Oberdorfer M202-7 has a taller "shoe" for higher output. This shoe is interchangeable between the models.
Water pump impellerOberdorfer
(M202-3 or M202-7)
Oberdorfer #B6593Sherwood #09979
Globe (Barco) #815Globe #421
Sherwood #295628Jabsco #45280001

Other recommended spares:

The alternator belt is 3/8" wide and 25" around (approx. 12" long when flattened). The size may be marked 1 cm x 63.5 cm.
Alternator belt
Drive King 3L250 "Fractional Horsepower V-belt"
Gates HC-3VX-250 or #7250
NAPA Belts 25-06353
BFG Maxipower 3V250 57 ORS-M
Goodyear or Kelly/Springfield 10AV0635

General Specifications

Model Designation UJ, UJR
Engine Type Four Cylinder, Vertical, 4 Cycle, L-Head
Bore and Stroke 2 9/16" x 3 1/8"
Total Piston Displacement 64.46
Compression Ratio 6.3:1
Engine Rotation Counter-Clockwise (From Flywheel end)
Firing Order No. 1 on Flywheel End 1-2-4-3
Reduction Gear Ratio 2.04:1
Maximum Operating Angle Approximately 15 degrees
Fuel Regular Grade Gasoline
Lubrication Oil SAE 30

@ RPM 600 1000 1500 2000 2500 3000 3500
Brake Horsepower: 5 7.3 11.9 16.2 20 25 30

Suggested Oil LevelsAngle of Install'nAmount FullAmount Low
(Quarts) 0 degrees 5.75 5
5 degrees 4.75 4
10 degrees 3.5 2.75
14 degrees 2.75 2.25

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