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Ford LRG-423 Engine

The Ford LRG-423 is a 2.3 L 4-cylinder engine rated at 2800 rpm. It powers generator sets from Cummins/Onan, including the 20 ES.

Also known as: Ford Motor Company LRG-423

2.3 L

Displacement

Cylinders

2800 rpm

Rated speed

On this pageService parts Specs Generator sets Maintenance Filter cross-reference FAQ Service intervals Torque & specs Fluids Procedures

Service parts for the LRG-423

The cheapest captured merchant offer per filter — see the full cross-reference below for every OEM/aftermarket option.

Oil system

1 required

9576P550008Oil filter$18.95eBay

Prices captured from merchant listings; some links are affiliate links. Verify against your serial number before ordering.

Engine specifications

Displacement	2.3 L
Cylinders	4
Rated speed	2800 rpm

Generator sets powered by this engine

Cummins/Onan 20 ES

Common problems

The engine does not start SC1635c
Fix: Check the following while the genset is operating: START / STOP / REMOTE SWITCH INDICATOR LAMPS, CIRCUIT BREAKERS
Engine does not start
Fix: Check the following while the genset is operating: START / STOP / REMOTE SWITCH INDICATOR LAMPS, CIRCUIT BREAKERS

Compiled from service & troubleshooting documentation across every generator set that uses the Ford LRG-423.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Fuel filter			—
Oil filter			9576P550008		Amazon eBay $18.95
Belt	Pointer Triangle (on Inner Timing Belt Cover)		6K282		Amazon eBay
Coolant filter			—
Oil	XO-5W30-QSP (Super Premium Motor Oil), Ford specification ESE-M2C153-E	4.0 quarts U.S.	—
Spark plug	AWSF52C; gap 1.07-1.17mm (0.042-0.046 in.)		12405	400 hr	eBay $47.99 KuduParts $37.00

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Spark plugs	Clean	400 hr		Each 400 hours of engine operation remove spark plugs and clean and adjust the electrode. Clean and visually check spark plug high tension leads for secure fit and replace if necessary.
Timing belt	Replace	3000 hr	60 mo	If the timing belt has greater than 3,000 hours or five years of use, replace it.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Camshaft end play	0.001-0.007	in.	Service limit 0.009
Clearance	Camshaft journal-to-bearing clearance	0.001-0.003	in.	Service limit 0.006
Clearance	Camshaft runout (maximum allowable)	0.03	mm (0.0012 in.)
Clearance	Collapsed tappet gap	0.035-0.055 (allowable); 0.040-0.050 (desired)	in. @ cam
Clearance	Connecting rod bearing clearance	0.0008-0.0015 (desired); 0.0008-0.0026 (allowable)	in.
Clearance	Connecting rod side clearance	0.0035-0.0115	in.	Service limit 0.014
Clearance	Crankshaft end play	0.07-0.20	mm (0.003-0.008 inch)
Clearance	Crankshaft runout (maximum)	0.05	mm (0.002 in.)
Clearance	Cylinder bore out-of-round (maximum allowable)	0.127	mm (0.005 in.)
Clearance	Cylinder bore taper (maximum allowable)	0.127	mm (0.005 in.)
Clearance	Cylinder head/block deck flatness - maximum variation	0.076 over 152; 0.152 overall	mm (0.003 in. over 6 in.; 0.006 in. overall)
Clearance	Main bearing clearance (bearings 2-5)	0.020-0.066	mm (0.0008-0.0026 inch)
Clearance	Main bearing clearance (front main)	0.010-0.056	mm (0.0004-0.0022 inch)
Clearance	Piston-to-bore clearance (select fit)	0.0254-0.0508 (new); 0.0254-0.0762 (service limit)	mm
Clearance	Valve stem-to-valve guide clearance (exhaust)	0.0015-0.0032	in.	Service clearance limit 0.0055 max.
Clearance	Valve stem-to-valve guide clearance (intake)	0.0010-0.0027	in.	Service clearance limit 0.0055 max.
Gap	Spark plug gap	1.07-1.17	mm (0.042-0.046 in.)
Other	Camshaft lobe lift (intake/exhaust)	0.2163	in.
Other	Fuel pump maximum current draw	1.5	Amp.
Other	Fuel pump minimum flow	1.3 qt./minute, 2.6 pint/minute		@ 4 PSI, 12V input
Other	Hydraulic leak-down rate	2-8	seconds	plunger to leak down 3.18mm (1/8 in.) of travel with 22.65 kg (50 lb.) load
Other	Theoretical valve lift zero lash (intake/exhaust)	0.402	in.
Other	Valve spring installed height	38.61-40.38	mm (1.52-1.59 inch)
Pressure	Engine oil pressure	250-490	kPa (36-71 psi)	at 3,000 rpm
Pressure	Fuel pressure maintained at full load	minimum 4	PSI
Pressure	Fuel pump shutoff pressure	6-7.5	PSI
Pressure	Oil pressure (hot)	40-60	psi	at 2000 rpm
Speed	Base ignition timing	9	degrees BTDC	at 750 rpm, not adjustable
Speed	Low idle speed	700-800	rpm
Speed	Maximum engine operating speed - no load (high idle)	3050	rpm
Speed	Rated engine speed	2800	rpm
Torque	Camshaft sprocket bolt	71-95	N·m (52-70 lb-ft)
Torque	Connecting rod nut	34-41 (initial); 41-49 (final)	N·m (25-30 lb-ft initial; 30-36 lb-ft final)
Torque	Crankshaft position sensor bolt	8-12	N·m (72-108 lb-in)
Torque	Crankshaft pulley bolt	125-165	N·m (92-121 lb-ft)
Torque	Cylinder head bolts	70	N·m (52 lb-ft)	Tighten in sequence to 70 N·m, retighten in sequence to 70 N·m, then turn all bolts an additional 90-100 degrees in sequence
Torque	Engine front cover bolts	13-16	N·m
Torque	Exhaust manifold bolts	20-30 (step 1); 60-80 (step 2)	N·m (15-22 lb-ft; 44-59 lb-ft)	Two stages
Torque	Generator mounting bracket bolts	40-55	N·m (29-40 lb-ft)	Sequence required
Torque	Intake manifold bolts	26-38	N·m (19-28 lb-ft)	In sequence
Torque	Main bearing cap bolts	68-81 (initial); 102-115 (final)	N·m (50-60 lb-ft initial; 75-85 lb-ft final)
Torque	Oil filter insert to cylinder block	28-35	N·m
Torque	Oil pan bolts	14-16	N·m (124-144 lb-in)
Torque	Oil pressure sender	11-24	N·m (8-18 lb-ft)
Torque	Oil pump screws	10-14	N·m (89-124 lb-in)
Torque	Oil pump shaft sprocket bolt	40-55	N·m (29-40 lb-ft)
Torque	Spark plugs	9-20	N·m (7-15 lb-ft)
Torque	Starter mounting bolt	21-27	N·m (15-20 lb-ft)
Torque	Timing belt tensioner adjusting bolt	35-45	N·m (26-33 lb-ft)
Torque	Timing belt tensioner spring pivot bolt	40-55	N·m (29-40 lb-ft)
Torque	Valve cover retaining bolts	9-13	N·m (80-115 lb-in)
Torque	Water pump to block bolts	20-30	N·m (15-22 lb-ft)

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Capacity	Notes
Engine oil	1OW-30 or 1OW-40 engine oil			For mechanical governor oil level; fill until it drips out of the oil level hole.
Engine oil	XO-5W30-QSP (Super Premium Motor Oil)	Ford specification ESE-M2C153-E	4.0 quarts U.S.	Add one quart with filter change.
Grease	Ford Multi-Purpose Grease DOAZ-19584-AA	Ford specification ESR-M1C159-A		For lubricating cam follower/roller finger follower contact points and valve spring retainer keys.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Float Adjustment (Holley Model 1940) adjustment

⚠ When bending the tang, do not force the Viton-tipped fuel inlet needle against the seat or the Viton tip on the needle will be damaged.

Tools: Straightedge

Remove carburetor assembly from the intake manifold and drain the fuel from the fuel bowl.
Invert the fuel bowl cover and place a straightedge across the surface of the fuel bowl.
The toes of the floats should just lightly touch the straightedge; adjust by bending the float tang.
Both floats must be parallel and not cocked or offset; bend the float shafts to even out the floats and recheck.

Idle Mixture Adjustment (Holley Model 1940) adjustment

Run engine 5-10 minutes at a fast idle speed or until normal operating temperature is reached.
With engine off, turn idle mixture adjustment screw in until lightly seated, then back out two turns.
Start engine. Turn screw in until engine begins to run rough or stumble due to a lean mixture.
Slowly turn needle out until engine begins to roll due to a rich mixture.
Slowly turn needle in to a point between the two extremes until engine runs smoothly (favor a slightly rich setting).

Idle Speed Adjustment (Holley Model 1940) adjustment

Tools: Tachometer

Run engine 5-10 minutes at fast idle or until normal operating temperature is reached.
Connect a tachometer to the engine.
Turn the idle speed screw until engine speed is at specifications (in to increase, out to decrease).
After each adjustment, pull back on the throttle lever and release; engine speed should increase then return to normal.

Timing Belt Adjustment adjustment

⚠ Do not rotate crankshaft counterclockwise as the timing belt may jump a cog, putting camshaft out of time.

Tools: Camshaft Belt Tension Adjusting Tool T74P-6254-A

Loosen timing belt spring pivot bolt.
Hold tensioner with Camshaft Belt Tension Adjusting Tool T74P-6254-A.
While holding tensioner, loosen adjusting bolt and gradually release spring tension.
Using adjusting tool, pry tensioner away from belt and while holding, tighten adjusting bolt.
Install timing belt over crankshaft sprocket, then proceeding counterclockwise over oil pump and camshaft sprockets.
Loosen tensioner adjusting bolt allowing tensioner pulley to press against belt.
Rotate crankshaft two revolutions clockwise and bring slowly to number one cylinder firing position.
Recheck timing mark alignment; repeat if not aligned.
Rotate tensioner assembly against belt with torque wrench up to 40-45 N·m (29-33 lb-ft) and tighten adjusting bolt.
Tighten adjusting bolt to 35-45 N·m (26-33 lb-ft).
Tighten spring pivot bolt to 40-55 N·m (29-40 lb-ft).

Compression Test diagnostic

Tools: Compression gauge (Rotunda Compression Tester 059-R0009), Auxiliary starter switch

Make sure oil in crankcase is of the correct viscosity and at proper level, and battery is properly charged.
Operate the engine until it is at normal operating temperature; turn off ignition, then remove all spark plugs.
Set throttle plates in wide-open position.
Install a compression gauge in No. 1 cylinder.
Install auxiliary starter switch; crank engine at least five compression strokes and record highest reading.
Repeat test on each cylinder, cranking approximately the same number of compression strokes.

Oil Pressure Test diagnostic

Tools: Engine Oil Pressure Gauge T73L-6600-A, Transmission Test Adapter D87C-77000-A

Disconnect and remove the oil pressure sensor from the engine.
Connect an Engine Oil Pressure Gauge T73L-6600-A and Transmission Test Adapter D87C-77000-A to the oil pressure sensor screw port.
Run the engine until normal operating temperature is reached.
Run the engine at 3,000 rpm and record the gauge reading.

Spark Plug Removal and Installation maintenance

Tools: Spark Plug Wire Remover T74P-6666-A, Spark plug gap tool

Remove ignition wires as outlined.
Loosen spark plugs and remove any dirt or foreign material from spark plug areas of cylinder head with compressed air.
Remove spark plugs and mark location using a piece of masking tape.
To install, reverse removal procedure. Check and adjust spark plugs. Tighten spark plugs to 9-20 N·m (7-15 lb-ft).

Valve Cover and Gasket Removal maintenance

Remove ignition cables out of ignition coil and place to the side.
Remove bolts and valve cover (6582).
Remove valve cover gasket (6584) from valve cover.
If necessary, remove oil filler cap (6766).

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Aftermarket parts that fit this engine

7012679 FridayParts $135.99 400RTS FridayParts $7.88 40H+6 FridayParts $12.45 SinoCMP $229.00 500RTS FridayParts $7.88 601S FridayParts $8.00 SinoCMP $139.00 80HX FridayParts $7.88 SinoCMP $229.00 86HX FridayParts $14.01 SinoCMP $229.00 54222GT KuduParts $215.00 FridayParts $225.14 54222 KuduParts $215.00 FridayParts $225.14 Z-45/22 FridayParts $11.00 27915GT FridayParts $45.00 33963GT FridayParts $86.62 7022153 FridayParts $86.62 0E96180232 eBay $63.52 FridayParts $86.62 P167182 KuduParts $34.00 FridayParts $35.89 P165015 KuduParts $34.00 P167183 KuduParts $34.00 P165138 KuduParts $34.00 FridayParts $35.89 P165043 KuduParts $34.00 FridayParts $35.89 20880GT KuduParts $34.00 HP0653A06AN KuduParts $34.00 811001 KuduParts $34.00 HF165043 KuduParts $34.00 V3042B2C03 KuduParts $34.00 SF902083UM KuduParts $34.00 JHP165043 KuduParts $34.00 FK020GGB KuduParts $34.00 CHP283F03XN KuduParts $34.00 BN15776 KuduParts $34.00 PL0702A006ANP01 KuduParts $34.00 07160314 KuduParts $34.00 CH153FT11 KuduParts $34.00 20880 KuduParts $34.00 91902 KuduParts $34.00

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Filters for this engine

Oil filter: Ford 9576P550008 Donaldson P550008 Wix 51775 Ac Delco X29 Baldwin RS3934

Cross-referenced via Donaldson + OEM/engine-maker interchange — options to verify against your serial number, not confirmed for every exact variant.

Also used in

Genie S-60 — Boom Lift
Genie S-65 — Boom Lift
Jlg 600A — Boom Lift
Jlg 600SJ — Boom Lift

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.

Common questions

What is the displacement of the Ford LRG-423?

The Ford LRG-423 has a displacement of 2.3 liters with 4 cylinders.

Which generators use the Ford LRG-423 engine?

The Ford LRG-423 powers 1 generator set(s), including Cummins/Onan 20 ES.

What oil filter does the Ford LRG-423 use?

The Ford LRG-423 uses oil filter part numbers Ford 9576P550008, Donaldson P550008, Wix 51775.

What is a common problem with the Ford LRG-423 engine?

A commonly reported issue on generators using the Ford LRG-423 is: The engine does not start. Fix: Check the following while the genset is operating: START / STOP / REMOTE SWITCH INDICATOR LAMPS, CIRCUIT BREAKERS.