EXHAUST SYSTEMS
Models CJ-2A, CJ-3A, DJ-3A
On L-head engines, the exhaust and intake manifolds form one unit which is mounted on the left side of the engine. A valve is mounted in the exhaust section of this unit which, when open, directs the exhaust gases around the intake riser to assist in vaporizing the fuel when the engine is cold, thereby aiding in warming up the engine and reducing engine oil dilution. It also minimizes the use of the carburetor choke control.
When the engine is cold, the counterweight lever closes the valve and directs the hot exhaust gases against the intake riser to assist in vaporizing the fuel. As the engine warms up, the thermostatic spring expands and opens the valve sending the exhaust gas directly into the exhaust pipe. Note that the thermostatic spring is assembled to rest on top of stop No. 14 Fig. 135, on Models CJ-2A, CJ-3A, & DJ-3A.
The manifold heat control valve must operate freely without binding or excessive play. Each time the valve bushing are lubricated, proper operation of the valve should be checked.
When attempting to assemble the manifolds to the cylinder block, new gaskets should be installed, and the nuts drawn up evenly until they are tight to avoid leakage. Torque wrench reading, 29-35 ft. lbs. [4,01-4,84 kg-m].
Fig. 135-MANIFOLDS AND HEAT CONTROL VALVE-DJ-3A
1-Exhaust Manifold, 2-Gasket, 3-Intake Manifold, 5-Lever, 6-Nut, 7-Screw, 8-Washer, 9-Spring, 10-Shaft, 11-Bolt and Lockwasher, 12-Stud, 13-Plug, 14-Stop
Models CJ-3B, CJ-5, CJ-6
On F-head engines, the exhaust and intake manifolds are separate units. The intake manifold is cast as an integral part of the cylinder head and is completely water jacketed. This construction transfers heat from the cooling system to the intake riser and assists in vaporizing the fuel when the engine is cold.
With this construction, there is no heat control valve on the F-head engine and the only function of the exhaust manifold is to gather and direct the exhaust gases into the exhaust pipe.
When assembling the manifold, Fig. 136, to the cylinder block new gaskets should be installed and the nuts drawn up evenly until they are tight to avoid leakage. Torque wrench reading is 29-35 lb-ft. [4,01-4,84 kg-m.].
Fig. 136-EXHAUST MANIFOLD CJ-3B, CJ-5, CJ-6
1-Stud Nut, 2-End Gasket, 3-Stud, 4-Manifold, 5-Center Gasket, 6-Stud, 7-Gasket
Exhaust Pipe, Muffler, Tail Pipe
A typical exhaust system from the exhaust manifold to the tail pipe and including all attaching parts is shown in Fig. 137.
This system should be checked periodically and all loose or broken hangers and supports should be tightened or replaced. Also check for any dents or restrictions in the tail pie or muffler as these can cause faulty engine performance.
Fig. 137-EXHAUST PIPE AND MUFFLER
1-Exhaust Pipe, 2-Clamp, 3-Exhaust Pipe Extensions, 4-Clamp, 5-Tail Pipe, 6-Muffler, 7-Clamp, 8-Support Strap, 9-Bolt, 10-Support Strap, 11-Bracket, 12-Insulator, 13-Bracket, 14-Nut and Lockwasher, 15-Washer, 16-Bolt, 17-Gasket, 18-Bolt, 19-Nut
Exhaust Systems Specifications
Muffler Type, All Models…………………..Reverse Flow Metric
Exhaust Pipe Diameter X
Wall Thickness
F4-134 engines…………………………1 5/8″ x .050″ 4,12 cm. x 1,27 mm.
FL-134 engines…………………………1 5/8″ x .050″ 4,12 cm. x 1,27 mm.
Tail Pipe Diameter X
Wall Thickness
F4-134 engines…………………………1 1/2″ x .036″ 3,18 cm. x 0,914 mm.
L4-134 engines…………………………1 1/2″ x .036″ 3,18 cm. x 0,914 mm.
SERVICE MANUAL FOR UNIVERSAL ‘JEEP’ VEHICLES
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its #4 on diagram above cj2a
just installed new heat riser valve and weight fell off when I test drove it can I just buy weight thanks brian
When the engine is warmed up should the heat control flap be in full clockwise position?
will a freshly rebuilt f-head start and run with just a down pipe off of the manifold, or do i need to have a full exhaust for back pressure?
Did you get the two manifold photos reversed?