Edub1's SOHC guide to replacing valve seals

Articles, modifications, maintenance, DIY's, how-to's and general information for 240sx owners.
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dickie
Posts: 18107
Joined: Tue Sep 06, 2005 7:55 am
Car: Killer Turtle

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by EDub1

Overview:

Difficulty *****

Time: 4-8 hours

Cost: ~$1.50 per seal

Tools:

- Air compressor - 120psi- Air hold tool – Murray’s- Universal spring compressor- Pointer style retrieval magnet (must have)

Procedure:

1) Position car on clean hard surface – IMPORTANT

2) Remove valve cover

3) Remove rocker arm assemblies leaving cam in place

4) Remove spark plug and screw in air hold tool

Removing the rocker assemblies will close all the valves so there is no need to rotate motor. Compress cylinder to 140PSI as per FSM. 120PSI worked fine for me.

5) Compress valve until you have enough room to extract the valve lock shims from the top; pushing down and wiggling helps. Use your magnet to extract the shims.

6) Pull of old seal with a Channel Lock.

7) Put on new ones. Intake seals can be seated with the help of a deep well socket and light tapping.

8) Replace spring and valve lock shims. You will drop the shims several times. If you are on a clean hard surface use your magnet to retrieve them. If you are not on a clean hard surface you will never find them in a million years. Release spring compressor.

9) Install rocker assembly. Tighten from center outward. Torque to 27 - 30 ft lb or 37 - 41 NM

10) Replace valve cover - you are done.

IMPORTANT: Resist the temptation to observe the rocker arms by starting motor with valve cover off. Massive amounts of oil will spray everywhere.

Pictured is a universal spring compressor from Harbor Freight. The brass piece in the lower right is the air compressor hose and air hold tool.


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