Cummins/Onan — Cylinder Head Installation (4 and 6 Cylinder)
Repair & overhaul
From a Cummins/Onan operator's manual covering: G-1710, G-495, G-743, G-855, GTA-1710, GTA-743, GTA-855. Check it applies to your exact model before use.
Applies to: Cummins/Onan G-855
Before you start
- Do not use any type of gasket sealing compound.
Procedure
- Ensure cylinder heads have top breather holes plugged with 1/4 inch pipe plug.
- Wipe cylinder block and head mating surfaces clean.
- Install head gasket with stamped word 'TOP' on top over oil pipes.
- Place grommets in water passages.
- Lubricate capscrews with rust preventive; tighten each slightly in sequence then complete sequence.
- Insert push tubes into cam follower lever sockets after priming hydraulic lifters.
- Adjust crossheads as described in 'C' Check.
Tools required
- torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 5-1/2 inch bore head torque steps 225-275, 350-400, 460-480 ft-lb
Source: Cummins/Onan operator's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.