Perkins 4-108 poor oil to rocker shaft

[halima]

just rebuilt 4-108 new rings, bearings valves guides etc. Am getting 50psi on the oil guage but have very little oil getting up to the rocker shaft, am getting some oil through center shaft next to oil feed pipe but other rockers towards ends of engine are dry. This is after running engine at fast idle for a few minutes. Its out of the boat with water hooked up.

with rocker feed tube disconnected oil wells up with steady flow.

Have blown back though tube, cleaned shaft etc

Is this normal??

 

[penfold]

If the oilway in the rockershaft is clear of gunk then the rockers and/or the shaft may be worn out of spec and need replacement or refurbishing. The rockers don't need a pressure feed, are the ends getting no oil even when the engine is at operating temp(run on load for 10 minutes or so)? Fast idle for 10 mins won't warm the oil through, the whole engine needs to be warmed which will be difficult with it out of the boat. It's not ideal, but I would run at 80% throttle for 15 minutes or so. If you have a means of measuring the temp of the oil it needs to be getting up to 60 degrees C or higher.

Editted to add; bear in mind that even at high revs and with a warm engine the oil feed is only an automated equivalent of a bloke with an oilcan dribbling oil over the assembly, it doesn't need to (and indeed will not) resemble an oily Bellagio fountain.

 

[halima]

Thank you very much for the suggestions i will run tomorrow morning to the specs you suggest.

 

[jerrytug]

Just a tip,you can get your motor hot by using hot water,even boilin,it's better for it. Cheers Jerry.

 

[penfold]

Need a bloody big kettle to warm through a 4108!

 

[davidej]

If the rockers near the feed are well worn, then most of the oil flow will escape there leaving little to get to the further ones.

 

[penfold]

Another thing occurs to me; is the shaft the right way up? The oil feed holes for the rockers should face up the way.

 

[ianj99]

just rebuilt 4-108 new rings, bearings valves guides etc. Am getting 50psi on the oil guage but have very little oil getting up to the rocker shaft, am getting some oil through center shaft next to oil feed pipe but other rockers towards ends of engine are dry. This is after running engine at fast idle for a few minutes. Its out of the boat with water hooked up.

with rocker feed tube disconnected oil wells up with steady flow.

Have blown back though tube, cleaned shaft etc

Is this normal??

I had the same experience and I found the oil holes in the rocker shaft were blocked.

Ian