Adjusting A-4 Oil Pressure Nut
Hi Jim, Your oil pressure sounds just fine for a 20 year old A-4. Remember, it is going to have some wear from its years of service, and I believe it is the crankshaft bearings that wear first and allow the pressure to drop over time. If you crank it up too much, you run the risk of forcing oil around a seal - not a good thing. I tried to adjust mine about a month ago - could not do it. The screw would not budge. As it turns out, there is a locking nut below it, so you will need to loosen that first. Then, if you really want that 40-45 psi, I would try running the engine to see if there is any change in oil pressure. If not, I would try adjusting it with the engine off. I recommend this only because I have a 1979 C-27 also, and I know how tight the engine cave is. Ugh... Anyway, the pressure should be around 40-45 at cold start, then drop to around 20 under normal operating temperatures. I got these figures from the owners manual and other A-4 owners. I get about a constant 19 psi right now, and the engine has run very well at this pressure for the last 3 years. I still plan to adjust it, but I don't plan to bring the pressure beyond 30 psi. I figure the engine is over 20 years old now, so I am not going to push her too hard. Since there is no oil filter on the engine, the only thing the pump needs to do is recirculate oil, rather than force it through a filter. Let me know how you make out - I am interested in the results. Rob P.S. - If you haven't given the engine a full tune up in the last year, I would recommend it enthusiastically. I let mine go for a season, and my engine failed (at the dock, luckily) due to a worn rotor. A whopping $2.59 part...
