Bill - We have Gibsons on our 85 hp Champ. It takes those chrome cylinders forever to completely break in, maybe 200+ hours.
We had similar problems until ours broke in. As I remember, most Ercoupes should run oil temps of 100 + whatever the ambient temp. is. Jerry E. -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] Behalf Of bcflyer2003 Sent: Friday, May 09, 2008 3:15 PM To: [email protected] Subject: [ercoupe-tech] High Oil Temp I know this topic has a number of threads in the data base. I have read most and still have questions. The 46 Ercoupe I bought in December was topped in August 2007. The cylinders are Gibson's at .015" over. New pistons and rings..also .015" over were used in the top OH.The major was done in 1981 so the bottom has years on it, but only 154 hrs. Total time on the engine is 2766 hrs.. The oil pressure runs 35 psi except when at idle and warm when it is 10+ psi. The top was done because of high oil consumption at 2 hrs. per quart. The engine TOH now has 50 hrs on it. Before the TOH, oil temp never ran hotter than 180 even on the hotest day according to the previous owner. At this point, the oil temp runs 205 to 210 on a 75 to 80 deg. day. Oil use is 4.5 hrs per quart. There are some oil leaks, but none that I would consider extreme. The temp gage has been checked and reads high so I see 215 when I report it is 205 accounting for a 10 degree bias in the gage. Basically, the oil temp is 35-40 degrees hotter than before the Top OH. I have tighted up on air leaks on the baffles, closed the gap on the air intake to carb. and plenum to the bottom of cowl. Intalled an oil filter with cool air duct from the plenum blowing on the oil filter assembly for cooling. Checked the mixture control to be certain the engine is running rich of peak. These changes and others I'll not mention, have had absolutly no effect on the oil temp. The only way the oil temp stays below 200 is at idle. I don't have enought thermals to do this for long. I borrowed a cylinder head temp gage and hooked it to the #1 cylinder which I believe to be the hottest, and the cylinder temp never goes above 350. I will be moving the sensor to the other cylinders to find the hottest for certain. >From all of this and discussions with others, I conclude the only possible cause of the high oil temp can be that 1 or more cylinders are blowing by. All compressions are 75+ so can't decide if it's one or all. I have decided to continue to fly the plane every day and continue to observe temps. I have no illusions this will heal itself, but do not believe any damage will result or undue risk is involved in using the plane for cross country flight. If any of you have suggestions, advice, or questions, please advise. Bill Chalker N94191
