Starting rebuilt engine for the first time

[skyjeep50]

The rebuilt engine is back in my M38 and I've gone through everything I can think of before starting for the first time. The engine was rebuilt a long time ago by a PO so I took the oil pan off and everything looked right and tight, the valve clearance was right on. Any tips or things to watch for other than fire or smoke! Break-in suggestions?

[wesk]

I would suggest you start with TM 9-1804A Par 106 Pages 98, 99 & 100 and TM 9-8012 Par's 7, 8 & 9Pages 18 thru 20.Then Sect III Par's 42, 43 & 44 on pages 28, 29 & 30. After a thorough review of that data then bring any remaining questions here to the board.

[TomM]

Also would suggest pre-lubing the engine and installing a known-good mechanical oil pressure gauge.

Tom

[skyjeep50]

I re-read all the TM info, good stuff. Two more questions: 1. What kind of oil for the break-in period, TM calls for 0E-10 and I'm not sure what the modern equal would be. 2. What is the best port to pre-lube the motor through - how about the line from the Cuno oil filter to the block? It would be easy to rig up some kind of pressure pot at that location.

I do have a direct reading oil pressure gauge in the dash so I can monitor oil pressure.

Thanks!

[wesk]

Any quality straight mineral oil of a weight that conforms to your area's current average temps. Most car engines are broke in over about 500 miles but unless your jeep is a daily driver you may have to extend that a bit. Generally as a rule of thumb when you see a sudden decrease in oil consumption the rings are seated.

Pressurizing the left side main oil gallery is about your only choice. You can do it at any of the fittings in the left side gallery. Keep in mind the greater the resistance (tighter the clearance) is in one area will cause the oil to divert to the path of least resistance. To insure you have gotten your pre-oil completely through all spaces you will have to run the external pressure source for about 5 minutes or more. Your pressure gage will only tell you you have pressure at the back end of the left main oil gallery. Your pan may over fill so be prepared to extract oil from the pan during the pre-oil.

[BullRun]

I think it is this months issue of Popular Mechanics has an article on breaking in a new car for maximum longevity. One of the tips I have never heard before was changing the oil and filter after only 20 miles of use instead of later. The premise being that oil is cheap and if anything breaks loose like sealant, a lost washer or nut, and or lots of micro metal dust from the machining process, it will get flushed out before it can do any harm.

[wesk]

That oil change is usually performed at the overhaul shop right after the initial run-in on the stand. But it's a good point to bring up for those that assemble their own engines and don't have the equipment of a test run facility.

As an example about three years ago I ordered in a $24K factory reman aircraft engine from TCM. After hanging the engine and before servicing the oil I drained any remaining first run oil or shipping preservative oil and while draining out drops a 1/4"x28 nut. It cost another 6 hours labor for me and round trip shipping to Mobile AL for the factory tear down and inspection and re-assembly for Continental. Fortunately for my customer it was only a 2 week delay in finishing the engine change.