mobil 1 results on two cars I owned

I have used mobil 1 since it was introduced. I had first used amsoil and then couldn't get it. The thing that impressed me most was the fact that my car started up in the cold (20 degree f) and didnt knock and bang parts together waiting for oil pressure. The two cars I have used it in that have impressed me was my 1983 plymouth reliant and my 65 belvedere with a balanced blueprinted 340 I built. The plymouth reliant was bought new and broken in on havoline 10w-40 and hastings depth filters equivalent to the fla-a. At 5000 miles I changed over to mobil 1 and kept using the hastings filters. After that I changed oil every 10,000 miles and the filter every 5,000 miles and added a quart with filter change. The car used 1 qt of oil every 2500 miles until I got rid of it. At 70,000 miles the engine burned a valve. I decided that while I had the head off I would go ahead and rebuild it. When I took the head off, it was as if the inside of the engine had been cleaned with a wire brush it was so clean. The main bearings did not look like they had ever been in an engine. The bores were measured using a mechanic's bore checker and they all measured the stock diameter bottom and top. No ring ridge was apparent and I was able to push the pistons out with my hand. In fact the factory cross hatch was still easily seen. I put stock size rings back in, left the factory rod and main bearings in and put it back together. the car had 170,000 miles on it when I sold it and it was still running three years later. The other car, I built to be a sleeper. I built the 340 using trw forged pistons with medium tension oil rings. Had the crank ground, new cam bearings and heads were ported by a professional. Broke it in on havoline 10w-40 using hasting depth filters. At 3000 miles I started it on mobil 1. I continued to change oil and filter at 3000 mile intervals. After the car was broken in i raced it every week at the local drag strip for three years. Every week I had at least 6 runs at 6000 rpm on the engine in addition to all the other abuse I heaped upon it regularly. The car rusted out, so i took the engine out to put it in another car. At this time there was about 18,000 miles on the engine. I pulled the heads and oil pan to check it. As with the 4 cylinder, the bearings looked like they were out of the factory box. The cross hatch was still there with no ring ridge. The inside of the motor was extremely clean. This was after 100s of full throttle passes down the quarter. I buttoned it up and am still having fun with it now. I worked as an ase certifed mechanic for about 5 years and tore many engines down with few miles and lots of miles. Dino oil, even if changed frequently showed wear and sludge when I tore an engine down. to me, synthetic oil is good stuff, the above is just my experience. I really wish hastings still sold their depth filters. Dan [ May 20, 2003, 04:00 PM: Message edited by: Dan4510 ]


Staff member
Iowegia - USA
Dan, I had to do something similar to my '86 Burb 350. I had used Amsoil 10W40 and 10W30 since the engine had run-in, at 3,000 miles. The engine started smoking at 124,500 miles on deceleration. I found out that GM had installed the wrong type valve stem seals and of the wrong material type in the heads. Engine was past 30,000 mile warranty, so GM said "Sia Nara." I pulled the heads and took them to my favorite machine shop, where the seats and valve faces were reground and new seals of the correct type and material were installed. In the meantime, I decided to install a Competition's Cam 260H "High-Lift, Long Duration (Overlap)" cam for towing. I pulled the cam and measured the came bearings in the block and the old cam lobes. NO detectable wear from micrometer readings. While I was waiting for the heads to come back from the shop, I decided to drop the oil pan and measure the main, connecting rod bearings, and journals for wear. Again, no detectable wear with respect to the shop manual's specifications. The sump pan was clean and almost spotless. A small amount of reddish lacquer could be seen on the rocker arms and the conn rods, but that was it. Engine was clean throughout. I then installed a Holley Spreadbore 4-barel, dual exhaust, RELOCATED the EGR and CATS, and put on Coyote headers to up power even more. Ignition was HEI stock, since I could never find another ignition or curving to best the stock system. I then installed an Auburn LSD with a 3.42 gear for the added traction of the 2-Wheel drive. I also about the same time installed a remote bypas filter. I always changed the oil between 7K miles and 10 k miles before and after the modifications. I sold the ole boy recently at 283,756 miles and it was still going strong. Now if I had used an oil like Schaeffer's or a good dino oil and changed it every 3k, it might have had the same cleanliness and service. But slightly lower water coolant temps and slightly greater gas mileage (before and after the mods) convinced me that full synthetics may have had a slight advantage in this application. [ May 20, 2003, 04:30 PM: Message edited by: MolaKule ]
Originally posted by Greaser: I dropped the factory oil on both my Jeep's 4.0's at 2000k and went to Mobil oil...lets see if they'll go 3-400k [Big Grin]
...without changing the oil! [LOL!]