Best Oil for GT350

[David Simpkins]

On 2/12/2019 at 8:15 AM, mhr1961 said:

Don't listen to some of the above posts except for 2BJShelbys' recommendation to use the factory recommended oil.

The 2018 GT350( or any recent GT350 for that matter)  does NOT require 500 miles of babying and rowing through gears for the engine break in period, in fact it can be harmful to do so. 

There is a lot of good information out about the 5.2 FPC and there is a lot of wrong information as well on the net about break in. Ignore it all and follow your manual and supplement manual. I will provide some information below as to why you should follow your Ford GT350  Supplement Manual on break in procedure. It’s a bit long but important to know.

 People who bought the GT350 thinking it would not burn oil at times did not do any research or are typically not familiar with race type engines. Some people think because it is a race type engine it is built to some high tolerances. There are indeed areas of the engine that are machined to high tolerance but race type engines will typically have looser tolerances in regard to piston/cylinder wall clearance and will also have thinner rings  sets for sealing the combustion chamber.They are designed as such to reduce as much friction as possible while also reducing blow by as much as possible.   They are built this way intentionally to maximize hp over a broad heat range. This “slop” in piston/cylinder wall clearances allows for a higher degree of thermal expansion, because going from cold to race or track conditions generates a broader heat range and thus a broader range of thermal expansion the engine components will see.

If the 5.2 FPC was built to standard production engine spec it would start just fine and then seize up when put on a track. The “slop” is there for a reason.

The result of building a race type engine this way maximizes horsepower but it also can cause some Oil Burning and sometimes “Piston Slap”. The the biggest complaints from consumers have been these two conditions in the 5.2 FPC. Both conditions are normal if neither are excessive. The piston slap or “ticking” upon cold start that goes away is normal. If it continues after engine warm up and does not go away then get it checked. If your car burns a quart or so of oil between a 3k to 5 oil change intervals I would consider that normal. Yes some people are claiming no oil burn and some people are claiming 2 or 3 quarts between intervals.  If you have your foot in it all the time you are probably going to burn more oil, also if you have frequent cold starts you may burn more oil , if it burns excessive amounts of oil get it checked. It’s not a production engine, it’s a production race engine. A little oil burn and some ticking on start up is normal for the 5.2 FPC. 

There is a lot of old school thought about engine break in. You don’t have to to run 500 or 1000 miles of varying speed, play “row row row your boat” with the gears, etc. In fact the manual says don’t play heavy with the brakes and the gear rowing for the first 100 miles. Extended 500 mile to 1000 mile engine break in typically applies to standard production cross plane crank engines and yes the standard Mustang manual in the engine break in section of the 2018 Mustang Manual on Page 202 says the following:

 “BREAKING-IN:

Tires: New tires need to be run-in for approximately 300 mi (500 km). During this time, you may experience different driving characteristics.

 Brakes and Clutch: Avoid heavy use of the brakes and clutch if possible for the first 100 mi (150 km) in town and for the first 1,000 mi (1,500 km) on freeways.

 Engine :Avoid driving too fast during the first 1,000 mi (1,500 km). Vary your speed frequently and change up through the gears early. Do not labor the engine.”

HOWEVER, you do NOT have a standard Mustang, you have a Ford Shelby #GT350 with a Flat 5.2 Plane Crank Engine, you need to refer to your 2018 GT350 SUPPLEMENT MANUAL, which on page 33 says the following:

 “BREAKING-IN

 Your vehicle requires a break-in period. Drive your new vehicle at least 100 mi (160 km) before performing extended wide open throttle maneuvers and at least 1,000 mi (1,600 km) before performance or competition conditions.

Note: Vary your speed frequently in order to give the moving parts a chance to break in. “

 After 100 miles you can rev to wide open throttle intermittently all you want and it will actually help bed the rings properly rather than "hurt the engine" ………but just don’t keep your foot in it too long.

 In many cases the worst thing you can do is baby a race type engine too long. You have a limited amount of time to bed the rings. It isn’t about the crankshaft, cams, rods, lifters and other components, those are highly machined  and finished. The main focus of 100 mile engine break in procedure on the 5.2 FPC per the manual is bedding the rings. The cylinder walls are PTWA (Plasma Transferred Wire) This process creates a  low friction surface with a good dimensional characteristics in the cylinder liner, which is required for the 5.2 FPC. After this process the cylinders are honed.

Controlled bedding and wearing in of the new piston rings on to the hone of the cylinder walls that is the most important in break in. You want to bed those rings so that they achieve a correct seal against the cylinder walls, and you have a small window of time in which to do so in order to bed the rings properly in order to reduce oil consumption and keep blow by to a minimum.”

So again, You don’t need to baby the engine and row through gears a lot for 500 miles. The transmission does not need a lot of rowing through the gears either to break it in, and doing so doesn’t do much to “load the engine”. You want to break in the engine under load. That mean accelerating and decelerating within about 75 to 80% of the recommended max rpm range using the engine to speed up or slow down (applying throttle and taking your foot off it). After one hundred miles of doing so, then  the rings will be bedded and you can go wide open throttle from that point as it says in the GT350 supplement manual……….just don’t go wide open throttle for extended periods until after 1000 miles as the manual says.

This short break in before being able to go wide open throttle is important. It may seem counter-intuitive to some people who have grown up on a steady diet of regular production cross plane crank engines but the supplement manual instructions are the correct way to do it. Babying a racing type engine for 500 to 1000 miles may actually cause your rings not to bed in properly and will actually increase your oil consumption or piston slap.

 Follow your manual, not anecdotal input.

BTW, Some race engines are only tested on a dyno for 30 to 45 minutes, they are then pulled and components and oil are checked for wear and metals and contaminants in the oil. Then they are put back on the dyno and ran through their paces for only a couple of hours and then they are thrown in the race car to let it rip in competition.

 Do your hundred miles as instructed in the manual, then "let it rip" some here and there for your own delight and the benefit of the engine, and after 1000 miles of letting her rip at wide open throttle here and there, you can then take it to the track and keep your foot in it. Good Luck and Enjoy.

 

 

This is PRECISELY what should be done! Well put good sir. I followed my manual verbatim, changed my oil after 1,000m, and my GT350 runs perfectly at all RPM's, and yes, she burns a little oil, just like she's supposed to. I do not understand why people do not simply read... and then re-read their manual(s) and do as instructed. The manufacturer knows more about that vehicle than does anyone on any thread. Just treat the vehicle according to the manufacturers guidance and you should have no issues. It's simple. 

[mhr1961]

3 hours ago, David Simpkins said:

This is PRECISELY what should be done! Well put good sir. I followed my manual verbatim, changed my oil after 1,000m, and my GT350 runs perfectly at all RPM's, and yes, she burns a little oil, just like she's supposed to. I do not understand why people do not simply read... and then re-read their manual(s) and do as instructed. The manufacturer knows more about that vehicle than does anyone on any thread. Just treat the vehicle according to the manufacturers guidance and you should have no issues. It's simple. 

Thank you for the positive feedback on my write up. The write up I did  was also re-posted by others and shared over on a couple of other Mustang/Shelby sites and hopefully was of some help to people who were concerned about proper break in procedures.  Welcome to Team Shelby. Congrats on owning a GT350 and glad to hear your car is running well.

[MikeyTX]

On 2/10/2019 at 8:20 PM, twobjshelbys said:

Why not use what the owner's manual recommends?  With all the stories about oil consumption on the 350s I'd stay with Ford products. 

What ? Blasmephy I say .............. 🤣  Sadly, doing something that uses logic ceases in all things related to cars and marriage. Go figure .......... 

Edited August 17, 2020 by MikeyTX

[MikeyTX]

On 2/15/2019 at 6:57 PM, Thomas Stetson said:

Thanks for the info! At this point, with extended Ford PremiumCare warranty, I'm going to rely on Motorcraft and the Ford techs. Amsoil does make a great product though. 

The primary benefit of factory oil is that should there be an engine issue, FOMOCO will ask for a sample draw of the oil. Also another reason to use the dealers quick change services. Ford has a record ! Plus, you gain points to your Fordpass ............ You did register right ?