i've got a 97 mark-viii engine and i'm about to do my first oil change since I swapped it in. I put 10w30 in when i first did the swap but I see people saying it should be 5w20. what are people using? also, the car gets driven in the winter if that changes things
oil recommendations, 5w20 or 10w30?
- Thread starter jakemarsh77
- Start date
10w30 will be fine.
115k on my mod motor running 15w40, 5w50, and 5w40. Stock shortblock at 540hp and shifting at 7k. My latest combo is doing a mix with 20w50 VR1 conventional.
I would run no heavier than 530. I am no "expert" but I do work for an oil distributor and rep for major oil manufactures. I would run either a quality high mileage or synthetic blend. If you beat the hell out of it then run full synthetic. They have full synthetic with high mileage qualities. Don't worry about fancy oil additives and such. By the time you buy it and add it to a middle of the road oil you will end paying the same price and likely not have that much better protection, if not worse.
Personal preference is Valvoline, I have always been a Valvoline guy not for any particular reason (before this line of work).... I just am. I would avoid Mobil One and Amsoil .... don't want to start a pissing contest but the ROI doesn't payout. The cost of the products and the quality of protection don't make fiscal sense. Not saying they don't work but they aren't that great for the price you pay.
I also happen to have a Mark 8 and have run other modular motors in the past. These things make enough noise on cold start in the winter, 10w30 or heavier will only make it worse. It will also slow the time for lubricant to get to the top of the motor and so on. Like what was said before the tolerances are too tight for such a heavy weight.
Oil is a tool for the engine no different than the ones in your tool box. Using the right tool for the job makes the job go smoother, you don't break stuff and you won't get hurt....
VR1 is great stuff! Be aware it is a short term or short life oil. It cannot take 3,000 miles under any conditions no matter how light. This goes for ALL RACING OILS regardless of mfg.
Sorry I got long winded but it is a subject that is quite simple but can get complicated if we think too much or reengineer.
Personal preference is Valvoline, I have always been a Valvoline guy not for any particular reason (before this line of work).... I just am. I would avoid Mobil One and Amsoil .... don't want to start a pissing contest but the ROI doesn't payout. The cost of the products and the quality of protection don't make fiscal sense. Not saying they don't work but they aren't that great for the price you pay.
I also happen to have a Mark 8 and have run other modular motors in the past. These things make enough noise on cold start in the winter, 10w30 or heavier will only make it worse. It will also slow the time for lubricant to get to the top of the motor and so on. Like what was said before the tolerances are too tight for such a heavy weight.
Oil is a tool for the engine no different than the ones in your tool box. Using the right tool for the job makes the job go smoother, you don't break stuff and you won't get hurt....
VR1 is great stuff! Be aware it is a short term or short life oil. It cannot take 3,000 miles under any conditions no matter how light. This goes for ALL RACING OILS regardless of mfg.
Sorry I got long winded but it is a subject that is quite simple but can get complicated if we think too much or reengineer.
I like 5W-30 winter, 10W-30 summer Mobil one with a Motorcraft filter. Dont think the winter switch does much but if im doing a oil change late fall before it gets too cold to work outside, I do it. M1 isn't that expensive if you buy the Walmart jugs. $25 for 5 quarts, haven't found another full synthetic at $5 a quart.
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Mobile 1 10w-30 (warm climate) 180k miles
+1. What many people may not understand is how thin these motors clearances are. If mod motors had bearing clearences of .002-.003 like a SBC or a SBF then I would say 10/30 10/40 all day. But when they are .0015 (keep in mind, that's measured when the motor is cold) you need a thin oil that will can be pushed with oil pressure to all the areas of the bearing and crank/rods surfaces. Otherwise you'll get hot spots.
Mach- I'd love to pull a cap and inspect your bearings. Has all of those 115k miles run with the thicker oil or did you find a 115k mile shortblock and put your heads on it? Obviously older motors will have larger clearance due to it's age and you can get away with a thicker oil.
I bet you'll have some heat spots out on the outer areas (farthest from the oil passage) on your mains but the middle will not be as bad.
The weight of the oil should be dictated by the bearing clearances. On any motor for that matter.
-Mark
I am going to get myself in trouble but... ONE of the purposes of using a heavier weight oil is to fill in the larger bearing clearance, this does give better oil pressure in some cases where the clearance is too great over an application that should have 520 or 30.. Worn engine components.
If you are burning oil on a 520 engine switch to 1030 would help it is heavier and could help keep the oil from slinging around up onto the cylinder walls. However if the valve seals leak your stuck. Now with the heavy oil at the top of the motor it has a tougher time running back to the pan..... Possibly...
I have seen where an engine is built right and tight .0015-.002 and it has had negative effects due to running 20w50. The oil prematurely wears, viscosity breakdown; hence bearings and journals wear as well due to insufficient oiling and cooling.
Would I put 5w20 conventional in a 500 RWH car with .0015 bearing clearance? Not for very long.... 5w20 full synthetic you bet.
Cold weather start up... The oil is heavy and the filter is filled with it. The pump is shoving in heavy oil. The oil is not thinned out yet and will put the filter in bypass to some extent till such time that the media can handle it. Take hot oil and pour it through a screen, then do it with cold oil.
Now the question comes... How can all this be true when so many are running heavier oil with no problems? The simple answer comes with a question. What do synthetics do better than other oils? They handle the extremes better, cold/hot and their flow characteristics are much better. Less drag, less aeration, better heat transfer. Just hitting the high points.
Not an expert but don't the modular motors have issues with the oil pumps at times? I recall something about their internal clearances at one time and them being a bit on the light side for durability?
Long story short, if you want better protection use better oil not heavier. For those that have been using the heavier oil DO NOT go back, it is too late. I am not being a jerk, but the clearance has already been done.
You can ban me now...
If you are burning oil on a 520 engine switch to 1030 would help it is heavier and could help keep the oil from slinging around up onto the cylinder walls. However if the valve seals leak your stuck. Now with the heavy oil at the top of the motor it has a tougher time running back to the pan..... Possibly...
I have seen where an engine is built right and tight .0015-.002 and it has had negative effects due to running 20w50. The oil prematurely wears, viscosity breakdown; hence bearings and journals wear as well due to insufficient oiling and cooling.
Would I put 5w20 conventional in a 500 RWH car with .0015 bearing clearance? Not for very long.... 5w20 full synthetic you bet.
Cold weather start up... The oil is heavy and the filter is filled with it. The pump is shoving in heavy oil. The oil is not thinned out yet and will put the filter in bypass to some extent till such time that the media can handle it. Take hot oil and pour it through a screen, then do it with cold oil.
Now the question comes... How can all this be true when so many are running heavier oil with no problems? The simple answer comes with a question. What do synthetics do better than other oils? They handle the extremes better, cold/hot and their flow characteristics are much better. Less drag, less aeration, better heat transfer. Just hitting the high points.
Not an expert but don't the modular motors have issues with the oil pumps at times? I recall something about their internal clearances at one time and them being a bit on the light side for durability?
Long story short, if you want better protection use better oil not heavier. For those that have been using the heavier oil DO NOT go back, it is too late. I am not being a jerk, but the clearance has already been done.
You can ban me now...
I will probably pull this engine out in a few months, and will take pics of the tear down. I have a built auto and forged internals waiting to go in the car. I have ran thicker oil since I bought the car with 50,000 miles on it over 5 years ago. The longblock is stock except 96 cobra intake cams. Its seen hundreds of 1/4 mile passes and even some road racing. If it was an issue a bearing would have already seized up at this point. Hopefully some pics will put this debate to rest.
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For a higher mileage mod motor thats always had motorcraft 5w30, would it be a good idea to switch to full synthetic now or should I just stay with synthetic blends like motorcraft?
Not picking a fight brother.... I am not an engineer and it is not my theory. I do buy into it though. Do a little google searching and reading and you will find much of the same. In fact they will likely explain it better. The potential of lower end wear wouldn't really surprise/interest me. With that many miles and lifestyle we would expect something to have wear. Right? What we should really look at are the cam journals, depending on how long they have been in there. They are the end of the line and tend to tell their own story.
All of that said, I bet your not using crap no name oil are you? I am sure everything will be and is just fine. It has lasted this long...
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