Which oil would you use?

[Skunksmash]

I just wanted to get you guy's opinions on what the best quality oil to use on our flat tappet motors is. I know that opinions will vary, but maybe you can also say why you choose the oil that you do. I know the top dog in synthetics is AMSoil, but i really dont know what i should use in my 87 5.7L TBi. They have so many that it's confusing. The odometer says 45k, but i am guessing that could mean either 145k, or 245k. Or something else entirely. So whats the best quality oil to use on these old trucks?

[VileZambonie]

http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/index.html

[choptop]

I run Amsoil in most of our vehicles ( We're dealers for it) and Castrol GTX in the others. I like Amsoil because I found that it reduces the piston slap sound common on LS engines, and has an awesome filter that filters smaller contaminants out. Other than that, I use A/C Delco filters or Hastings filters with the Castrol. I dont use Pennzoil or Quaker State because I have seen engines sludge up using the stuff, and I dont use fram filters because I have pulled the guts ftom one of them on a Cat engine more than once. (Before anyone gets upset about the Penzoil or Quaker State, these cars were city cars that never saw the highway. Experience has shown that vehicles that see moderate highway use dont have the same problem.)

[Skunksmash]

Thanks for the link vile.

But uh, AMSoil is all synthetic, right? Well snythetic is not supposed to be the best thing for our type of engine. Supposedly. As for the filter, bobistheoilguy.com has done numerous tests and concluded that Puralator, motorcraft, and .... crap i forgot the name but there are 3 best, two of which i never even heard of and motorcraft that i always thought was kinda off brand like GM goodwretch.

[eventhorizon66]

I use 10W-30 Valvoline dino oil and add 4 ounces of GM EOS (for my dose of ZDDP) at every oil change.  But I don't have enough miles to tell you if it's working or if it's ruining my cat.  For filters I use Wix, ACDelco, or Purolator - never Fram.

I don't think that factory GM flat cams are having nearly the same number of failures that aftermarket cams are.  They were MUCH less aggressive than the average aftermarket cam and were accompanied by much lighter springs.  If your '87 TBI engine has made it this far on the original cam, I wouldn't worry about it.

[Skunksmash]

So you are saying that it would probly be fine to run synthetic? I have to make this motor stretch for a year and a half at least lol. It can break after that and i will be able to get a new one. Most if not all of my driving will be city. I wonder if that valvoline max life stuff is any good... Also, what would it take to convert a flat tappet motor to a full roller motor?

[choptop]

I have run Amsoil in my engines for many years. They all seem to run cooler and smoother. I dont run them in a fresh engine. I wait til about 10,000 miles then switch. I have been told that you can run synthetic in a new motor, but I choose not too. Synthetic is great for older motors. I have pit in 20,000 mile motors and 200,000 plus miles motors, and never had an issue. Not saying Amsoil is the best, it is very good and I havent ever had any trouble. I also like Castrol Syntec. Have seen articles comparing Amsoi to Mobi one, and they are pretty much equal. Amsoil is 25,000 mile or 1 year, and Mobil one is more often. Depends on your preference. On our 01 Silverado it has the magnet in the drain plug. I have seen less particles on the plug at 25,000 miles with Amsoil than I ever did with conventental oils. PLus the Amsoil filters filter out smaller particles out than standard. I believe Amsoil filters are 2-5 micron, Fram, Ac Delco etc are 12 Micron.

[eventhorizon66]

The only thing I'm not sure about is using a full synthetic in any flat-tappet motor.  I "heard" somewhere that full synthetics would lubricate too well and prevent the lifters from rotating as they slide across the cam lobes.  Seems like a bunch of nonsense, but who knows, maybe there is some truth to it.

Also, what would it take to convert a flat tappet motor to a full roller motor?

For an 87-up block you should have the three drilled and tapped bosses down the middle of the lifter valley.  If so, you can use a factory roller lifter set up like this.  If not, you can go with retro-fit lifters like these.  Notice the price difference between the two - it pays to have a late model block with provisions for the factory setup.  After the lifters are addressed you need to determine whether your block has provisions for a factory style thrust plate (cam retainer) like this.  If not, you can use a thrust button like this along with a reinforced timing cover, otherwise your cam will walk and your spark timing will be erratic.  Also, your pushrods will now be too long and your valvesprings will likely be too light.

[joesgarage71]

 I wouldn't use any of todays dino oil in any flat tappet engine they have taken out most all of the pressure additives (unless like above you add GM's EOS to the oil ) from it. The less expensive route would be to use rotilla or another HD truck oil. I use rotilla on new engines till they are broke in then I use the pennsoil Full syn oil. I use to use Mobil one till Pennsoil came out with the Platium syn oil,  its better oil for less monies. For filers I use Napa gold or Wix (same filter)
 For more info on oils, additives go to  www.bobistheoilguy.com  you can spend hours there just reading.

[Skunksmash]

What exactly do you mean by "dino oil"? do you just mean today's non-synthetics?

[eventhorizon66]

Yes

[joesgarage71]

 Yup

[Skunksmash]

So by that you also assume that the whole "Synthetic is bad for flat tappet" idea is totally bogus? So i should just be able to run royal purple in my truck if i want to with no problems. The truck is coming up for it's very first oil change since it has been in my hands and i have to decide what oil i am going to stick with. With newer motors its pretty easy lol. You just buy the best grade 4 synthetic that you can afford.

[choptop]

Royal Purple is very good oil.Go for it.

[the dan]

wow! i cant believe no one has said Mobil 1!, but building racing mx engines i know that Mobil 1 is what i have always used and never seem to have a problem, conventional oil is bad, fully synthetic is the only way to go