Which Oil to use for Robins?

atwood · Mar 23, 2006

Well, I finally reached the 20 hour mark with the PT425 and need to change the filter and oil on the Robins. The manual doesn't neccessarily reccommned a particular weight of dino oil more like a range of differnet weights. I've read in posts that some of you are using synthetic. I was thinking 10W 30 would work well. What are most using? What brand, dino or synthetic, weight?
Thanks! /forums/images/graemlins/smile.gif

MossRoad · Mar 24, 2006

Some manufacturers specify the number of "break in" hours before switching to synthetic. Be sure to check that, too.

Viscosity choice really depends on the weather, I suppose. If it is going to continue to be cold, choose the one in the range in your manual for those temps. If is is going to be warmer, go up one. That's the nice thing about multi-viscosity oil. Starts are easier and it will adjust to the temps within range.

I switched to Mobil1 after 50 hours in our Kohler a couple years ago. I'm convinced it has allowed easier starting over the last three winters.

MuncyBob · Mar 24, 2006

I'm using Mobil 1 10-30 in my Robin...made the change at the 50 hour mark and change the oil & filter(Purolator One) at every scheduled oil change. I've used the PT in the winter with minimal problems starting her up. Using the Mobil 1 oil since it's readily available here and fairly inexpensive but I may change to Amsoil on the next change.

Piedmont3 · Mar 24, 2006

I use the oil that the mechanic at the small engine shop recommended, it is an oil that is supposedly designed for the air cooled engines, it meets the Robin specs and cost about $2.00 a quart. I can't remember the name... I'm lucky to remember my own name most of the time. /forums/images/graemlins/smirk.gif I am planning on changing to Amsoil at the next oil change.

Phils · Mar 24, 2006

Count me in the group that uses synthetics.

I probably have Mobil 1 in mine, but I also use Amsoil in my truck and car so may have put it in the PT at the last change.

I've used synthetics since 1977 and that's what goes into every engine I own after breakin. EVERY synthetic is better than ANY dino oil so I just go by price mostly (which means Mobil 1 at Costco). But our car requires 5W-30 and I haven't seen that in Mobil 1 so I get that in Amsoil. My pickup is used to tow a very heavy fifthwheel in extremely hot weather up steep and long grades so I use Amsoil's 20W-50 oil. Anything less weight and the lifters will start to clatter before I reach the top, since I'm usually pulling very high RPMs.

So my PT has synthetic but I can't say for sure which brand.

Phil

MossRoad · Mar 24, 2006

Mobil1 5w30

Mobil1 5w30 Extended Performance 15,000 mile

The rest of the Mobil1 lineup /forums/images/graemlins/grin.gif

Gravy · Mar 24, 2006

Phil,

FWIW again,

I would guess that "lifter clatter" is more likely spark knock due to high temperature in the combustion chambers. If you were really losing oil pressure badly enough to collapse the lifters, the engine would likely sieze or throw a rod very soon after. Good synthetic oils apparently lower temperatures enough to make a noticeable difference in performance, but you might get more improvement by adding cooling capacity with an engine oil cooler, or a bigger radiator and heavy duty fan clutch.

It may also be worth trying higher octane fuel, and investigating ECM programming options ("chips") optimized for heavy towing. That would likely reduce your overall fuel mileage, but it might be worth it.

Gravy

Phils · Mar 25, 2006

Thanks, Gravy. The lifters aren't collapsing tho. It's more that they are 'floating'. I don't have a tach but the powerband is high and I'm in it. It's just that using 10W-40 oil, after pulling long and hard and hot and high RPM they will just start to lightly rattle towards the end of a long hard grade. 20W-50 eliminates it.

I have a chip and I have to use the highest octane I can buy to get the most out of it. It's a '91 Chev K2500 w/5.7L so the knock sensor will adjust timing as soon as knock barely starts to appear. And the sensor will lower the timing sooner if I use lower octane fuel, which occasionally happens if I won't be towing for awhile. Basically, I can use any fuel but there's no benefit from the chip if it isn't higher octane. And.... there's not a huge benefit from the chip anyway, just a little.

The truck worked great pulling my 6000 lb fifthwheel. Then I traded up to one with a big slide at 10,000 lbs. I have a "tow test" road and measure any modifications by "how far I get up the hill before it downshifts to first gear". I'm within 100 feet of the top. When I started it was going into first about a 1/2 mile from the top. Despite what others might say, a TBI spacer made a difference in that test that even my wife noticed. I really need a diesel pickup to stay out of the lower gears and I could have afforded one for what I spent on the PT, attachments and carport to put over it. So given the choice of 1) spending an aggreate hour per year longer pulling the really bad hills when we are towing the RV or 2) having the PT to "power-landscape" my 40 acres, I can live with the truck's shortcomings.

It's not overheating as I conqered that demon years ago. When I first got the truck it overheated horribly. Finally discovered a prior owner had added an aftermarket tranny cooler but plumbed it incorrectly. After consultation with my local tranny shop, I removed the added cooler and haven't had a heat problem since. There's synthetic in the tranny, of course, and it gets changed every year. And there's still the stock tranny and oil coolers built into the radiator.

Phil