GC 0w-30 pulls harder than PP 5w-30? Why?

[Fordiesel69]

I know GC is near a 40wt when operating and this is what I wanted. The PP 5w-30 was being vaporized / burned more than the dino oil I used before, so I opted to try GC 0w-30 due to its hot thickness and the fact the engine works real hard once warm. When it sits all night outside under a cover, its alot harder to pull over now vs. the PP 5w-30. My ambient temps are 5 degrees to 30 degrees F. I would think the GC would be better for starting cold.

The engine is a tecumseh / ariens 6HP used on a snowblower. I had to rebuild the engine over the summer of 07' because it burned .5 qts per 30 minutes of use and made you sick after using it. The rings were shot and the piston was worn too small. A new standard piston kit and rod fixed it right up. I did however order 0.10" over rings and filed them to fit as a result of the cylinder being worn ever so slightly. However the engine still smells like its burning a little oil but uses .5 qt a month now which is great. Entire sump is 20 oz, so 1 sump a month is good enough for me as it is old and tired.

 

[bmwtechguy]

It is only at the really cold temps like 20-30 deg below zero deg F that you will see the benefit of the GC pull-starting easier. At your normal ambient temps, the GC is more viscous IIRC. There have been several discussions over the years on this aspect of GC viscometrics. It is usually MORE viscous at all but the lowest temps compared to most 5W-30 oils.

 

[Pete591]

GC 0w-30 is similiar to a 5w-40 in specs I think.

I think I may try Amsoil 0w-40 next year instead of a 5w-30.

Anyone have a VOA of the 0w-40 Amsoil 4-stroke oil?


http://www.amsoil.com/StoreFront/aff.aspx

 

[Fordiesel69]

Very interesting. I thought the type of base oil allowed awsome flow characteristics at low temps. I would consider anything lower than 20 degrees F low temps. Thats when I feel it in the pull starter. The engine starts quick with only 1-2 pulls, I really hate to drag the extension cord out every time.

 

[Pete591]

Amsoil's 5W-30 ASL in my 9 HP Honda at 20*F allows the engine to start as you pull up 1/3 on the cord. That's instant lubrication and probably when the engine needs it the most.

I am begining to think I should not mess with success.

 

[Craig in Canada]

I'm really surprised that so many people feel they are feeling oil viscosity interfering with pull start on a splash lubricated engine... Seriously.... I've changed grades around on OPE and can't say I've really felt any starting difference in the pull cord.

On engines with pressure lubrication and oil pumps trying to push cold, thick sauce through the system at high PSI, that would definitely cause drag, but a thin layer of left over oil in the cylinder from the last time it ran? Or the little slinger going through 40wt instead of 30wt as you pull the cord? I don't know....

Call me skeptical.

If anything, PERHAPS the compression is higher with more oil staying with the rings between starts? I'm not trying to say you don't feel a difference, I'm just skeptical that oil viscosity is directly responsible for drag when pull starting.

 

[StevieC]

When I drained out the factory oil in the summer time and replaced with Amsoil 4 Stroke 10w30 I noticed a huge difference in how easy the engine was to start... Even in the winter...

 

[jldcol]

I think the harder start pull you are experiencing is from the thicker oil giving better sealing/compression. Does the engine have the compression relief feature?, also may be involved. Does it have a oil pump?, or is splash lubed? A splash lubed engine will not know if oil is present or not until runnig fast enough to sling oil all over inside, at a rpm level that is much faster that the cranking rpms.

 

[dave123]

switched to 0w40 arctic blue this year on my flat head tec pulls the same as any othe weight or brand used. I find they pull a little harder the longer they sit.. I keep the motor TDC after use and in storage many people never do this or heard of doing it. helps for long life and avoiding problems down the road...

 

[jldcol]

Storing motor at TDC will reduce the amount of cylinder exposure, also with first starup after storage the first stroke in this case is a intake stroke, instead of a power one, so maybe helps it fire up faster in that case or is this to much of a stretch?