Straight 60 weight in a Harley Shovelhead

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Hello folks, a new guy here.

I've an early '84 Harley FLH Shovelhead. I'm currently using Amsoil's straight 60w synthetic oil(AHR)in the motor.

I live in Northern Mn. where temps are on the cooler side, but rarely ride it when it's below 50F.

I'm using this weight oil due to the fact Amsoil has it as their first pick(over their motorcycle 20W50) for use on Harley's pre Evolution motors.

I've been asked, and don't know the answer, why I wouldn't run 20W50 instead. I have read that synthetic straight weight oil's do act somewhat like a multi viscoity dino oil, ei they thicken less when cooled, but not sure to what extent. Shovelhead's have roller bearing's in their lower end's and generally tolerances are much looser than on most modern engines, but still?

Will a synthetic 60 weight provide adaquate protection on cold start-ups @ 50F in this type of motor?

Does it's ability to hold up better to the higher shearing effect these motor's have on an oil outweigh the cold startup protection a multi viscosity synthetic 20W50 would provide?

I figured I'd ask the experts, and thanks for any input!
 
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A couple things, Amsoil's MC recommendations are good and the SAE 60 is basically a 25W-60. The oil is very shear stable and has a fairly huge HT/HS of greater than 6.
 
Thank you Gentlemen for the replies.

So if I understand correctly then:

Having no viscosity index improver's means an oil will remain it's intended viscosity (60 in this case) longer than one with VII's added, such as most multi viscosity oils?

Amsoil's AHR 60 acts similiar to a 25 weight oil when cold? This is adaquate protection, in my case, with >50F cold start-ups?

Pablo, what does the term HT/HS refer too?

Thanks & Sorry so many question's, still learning.
 
Originally Posted By: Jeff_D
Thank you Gentlemen for the replies.

So if I understand correctly then:

Having no viscosity index improver's means an oil will remain it's intended viscosity (60 in this case) longer than one with VII's added, such as most multi viscosity oils?

Amsoil's AHR 60 acts similiar to a 25 weight oil when cold? This is adaquate protection, in my case, with >50F cold start-ups?

Pablo, what does the term HT/HS refer too?

Thanks & Sorry so many question's, still learning.


Yes. Very shear stable.
50°F will be no problem.
High Temperature/High Shear = High Temperature/High Shear Viscosity cP, X°C, X s-1 (ASTM D4683)

http://www.astm.org/Standards/D4683.htm
 
That 60w in that engine is a great combination. Just don't start it under 50*F and all is good IMO. When you do start it at 50*F just let it warm up for 2-3 minutes before you ride away.
 
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I watched an episode of American Chopper where they filled a new engine with 60 or 70W oil from a bulk barrel sitting right next to the garage door in the winter. The engine almost was ruined because Pauly started revving the thing right away and the oil was so thick that it wasn't getting to the top end. They are great fabricators, but don't know much about an engine.
 
I with you guys on letting the engine warm up first.

I read somewhere to let a Shovelhead warm up until the rocker boxes get warm to the touch, and even then don't rev the snot out of it, or work it hard, until the oil tanks warm too.

That's what I try to do.

FWIW, I've never been one to rev an engine just to hear it rev, anyways.
wink.gif
 
Originally Posted By: Jeff_D
I with you guys on letting the engine warm up first.

I read somewhere to let a Shovelhead warm up until the rocker boxes get warm to the touch, and even then don't rev the snot out of it, or work it hard, until the oil tanks warm too.

That's what I try to do.

FWIW, I've never been one to rev an engine just to hear it rev, anyways.
wink.gif



Good habit to get into. On my TC88 I wait until the rear jug is warm as well.
 
I typically run Amsoil 20W-50 in all my old machines. My habits have always been different from my peers, in that I pay attention to the hot operating pressure of my engines. I always do a warm-up of my engine, running at lower speeds (around 45 mph in high or drop it down a gear and run at 35 mph). Even my high mileage engines. Treat 'um just like new. Now, I have moved over to the Amsoil 60W over the past few Summers, as they have been 100°+F. With night-time temps in the 70's. My '59 has been pressed into service as my primary road machine, since totaling my '76 in '04. It has always been a high mileage, tired old machine until last Summer when it finally gave up. It's on its way back, along with the '76.

Anyway, I have no qualms about 20W-50 in these machines. Also, 75W-90 gear lube in the transmission. It is equivalent to about a 30W-60 in engine oil weight. Some say more like a 20W-50. But, it pours a bit thicker than that. I run both in Flathead 45's, and Big Twins.

Jack
 
I ride a 79 FXS I use MCV 20/50 most of the year,until it gets real hot in the summer. Then I switch to AHR 60 wt. I switched to amsoil about 7 years ago from Harley dino oil. its been great, bike runs cooler and uses less oil between changes. I also use 75/90 svg in my tranny.
 
You gotta wonder about a motorcycle that would even need straight 60 weight oil in the first place, I don't even use straight weight oil in my Massey-Ferguson tractor that is 40 years old and Massey recommends 10w-40 in that tractor -- 40 years ago they didn't even recommend oil that thick in a farm implement. Hhmmm..... You know those bikes have roller bearing rods, roller bearing crank, roller lifters, [censored], they could nearly lubricate with splash lubrication -- why do they need straight 60 weight oil? To slow down the leaks? Which parts are going to shear the oil with all the roller bearings?
 
Originally Posted By: ZGRider
You know those bikes have roller bearing rods, roller bearing crank, roller lifters, [censored], they could nearly lubricate with splash lubrication -- why do they need straight 60 weight oil? To slow down the leaks?
ZG, I'm under the impression these engines are designed for a high volume/flow of oil rather than pressure. I know the hot oil pressure is considered good if it's 2psi.
Originally Posted By: ZGRider
Which parts are going to shear the oil with all the roller bearings?
I'm curious to that answer myself? What normally shears an oil? Gears?
Can oil be sheared in a roller bearings?

For whatever reason , gears, bearings, loose tolerances, being an air cooled engine, the UOA's I've read do seem to show oil's go out of grade faster on engines designed like this than on other designs.

Anybody have ideas?
 
Originally Posted By: Jeff_D
Originally Posted By: ZGRider
You know those bikes have roller bearing rods, roller bearing crank, roller lifters, [censored], they could nearly lubricate with splash lubrication -- why do they need straight 60 weight oil? To slow down the leaks?
ZG, I'm under the impression these engines are designed for a high volume/flow of oil rather than pressure. I know the hot oil pressure is considered good if it's 2psi.
Originally Posted By: ZGRider
Which parts are going to shear the oil with all the roller bearings?
I'm curious to that answer myself? What normally shears an oil? Gears?
Can oil be sheared in a roller bearings?

For whatever reason , gears, bearings, loose tolerances, being an air cooled engine, the UOA's I've read do seem to show oil's go out of grade faster on engines designed like this than on other designs.

Anybody have ideas?


Yeah...Shovels are shear monsters with very loose tolerances. Oil shears anywhere it gets pumped or squeezed. Crank bearings especially.
 
Gears are the main cause of shearing, hence the problems with shared-oil trannys. Since Shoveheads don't share oil with the trans and use dry sump lubrication with lots of oil capacity, I restate my doubts about Harleys needing 60 weight oil other than some superstitious reason or limiting leaks. As all of you know mono-grade 60 weight doesn't cool the engine any better than a multi-grade oil. I would have to see some UOAs from a Shovelhead using monograde 60 to believe the shearing reasons. But I would believe excessive heat breaking down the oil prematurely. Any BTW, roller bearings do not produce much shearing as they distribute the forces well and oil is free to circulate freely around the balls. Why do you think they were used in early engines with splash lubrication and primitive oils? I've seen oil in tractor transmissions that hadn't been changed in years and the bearings and gears looked new. Shearing is a product of the amount of pressure the oil must support.
Ball bearings were used in early Harleys just because proper oiling could not be produced and hence high-pressure plain bearings could not be considered. They have been carried over by tradition rather than superiority over plain bearings, and they are much more expensive to use as the increased work to produce the same parts (build-up cranks vs. machined one-piece cranks)
I can absolutely guarantee that a high-quality, synthetic 20w-50 oil would withstand any abuse that a Shovelhead could make. It would be much better for any air temps under 80 degrees. As an owner of old Nortons and Triumphs that are also air-cooled, produce much heat and have loose tolerances, I stand by my recommendations as they serve my ancient machines very well. I would never consider monograde 60 no matter what some "old farts" say.
 
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ZG, I won't agrue the other points you brought up due to the fact that I'm not that knowledgable on oil, hence my being here with my questions.
But, in regards to this:
Originally Posted By: ZGRider
I would never consider monograde 60 no matter what some "old farts" say.
I asked in my original post about straight 60weight because Amsoil is recommending it over their 20W50 synthetic.

They sell both grades, so the reason can't be simply for a sale. They may possibly be wrong in their recommendation, but I would assume they should be fairly knowledgable on the subject of oil. I wouldn't think they could be catagorized as "old farts".
 
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"HD extra heavy, SAE 60, HARLEY DAVIDSON rating HD 240, Above 80 degrees to 100 degrees, cold weather starts below 50 degrees poor"

extract from the owner's manual from my 1992 fatboy

yes, THE OFFICIAL HARLEY ONE ...
 
Bonnie John, your manual wouldn't happen to show the cross reference between the actual grades of oil & Harley's brand oils, would it?

My Shovelhead manual gives:

10F to 100F = Power Blend Super Premium

>80F =Extra Heavy (60 weight?)
>60F =Regular Heavy
>40F =Medium Heavy
-20F to 40F= Special light

but not the actual grades.

Amsoil has no temperature ranges given in their chart, simply first pick and second pick. If Harley's Power Blend Super Premium = SAE20W50 then it appears to me, and as some others have said, that might be a better choice, given my location our usual temps.

Thanks
 
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