classic car forum header
Classic cars forum & vehicle restoration.
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Register     Posting Photographs     Privacy     F/book OCC Facebook     OCC on Patreon

humber hawk gearbox oil
Post new topic   Reply to topic    Classic cars forum & vehicle restoration. Forum Index -> Mechanical Restoration
Author Message
jiminox



Joined: 12 Dec 2011
Posts: 5

PostPosted: Sun Dec 18, 2011 10:27 pm    Post subject: humber hawk gearbox oil Reply with quote

Hi can anyone tell me where i can get 20w/20 oil, or something equivelent please. cheers jim.
Back to top
View user's profile Send private message
richardlw



Joined: 08 Jun 2009
Posts: 138

PostPosted: Sat Dec 24, 2011 4:50 pm    Post subject: Reply with quote

As you will note on this chart, a 20w/20 oil from the motor oil chart would land it as a 75W-80 in the gear oil chart.

I would look for a GL-3 or GL-4 75W-80. Very common for manual transmission Jeeps and late model (> 2008) Mitsubishi's, some Nissans, etc.

Here is one that should be commonly available.
http://www.mobil.com/UK-English/Lubes/PDS/GLXXENCVLMOMobilubeXHP75W-80.aspx

Mitsubishi's is DiaQueen 75W-80
Redline and Amsoil also make it.



_________________
Richard's Cars - NEW **
Motor oil for Flat Tappet Engines
Transmission oil
Back to top
View user's profile Send private message
jiminox



Joined: 12 Dec 2011
Posts: 5

PostPosted: Sat Dec 24, 2011 9:54 pm    Post subject: Reply with quote

thanks richard
Back to top
View user's profile Send private message
welshrover



Joined: 09 Aug 2011
Posts: 326

PostPosted: Wed Sep 19, 2012 12:08 pm    Post subject: Reply with quote

id put 20/50 engine oil in it. the rootes gearbox has small oilways. too small for gear oil ,all the rootes gearboxes are the same minx,gazelle etc
all the manuals say 20/50 and not!!!!!! gearoil


Last edited by welshrover on Wed Sep 19, 2012 10:53 pm; edited 1 time in total
Back to top
View user's profile Send private message
richardlw



Joined: 08 Jun 2009
Posts: 138

PostPosted: Wed Sep 19, 2012 1:13 pm    Post subject: Reply with quote

If the says 20W-50, then 20W-50. That is different from 20w-20.

But don't get terms mixed up. 20W-50 motor oil is the same viscosity as 75W-90 gear oil. So small oil ways have nothing to do with it.
_________________
Richard's Cars - NEW **
Motor oil for Flat Tappet Engines
Transmission oil
Back to top
View user's profile Send private message
welshrover



Joined: 09 Aug 2011
Posts: 326

PostPosted: Wed Sep 19, 2012 10:53 pm    Post subject: Reply with quote

gear oil damages the syncrho hubs. there is some sort of reaction with the type of metal used in the hubs and the gear oil .thats what the rootes original factory manual says as well as the oil holes ,
Back to top
View user's profile Send private message
richardlw



Joined: 08 Jun 2009
Posts: 138

PostPosted: Thu Sep 20, 2012 12:06 am    Post subject: Reply with quote

That would be the true reason, not the viscosity. Although the difference is less than it was. About 15-20 years ago the oil producers started using buffered sulfur/phos compounds that are not corrosive. But, they wear the teeth off the sychncronizers if used in high enough concentrations. That is why you don't ever want to put GL-5 in transmissions, only GL-4.

But you can also consider that Diesel engine oil in general meets the GL-4 EP requirements, so that is why you can use it in the transmission.
_________________
Richard's Cars - NEW **
Motor oil for Flat Tappet Engines
Transmission oil
Back to top
View user's profile Send private message
exbmc



Joined: 18 Jun 2009
Posts: 236
Location: Derby East Midlands

PostPosted: Thu Sep 20, 2012 4:21 pm    Post subject: gearbox oil Reply with quote

It would be worth checking if one of the smaller oil companies, like Millers, Smith and Allan, or Morris's, have a 20w/20 oil in their classic ranges. What richardlw is saying is correct regarding viscosity, but i think you feel uneasy about using gear oil? It's not a common blend, in fact the only 20w/20 i recall using, was a Shell Rotella or BP for diesels. Some of the BMC light truck engines, had 20w/20 specified in the 60's.
Back to top
View user's profile Send private message
Farmer John



Joined: 18 Feb 2010
Posts: 181
Location: Manawatu NZ

PostPosted: Sun Sep 23, 2012 11:13 pm    Post subject: gearbox oil Reply with quote

Hi Jim. The proper oil for your vehicle is that which the manufacturer recommends. That recommendation might have unfamiliar and unusual codes or letters and numbers to define the correct oil, but any oil you buy should have a spec sheet available from which you can match up the rating.
Some of those terms might have changed and that is where you will need someone who can translate for you. Maybe Richard can do that?
Richard had stated in your original thread that engine oils and transmission (industrial) oils have different rating systems, typically 212 deg F for one and 100 deg F for the other. That is because they are different oils, treat them as such.
The question of erosion of bronze synchro rings and thrust washers should also be answered from the spec sheet by reactivity with copper. Should not be a problem except for GL5.
Firms who supply oil to heavy vehicle and heavy industry are a good source for information and oil. Cummins, Caterpilar and the like are very specific on lubricants so the firms who supply them have to be right up to speed and have access to the best info. Unfortunately there are not so many of those firms around, but if you wander in with the manual or just the specs they will help.
Jim, if you put the right oil in the box you have eliminated one possible cause from your list.

John
Back to top
View user's profile Send private message
richardlw



Joined: 08 Jun 2009
Posts: 138

PostPosted: Mon Sep 24, 2012 2:38 pm    Post subject: Reply with quote

Let's go back to square ONE for a minute. The first thing I would do is verify that the the manual or spec you have is correct. There are a lot of misprints out there. Check with someone who has the same transmission in a different vehicle. Is is 20W-20 or 20W-50? There is a big difference.
Most SAE 20W-20 oils on the market would give you an oil that is approx. between 60 and 70 cSt at 40˚C and 8 to 9 cSt at 100˚C (from common spec sheets).
SAE 20W-50 would give you approx. 150 to 160 cSt at 40˚C and 18 to 19 cSt at 100˚C.

Once you have determined that, it is easy to put a good product in it. I will assume it has brass, so I will only mention products that are compatible and won't induce wear.

If it really says 20W-50, use a diesel formula 20W-50. that will give you about 48 lbs on the Timken EP test, passing GL-4 requirements without any Sulfur/phos. Just ZDDP. This is what Isuzu uses in the Trooper, Rodeo, and pickups.

If it is 20W-20, come companies sell it, and it should be CI-4 or CJ-4, which will be harder to find. But you have other choices.

Our objective is to find something that doesn't thicken up to more than about 60 to 70 cSt at 40˚C and maintains at least 5.6 (but I'd prefer 7) to 9 cSt or so at 100˚C.
-- That could be the 75W-80 gear oil that I mentioned originally, normally available in GL-3 or GL-4. That would probably be around 40 to 45 at 40˚C and 7.5 at 100˚C.
-- Another choice would be a Synchromesh fluid (GM, Pennzoil, Quaker State, etc.) that would give you about 40 to 50 cSt at 40˚C and only thin down to 9 to 10 cSt at 100˚C. These are specifically designed for brass sychronizers.
-- Another choice would be SAE 5W-30 diesel formulation (CI-4, CJ-4) motor oil. Again, it would be giving you the 48 or so lbs on the Timken (Falex) test, and would give you about 60 cSt at 40˚C and about 10 cSt at 100˚C.

None of these oils will hurt the synchronizers. All will protect the gears, bearings, etc. (actually more important in viscosity than the passageways are the needle bearings that are present in many transmissions).
_________________
Richard's Cars - NEW **
Motor oil for Flat Tappet Engines
Transmission oil
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Classic cars forum & vehicle restoration. Forum Index -> Mechanical Restoration All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
OCC Merch link
Forum T&C


php BB powered © php BB Grp.