90 Gearbox Oil

jono · Post by **jono** » Tue Dec 02, 2008 5:53 am

Ihave acquired a Silver Century, plus a Forty Plus - both have had the geaboxes modified with the later seals to run Mono 90 - but what is suitable? I rang Castrol tech support (Australia) and the tech advised that an EP 80/90 Caltex Thurban GL5EP80W-90W would be fine and is readily available here. Another recommendation (non EP was Castrol Torque Fluid 454 which is a 50 motor oil but classified as a mono 90 as a gearbox oil - apparently. The Torque Fluid 454 is only available in 20 litre drums. Would appreciate some feedback re what is best and available in Austrlia. Thanks.

Hugz · Post by **Hugz** » Tue Dec 02, 2008 7:13 am

Going to be more aussies here than the other people! (but we are much quieter and so subtle <grin>) I'll be interested in the replies. The original 140 was designed to emulsify with the water and as such would become thinner so I'm assuming 90 would be ok but don't quote me.

I buy by mail order from Penrite. They have a transoil 90 in one litre bottles. 1300 722 922.

Cheers Hugo.

jono · Post by **jono** » Tue Dec 02, 2008 7:19 am

Thanks Hugo - much appreciated. Yes, big following here it seems!

Hugz · Post by **Hugz** » Tue Dec 02, 2008 10:30 am

Now all you need is a 102 and you have the trifecta!

Hugo.

Post by **Charles uk** » Tue Dec 02, 2008 3:33 pm

Neither of these 2 Seagulls were fitted with a sealed gearbox from new.

Are you sure they have seals fitted? it's not an easy job, they would both require 2 seals, 1 on the prop shaft & 1 on the pinion shaft below the water pump impeller.

If they have both seals fitted & the seals are in working condition any 80/90 grade outboard gear oil will suffice, as long as you check it's condition often.

But please bear in mind that the bronze bearings in these gearboxes were designed for the use of 140 weight oil & were built with a slightly larger oil clearance to allow for the thicker oil, so check the drained oil for traces of bronze & water

I'd like to see how the seals were fitted to both of these boxes, a picture would be very informative for all.

The only people that I've heard of trying to fit seals, were Seagull racers & most of them gave up as the difficulty outweighed the minimal benefits.

It's good to hear our colonial bretheren are gravitating to boats powered by some of the highest technology marine power plants ever to come out of the UK.

This reminds me of a story that I heard many years ago.

One of your Prime Ministers (who shall remain nameless) was talking to the Queen & was heard to say that when Australia leaves the British Empire we will call it the "Empire of Australia". the Queen replied you can't as your not an Emperor, all right he responded we will call it the "Kingdom of Australia", sorry she said your not a King, all you can do is call it the "Country of Australia"!

Post by **charlesp** » Tue Dec 02, 2008 5:11 pm

I agree with Charles. It's unusual in the extreme to hear of anyone 'modifying' gearboxes. Did a previous owner tell you that?

When you say 'the later type', well, there wasn't a 'later type' of oil seal - the so called oil seals were really a rubber washer that was no more than a dosrt of sand shield. Many Seagulls no longer have them. They did absolutely nothing to retain oil. Thaqt didn't change until right at the later end of production, with gearbox castings that were designed for a real oil seal.

The strength of the classic Seagull is that it didn't have seals, it didn't need them. The bronze bushes were accepted a leaky, and as a previous poster has stated, this allowed the oil to emulsify with water, and that's how they were designed to run.

You can't just pop along to a dealer and pick up 'later type seals' and pop them in place as there isn't a 'place' to put them. The gearboxes that used them were completely different castings, save for the featherweight

Photos would be of great interest here, but meanwhile I find it very difficult to believe that your gearboxes are other than standard, and that they will need 140 grade oil.

As ever, the engine numbers will reveal much, please let us have them.

Unless, of course, there is something here I have failed to understand, in which case forgive me!

Hugz · Post by **Hugz** » Tue Dec 02, 2008 10:57 pm

Charles uk wrote: But please bear in mind that the bronze bearings in these gearboxes were designed for the use of 140 weight oil & were built with a slightly larger oil clearance to allow for the thicker oil.

Would not the 140 become thinner when emulsified and as such the clearance would work for thinner oils as well if not emulsified?

Phonetics aside, I didn't know we had a Count as a Prime Minister!

Cheers hugo.

jono · Post by **jono** » Tue Dec 02, 2008 11:00 pm

Thanks Charles and Charles! I bought both motors from a "Seagull" mechanic here who has recently retired from Seagulling. His main interest was restoring and repairing these beasties. I questioned him re the gearbox and he said he had replaced both gearboxes completely in doing a long shaft to standard shaft conversion. He was quite adamant that both used 90 grade, not 140. The engine numbers (in the case of the 40 plus) didn't help me as mine has a later block, but the Mark1 ignition. The block was replaced as part of the refurbishment - which caused me confusion when I was trying to reconcile the Mark 1 ignition (silver flywheel) to the date on the engine number - a later build using the Mark 2 ignition.
The Silver Century (clutch) I believe is totally original and immaculate except that Leo again changed the gearbox - this engine was originally a long shaft as well going by engine number. I will see him again on Saturday (to pick up a boat) so will again confirm. So, no he didn't modify the original gearboxes.

jono · Post by **jono** » Tue Dec 02, 2008 11:05 pm

Hugz wrote:Now all you need is a 102 and you have the trifecta!

Hugo.

Ah yes Hugo, I also have a 102 - not a runner, but I have the bits to restore!

Post by **Charles uk** » Wed Dec 03, 2008 12:29 am

Hugz, you might not have at the moment, but we do! I didn't say the story was true, you would have to judge it's veracity.

Without pictures & engine numbers we cannot help further on these gearboxes.

When 140 & water mix it seems just as gloopy as when new.

chris · Post by **chris** » Wed Dec 03, 2008 1:00 am

Is that old Leo from Nudgee Beach

pistnbroke · Post by **pistnbroke** » Thu Dec 04, 2008 6:25 am

Penrite Limslip gear oil 140 seems to be widely availabe in australia in 1 litre bottles....extreeme pressure extra heavy duty its says on the bottle ....

chris · Post by **chris** » Fri Dec 05, 2008 1:29 am

you use penrite transoil 140 for the gearbox, it is the proper oil for the seagull it is a non additive gear oil specially formulated for vintage vehicles

jono · Post by **jono** » Fri Dec 05, 2008 2:16 am

chris wrote:you use penrite transoil 140 for the gearbox, it is the proper oil for the seagull it is a non additive gear oil specially formulated for vintage vehicles

You are spot on Chris - there are two Penrite Oils 140 grade. The LIMSLIP 140 pisnbroke referred to and the TRANSOIL 140. They are actually two different products according to Penrite Tech Support. The Transoil 140 (or 90) is the correct oil for Seagulls. The LIMSLIP140 is now used in V8 Hi Perf Commodores apparently which is why it is now more commonly available.
I have obtained the Transoil locally.