Trunnion Lubrication

[Footer]

Thanks guys, these are all good solutions to gear oil in a grease gun, which I wasn’t looking forward to.
Tomorrow I will do some shopping.😊

[Bryan Boyle]

When I built my car, I just poured some gear oil in the trubnions and assembled letting the extra oil flow out. Now that I'm getting ready for the LOG, I want to make sure they are lubed. I thought I remembered where it was advised to screw a grease zerk into the trunnion and pump the oil in with a grease gun but I haven't found that again and I'm not sure if a grease gun would work. How do you guys lube your trunnions?

I just tried Mr. Collier's oil gun description...even though the bits are back together for only a week...figured I'd try it out.  Picked up an oil gun from the local parts store, found the right size bolt that screws into the upright, cut off the head and drilled out the center...screwed in, pushed a piece of tubing over the nozzzle and the self-made fitting, squirt squirt...oil came out of under the dust seal.  Guess I have enough (and removed and capped everything back to normal) in there now.  Necessity is the mother of invention, right?

[GavinT]

<SNIP> There's been lots of debate on Elan forums about the grease vs oil argument . . .

Brian,
I expect you know Rohan from the Elan forums. He's also a lubrication engineer but I can't remember the oil company he used to work for. Rohan was an active member of the Lotus club in Victoria, Oz where I used to live and he raced a pretty quick Elan. Below is a parting snippet I clipped from one of Rohan's replies on synthetic oils.

As for using oil versus grease in trunnions I only discuss that now with lubrication engineers and even many of them don't understand the fundamental differences and why grease is far superior :roll:

cheers
Rohan

All this is above my pay grade, of course, but I reckon given trunnion wear doesn't seem to have shown up as a major issue over the last 50 years, I'm wondering if there's a real world concern provided there's something slippery actually in there.

[EuropaTC]

Hi Gavin,
Yes, I know of Rohan and the guy deserves respect for his knowledge. I've been following his articles about TC engines on the Elan forum and been saving them as he's posted up the PDF's. No doubt at all, the guy knows what he's talking about.

As for oil vs grease debate I know what the manual says and having had the Elan since the mid 70s, the Europa from the 80s, I've had plenty of time to try things out. I've done the 90wt oil, the 50/50 oil/grease and finally 100% grease. I have no idea which is best although having done a couple of lubrication courses when I was working, I think I can understand the theory about how the hypoid oil should work.

Back in the 70s/80s/early 90s I used either the Elan or Europa daily, summer and winter. Initially I followed the manuals, filled up the grease gun with hypoid 90 (very messy)  and did the 3 monthly service interval. One thing I did notice was that very often some water would come out from under the top trunnion rubber seal when I squirted oil in. That made me think that oil was getting displaced too easily and so I tried the 50/50 thing, just as messy and not significantly better. In theory water shouldn't get in at all, but it did because I saw it on more than one occasion.

I had visions of water sitting at the top of the trunnion, gently rusting away the steel and forming a weak point which could lead to fatigue failure.

So I went to 100% grease and decided that as the car was in daily use I'd just lift it up and give both sides a squirt at the start of the month. Dead easy and no chance whatsoever of the grease drying out. I no doubt wasted a lot of grease over the years (not now, the cars don't get used as often) but I stopped seeing water droplets and that made me happier.

as always, YMMV.....

Brian

[Kendo]

Brian, is that the lithium grease as described by BDA?

[BDA]

Kendo, I'd remind you that I use moly grease. Moly is especially effective for sliding friction which is what you have in a trunnion.

[Kendo]

Apologies, BDA. I went back and looked at what you posted from your lube expert, and abstracted the wrong adjective. At the time he wrote” lithium 2 hydroxystearate grease with moly in it”

[BDA]

Yeah, he was probably being a little overly specific. I thought that moly grease was lithium grease with moly added but wasn't sure so that's why I worded my previous post the way I did. Also, the important thing is the moly which is what enhances the grease's performance with sliding friction. I expect that any "moly grease" you get will be similar to what my buddy specified.

[Clifton]

Anyone who has taken apart a gear reduced tool like a drill know grease is pushed out of the gears. Grease is good but you wouldn't use it in a transmission or differential. An oil engineer may say grease but a mechanical engineer would say there is the weight of the car on those threads pushing the grease out to the sides.

https://www.motorsportmagazine.com/archive/article/october-1999/67/the-alford-alder-upright/

" Triumph upright remains in manufacture today, by Coventry company ESP Ltd using refurbished original tooling. Alford and Alder itself, with a history stretching back to the early years of last century, ceased to exist when it was absorbed into British Leyland. ESP boss Tony Cook still receives enquiries about the upright from around the world and makes a special variant for racing in which the central bore through the lower section – designed to carry lubricant (strictly engine oil, not grease) from a rear-mounted nipple to the base of the trunnion thread – is eliminated to enhance stiffness, this particularly when the trunnion thread is machined off to accommodate a rod end bearing instead."

[jbcollier]

To use grease, the trunnion needs to be redesigned.  Right now they have a wide groove that goes from top to bottom.  This allows oil to flow in quickly and seep into all the threads.  When you use grease, it doesn't displace the old grease, a small amount flows up the slot and out leaving the bulk of the old grease in place.  You would need to make a new trunnion without the slot.  That way grease coming in from the bottom would push the old grease out.

Whether you have disastrous outcome, or not, seems to depend mostly on your local climate and whether you drive in the rain.  If your humidity levels are on the low side, and your car stays inside when it rains, probably you'll be fine.

[EuropaTC]

Brian, is that the lithium grease as described by BDA?

Hi,
No, I've always used the standard moly grease that you buy from most places, nothing fancy.

The debate over oil/grease will carry on.  My reasoning was simply that I have seen failed links that have gone at the junction where the rubber seal sits and corrosion has been present. When the cars lived outside and drove daily in our wonderful British weather I saw water droplets appear when I topped up the trunnions. Cause & effect.

I'd agree that the failures I saw were most probably due to lack of maintenance but then again, how many would stick to a 3 monthly service interval on a daily car after the novelty wore off ?

Grease isn't the ideal choice because most greases need a certain temperature to function & flow as intended which they're not likely to get in the trunnion. I can see why, in the 1950s when some greases would dry out and cake, an oil lubricant was the better choice. I can even see why some prefer it today.

But then again, I've never replaced a vertical link on either the Elan or Europa.  IIRC the Elan is on something like 160k and that's mostly been commuting, so for me, it worked. These days when the cars only come out in good weather and do very low mileages, I don't suppose it matters what I use.

[GavinT]

Anyone who has taken apart a gear reduced tool like a drill know grease is pushed out of the gears. Grease is good but you wouldn't use it in a transmission or differential. An oil engineer may say grease but a mechanical engineer would say there is the weight of the car on those threads pushing the grease out to the sides.

Yes, I do hear ya  . . though I don't think a drill is a comparable usage case.
We happily put grease in UJ's though.

Perhaps something like Penrite semi fluid grease covers all the bases? I recall someone suggesting semi fluid grease for the steering rack as well which made sense to me. It comes in a cartridge, too so that should make the change-over less messy if you have a grease gun which accommodates them.