3 series vs NG series Renault gearboxes

[BDA]

While doing research for rebuilding my NG3, I joined TurboRenault (https://turborenault.co.uk/) for some help in finding a source for some Renault specific bearings. A gentleman replied to my thread (in which I had mentioned that I had replaced my 365 with an NG3) and offered his opinion and insights into 3xx and NGx Renault gearboxes:

These boxes [NGs] are easier to strip and build compared to the 3 number series, but that was when the parts were available, which they are not now, which makes them less serviceable than the early stuff. For what it's worth your 365 is a better thing than the NG3 , not as good as a late Renault 365 (74-76) but pretty good.
NG boxes work better with multigrade oils as the synchros are weaker than 3 number series with lighter hubs . If you are in the US you should be able to get Lucas oil products 75/140 EP oil. this is what I usually recommend to people. Don't get the thicker version 85-140 or you'll never get a gear when cold.
The gears want a light oil, but the CWP needs a high EP oil, it's the eternal transaxle problem.

I am not promoting his opinion as correct or not, though I suspect it is. I've certainly had a hard time finding two Renault specific (and maybe NG3 specific) bearings which surprises me because I figured that with more recent production, parts would be more available. That was a major reason why I replaced my 365 with my NG3. Anyway I thought his comments might be a point of interest and maybe discussion for some of us.

[EuropaTC]

Hmm, now that's an interesting viewpoint and coming from someone who sounds to be into Renaults, it does shake up my perceptions. As you know, I've wondered every now and then about getting an NG3 as a backup even if I just park it in the garage until needed, but maybe I'm out of step with reality.

I know you've had a struggle getting parts for yours but the tone of what this guy is saying makes it sound like going for a more modern box isn't the long term security I thought it was.  Thanks for posting, it's something worth thinking about.

Brian

[jbcollier]

The 3 series boxes are now better supported for a variety of reasons.  First, a rise in interest in preserving the ordinary cars they came in (R16, R12, R17, etc).  Second, the fact they were used in very desirable specialty cars, notably Alpine A110 and A310.  Lastly, the same interest is only just starting for Fuegos et al.  People switched to NG3s because of the enormous reserve of scrap vehicles and, at the time, continued factory parts supply.  Both of those have timed out now.  It is getting very hard to find Fuegos now.  Barely a blip on the production map when new, Europas easily out number them now.

That all said, the person quoted may not be familiar with the Lotus-Renault 365 with its Hewland supplied 0.85 5th gear.  Spares are rapidly approaching pure unobtainium and was the reason for Banks to start the shift to NG3s in the first place.

My transaxle project was delayed a year but I will probably have a few rare 365 spares available when it is completed: ring and pinion set, excellent 5th gear set, rear housing, and a NOS 5th shift hub assembly.

[SwiftDB4]

BDA- Which Renault specific bearings are you referring to?

[BDA]

At the moment I'm waiting to see if Michel can get the pinion bearing (bearing on the secondary shaft near the pinion) and its cousin on the primary shaft (the bearing on the pinion end of the primary shaft). These bearings do not have an inner race. The races are ground in the shafts. There are no identifying marks of any kind on the outer races. Renault16Shop has the same type bearings for at least some of the older boxes and they might have had them for other Fuego boxes but not the NG3, I don't remember specifically.

If you've talked with Michel, you know understanding him can be a challenge if you're not up on your French (which I am not) but I understood him to say that he has never (or maybe rarely) replaced these bearings on an NG3 (I got the feeling that he had replaced them on other boxes but I'm not positive). I'm hoping to change these because the ones I have appear to have very slight pits probably a little less then .5mm (comparing to a pencil point) in the outer races. You can't feel them with your finger but you can see them. Also, I am changing all the other bearings so I'd prefer to change them all if possible. Michel thinks he'll be able to get them but if not, I'll obviously be forced to reuse the ones I have which would not be the end of the world for me.

[Kendo]

Send me packing if this is a terrible idea, but can you take a bearing with otherwise the right dimensions and construction and cut out the inner race? In the original, the balls must be retained anyway or you couldn't install the bearing.

[Bainford]

BDA, have you tried bringing the bearing to an industrial bearing supply shop (industrial power-transmission shops or industrial seal shops also a place to look)? They may be able to measure the bearing and identify a suitable replacement. The array of sizes and styles of bearings in industry is immense, and there may be something out there that will fit. I used to work in an industrial mechanical shop and overhauled all manner of pumps and equipment, often old and unsupported equipment, and with bearings whose identifying marks were indiscernible or the maker no longer existed. I'd measure the bearings and bring the them to one of three shops available locally, and a suitable replacement was usually obtainable. A roller bearing for which the shaft is ground as the inner race is not that uncommon, so that might not be an issue.

Just a thought...

[BDA]

Kendo, these bearings are both roller bearings and are different from most because they don't employ a cage. Also, for "traditional" bearings (ie. those with an inner race), the critical dimensions are the OD of the outer race, the full width of the bearing and the diameter of the shaft it's intended for. I'm sure that for "standard" bearings such as a bearing supply house would provide, the dimensions of the rollers or balls would also be called out but these are unusual compared to "traditional" (dare I say "normal"?) bearings so there is no way that I know of to translate the inner diameter of the rollers without (since we are talking about French bearings I should say "sans"  inner race even to the diameter of the races ground on the shafts if I could find similar roller bearings without races. But even if I could do all that, there is a positioning ring in the outer bearings that positions the bearing in the case. Even with similar Renault bearings for other boxes, the positioning ring is not in the same relative position on at least the big bearing.

I've attached some pictures to give you an idea what I'm dealing with.

Bainford, I enquired about these (not even mentioning the positioning ring) at 123Bearing which is a French company that is a general bearing supplier. They couldn't help me. I didn't try any US bearing houses for these because I figured if a French outfit could not supply a bearing from a French car, it was highly unlikely to be available from a US bearing supply house that would deal more commonly with Imperial sized bearings. I could be wrong but I think Michel is my best bet.

Thanks! I appreciate everybody's thoughts! 

[SwiftDB4]

I'd be really wary of trying to get some other bearings that would match all the necessary dimensions of pinion bearings. From your description of your existing bearings I would just go with them. I've worked on a couple of NG3's and an NG1 and they seem pretty stout even with some wear.

[jbcollier]

In the first photo, there is an inner race.  Same/similar bearing is used in the 3 series boxes.  Check the Meca-Parts site, they offer a couple of variants, check using dimensions.  The inner race is on TIGHT.  You have to cut it off VERY CAREFULLY.  Renault never supplied these bearings separately, only complete with the pinion shaft.

[BDA]

I THINK this is a rare one that you missed JB - but I fully reserve the right to be completely wrong!!!

The secondary shaft shows no sign that I can tell that the inner race is not ground into it. There is no line and there is a radius between the radial surface of the race area and the shaft. The first picture is intended to show that but admittedly it doesn't do it very well. It was the best I could come up with. As a matter of fact, the fact that I don't see or feel anything that would draw me to the conclusion there is no separate race is not dispositive to me.

Another piece of evidence is that MecaParts sells a very similar bearing (second picture) that includes what must be a plastic ring on the inside to hold the rollers in during stocking and installation. The dimensions of this bearing are in the pictures. The dimensions of my bearing are 41.7x72x19mm. So close and yet so far!!

Another piece of evidence is the last picture taken from an exploded diagram from the NG manual. Part #44 is the bearing we're talking about and it appears to show rollers rather than an internal race.

Lastly, I see no way of getting that race off the shaft since there is no access to the pinion side of it as the pinion covers the race.

Well, I admit that what I've shown is not necessarily proof. I welcome rebuttals.

[jbcollier]

Did your tranny have water in it?  That race looks pooched.  Do you still have your 365?

[SwiftDB4]

Could you take another photo of the pinion bearing surface without the oil? JB may be right, but it's not clear to me.
You are right that the inner race is the shaft itself. See attached photo. I was able to get the pinion bearing I.D.
SNR
France
NU10552  S01

In fact it is still listed on NTN website
https://eshop.ntn-snr.com/en/product/RNU10552S01-SNR/RNU.10552.S01
Did find that 123 bearing has it in stock:
https://www.123bearing.com/bearing-housing/gearbox-bearing/rnu10552-s01-snr

Sorry no ID on the other bearing.

[BDA]

Bummer, Swift! I'm sorry about your secondary shaft. Yep, the pinion and crown are matched so you'll have to find a pair.

RNU10552-S01-SNR is the pinion bearing!!! How did you find it?! I plugged the OD and width in their dimension search and didn't find it. I even asked about it on their messaging app and they came back that they didn't have anything like that. I've already got Michel looking for me so I don't feel cutting him out and getting it on my own. If he ends up saying he can't find it, then I'll know where to go. A big thank you (even if it might be too late for me to use).

I assumed you used the same method to find the primary shaft bearing, right?

Attached are better pictures of the race. Not terrible but not as good as I'd like but then I'm not really sure how to grade it. I figure I've put about 20,000 miles on it and for grins and giggles, let's assume that the owner of the Fuego that it came out of threw his car away (or crashed it) after 50,000 miles. I think a reasonable mileage for my tranny is 70,000 miles. A new ring and pinion is not in the budget so it will have to do regardless.

[SwiftDB4]

The pinion shaft in my photo doesn't matter. It's from a box of used NG3 parts someone gave me. NG3 in the Europa is fine.
I got the pinion bearing # right off an old bearing itself. Used primary shaft bearing had no # at all.
As far as pinion shaft wear I'd go with it. Not ideal, but it should work. Trying to locate a new NG3  R&P is probably impossible.
Heck I had to grind down a wider snap ring from my used supplies because one in the trans was cracked. Renault used 2 different widths on the snap rings and they're unobtanium now.
Reusing snap rings isn't ideal either, but even Richard Winter admitted to doing it.
20,000 miles later no problems.