Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: BDA on Wednesday,July 19, 2023, 08:05:56 PM
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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.
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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
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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.
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BDA- Which Renault specific bearings are you referring to?
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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.
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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.
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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...
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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! :)
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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.
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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.
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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.
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Did your tranny have water in it? That race looks pooched. Do you still have your 365?
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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.
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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.
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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.
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Did your tranny have water in it? That race looks pooched. Do you still have your 365?
Sorry I missed this. No water that I’m aware of and I no longer have the 365. I think what you’re seeing is some grease I used to hold the rollers in the race to “install” the bearing onto the shaft.
That brings up a question: would it be a bad idea to use a little grease to hold the rollers in the outer race to make it easier to put the bearing on the shaft? Or would it be better to install them dry? Possible but not as easy.
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Found the primary shaft bearing.
Renault # 7703090256
https://www.renaultgenuineparts.com/renault-7703090256-bearing-gearbox/
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A little grease is just fine. Glad to hear what looked like pitting isn’t!
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PS: cleaned up, the pinion race looks fine.
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Thanks JB. That gives me some real confort.
Congratulations, Swift! You found the last missing piece. As I said before, I've already asked Michel to find this for me so if he actually does find one, I'll take his. If not, I know where to go.
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Try this stuff for tranny assembly: Dr. Tranny Assemblee Goo #19250 by International lubricants (206) 762-5343. I got under NAPA # 765-2615. BAR CODE is 0 83137 19250 3
Holds heavy rollers, needle bearing, etc and then just melts away when heated under operation.
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Thanks Kram!
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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.
Woops, didn't see this either. Glad everything with your box is alright!
Michel said to use the snap rings over again, too. Mine came out ok. Hopefully they'll go back in ok. As I remember, they came in two sizes (30mm and 32mm IIRC) but I think I measured them as the same thickness. Anyway, I think I labled the position they were when they took them out so I THINK I'll be ok there.
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In the 46 years I've owned my Europa, it's had 336 [OEM], 395 [18GTS] and NG3-99 [Espace diesel] gearboxes.
The 336 came out at 71k miles by which time it had developed a low pitched rumble in all gears. This turned out to be the fault of a well pitted pinion bearing inner race, by comparison the one BDA photographed looks nicely run in. I replaced the bearing, not simple because the inner race needed to be ground such that it ended up with a split to relive the clamp load, tedious but the only way it was going to happen. That was 42 years ago, at the time it was replaced in the car with an almost new 395. The 336 has been doing static dry endurance in a variety of sheds and garages ever since..
The NG3 has a more precise shift quality I think because it has two selector shafts, one for fore-aft gear selection and the other to move across the gates. More travel, therefore any lost motion has less effect, selecting gears is very predictable these days, if having the feeling of 'moving some mass' in contrast to a modern shift that feels very light.
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Very interesting, Richard! I’m curious about a couple of things:
Could you provide some details about how the inner race of your pinion bearing was ground and repaired? I assume the pits were ground out and something was applied to the surface to bring it back to the original diameter. I don’t understand about the “clamp load” or split but assume it is related to what brought the diameter back to spec. Since it has been doing “static dry endurance” since then I guess there’s no way to assess how successful that fix was…
What led you to replace the 395 with the NG3?
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The three series transaxles have a separate inner race for the pinion roller bearing. It is a VERY tight press fit and retaining compound is used a well. You have to grind a slot in order to break it free, very tricky but I’ve done a couple now with no issues.
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I see why you suspected that mine had a separate race. I suppose it was a cost saving measure to grind a race onto the shafts. I'm puzzled why so much attention needed to be paid to the inner race not spinning on the shaft (I assume that's why the tight press fit and retaining compound) since the bearings on the other end of the shaft are "regular" double tapered roller bearings and double row ball bearings. Maybe it has something to do with the fact that the nuts on that end of the shaft help lock in the inner race??
I hadn't thought about it till now but the outer races of the output shaft bearings are not locked in the tranny halves so they can be adjusted for preload. That would seem to allow a risk that the outer race might break free and spin. How are they installed? The manual explains how to get them out (by gently taping them out with a 71mm tube or similar). Should I assume they go in the same way?
Speaking of those output shaft bearings, the manuals says to set the preload for those bearings with only the diff installed in an assembled case. Wouldn't the preload need to be readjusted after the backlash was set? Why is the preload supposed to be set before the box is build? Just to get it in the ball park?
Yeah, I know... questions... questions... questions...
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It has to be super tight fit given the tremendous loads on the pinion bearing.
Had to scratch my head a bit. What you call “output shaft bearings” are really diff carrier bearings. The factory method is to set the preload in a position where there will be too much free play when it all assembled. Then move each nut equally to get the free play correct. It works, if a little involved. I just get the free play set slightly too large (a thou or so) with zero preload and then turn one side to add preload and get the free play perfect.
The tapered roller’ race is tight into the “nuts”. They don’t rotate. I use an old race to drive the new ones home. Do not drive the race out crooked. This can distort the nut and impair the fit of the new race. Make sure you drive it out square. I just tap it out alternating from one side to the other.
Finally hammers and bearings are both hardened surfaces. Hitting them together can cause chips which travel at very high speed. Use a punch instead and wear eye protection.
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Lastly, I have built a lot of diffs. I mostly set them up by feel now. Just go slow and don’t be afraid to back-up a bit if you’re not sure. Diff preload is light weight in these transaxles. Get it to zero, then add a smidge. When rotating the ring gear you should be able to feel the difference between zero pre-load and preloaded. Zero preload is just right when the free play in the diff carrier bearings disappears (No side to side on the ring gear).
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You are of course correct that I was referring to the diff carrier bearings. Being the first tranny or transaxle I've ever rebuilt, I haven't gotten all the terminology and sometimes the relative orientation right. I think elsewhere I've used "hub" incorrectly... I'm learning and I appreciate your correction! :)
I have set the bearing preload before (with your help - thank you again) so I pretty much know that drill but my curiosity was why did the manual say to set the preload before before installing the secondary and primary shafts. Since the ring and pinion back lash would have to be adjusted and doing that would require adjusting the finned nuts which moves the outer races and so you'll have to set the preload again. Is the reason to set the preload without the secondary shaft and pinion just to get a starting point? Also, I've noted the number of turns to take the finned nuts off each case half. Would it make sense to start there (primary and secondary shafts not installed) rather than actually set the preload?
Thanks also for the tips for getting the old races out of the case. I already got them out and they were very easy to get out which got me wondering about how well they will stay stationary in the bores of the case. After all, if they are loose enough to move in and out, it seems like they could also rotate.
I also noted that the manual calls out using molykote grease on the sunwheel in the diff. Since I'm not rebuilding the diff, that gives me pause when I consider washing out the diff in my parts washer (that sounds silly since whatever molykote was used to assemble the diff originally would certainly have been washed off long ago with tranny oil) but I just want to make double dog sure it would be ok to clean the diff in my parts washer.
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The idea behind setting the preload first is to eliminate the drag of the rest of the gears and bearings from affecting your readings. Given the preload is so low, I wouldn't worry about it, just zero preload + plus a bit. I recently did my Lotus Seven's diff as I fit a torsen unit. There you measure case spread. You tighten the adjuster nuts, keeping the proper freeplay, and spread the case by 12 thou. That's quite a bit more than what the Europa gets as its cases are so much stiffer and the bearings much larger. All that to say, if you get slightly too much preload, it is no big deal.
The races should be a tight fit into the adjuster nuts, not a push fit. If you feel they might be not tight enough, use retaining compound.
If you have kept it clean and covered, there is no need to wash the diff assembly. If it dirty such that you feel it needs cleaning, disassemble it and do it properly.
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Taking apart the diff... Oooh... I really don't want to do that. Besides replacing the self locking bolts, I'd also have to replace the planet wheel shaft retaining collar. I might be able to get those but given the dance I've had to perform just to find bearings (which I still don't have), I don't have a warm fuzzy feeling about it. I'm already starting to feel a bit overwhelmed with this project and I want to have it all together for the LOG in a little less than a month. I think I'll wipe it down with solvent and blow it dry keeping as much solvent out of the inside of the diff as possible.
When you say "retaining compound", what are you talking about? Do you mean something like Loctite 660? Wouldn't that essentially glue the bearing race to the case?
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Do not open up the diff unless there's a really compelling reason. I have had a couple open because I mistakenly thought the longer NG3 stub axles needed to be replaced with the shorter 'Lotus' ones. Because I have a twin link suspension that's not necessary. Everything went back together OK, but I had to reuse the bolts and retaining collar.
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Wait a minute, I’m full of crap. The races are pushed by the nuts but retained in the cases. They should be a snug fit, not a press fit. They should NOT be loose. No retaining compound, please.
You can absolutely reuse the ring gear bolts. Clean them and use red loctite when reassembling.
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No worries, JB. I explained on my "Never a Straight Line" thread in the Member's Cars forum how I got them in. They are snug so I worried in vain. I didn't use any Loctite. I elected not to take the diff apart. I had the bearings pressed on the diff carrier and then I just cleaned the outside of it and blew it dry. Everything went pretty smoothly so I'm ready to receive my pinion and primary gear bearings and start putting it back together!
Thanks for checking in Swift and JB!
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I'm anticipating receiving the last parts to rebuild my tranny (I'm holding my breath because I want to make the LOG on Aug. 25!). Getting all the parts cleaned and laid out so hopefully the assembly will be quick and error free (it is HIGHLY unlike me to be this organized!).
Can anyone who's built a tranny tell me if I should assemble it dry or should I squirt some tranny oil on the parts first?
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Outside of oiling the diff and R&P the rest of the internals probably don't matter. On start up oil will quickly get thrown onto everything else. You're also not loading most of it until you put it in gear.
However if it would make you feel better oiling everything it wouldn't hurt if you can keep the RTV case surfaces oil free.
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Thanks, Swift. That's what I thought but I wanted confirmation.
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I would lightly oil any rotating part (loose gears, bearings, etc). ESPECIALLY 5th gear. It take time for oil to get up there and work its way in.
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Good idea, JB! Thanks!
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I've set the ring/pinion backlash and when setting the bearing preload, the load to turn ring gear is too much - about 8 lbs (it's supposed to be between 2.25 lbs and 6.75 lbs) even though the side opposite the ring is loose. I can wiggle the output shaft on that side a little so it's clear the bearing isn't making good contact with the outer race. I squirted some oil on those bearings (not much inside the tranny though). There is a drag such that when turning the primary shaft with the box in neutral, the secondary shaft turns too. When you hold the secondary shaft it stops turning and the primary shaft spins by itself.
Because I don't know any better, I'm thinking this is because all the synchros are new, the pinion bearing and the equivalent primary shaft roller bearing have some grease on them (for putting it together), and that everything is a little tighter now.
I'm thinking I'll tighten the adjusting nut till the outer race makes good contact with the rollers in the bearing and then tighten a little more.
Does anybody have a better suggestion?
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After sending you a couple of PM replies I reread your post. You set backlash before preload? Preload needs to be set first, then backlash adjustment by turning one side clockwise and the other counterclockwise an equal amount until backlash is correct. 8-9 lbs. preload would be in the ballpark. In fact reading my Hewland FT200 gearbox manual some transaxles don't even give a preload spec, just tight enough so rotation effort of ring gear isn't excessive.
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The way I thought about it is the backlash is dependent on the interface between the pinion and the ring gear. That is set by adjusting the bearing on the ring gear side - making sure that the diff is fully against that bearing. Then the preload can be set by adjusting the bearing on the other side of the diff. This doesn't change the relationship between the ring gear and the pinion so your original backlash setting is preserved so less tail chasing.
I think either way works. I have to confess that I had trouble following the manual but looking at it again, it does go through the preload instructions first and much later goes through setting the backlash procedure.
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You can’t set the backlash first. If one side is loose, then the diff carrier can rock making it impossible to set the backlash. You set both at the same time. Dial in zero preload with slightly excess backlash. Then move each in sync until backlash is correct.
Check backlash in multiple places!!
Lastly, the preload spec is for when there are no other shafts, etc in the transaxle. You are setting it up fully assembled so the preload figure will naturally be higher.
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Thanks JB! That makes sense. I see now that I should have set the preload before I assembled the box. I would note that about five years ago you helped me with adjusting my backlash and preload and I was able to get the preload within stated limits. (http://www.lotuseuropa.org/LotusForum/index.php?topic=1960.msg18526#msg18526)
I’ll double check backlash at different places on the ring gear.