Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: BDA on Tuesday,July 25, 2023, 12:16:48 PM
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So some (all?) of you know that I'm rebuilding my NG3 tranny and I thought that while I was at it, I might replace the clutch disk and throw-out bearing. But, of course, I've got some questions...
1. I probably have about 20,000 miles on this engine and clutch. It has been working fine though there have been some exceptions to that. Sometimes, not all the time, before everything warms up, it will be impossible to get off from a stop smoothly. Sometimes shaking the whole car until the clutch is fully engaged. This usually goes away after a few miles. Other times and more commonly, things are as smooth as silk. Also, the throw-out bearing does not rotate as smoothly or as quietly as a new one. Does anybody have any guidance about whether to change the clutch given that situation?
2. I'm leaning heavily toward replacing the throw-out bearing at least given its less-than-smooth operation. I can't get my old one off. I don't remember how I replaced it when I built the car but I also don't remember any drama associated with it (I would think I would remember it if there was but then that was over twenty years ago and like pretty much everything else, brains don't work as well when they get beyond a certain mileage). So how do you get the throw-out bearing off?
3. I bought r.d.'s clutch alignment tool. It has the required number of splines but the part that should go into the clutch spigot bearing seems too large. Does anyone have the proper ID of the clutch spigot bearing? Interestingly, the end of the primary shaft has those splines but does not have a "nose" that would go into the clutch spigot bearing! I'm doubtful but I wonder if that might be a cause for my clutch issue in #1?
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"If you see the throw out bearing, change it!", is what I have always been told and usually do!
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Yeah, similar to the advice a buddy gave me when I asked him if I should change the tranny bearings - if you're wondering if you should change them, change them.
Now, how do I get the old one off?
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I had to tap out the pins by drilling holes out in the bellhousing , but for a 336. I built a tool for pulling out the pins but found it easier to drill out, but that is on an S2. My arm was hitting the case stop. RD had the new pins. sadly I did not swap out the pressure plate and disc.
I have a TC bellhousing out and can send you dimensions to drill out from the top if needed.
After looking at the manual, check or lube the release arm seal.
x2 on the release bearing.
Dakazman
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BDA, you have to have this to engage in the spigot ,or the clutch will wanderer around.
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Thanks D’man. I’ll let you know about those holes.
Exlimey, that’s what I expected to have on the end of my primary shaft but I got nutten there but a lathe center - just as I received it from Richard. I can’t say whether the clutch disk wandered around or not unless my shaking or juddering was caused by that. I doubt it since it has behaved itself until recently (after 20,000 miles) and even now, it’s only from a start on a cold clutch but I won’t say it can’t be the cause. And then if it is, I don’t know how I can fix it as the primary shaft is certainly hardened and not something easily drilled.
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I had an Fuego Turbo NG3 I picked up cheap so it wouldn’t be binned. I gave it to a lister from Vancouver. Unfortunately I never even looked at it but I recall that the NG transaxles (some/all/later/?) had your set up. The input shaft is originally supported by an internal bearing inside the tube that the release bearing runs on. Now your set-up uses the original Lotus TC bell housing (I presume?). This would not have the correct support for this style of input shaft. The shaft would be free to move at least somewhat and this would indeed cause clutch judder.
Grab a hold of your input shaft. Can you wiggle it up and down at all? Has the bell housing been modified with a support bearing/bushing? If yes, what condition is it in?
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My bell housing has that input shaft bearing/seal. Now I understand why it’s required!!
My tranny is all apart so I can’t grab the input shaft but I’ll take a closer look at that bearing/seal!!
Thanks for another lesson!!
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BDA, I know you have an NG box but if the clutch side of your bellhousing is still an unmodified TwinCam type, the release bearing is easy to remove and replace. No need for drilling unless you want to also remove the cross shaft.
Just unclip the spring from the bearing carrier (parts manual, section QA) and the carrier+bearing slides right off, heading for the press and the new release bearing.
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Does not the input shaft run in a bearing in the end of the crank and or flywheel.? If you change transmissions, bellhousings and or engines, how do you align the input irt crank centerline? If the input is off center you will have clutch issues. Maybe the machining and adherence to factory specifications are of a very high standard for these transaxles and engines, most people have no issues? In American engines you need to check alignment or you will have problems with input bearings, chatter, worn and blown clutches.
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Thanks Peter!!! I knew there was a simple way to do it!
UPDATE: Spreading the springs hooked into the TO bearing carrier wasn’t too difficult. Now, just have the bearing pressed off the carrier and the new one pressed on. Thank you Peter!
Kram, using an NG3 requires that you have the Fuego pilot bearing pictured below. The chrome end contains roller or needle bearings to keep the input shaft aligned. I have that (Richard sold it with the NG3) but never really thought about why it was necessary till JB mentioned it. Unless mined is lunched it should not be the issue. While all this is apart, I'll be changing the clutch disk and inspecting the clutch cover.
edit: I forgot to add the picture of the pilot bearing!
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The clutch plate alignment tool I bought had several sizes for both the spigot bearing in the end of the crank, and the clutch plate splines. None were the correct size, so I used smaller sizes and wound plastic insulation tape around them until I got to the right size for each.
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I guess r.d. sells the cheapo alignment tool! It is plastic, the end that goes into the spigot bearing is way too big, and there is no adjustment provided. :-\ I don't have anything I can chuck it into to sand it down while it spins so I may have to take it to a friend who has a lathe. Jeesh!
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Just wrap tape around an extension until you get the sizes you need.
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DBA, Cool pilot bearing, explains a lot.
Not sure how you check concentricity though? Are all potential mated candidates; engines, various transaxles, line bored blocks, belhousings, etc... that accurate that no matter what combination is bolted together all align within a few thou? I found very few such instances when checking most engine to bellhousing alignments.
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Certainly, there are some assumptions that the centerline of the crank lines up with the hole in the bell housing for the input shaft - at least close enough. Judging from the previous 20,000 miles and the fact that mating an NG3 to a TC (or other Kent based motor) or Zetec is a common situation, I think we can feel pretty confident that those assumptions are good.
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I guess r.d. sells the cheapo alignment tool! It is plastic, the end that goes into the spigot bearing is way too big, and there is no adjustment provided. :-\ I don't have anything I can chuck it into to sand it down while it spins so I may have to take it to a friend who has a lathe. Jeesh!
Broom stick.
Reckon you could carve the pilot end with a pen knife and have it accurate enough - only needs to be a cone shape, really. Build up the clutch fingers area with insulation tape.
The trick to this is to use a longer length of stick which better aids 'eyeing' in the 90° angle. The commercially available alignment tools are usually quite short and more reliant on close fitment than a long tool.
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BDA , I have a snap-on alignment tool with different size adapters for the pilot bearing inner diameter
I can mail it up to you.
Dakazman
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i appreciate the suggestion, Gavin, and the offer, D'man, but the clutch alignment tool I have was easily adjusted with a bit of sandpaper and elbow grease! It fits very nicely now!
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I've just replaced my clutch and throw-out bearing, as the engine and box were out for starter ring gear replacement. I decided to tidy up the engine bay and fit stainless coolant and heater pipes whilst the engine was out.
my original TC bellhousing was modified by Richard as described by BDA together with a new pilot bearing some 20 years ago and although I have only put about 10000 miles on the engine since then it leaked a bit of transmission oil past the seal. Richard said they all do this and its nothing to worry about. Sadly in the UK the pilot bearing seal combo is pure unobtanium, so I reused the old one. Just got the engine and box back in drove it and it pisses out now when hot! BTW NG1 series gearbox with Banks twin link.
Got to pull it again and think of a replacement. I wondered it the input shaft could be turned and a bush or bearing holder could be made to fit the flywheel? I guess the bellhousing would have to be returned to standard or buy a new one. Happy days :(
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When I was talking to Michel at Alpine-America about parts for my NG3, he mentioned they were difficult to get. Lotus Supplies says it's still available but you'd have to contact them to be sure.
I looked at mine and it appears that the seal is an O-ring deep inside it. If yours is truly bad, it might be worthwhile to try to pick that out and attempt to fabricate a replacement with a slightly bigger O-ring. Or maybe something could be fabricated to accept a standard lip seal in it.
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I spoke to Nick at Lotus supplies a couple of months ago and he cant get them! Richard said if you find one ...buy it!
I like the idea of an O ring mod first
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I have an NG3 so this thread is useful to understand supply issues with once available components
So a surf found me this:
https://www.3sx.com/3sx-high-performance-billet-input-shaft-bearing-for-5-6-speeds
I wonder if a combination of talking to Richard Winter and this company would produce a useful bespoke component for those of us who have this great gearbox? Pricing would be interesting !
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It appears those bearing/seals are meant for Mitsubishi 3000GTs. Should we assume they replace the Renault part?
If so, I would wonder if the standard 3000GT part is still available (at much lower cost). But on the other hand, having a rebuildable part would be very nice. They could out last the tranny!
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Ah! Sorry I didn’t mean to imply that these would fit our NG Renault gear boxes….I just found something similar on google images that shows that something akin to the NG could be machined…..and if they could be rebuildable using off the shelf parts that would be encouraging and help to swallow the higher price for bespoke parts
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I was about to post that someone could call them up and ask them the dimensions but I thought better of it and called them myself!
First, I measured what I considered were the most crucial dimensions:
shaft diameter: 25mm
bearing end diameter: 37.3mm
skinny end (throw out bearing end) diameter: 30mm
Then I emailed them and I should hear back in a day or two.
If anybody has their bearing/seal unit out and can measure it, please check my measurements. I had to use a scale graduated in 1/64ths by eyeball for the skinny end diameter so they all can stand review.
I'll post their reply. It doesn't look like anything that is that difficult to recreate in our dimensions should anybody have the inclination.
UPDATE: I heard back and our dimensions are not even close so they can't help us. Maybe a bug in Richard's ear might be helpful...
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Well done for getting hold of them and trying….Richard is an innovative man he must be considering how he’ll solve this unobtainium part
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BDA, Can the needle roller bearing be replaced?
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I don't think so. The housing appears to be made of sheet metal and the bearing is retained by rolling the edge of the sheet metal.
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Could not one of these be made on a lathe and a standard roller bearing pressed in? Doesn't look to be to complicated.
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Yeah, that's essentially what the 3sx Performance guys that S2Zetec54 pointed us to did. I think it's all about finding a bearing that will take the input shaft and fit inside the dimensions of standard bearing/seal that would take the rpm and have good life. I was poking around and found this one (https://bearingsdirect.com/25mm-bore-hk2520-needle-roller-bearing-25x32x20-tla2520z/) that seemed like a possible candidate. I would expect finding a seal would be a lot easier. Someone would have to take one apart to better re-engineer it but it shouldn't be too difficult.
I might try calling Richard tomorrow to see if he's up to it but don't make that an excuse for you not to call him if you have a mind. Anybody who calls him should reference the 3sx Performance page that S2Zetec54 linked earlier to make sure he gets the idea.
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If I had an example of the unit pretty sure I could replicate it for you.