420r diff bang and clatter fix (possibly)
Discussion
Hi all, just thought I'd share this from blatchat. My 420r has always had the banging and clattering on low speed turns and I was happy to see the thread about a 3mm spacer Caterham are now supplying to virtually stop this...
It slips in at the back of the gearbox once the two big nuts have been taken out:
I'll report back when it's fitted, fingers crossed!
It slips in at the back of the gearbox once the two big nuts have been taken out:
I'll report back when it's fitted, fingers crossed!
Have you tested your LSD using the techniques described in the Blatchat thread i.e wheel direction and preload?
The reason I ask is my 420R had the same problem of low speed knocking/chatter whilst cornering and it turns out it was because the Titan LSD was shot!
Hopefully that’s not your problem here.
The reason I ask is my 420R had the same problem of low speed knocking/chatter whilst cornering and it turns out it was because the Titan LSD was shot!
Hopefully that’s not your problem here.
slime bomb said:
Hi all, just thought I'd share this from blatchat. My 420r has always had the banging and clattering on low speed turns and I was happy to see the thread about a 3mm spacer Caterham are now supplying to virtually stop this...
It slips in at the back of the gearbox once the two big nuts have been taken out:
I'll report back when it's fitted, fingers crossed!
So it’s a spacer between gearbox and gearbox mount?It slips in at the back of the gearbox once the two big nuts have been taken out:
I'll report back when it's fitted, fingers crossed!
I’m assuming what that does is raise the tail of the gearbox in the tunnel?
I can’t see how that would get rid of diff chatter at all?
Unless the intent is to act as some type of insulator or harmonic damper?
What is it made out of?
nigelpugh7 said:
So it’s a spacer between gearbox and gearbox mount?
I’m assuming what that does is raise the tail of the gearbox in the tunnel?
I can’t see how that would get rid of diff chatter at all?
Unless the intent is to act as some type of insulator or harmonic damper?
What is it made out of?
Yes.I’m assuming what that does is raise the tail of the gearbox in the tunnel?
I can’t see how that would get rid of diff chatter at all?
Unless the intent is to act as some type of insulator or harmonic damper?
What is it made out of?
Yes.
Me neither.
Possible but doubt it.
Aluminum.
If the rain stays off today I'll take it out for a spin and report back, if not, tomorrow.
So, at first I thought there was a difference but I think that was physiological. The noise is still there. It doesn't affect the performance in any way, it's just a bit embarrassing.
Oakmere Lotus (where I bought the car) said the usual, "they all do that sir" but did admit that it was on the noisy side. CC denied there was a problem.
I must say though that after 12,000mls all is fine except for the banging and clocking. I will eventually end up at SPC for one of their diffs.
Oakmere Lotus (where I bought the car) said the usual, "they all do that sir" but did admit that it was on the noisy side. CC denied there was a problem.
I must say though that after 12,000mls all is fine except for the banging and clocking. I will eventually end up at SPC for one of their diffs.
So, just for reference, these are my photos, and this part resolved a noise which was suspected to be diff noise during PCB on my car. Obviously this spacer wont fix anything internal to the diff. My noise must have been gearbox touching the chassis, only in reverse, straight or going around a corner, hence I wasn’t convinced it was the diff.
Here is a video of the noise
https://youtu.be/F2PXEphbYec
The other thing which reduced noise was a change of oil to Road and Race Transmission special blend for the Caterham BMW Titan unit.
It’s also common that a diff tries a Freddy Mercury and wants to break free by shedding mounting bolts. A regular spanner check is recommended,
If your 420R is a 2018 vintage, do you know the type of plates you have fitted in the diff, and what your preload is?
Here is how to check your diff’s preload, if it is below 20 lbft it’s time to speak to a specialist.
https://caterham420detailedbuildblog.co.uk/2020/10...
Here is a video of the noise
https://youtu.be/F2PXEphbYec
The other thing which reduced noise was a change of oil to Road and Race Transmission special blend for the Caterham BMW Titan unit.
It’s also common that a diff tries a Freddy Mercury and wants to break free by shedding mounting bolts. A regular spanner check is recommended,
If your 420R is a 2018 vintage, do you know the type of plates you have fitted in the diff, and what your preload is?
Here is how to check your diff’s preload, if it is below 20 lbft it’s time to speak to a specialist.
https://caterham420detailedbuildblog.co.uk/2020/10...
HeliChris,
I'm guessing my plates are sintered as when I checked the preload it was 39lb with 12,000mls on it! All bolts are checked regularly and are fine, nothing is touching or catching the chassis either.
Like I said, it's only the noise that's embarrassing, everything else is a hoot!
I'm guessing my plates are sintered as when I checked the preload it was 39lb with 12,000mls on it! All bolts are checked regularly and are fine, nothing is touching or catching the chassis either.
Like I said, it's only the noise that's embarrassing, everything else is a hoot!
Your preload suggests all is healthy (which I think you knew), have you tried the RRT oil?
My experience with my 420R, the effect of the oil was masking by the noise caused by clearance issue with the gearbox. It just goes to show it’s difficult to isolate where noise is coming from.
On reflection the reason my noise was unusual was it was present when reversing in a straight line. I can’t see why the plates would make nose in that situation. I can see how the ramp angle / plant gear pins could, but I think the Titan LSD is a one way LSD. So I shouldn’t be surprised that the fix wasn’t diff related.
RRT is local(ish) to me, and I have used them for various upgrades over the years. I even dropped a gearbox off to them a few years back when I had a warranty issue, under Caterham’s instruction. So they will be fixing any issues I have, so can’t see a problem running their recommended oil.
My experience with my 420R, the effect of the oil was masking by the noise caused by clearance issue with the gearbox. It just goes to show it’s difficult to isolate where noise is coming from.
On reflection the reason my noise was unusual was it was present when reversing in a straight line. I can’t see why the plates would make nose in that situation. I can see how the ramp angle / plant gear pins could, but I think the Titan LSD is a one way LSD. So I shouldn’t be surprised that the fix wasn’t diff related.
RRT is local(ish) to me, and I have used them for various upgrades over the years. I even dropped a gearbox off to them a few years back when I had a warranty issue, under Caterham’s instruction. So they will be fixing any issues I have, so can’t see a problem running their recommended oil.
I have commented before about LSD,s.
Fitting one obviously changes the drive, feel and handling of the car. What you gain is traction, and the ease of cornering at higher load. What you loose is some of the "seat of the pants" driving and rear end movement. There is fun and skill in both setups.
If that was the only difference, it would be a hard choice, however there are two other additional difference - the LSD whines, rumbles, clatters and chatters. It's just under you left elbow, the noise is constant and awfull to listen to, plus it suffers from wear and breakage so needs constant service, repair and parts replacements. ( All detracting from the driving pleasure ).
Taking all this into account, I feel a standard diff is my choice. My car is top end spec in every way but no LSD, so no hassles, noise, worries, repairs, failures or expenses. The only time your likely to miss it is on a track day. For road use my car is ace without one. Playing with the back end on the throttle is all part the fun.
My advice would be to run your car with a standard diff and swap it out just for track days ( if you feel the need ). With a de Dion setup I think anyone could do this in a couple of hours with a basic set of spanners. Once you've done it once, you could do it with your eyes closed.
The only other advantage of having a LSD is pure bragging rights. If that's a factor in swaying your decision, there's not much I can say without being rude, but I'm sure there are some of you out there and you know who you are. ( I don't think that includes anyone posting on this thread, so you guys can relax. I don't mean any of you ). Some people tick all the extras boxes without really understanding what they're buying. They just think that the more expensive - the better. But sometimes less is more.
Fitting one obviously changes the drive, feel and handling of the car. What you gain is traction, and the ease of cornering at higher load. What you loose is some of the "seat of the pants" driving and rear end movement. There is fun and skill in both setups.
If that was the only difference, it would be a hard choice, however there are two other additional difference - the LSD whines, rumbles, clatters and chatters. It's just under you left elbow, the noise is constant and awfull to listen to, plus it suffers from wear and breakage so needs constant service, repair and parts replacements. ( All detracting from the driving pleasure ).
Taking all this into account, I feel a standard diff is my choice. My car is top end spec in every way but no LSD, so no hassles, noise, worries, repairs, failures or expenses. The only time your likely to miss it is on a track day. For road use my car is ace without one. Playing with the back end on the throttle is all part the fun.
My advice would be to run your car with a standard diff and swap it out just for track days ( if you feel the need ). With a de Dion setup I think anyone could do this in a couple of hours with a basic set of spanners. Once you've done it once, you could do it with your eyes closed.
The only other advantage of having a LSD is pure bragging rights. If that's a factor in swaying your decision, there's not much I can say without being rude, but I'm sure there are some of you out there and you know who you are. ( I don't think that includes anyone posting on this thread, so you guys can relax. I don't mean any of you ). Some people tick all the extras boxes without really understanding what they're buying. They just think that the more expensive - the better. But sometimes less is more.
Yes, RRT oil will be the next step. And thanks for the tip HeliChris.
I didn't spec my car, it already had it when I bought it. The only have the experience I have of any other is of a live axal I had in my old 1992 Super Sport. I'm too long in the tooth to do 'bragging rights' I'll leave that to the younger folk!
I didn't spec my car, it already had it when I bought it. The only have the experience I have of any other is of a live axal I had in my old 1992 Super Sport. I'm too long in the tooth to do 'bragging rights' I'll leave that to the younger folk!
I did already say that I didn't think the bragging rights thing applied to you.
What I'm advising is this : Owning and driving these cars is all about the fun. If you have a component that is causing you hastle and worry that detracts from your enjoyment - change it. It only serves any tangible advantage in lap time, if your not racing it competitively on a regular basis, a standard diff is fine. It will alter the behaviour of the rear but only at more extreme load though won't make it any less fun to drive, in fact it will most likely put a greater grin on your face as you can more easily steer the rear on the throttle.
Just imagine cruising or blatting round the countryside while being able to hear the birds or other regular noise without a care in the world, instead of a loud clatter, chatter, rattlle, whine, crunching etc while that voice in your head is asking " is something about to let go and leave me stranded ??? !!! "
For me it's a no brainer. As I say, you can always swap it in and out really easily just for track use if your particularly competitive.
What I'm advising is this : Owning and driving these cars is all about the fun. If you have a component that is causing you hastle and worry that detracts from your enjoyment - change it. It only serves any tangible advantage in lap time, if your not racing it competitively on a regular basis, a standard diff is fine. It will alter the behaviour of the rear but only at more extreme load though won't make it any less fun to drive, in fact it will most likely put a greater grin on your face as you can more easily steer the rear on the throttle.
Just imagine cruising or blatting round the countryside while being able to hear the birds or other regular noise without a care in the world, instead of a loud clatter, chatter, rattlle, whine, crunching etc while that voice in your head is asking " is something about to let go and leave me stranded ??? !!! "
For me it's a no brainer. As I say, you can always swap it in and out really easily just for track use if your particularly competitive.
I guess these things are subjective, but having owned Caterhams with open, Quaife ATB & clutch plate type diffs & covered substantial mileages with each type, I feel an open diff isn’t the best choice if you enjoy steering the car with the throttle. The rear end may slide more readily initially, but keeping the slide going is difficult as the inside rear wheel tends to spin, giving a feeling of the power bleeding away, even with the throttle pinned.
For me, that feeling of the throttle input having a predictable & repeatable effect on the attitude of the car is one of the joys of a rear wheel drive sports car. An open diff fails you just at the point where you need the control the most.
I feel a LSD is of benefit even if you’re not sliding luridly around corners, Top Gear style! That sense of being able to subtly point the nose with the throttle & have the assurance that the tail will gently edge out when you want it to, without the power bleeding away through the lightly loaded wheel really adds a feeling of satisfaction for me.
I’m not saying a LSD is essential, I drove my first 7 for ten years with an open diff & still enjoyed the car enormously, but for me it’s undoubtedly worth any additional hassle it may bring.
I swapped the BMW Titan in my 420R for a Tracsport last year & almost 5000 miles later there’s barely any noise from it, so fingers crossed on the maintenance front!
For me, that feeling of the throttle input having a predictable & repeatable effect on the attitude of the car is one of the joys of a rear wheel drive sports car. An open diff fails you just at the point where you need the control the most.
I feel a LSD is of benefit even if you’re not sliding luridly around corners, Top Gear style! That sense of being able to subtly point the nose with the throttle & have the assurance that the tail will gently edge out when you want it to, without the power bleeding away through the lightly loaded wheel really adds a feeling of satisfaction for me.
I’m not saying a LSD is essential, I drove my first 7 for ten years with an open diff & still enjoyed the car enormously, but for me it’s undoubtedly worth any additional hassle it may bring.
I swapped the BMW Titan in my 420R for a Tracsport last year & almost 5000 miles later there’s barely any noise from it, so fingers crossed on the maintenance front!
It's great to hear someone with a LSD with all the advantages and no hastle.
Why haven't caterham supplied this unit as their LSD of choice ? Instead, all you hear are owners stories of noise and poor reliability.
I'm not really a hard core racer, more a tourer. So a regular diff is just fine for me. I have a well tuned suspension and 200 bhp to play with and I'm more than happy.
Why haven't caterham supplied this unit as their LSD of choice ? Instead, all you hear are owners stories of noise and poor reliability.
I'm not really a hard core racer, more a tourer. So a regular diff is just fine for me. I have a well tuned suspension and 200 bhp to play with and I'm more than happy.
A clutch plate type LSD, by it’s very nature is always going to be a component that requires servicing, but I think Caterham have made a mistake with the Titan. My carbon plate Titan had no pre load due to heavily worn plates & broken Belleville springs at 4500 miles. With the sort of miles I do that would mean I’d have to rebuild the LSD every year & I didn’t fancy that!
Having spoken to other 7 owners, it seems that other types of plate LSD last far longer between rebuilds. I have a friend who has a 190bhp K series car with a ZF LSD. He has owned the car since the 90s, covered tens of thousands of miles on road & track & has never had the diff rebuilt. The ZF isn’t made any more, so a Tracsport seemed to be the best modern option.
Speaking to Steve Perks who makes the Tracsport diffs, he told me he’s offered the unit to Caterham on a number of occasions, but they weren’t interested.
I know what you mean about well tuned suspension. I had my car properly set up earlier this year & what a difference it makes!
Having spoken to other 7 owners, it seems that other types of plate LSD last far longer between rebuilds. I have a friend who has a 190bhp K series car with a ZF LSD. He has owned the car since the 90s, covered tens of thousands of miles on road & track & has never had the diff rebuilt. The ZF isn’t made any more, so a Tracsport seemed to be the best modern option.
Speaking to Steve Perks who makes the Tracsport diffs, he told me he’s offered the unit to Caterham on a number of occasions, but they weren’t interested.
I know what you mean about well tuned suspension. I had my car properly set up earlier this year & what a difference it makes!
the av8er said:
It only serves any tangible advantage in lap time, if your not racing it competitively on a regular basis, a standard diff is fine. It will alter the behaviour of the rear but only at more extreme load though won't make it any less fun to drive, in fact it will most likely put a greater grin on your face as you can more easily steer the rear on the throttle.
Just imagine cruising or blatting round the countryside while being able to hear the birds or other regular noise without a care in the world, instead of a loud clatter, chatter, rattlle, whine, crunching etc while that voice in your head is asking " is something about to let go and leave me stranded ??? !!! "
For me it's a no brainer. As I say, you can always swap it in and out really easily just for track use if your particularly competitive.
Sorry, but I have to disagree with this (a lot!)Just imagine cruising or blatting round the countryside while being able to hear the birds or other regular noise without a care in the world, instead of a loud clatter, chatter, rattlle, whine, crunching etc while that voice in your head is asking " is something about to let go and leave me stranded ??? !!! "
For me it's a no brainer. As I say, you can always swap it in and out really easily just for track use if your particularly competitive.
My Caterham is the first car I've felt needed a LSD; I was determined it didn't - an elise doesn't. But I finished up retrofitting one (ZF plate) to mine, and yes, I did it myself - more on that later.
With an open diff it's not that predictable, to some extent it's more idiot proof as it tends to self-recover; as the slide builds angle and lateral load the inside spins away the power and it comes back - except when you've got used to abusing it, go too far and then it just goes all the way around. It's not terribly predictable, and you can't hold any kind of (even small) angle.
If you want to just have the feeling of a little wriggle now and again, it's probably fine, it goes earlier and immediately recovers by its self so long as you don't provoke it too much, and as you say traction isn't a problem until proper lateral loads. But if you want to 'balance' the car/steer with the throttle, then the LSD is far far more predictable, linear and just downright effective - and no, I'm not talking about fast and furious drifts on the public road, just the feeling that the car has hooked up with a bit of attitude and is both turning and driving. Double all of that in the wet.
Pretty sure I can't hear birds or anything much in mine, between earplugs, engine noise and the gearbox (not LSD), it's not the place for idle chatting or classic FM
But still, I'm lucky I guess; my gearbox makes more noise than the diff ever does. Granted it seems that the titan diffs with carbon plates give a lot of problems, but the ZF seems to wear very slowly - while I'm sure the preload is lower now than when it went in, the last time it was serviced the verdict was basically that it could've been left well alone.Finally, having had it in and out a couple of times, you're having a giraffe, bigtime. No it's not complex, but it's a pig of a job. The diff weighs a ton, is full of oil that stinks like satans armpit (and you WILL finish up wearing most of it). You also have to unhook half of the rear suspension and fight the de-dion out of the way. To get it in you have to bench press the diff back into place while simultaneously making sure the nose of the diff and prop meet up, bash in the main bolt while inserting exactly the right amount of washers to achieve the correct lateral alignment, and not drop it on your face..
I'm sure I'll do it again, but it's about my least favourite job on the car, and definitely not something you'd contemplate on a (quasi) regular basis.
upsidedownmark said:
Finally, having had it in and out a couple of times, you're having a giraffe, bigtime. No it's not complex, but it's a pig of a job. The diff weighs a ton, is full of oil that stinks like satans armpit (and you WILL finish up wearing most of it). You also have to unhook half of the rear suspension and fight the de-dion out of the way. To get it in you have to bench press the diff back into place while simultaneously making sure the nose of the diff and prop meet up, bash in the main bolt while inserting exactly the right amount of washers to achieve the correct lateral alignment, and not drop it on your face..
I'm sure I'll do it again, but it's about my least favourite job on the car, and definitely not something you'd contemplate on a (quasi) regular basis.
A fabulous description of diff out and in! I thought you'd have to be dedicated to change it to do a track day!I'm sure I'll do it again, but it's about my least favourite job on the car, and definitely not something you'd contemplate on a (quasi) regular basis.
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