R8 Alpine clutch shudder

BobG

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I have a problem with clutch "shudder" in my R8 with an R5 Alpine motor. The car shakes violently when I let out the clutch in reverse. The shaking is worse when I try to back up on an incline. I get a similar vibration when down-shifting to 2nd gear without rev matching, but its not as severe. Up-shifting is not a problem though. I believe the problem is caused by the increased weight of the R5 motor compared to a stock 1100 motor coupled with too-soft gearbox and engine mounts. I've installed stiffer mounts from Mecaparts, but that hasn't reduce the problem. Could it be related to the clutch itself? The flywheel and clutch are from a Lecar (R5). The flywheel has been resurfaced and the pressure plate, disc and release bearing are new. Has anyone else had this problem when adding a heavier motor to an R8? Any ideas on what might be the cause of the vibration?
Bob G
 
It has nothing to do with the weight. I had a similar problem and it was due to a non-standard clutch cable that was too short. Make sure you have the outer casing in a slight bend and not straight into the gearbox. It could be mountings as well. The shudder is normally caused by some movement of the drive unit and then the one end of the outer casing is mounted to the non-movable body/chassis and the other end to the moveable drive unit. If that is too short or to tight it will cause that shudder.
Frans
 
It has nothing to do with the weight. I had a similar problem and it was due to a non-standard clutch cable that was too short. Make sure you have the outer casing in a slight bend and not straight into the gearbox. It could be mountings as well. The shudder is normally caused by some movement of the drive unit and then the one end of the outer casing is mounted to the non-movable body/chassis and the other end to the moveable drive unit. If that is too short or to tight it will cause that shudder.
Frans
I just looked under the car and the clutch cable has some bend to it. I also saw that the rear springs are compressed so much that the axles are almost touching the bump stops. This is probably due to the heavier motor and old sagging springs. So now I'm thinking that when the car starts moving in reverse and the rear end of the car tends to rise, then if the clutch slips (for whatever reason) the rear end falls and hits the bump stops (instead of the softer spring/shock) which causes the clutch to slip again and a feedback sort of thing happens. Does this make sense?
Bob
 
Hi BobG :)
I would second what Frans said about the clutch cable. Back in the old days I fixed a few engine conversions with exactly that problem by fitting or adjusting for a longer clutch cable with plenty of slack and bend in it. Just a small bend may be all 'used up' by the movement in the mounts.
On rear engine VWs there is a spec in the manual to check for the min bend in the cable to solve shudder problems. I suggest you look carefully again. ;)
Jaahn
 
I run a R5 Alpine motor in my R8 and its been lowered so much that I have had to take around 20mm off the bump stops and its clearance now is still only 15-20mm. I don't get the shutter you describe at all.
What flywheel size and clutch are you using? I run a lightened R12 1.4 flywheel with a 180mm LUK clutch - no slip no shutter at all.
I am surprised that you believe the R5 engine is so much heavier, the block is the same size and the head is an aluminum crossflow so only slightly bigger.
Put some paint on the bump stops, go for a drive and see if there is any paint on the tube axels, then maybe your theory is correct and you need taller/stiffer springs i the back. I used the same std springs, just had them reset lower.
 
I just looked under the car and the clutch cable has some bend to it. I also saw that the rear springs are compressed so much that the axles are almost touching the bump stops. This is probably due to the heavier motor and old sagging springs. So now I'm thinking that when the car starts moving in reverse and the rear end of the car tends to rise, then if the clutch slips (for whatever reason) the rear end falls and hits the bump stops (instead of the softer spring/shock) which causes the clutch to slip again and a feedback sort of thing happens. Does this make sense?
Bob
Does this make sense? No.
 
I think your problem is that the clutch is not working properly. It may be the reason Frans described (clutch cable too tight and engine/g'box movement takes up whatever little slack you have and partially disengages the clutch) or other internal (clutch related) reason - say clutch doesn't fully clamps, problem with the clutch springs who knows? I would explore the avenue suggested by Frans and then take the clutch out and have a look at it.

Can this R5 clutch disc go either way or does it have a certain face to go say against the flywheel?

Did it always have this shudder after the new clutch/engine were installed or did it appear some time after that?
 
I would suggest the clutch plate springs are stuffed. New clutch plate will solve this problem, nothing else.
 
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I think your problem is that the clutch is not working properly. It may be the reason Frans described (clutch cable too tight and engine/g'box movement takes up whatever little slack you have and partially disengages the clutch) or other internal (clutch related) reason - say clutch doesn't fully clamps, problem with the clutch springs who knows? I would explore the avenue suggested by Frans and then take the clutch out and have a look at it.

Can this R5 clutch disc go either way or does it have a certain face to go say against the flywheel?

Did it always have this shudder after the new clutch/engine were installed or did it appear some time after that?

I agree. Its very easy to have the clutch disc the wrong way around or even the fork spring installed the wrong way about.
But the clutch cable needs to have around 5mm play at the fork end, this is easily viewed when you remove the cover plate from under the gbox (assuming you have the later 330 bell housing.

Also clutches are not all equal. The new Valeo kit I had originally was weak and slipped to no end. After fitting the LUK kit, all problems of slipping had disappeared.
 
A suggestion.
Stick your phone or lens under with a view of the cable, mounts etc and watch what happens.
Might give you some clues before you tear it all apart.
 
I run a R5 Alpine motor in my R8 and its been lowered so much that I have had to take around 20mm off the bump stops and its clearance now is still only 15-20mm. I don't get the shutter you describe at all.
What flywheel size and clutch are you using? I run a lightened R12 1.4 flywheel with a 180mm LUK clutch - no slip no shutter at all.
I am surprised that you believe the R5 engine is so much heavier, the block is the same size and the head is an aluminum crossflow so only slightly bigger.
Put some paint on the bump stops, go for a drive and see if there is any paint on the tube axels, then maybe your theory is correct and you need taller/stiffer springs i the back. I used the same std springs, just had them reset lower.
The clutch is 170mm (I think). The flywheel and clutch are R5 parts so they will fit in the 330 belhousing.
The block is the same size as the 1100 motor but the head is considerably bigger than a wedge head and the dual webers are are alot heavier than the 1100 carb.
I removed the bump stops last night. I'll seem if that makes a difference later today.
Bob
 
I would go along the lines of Frans opinion. Many years ago I had an R16 motor in my R8 with a 330 box fitted with an R16 bellhouaing. The clutch lever needed to be moved toward the rear of the car to release it. The easy solution was to turn the lever 180 degrees and put a cable mount on top of the crossmember meaning I could pull the lever.

In this case as the engine was rubber mounted and thus moved as the power was transferred to the wheels, terrible shuddering went on. I changed the clutch arm back to the original position and mounted the clutch cable to the bell housing and used the outer of the cable to push the arm. No shudder, with no other changes to the mounts or clutch.
 
I think your problem is that the clutch is not working properly. It may be the reason Frans described (clutch cable too tight and engine/g'box movement takes up whatever little slack you have and partially disengages the clutch) or other internal (clutch related) reason - say clutch doesn't fully clamps, problem with the clutch springs who knows? I would explore the avenue suggested by Frans and then take the clutch out and have a look at it.

Can this R5 clutch disc go either way or does it have a certain face to go say against the flywheel?

Did it always have this shudder after the new clutch/engine were installed or did it appear some time after that?
I agree that the source of the problem is the clutch. The added weight and limited suspension travel just make the resulting shaking worse. I'll post a picture of the clutch cable arrangement later today. There is 4-5mm of free play in the pedal.

I was careful to install the clutch in the correct orientation.

The first motor I put in the car was a 1.4 wedge head with the same flywheel/clutch setup as now. The shudder in reverse was as bad or worse than it is now. But I had a coolant leak from the head down into the bellhousing. So I assumed the shudder was due to coolant on the clutch disk. I cleaned the flywheel and pressure plate when I installed the new motor and used a new clutch disc.
Bob
 
Here is a picture of the clutch cable. There is very little droop/slack, counter to what I said earlier. This confirms what Frans and Jaahn (and others) had suspected. I'll try to re-clamp the cable casing at the gearbox to get some slack.
Bob

IMG_0462_small.JPG
 
Hi Bob :rolleyes:
Yes no slack in that cable. If you can pack the end on the outer so it has a good bend that will fix it. The slack need to be between the gearbox and the body run.:cool: As has been said an easy magic fix.
Note for other posters ! The initial slack at the adjustment has nothing to do with the shudder as that is caused at the point of drive takeup.
People always make the cable neat and tidy with a straight run and no slack. BAD BAD BAD. 🥴🥴
Good luck with it. Jaahn
 
There's your problem right there. Not enough bow in the clutch cable. My 1600 R8 with big box has about 4 to 6 times more Bow in the cable. It has Gp 4 lowered springs, no bump stops and no shudder. Give the cable more bow then see what happens. The 1.4 R10 Alconi and the A110 Floride all have lots of bow in the clutch cable and no shudder.
 
Here is a VW Beetle clutch cable with the correct bend. Looks too much does'nt it but it will be good and smooth takeup.:cool:
 

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Hi Bob :rolleyes:
Yes no slack in that cable. If you can pack the end on the outer so it has a good bend that will fix it. The slack need to be between the gearbox and the body run.:cool: As has been said an easy magic fix.
Note for other posters ! The initial slack at the adjustment has nothing to do with the shudder as that is caused at the point of drive takeup.
People always make the cable neat and tidy with a straight run and no slack. BAD BAD BAD. 🥴🥴
Good luck with it. Jaahn
exactly as quoted by others about no slack,bow,in outer cable as with soft mounts drive train will want to move forward towards front of car in forward gears, this increasing slack in outer cable but in reverse drive train will want to move rearward tightening outer cable to point of partially releasing clutch slowing vehicle and engaging clutch and repeating process and head wobbling on neck.......... just a thought. Jim TV
 
I removed the cable from the clutch and gearbox tunnel (tube) and realized that it was not anchored to the box. I think it should be right? The cable came with the car and is an older style with the adjuster in the solid rod coming from the pedal not at the gearbox. I just assumed it didn't need to be anchored to the gearbox. I am now looking for a new cable. Thanks to all for the advice.
Bob
 
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