Lotus Elan

Judder after about an hour

PostPost by: terryp » Sun Oct 18, 2009 12:56 pm

Hello!
Been out with the family today for about an 85 mile round trip. Towards the end of the journey there and on the way back I experienced a judder (never had it before) and only in first when pulling away. Also the slight hesitation some of us get on pulling away was quite a bit worse.
I checked the engine mounts and there is a slight gap between the metal and the rubber. The engine does not visibly rock or anything.
Does it sound like the mounts are worn , i.e. getting warm then the problem occurs?
Maybe a red herring but on the way back it was running very slightly hotter than it normally does.

Thanks
Terry
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PostPost by: Ross Robbins » Sun Oct 18, 2009 2:10 pm

Terry,

I cannot tell you if the mounts are bad without seeing them, but I can say that the separating rubber is a bad sign. I just replaced mine and they were really bad. The U part of the mount was actually resting on the center blade so I had a "Magic Fingers Massage" driving experience and yet the engine did not visibly rock. By the way, it is not a happy job so clear any impressionable ears from listening distance.

A couple of helpful hints...Take the airbox and carbs off along with the starter or access to the bolts is grim, and get all the bolts started before you tighten them fully as the alignment is not exact on the new mounts. Good luck sir!
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PostPost by: Frank Howard » Sun Oct 18, 2009 2:17 pm

Terry,

Sounds to me like your clutch is on it's way out.
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PostPost by: terryp » Sun Oct 18, 2009 2:24 pm

Thanks for the replys , I took the car out again about half an hour later on my own and could not make the same thing happen, no matter how I lifted the clutch or drove
Could it be something to do with the extra weight ie wife + 2 children = 107KG

Thanks
Terry
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PostPost by: 69S4 » Sun Oct 18, 2009 2:33 pm

The "grim reaper" side of my diagnostic skills would have me convinced it was the rear engine oil seal leaking onto the clutch but I'd hope it was the engine mounts as they're a lot easier to change. It might just have been the extra weight and nothing is really wrong. I had something similar happen, but only in reverse, recently which was one of the diff torque arms loose.
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PostPost by: collins_dan » Sun Oct 18, 2009 3:37 pm

You could check the clearance of the differential to the frame. Could be the differential mounts, or the rubber bushings on the braces that hold the differential at the bottom.

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PostPost by: terryp » Sun Oct 18, 2009 3:59 pm

Hello
I've just checked the mounts and although the rubber is coming away from the metal , they have not dropped at all. As for the rear seal going , I get a small drip of oil under the bellhousing after going for a spin but nothing really serious.
I'll check the diff and the diff mounts (these are new TTR type) and the torque arms.
The judder felt like it was at the front of the car.
One other thing was I had the carbs off recently and had to set them up again. It seemed that during the return trip today, they became slightly out of balance, as when I returned home and lifted the bonnet the engine was wobbling a bit at idle. I turned the balance screw very slightly and all was well again?
So it could have been , extra weight , carbs out of balance ??????
I'll get some engine mounts anyway and change them and keep the Children clear ready for the profanities (Thanks Ross)

Terry
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PostPost by: david.g.chapman » Sun Oct 18, 2009 6:54 pm

I had a similar problem with judder (with a new clutch and a flywheel runout of less than 4 thou), and changing the engine mounts helped. I went for a TTR mount on the exhaust side only, which has the empty space at the top of the mount filled with RTV to firm it up a bit.

I also covered the ourside of the mount (the upside-down U piece) with aluminium tape to reflect some of the exhaust heat. I believe it is this mount softening from the exhaust heat that causes a lot of hot judder problems.

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PostPost by: kstrutt11 » Sun Oct 18, 2009 7:59 pm

I have found keeping the engine rpm higher resolves the issue. The problem is that the driveline stiffness is very low on the Elan which makes it very sensitive to judder anyway and in my case I have a type 9 transmission which has a lower 1st / reverse and again makes the stiffness effectively lower still (more weight also decreases the natural frequency and makes things worse as does the rubber components softening as the warm up). The torn mounts will make things worse as will worn dougnuts, suspension bushes and gear box mounts.
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PostPost by: alexblack13 » Sun Oct 18, 2009 8:11 pm

Hello Terry,
I hope you get to the bottom of the clutch judder. Like all the guys have said and as normal it is difficult to get to the bottom of via discriptions etc.. Tell us, how old is the clutch plate? The reason I ask is that new and newish clutch plates no longer (Normaly!) contain asbestos. This can result in a judder when the clutch gets very hot. Driving thro' town, stop start fashon etc. esp' as you say with a full car. I.E. family on board.

I used to notice this on a 5 ser' BMW I had. Only with the caravan on though. Reversing the caravan into place would produce quite severe juddering. I removed the clutch to find it perfect. On Checking with BMW I was told this was a possibility due to no asbestos in the driven plate. A new cover, driven plate and bearing resulted in no improvement. Dammed thing still juddered (When V hot)...

Failing that I go with the oil on your plate Terry. Sorry!.. That's the usual cause.

Alex..
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PostPost by: 1964 S1 » Mon Oct 19, 2009 1:45 am

I ditto Alex. Car loaded, running a tad hot, oil a bit thinner, pressure plate and clutch are just a few degrees hotter than normal but gosh they've still got to get off the line with the extra weight! Heats up even more.

I'd just drive it and if the judder returns I'd guess it's oil on the pressure plate too. Then, first, I'd try thicker oil... good luck

Eric

ps; or it could be a rotoflex getting ready to let go, do you have them?
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PostPost by: terryp » Mon Oct 19, 2009 6:34 am

Hello Eric , Alex , Dave , kstrutt11
I have Susan Miller driveshalfs so no rotoflex. The clutch is about 20 thousand miles old but I think it dates from around 1997.
I really tried the second trip to get it to happen again, but without the extra weight (!) on board , no judder.
It may have been as kstrutt11 suggested as I think I get complacent and go for fewer and fewer revs to pull away?
I'm going to do the engine mounts anyway exactly as Dave suggests and then wait and see if it happens again!

Thanks to all!
Terry
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PostPost by: paddy » Mon Oct 19, 2009 6:59 am

My vote is with the engine mounts. The idea that the exhaust side gets more compliant when very hot sounds quite plausible. Even with a perfect clutch, loose mounts will have a tendency to judder. It's also cheaper to try and see if that fixes it first.

These are very light cars to begin with, compared with the orignal cars the components came from, and the extra weight still shouldn't cause it to have a problem.

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PostPost by: alexblack13 » Mon Oct 19, 2009 8:31 am

Hi again Guys, Terry..

A driven plate from late 90's is quite poss' Asbestos free. This when hot will judder. Does it judder when cold when you first drive off etc? NO?? Then its not oil on your plate. If it's normal coldish then just live with it and stop worrying. :wink: :wink: When it does it, minimise slip and get the car moving with min revs etc. You will soon find the best way. By the way my sprint does it when stinking hot. I just drive round it.

Hope you find it soon. An engine mount goosed would be ok.. Not too expensive or time consuming..Prob' yr best option.

Alex..
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PostPost by: terryp » Mon Oct 19, 2009 8:38 am

Alex
I think you are right.
I think I worry to much. I do tend to drive with 1 ear listerning to the engine, the other ear for clonks , 1 eye on the oil pressure , 1 eye on the water temp , paranoid or what. I'm not quite so bad if I drive it on my own.

Cheers to all

Terry
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