Split Engine Mounts

[iainskea]

Hi All,

You may recall, my L-Plate lad snapped the gear lever with some aggressive frustration between 3rd and 2nd gear - and he also split both engine mounts with some kangaroo hopping.

I reinstalled both engine mounts with nice Lotus parts, only to have both split again in a matter of weeks.

I found this thread: http://www.glcforum.com/esprit/forums/inde...hl=engine+mount

discussing an upgrade from SJs - but I would have thought the mounts should be more than adequate under normal conditions.

I installed both carefully, with the heat shield on the exhaust side. Is anyone else having problems with engine rubber mounts or am I missing something?

Iain

Edited June 28, 2007 by iainskea

[dglotusltd]

Iain,

The mounst should be adequate. However, they do not HOLD the engine in place, rather they just hold it up. The mounst that hold the engine in place are the transaxle bushings at the back of the engine bay.

On my S1 they failed and extruded forward allowing the whole engine to shift forward and stressing my mounts. They actually looked like the rubber was angled towards the front fo the car as the engine had shifted over 1 inch forward.

I caught it in time and replaced the bushings and added some rubber coated steel washers to provent future movement. I also replaced the broken Lotus engine stay with a bigger one of my own design...again to stop the negine from creeping forward.

Besides the stretech mounts, my engine/tranny lump moved so far forward the I had troubel with 1st gear (the linkaed was hitting a frame member) and my crank pullly cut 2 neat holes in the coolant hoses in the front of the engine.

I'd try to find out of the engine is in place properly and determine why the mounts in front are stretching and failing....assuming they are stretched.

the turbo mounts actually do provide holding power as they have bolts through the center but do so at great expense. US quotes for 2 mounts were over $600 vs the $20 stock mounts. So I decided to some the problem rather than try brute force.

DomG

[Hegg]

If it's any consolation, I have had the identical problem on my S1. I replaced just the motor mounts and within days they were slid forward because the tranny mounts have popped out enough to create the force. And along with that comes the same coolant hose interference problem and inability to hit first gear.

The right answer based on what I know is to get the tranny mounts replaced (not cheap though).

[dglotusltd]

It wasn't that expensive. turns out that the S1 mounts are these two triangrlar aluminium frames that contain 3 bushings each (one on each side).

Two of the bushings are sort of captured by the Esprit frame which looks like a u channel brace. So you likely don't need to worry about those. The two remaining bushings (one on each side) are the ones that fail and allow the engine to move forward.

You can get to them easily and its doable as a one man job.

Jack the car up at the rear and support the frame or body with jackstands

Position a hudrilic jack under the transaxle (I used wood to spread the jacking force) and relieve the prossure on the bushings.

Now if you look at how they are mounted you can remove the bolts that go through the bushing that holds the transaxle and then the bolts that hold the trangular assembly. There is some fiddleing like with some metal capture tabs that cover some of the bolts but its doable.

Once the piece is loose, you can wiggle them off the car while the tranny/engine lump is supported by the jack. You might want to add anothr jackstand for safety.

Take note of which bushing on each trangular piece is the one that meets the tranny. That will be the one where the rubber is extruded out of the metal sleave. I check a local US supplier and had preorder the smaller bushing (the ones required). I cheaped out and only order 2 (1 for each side) as the other bushings looked fine.

My local auto shop was happy to put them on a press and remove the old failed bushing and press in the new ones for $20.

Now wiggle them back one the car, attending to how they mount to the frame first. I had also bought two rubber covered steel washers (about 2.5 inches in diameter) and those went on the end of the bolt at the back of the car. The idea is that the washer stops the bolt head from applying direct pressure to the rubber of the bushing as the engine moves. Its this action that helps the failure along. The washer is larger that the metal sleave so the only way it will move is if the sleave itself moves and even that would onlu be 1/4 inch before it hits the metal frame. So it effectly stops the lump from moving forward.

I was luck and when I got to the tranny bushing I was able to get the bolt and nut to just make up. So I was able to use that bolt to slowly pull the engine back into place. Once I could get the other bot started, i alternated between them to pull the engine back evenly.

Took about 3 hours all total, including the trip to the local auto shop. OF course I had preordered the bushing and washers before I started. Got my stuff from JAE in the US. One warning though, the bushings are in short supply...at least in the us.

I have some pictures. If I can find them I'll post them.

DomG

[iainskea]

Excellent replies Dom and Hegg, I knew something was wrong.

Photos would be great Dom, and thanks for the step by step. I will have a look this weekend and post a status.

Many thanks,

Iain

[dglotusltd]

ok here go some pictures

The first is looking at the right side bracket. The rear valance is removed for easy access. You see two bolts still in the upper bracket holding it to the frame u-channel. the lower bushing is where the bolt goes though and then through the tranny bracket.

The second shot should the frame hole with the trangular bracket removed

The third image is the trangular bracket removed and showing the extruded bushing.

Next is a shot of the two brackets as they should look with new bushings correctly positioned (not from me...I forget who sent them to me during my troubles)

and finally the installed bracket with new bushing. Note the bolt and the large rubber coated washer on the end of the bushing.

and while I am at it...here is a shot I also got showing the wimoy engine stay Lotus used to try to hold the engine in place...or rather hold the engine from moving forward. Also not me photo.

Email me at dglotusltd@optonline.net if you want to communicat outside the forum.

DomG

Edited June 30, 2007 by dglotusltd

[iainskea]

Thanks for the pics Dom. I note that the manual has nothing on their repair or pics - a bit frustrating, so your step by step is great.

I want to pre-order the bushes, so if anyone knows a reasonable supplier - most appreciated.

Iain

[dglotusltd]

Got mine at JAE in the US. SJ Sportscars in the UK seems to get a lot of good press from the Uk forum users.

When I ordered I was told that the big bushing in the apex of the triangular piece is not available. But mine looked ok. Its one of the ones trapped inside the U channel so it sort of tough for it to fail. Still it would have been nice to replace. The small ones, which is the one that attaches to the transaxle and is the one that fails, is available. JAE did have to order mine from the UK so it took about 2 weeks total to get them. So I'd try a UK supplier first.

Yes, I noticed the complete lack of info in the manual too. My thanks to Tony K who explained it well enough for me to catch on. Also to a few other folks, whose name I cannot recall for some of the pictures that crystalized it in my mind.

DomG

77 Esprit

Edited July 19, 2007 by dglotusltd

[iainskea]

I have finally got around to checking out the transaxle bushes, since my forward engine mounts have split a couple of times.

Here are some pics of mine:

I dunno, they 'seem' not too bad - a little old, but not fallen apart like the one Dom pictured. I suppose there can't be any other reason for the engine moving forward than these bushes though.

Thoughts?

Iain

[rgh0]

Hi Iain

Every S1/S2 I know with original mounts suffers regular failures. The mounts where not designed to contain the upward lift due to the torque reqaction of an enthusiastically driven car. The rear mounts cannot contain that torque reaction and are not designed to restrain for / aft movement. The extrusion / distortion of these mounts is due to the front ones failing and allowing the engine to move around (rather than the reverse).

I have attached my write up to this topic with my alternate engine mount design again as more relevant to this topic than the one I added it to a couple of days ago when you asked the question as an aside in another topic.

cheers

Rohan

REPLACEMENT_ENGINE_MOUNTS_FOR_S1.doc

[giorgio67]

HI,

for what can I see in my chassis the S1/S2/S2.2 engine mounts are really poorly designed and are not adeguate...the rear mountings suffer after the fronts fail..I think the best solution is to swap to turbo engine mounts..

I'm waiting an answer (availability) for a full Turbo style kit conversion for the early Esprit.

The kit contain the plate adpter mounts on the chassis, the two mounting rubbers for the plate and the two specific designed engine legs with the correct mounting angle on the chassis mounts.

Actually I don't know the price, but it would be near 200 GBP, a very good price for a specific designed kit.

If you are interested I will ask you the current price and the availability for two order , maybe we can save some money...theya are designed and made by a Lotus owner guru...in USA.

I have a photo of the kit if you want to see it I will send you via email....no more space for the attachment here.

Cheers

[Paul Coleman]

Hi Iain

Every S1/S2 I know with original mounts suffers regular failures. The mounts where not designed to contain the upward lift due to the torque reqaction of an enthusiastically driven car. The rear mounts cannot contain that torque reaction and are not designed to restrain for / aft movement. The extrusion / distortion of these mounts is due to the front ones failing and allowing the engine to move around (rather than the reverse).

I have attached my write up to this topic with my alternate engine mount design again as more relevant to this topic than the one I added it to a couple of days ago when you asked the question as an aside in another topic.

cheers

Rohan

Hmmm... I must have completely missed somthing here because my S1 engine mounts don't look anything like that? My S1 has two brackets which bolt to the chassis and each bracket has a round rubber bush fitted in it with a steel tube insert. The engine had a couple of 'U' shaped brackets which fit over the rubber bushes and then a bolt goes through each one. I can't see how I could replace these with what you have shown in your document as they look nothing like mine?

Confused, Paul.

[rgh0]

Hi Paul

Sounds like someone has already made up a modified engine mount for your car to replace the original mounts. Not surprising as the orginal mounts were never up to the task.

As long as your mounts dont break and dont transmit excessive vibration to the car then they should be OK and not need replacing.

cheers

Rohan

[dglotusltd]

Paul,

Got a picture? It does sound like your mounts were modified already. I decided against the Turbo mounts because for the expense (horrific) they do a better job but not perfect. The key is that the stock mounts are only designed to support the engine, not hold it in place. If your engine is secured by other means then they are not as big a problem. If you have modified mounts or turbo mounts...all the better.

DomG

[lionelmac]

Hi Iain

Sorry to bring this old thread up again, but the last reply on it was a request for pictures of your (different) engine mounts.

I would love to see these if you took a pic.

I am in the middle of Rohans engine mount mod, but found it impossible (for me) to file down the inside washer - because its inside. I took it to a machinist and when he tried to turn it down both the washer and the top cup spun on the central tube, so he is now going to tack weld both and try again.

I hope this works as they are now about A$197.00 for the pair.

Great to see you head job turned out OK in the end - nothing Lotus is straight forward is it - makes me wish I had a VW again.

I found my old Airconditioning instalation photos if you are still interested.

xisab

Edited July 23, 2008 by xisab

[rgh0]

I never had the problem you describe. The assembly of the washer must be looser on yours for some reason.

I did put a bolt through and clamped the mount top and bottom by tightening the bolt before I machined the washer and this probably helped prevent the washer spinning. I used the bolt to set the mount in the lathe before turning it down.

Tack welding the washer to the mount centre tube should achieve the same.

cheers

Rohan

[lionelmac]

Hi Rohan

Yay - I did supply a bolt to the guy and when you look at the mount you can see the washers are only a press fit so I thought it would have been elementary to use it, but I didn't like to tell him how to do his job. A smaller cutting tool and he might have got away with it, but he tried to take the whole 5mm at once. Awkward for me too his boss is an old friend of a friend - you know how it is.

By the way, what thickness is the plate on the bottom?

I was thinking of using 3mm and picking up all 4 holes in the frame, as 1/3 of the new mount will be off the mounting point on the frame. Then I would probably not need a top spacer.

With no instructions in the Lotus manual on how to change an engine mount, I suppose I just jack with a block on the higher/narrower part of the sump to take the engine weight off - can it take it?

I will finish one side before I start the other

xisab