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MG Midget and Sprite Technical - Vibration (Engine Mounts)

Has anyone had a problem with new engine mounts on 1275 engines?

I have just replaced mine for the second time. The first set left me with a lot of vibration making the car horrible to drive. The supplier replaced this set with another from a different manufacturer. The second set is better but the car still vibrates more than it did with the old set.

There are a couple of threads on other boards that suggest that the modern mounts are made with harder rubber. Does anyone have any information on this?

Should I try and obtain an old set of mounts? Where do I go to get mounts made from soft rubber?

M Parris

Is it possible that your engine has a vibration problem which was being masked by your old, soft mounts?
Dave O'Neill 2

Don't think it's the engine as there has been no change in the engine vibration since new (I am the first owner!). The engine was rebuilt 15 years ago and there was no change at that time.

Also if it were the engine, the two new mounts would have been the same but the first was markedly worse than the second.

The vibration is not rev dependent. You notice it more at tick over.
M Parris

.
Prop and the Blackhole Midget

Im not aware of or seen any comments about defective engine mounts... once in a blue moon they do seprate from there metal plate shoe ...but they are probably all made in china, so there is that

But I have to side with dave, there is most likely a structural vibration problem somewhere in the drivetrain, these mounts take alot of oil , years and miles to wear out you and your discribing a situation that has alot of coincidences.

If you belive your 15 year old engine is not the issue... ( Hhmmm ) id look at vibration issues in the clutch system, propeller shaft, u joints, and suspension hardware

Anthor place id look for that kind of vibration would be the transmission securing bolts and there mounts...if the transmission is not locked down and secure you can get alot of vibration from the tranny moving around and that would create alot of wear on the front engine mounts in a short period of time

Make sure the 2 bolts in the cross memeber frame are still there and tight, as well as the 4 bolts that secure the tranny inside the car On the tunnel

But like dave.. I really think this is a structural vibration issue and not a incidental manufacture defect in multiple factory brands

Prop
Prop and the Blackhole Midget

incidental = coincidental, in the last paragraph of my above posting

Prop
Prop and the Blackhole Midget

what sort of vibration is it? only at idle? gets better with rpm, gets worse with rpm? If it's genuinely not rpm dependent then it should be easily sorted as it'll be some kind of resonance effect..
Rob Armstrong

1275 engine? Could it be the rubber crankshaft damper on the pulley starting to de-laminate from the steel part?
Bernie Higginson

The vibration is independent of drive train and suspension. It is there when the car is stationary, whether on or out of gear, clutch in or out.

The symptoms are that the body vibrates. It is pretty constant over the rev range with no obvious resonances.

It was Definitely not present before the recent work done on the car. I can't believe that a faulty engine mounting had exactly cancel out another issue with the engine.

The second set that we fitted was so much better than the first that I am sure that the first set was faulty. The supplier agreed that he had had similar problems with the manufacturer of the first set.

The set now fitted is livable, just not as good as the original set. It would be nice to get it back to how it was.
M Parris

That certianly narrows it down

I now thinking loose exhaust pipe


For 2nd place .. I like bernies thinking about the harmonic balancer becoming delamenated


Also im throwing in as a freebee, a worn bearings in the alt/gen, bearings in the water pump, and an off remote chance of a timing chain issue

My gut tells me somethig got out of wack/disturbed during the motor mount removal/installation

Visualise what the shop would have had to tou h and handle esp roughly and.I think you find your ansewer

Just for clarification... the vibration started to occure before the old mounts were replaced ?

Or after the 1st new set of mounts where installed ?

Almost there .... your above info is very informitive, thanks for posting that
Prop and the Blackhole Midget

Do you know if the shop used a floor jack or an engine crane to lift the engine up in the air to replace the mounts.... that info would be very helpful also
Prop and the Blackhole Midget

seems quite strange it's not related to rpm at all.

Not that it isn't that! I'm often surprised by things.

might it be a vacuum leak from something like a recently split hose? Mine did that and idled like a piston had come off.

Are you replacing the gearbox mount as well? Mine was well spongy having soaked up all of the oil it could have done that fell out of the back of the engine...
Rob Armstrong

Clarification -

Original (old) mountings - sweet running, no vibration
No 1 replacement (new) - Very bad vibration
No 2 replacement (new) - Livable but not as sweet as the original set.

On each mounting in the very bad set, the rubber was 2mm thicker than the No 2 set.

The exhaust has been inspected and looks fine.
Harmonic damper (pulley wheel) was inspected and is OK.
Gear box mounting was inspected and was OK.
Engine was raised using a crane.


M Parris

"""On each mounting in the very bad set, the rubber was 2mm thicker than the No 2 set.""

Bingo !! ... Theres your problem


The shop got and then tried to install the wrong front engine mounts, so the front engine plate has gotten bent, warped, and deformed meaning the camshaft, timming chain, and if bad enough maybe even the oil pump has been effected

Once the correct engine mounts were installed the front engine plate relaxed taking the pressure off the the various components that rely on the front engine plate .. but the plate got warped but not as bad as when the incorrect mounts were installed thus your current minor vibration. Theres a good chance you will start to see an oil leak from the front engine oil seal over the next 300 to 500 miles

These plates dont take alot of effort to warp but with enough muscle its not hard to accomplish

2mm = almost 1 inch, and to do 1 inch on both sides, it ALOT, installing the correct size mounts is bear enough, and takes some personal experiance to do it in a decent time so i can not even imagine the fight that the mechainic had trying to install the wrong mounts... im sure he was pissed and exhausted at the end of that project

If the front engine plate is warped like mine was, you wont be able to see it untill its removed from the engine and placed on a flat surface

Removing the front engine plate removal is a slow, challanging, and very involved project ... id find an MG mechanic thats done this a few times, experiance is going to save you good money compared to someone that just turns wrenches

I feel for you buddy, I really do... this might be one of those moments you may want join a local mg car club, and learn to do the wrenching yourself

Another option get an estimate, it may be less expensive just to replace the engine with a kwon good engine

Prop
Prop and the Blackhole Midget

Prop,

You are getting your mm mixed up with your cm :)
2mm is less than 1 tenth of an inch.

Ray Rowsell

On further thought... probably not the oil pump that would be very extreme

Could it effect the camshaft and cam bearings... im on the fence, i think it could. With the wrong mounts being forced into place esp with both mounts being 1 inch to tall, the damage has got to be fairly significant

Im curious to what guy and lawerwnce thinks the damage will be





Prop and the Blackhole Midget

Ray

Im a true american.. I know standard measurments system and no need to learn a 2nd language... haha

Thanks...I did confuse cm with mm

Hmmmm... 10th of an inch is inside the gray zone id think...thatbwould be hard to even measure without a DTI, or digital caliper.

Certianly not enough of a gap to create any vibration

Prop
Prop and the Blackhole Midget

Ive got very little left... ill certianly continue think about it

What I have left is ... damage from the crane hook up maybe something in the valve train as the crane is attached to the 2 studs in the center of the cly head

Or sometimes the crane is connected by the intake manifold so maybe the gasket got over crushed and you have a vacume leak

But the only real last idea I have ... if you still have the facory header then the prblom could be with the exhaust donut. Its dunut that fits hidden inside the connection between the pipe and the exhaust manifold


These things normally fall apart into clumpy dust chunks once the exhauste system.is distrubed /separated at this location

It could be the shop didnt realize this and bolted.the system back togather without replacing the dunut and its getting an exhaust leak and thus the vibration

Beyond any ive posted above... ive got nothing else

Prop

Prop and the Blackhole Midget

I just had another long shot thought

Check thst the engine mounts fully fully tighted....put wench on the hardware, not just a feel and go

Another thought is a cracked or broken bracket

Prop
Prop and the Blackhole Midget

Thanks for all your thoughts guys.

I've checked all the suggestions. I am pretty confident that the guy who did the work did not make any boo boos and the car is running correctly, if not quite as sweetly as before.

As there has not been any feedback on poor mountings I think we are down to it being "just one of those things". I will drive the car for a bit and see if it settles down and/or I get used to it.
M Parris

Hi, having recently dealt with a set of new old stock mounts and modern repro ones I'd be confident based on the above that your problem is lack of resilience in the new mounts which is transmitting additional vibration into the body of the car.

As NOS are hard to find and repro are in my opinion not fit for purpose, (they're often not bonded properly either, a recent new MGB one could be pulled apart by hand) if I was in your position again I'd look at adapting OEM mounts intended for more modern cars which will be manufactured to the correct standards and will have similar or more resilience than original.

Regards
Chris
C Armitage

Like http://www.speedwellengineering.com/engine/speedwell-competition-engine-mounts/
David Billington

$179 !!!

Not a bad profit margin, figuring there maybe $6 in mateials and an hour of labor.

the engine mount on the in the 2nd photo was interesting and a little more involved ... im not sure what the bracket was about on top of the lever arm shock

The 3 rd photo I did not understand at all... was it an oil driller car, what the heck was that massive oil pump hanging off the side of the engine about...

I just installed a sump pump in basment in this old house im working on and its essliy 1/2 the size of that monster... id think on just idle, that pump could easily pump 100 barrels a day out of the ground

Prop
Prop and the Blackhole Midget

Just at a loose end and moved over from B and V8. I had oceans of problems with new engine mounts. i.e., much too hard and rigid. Might as well have bolted in pieces of wood. BUT this is an issue across the board with "NEW" rubber products, whether windscreen wiper blades, door and boot seals, windscreen surrounds or engine mounts. MY guess, without and real knowledge of compounds, Shore etc, is that this is cheap rubber with too much filler and not enough latex!! I believe there is a company making PU mounts.
Allan Reeling

Well...

poor engine mounts quality is a new one on me, but I guess its par for the course and should have been expected

I guess this will be the 1st new thread of many new FWB issues to come until someone comes up with a better solution.

Like the system above... we may have to budget $200 for those advanced engine mounts

Or learn how to modify existing new stuff

The joy of classic cars

Prop
Prop and the Blackhole Midget

Some experiences from a DIY PU gearbox mount for a Metro:

http://www.mgmetrocup.co.uk/forum/index.php?topic=265.0
Doug Plumb

Hi,

I completely agree with Allan. I think the issue is that classic car repro parts are not required in sufficient volumes to make it worthwhile for the 'OEM' source to produce them, at least at a price most people would pay.

Hence they are put out to far east manufacturers who simply do not have the processes / materials / know-how to produce to the OEM specification. Or they are made by UK cottage industries who may or may not have the above issues / limitations.

In my experience the only way is to scour eBay / autojumbles etc for new old stock, or discover or adapt modern rubber items to suit.

However- I have just replaced the hood on an MGB, and sourced the header rail seal from the hood supplier (Don Hoods). The guy there said that recent hood seals have been useless (too hard) but the latest batch are OK. And so they are- it fitted with no problems at all. So maybe the message is getting through and maybe there is hope!

Regards
Chris
C Armitage

Your new mountings wouldn't be Nolathane by chance would they - ?
Repco here sell Nolathane mounts as performance mounts which in itself is ok but at idle, even in a standard 6cylinder auto car they vibrate through the car
The first sey I fitted, I thought there was a torque convertor problem it shook that much when you put it in drive - a new set of std. rubber mounts fixed it
Might just pay to check with he who sold them to you.

Do your bolt holes line up nicely without distorting the mounting at all. If the mounting is getting pulled out of shape there will be vibration problems

Are the new mountings the only work that has recently been done to the car

willy
William Revit

The mounts are not made from anything exotic, just regular rubber.
M Parris

New old stock is your friend.... ebay or car shows will be the main source for new old stock
Prop and the Blackhole Midget

Considering this is a fairly new problem, (1st im aware of) You might try buying from the usa side of the pond as the new poor mounts probably havent made it to our shores yet...

Victoria british, little british car co., mini mania usa. Would be the 3 places id start

Engine mounts are not a real high demand item so there would be plenty in stock of the good ones

Prop
Prop and the Blackhole Midget

Some apparently NOS mounts on ebay, if anyone is interested?

£5.99 Buy-it-now + £7 postage from Italy.

http://www.ebay.co.uk/itm/371507132060?
Dave O'Neill 2

Yes, have had the same problem after fitting 'NEW' front mounts. Horrible vibration at around 4-5,000rpm.

Was not there before mounts were changed, engine fully balanced and was very smoooooth!

I do believe there is a problem with the current supply of engine mounts. Like many things automotive, there is usually more science involved than is recognised.

Richard
Richard Wale

As I was planning to remove the g/box for reconditioning, I followed this posting with interest as the engine mounts may be in need of replacing.

As one mount had separated from the 'rubber', I needed to source some replacements. Before ordering, the supplier confirmed he hadn't heard of any of the issues that Mike had experienced so I ordered a pair.

After refitting the g/box, a harsh 'vibration' throughout the bodyshell was felt immediately on start up. After confirming it wasnt due to the exhaust knocking etc, I did a test drive which confirmed my fears as the 'vibration' was felt constantly.

As a test, I loosened the four top nuts on the mountings to find the vibration was much reduced both stationary and when driving. In the interim I had bought one mount described as 'HAVE BEEN IN MY GARAGE FOR A FEW YEARS YEARS' so I assumed it was NOS.

However, once recieved it seemed from the finish etc that it was probaly not an original BL item but a pattern part. I then compared the softness of the 'rubber' with both the old one I removed and the new ones fitted to the car. The old one was the softest and the new ones fitted to the car were the hardest with the NOS one in between.

I then removed the new mounts and fitted the old and NOS ones. On start up it was immediately obvious that the harsh vibration was gone which was confirmed with a test drive.

I had also contacted Speedwell Engineering in the US who can supply [for a hefty price] a different style
of mount but it was designed for racing so is probably too firm for road usage. If they could supply it in a road version and for a reasonable price, this would appear to be the way forward.
M Parris

Sorry Mike, the reactivation has appeared under your name for some reason.

Doug
Doug Plumb

This reminded me of a conversation with a bloke I worked with in Aberdeen many years ago. He raced Minis and told me he used mounts that were meant to be compliant mast mounts for windsurfers. I've never seen a windurfer mount close up, despite having sailed for more than 50 years so I have no idea what it's like, but he told me they came in various flavours of stiffness which was apparently handy for different states of tune.

I never liked Minis so I didn't take in any detail but I suddenly remembered it so I wondered if it might be useful.

Just sayin'

Cheers.
Greybeard

Well that really sucks

any chance we will have a 700 posting on the topic of engine mounts in the near future

if its not one thing its another

the mounts from speedwell dont look to complex... i think the issue is all in the chemical make up of the mounts

prop
Prop and the Blackhole Midget

I've got a funny feeling that I bought some 'heavy duty' engine mounts for my 'B'.

Something to watch out for when I finally get the engine back in.
Dave O'Neill 2

I wonder if a sheet of rubber can be cut to size and used as a gasket over the block to give some extra cusion and give
Prop and the Blackhole Midget

It sounds like the new rubber mounts are too stiff, hence they are transmitting too much vibration from the engine to the chassis (they are probably too stiff because the grade of rubber is too hard). How about drilling some holes through the rubber so there is less material to transmit the vibration?

This video shows one way to drill holes through rubber https://www.youtube.com/watch?v=S9Webmd9Jvw
Jonathan Severn

http://www.youtube.com/watch?v=S9Webmd9Jvw
Prop and the Blackhole Midget

M Parris.

Who was the supplier? Was it Sussex Classic MG parts?

It's useful to know, so as to try a different supplier.

Why not by used mounts? Mine are yonks old, and still going strong. I'm guessing a set pulled from an old Spridget being broken for spares, are likely to be fine, since most being broken have sat unused for years. And the Ebay description of "used", means they have to be in perfect working order. Hence if they aren't, you return them for a FULL refund including postage. -- Different if they are described as having a fault of some kind of course.

These should be ok I reckon. "Pair of engine mounts in good order."
http://www.ebay.co.uk/itm/MG-Midget-Sprite-Engine-mounts-A30-A35-A40-etc-/121877055335?fits=Car+Make%3AMGModel%3AMidget&hash=item1c60704767:g:aW4AAOSwZd1VbwUg

PS. Am I helping to push the posting count Prop? ;)
Lawrence Slater

Good idea Jonathan ,an old trick that works well
Seeing as the mounts are useless as they are,there's nothing to loose
A nice big hole across the middle leaving pedastals at the ends or even two holes for even more softening

Worth a try
William Revit

I was told that it was Sussex Classic MG parts who supplied my new parts, but when I spoke to them they said they had not supplied any mounts to my local garage, nor had they had any problems with the mounts they have supplied. So my supplier is a bit of a mystery.

Doug, where did you get your bad mounts from and have you contacted them about the problem?

I bought some NOS mounts from a guy in Italy, they look old but unused so may be my best bet, but I have not got round to fitting them yet.
M Parris

I have just bought 2 'NOS' front mounts for our A-Series, and will be very interested to see if the vibration at ~5,000rpm that started when fitting the 'new' mounts 2 years ago, disappears.

The engine will be going back in about 2 month's time.

Richard
Richard Wale

I have sent my feedback to Peter May who supplied the mounts. Knowing he specialises with competition Spridgets, I specifically asked of any problems for road car usage before ordering.

Doug Plumb

The 'NOS' mounts arrived today from the eBay seller in Italy. Look very good and are definitely MUCH softer than the 'New' ones fitted 18 months or so ago.

Engine due back in after getting the car back from the paintshop in 3/4 week's time, so will report back when I know a bit more.

Richard
Richard Wale

This thread was discussed between 04/12/2015 and 12/02/2016

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