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Vibra-Technics Engine Mount Installation

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Angus McCoatup
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Vibra-Technics Engine Mount Installation

Post by Angus McCoatup » Sun Nov 03, 2013 1:27 pm

Inspired by the collected works of Exdos and Beedub :thumbsup: , I decided to do my first bit of DIY on the car.

I started with a mid-service interval oil change. It's been a year and around 6,000 miles since the last change, but the state of the gloop that came out of the sump suggested leaving it for another year or 8,000 miles would be too long. I'll certainly be doing annual changes from now on regardless of whether the service indicator suggests it's not needed for another 8,000 miles..

After that I thought I'd have a go at fitting these:

Image

to this:

Image

After taking these shots my camera stopped working, so my aim of letting pictures save a thousand words came to nothing. But I thought I'd do a write-up anyway in the hope that some of the information might be of help at some time. Quick disclaimer - this is posted only for information purposes about the way I did this job. I am not a trained mechanic so please use your own judgement before following it.

I started with the car on four axle stands giving me around a foot of clearance underneath. You could probably do it just as well with two stands at the front, but I just felt it was better to have the car on the level. Remove the front wheels and then remove the plastic undertray. This is secured by three philips headed screws on its leading edge, three hex-headed bolts on its trailing edge that attach it to the large aluminium chassis reinforcement plate and two hex-headed bolts on either side just in front of the wheel arches. Once these are all undone it just pulls out from the front lip.

Having removed the plastic undertray I thought it looked possible to do the job without also removing the large aluminium plate. This turned out to be possible, so it saved the time and effort of taking it off, buying eight expensive one-use bolts, angle torquing them back on and worrying about whether it was necessary to have the normal weight of the car through the chassis before tightening them down (something I was unable to do with the facilities I had).

Next, remove the air filter lid by lifting the clips around its body, unplugging the MAF sensor (no need to unscrew the sensor from the intake cover - just press in the clips on the plug and pull back) and loosening the clamp holding it to the intake trunking. Remove the remaining section of trunking from the air box by undoing the clamp and removing the attached hose by pinching in the thin plastic strips at its end and pulling back. This reveals another lead which I disconnected to create more space.

Then remove the lower part of the air filter housing. This is only attached by the rubber flange coming from the front of the car (an easy pull off) and by two spigots running through rubber bushes just in from the left wing. It's a straight pull upwards using steady force and I found it helped to insert a small flat-headed screwdriver blade down between the oval plastic piece with the arrow on it and the rubber bush.

Next, remove the two bolts attaching the power steering fluid reservoir to its stand. It won't move much after the bolts are removed, but every little helps when trying to reach the front two engine bracket bolts on the intake side of the engine. Removing the air box looks like it would create much better access to these but I didn't want to have to remove the clips from around each intake on the top of the engine, so left it in place.

The final step before starting work on the bolts is to reach under the air box above the lower of the two rear engine bracket bolts. There is a plug under there that needs to be unplugged and moved out of the way. If you're unfamiliar with its locking mechanism, it uses the same method as the plug just to the left of the oil filter canister, so you can practice on that before working blind near the engine bracket.

All four bolts holding the intake side of the engine to its mounting bracket and the single bolt on the top of the engine mount itself are best worked on from above the car - so it's best not to raise it too high. The lower engine mount bolt is accessible from under the car.

On the exhaust side, all four bracket bolts and the bolt on the underside of the engine mount are only accessible from below, but the top engine mount bolt can be worked on from above.

I started by removing the upper and lower engine mount bolts on the intake side. Then using various extension bars and a universal joint I slightly loosened each of the four engine bracket bolts. Not easy to reach, but none were very tight.

I then supported the engine from underneath by using a trolley jack and a block of wood. I placed the wood immediately to the rear of the front anti-roll bar on the intake side of the sump. I tried to make use of the rounded area on the basis it is probably stronger than the flat part (there is a squareish protrusion on the exhaust side of the sump that looks stronger, but this was directly above the ARB with only a few cm clearance, so I couldn't get the wood under it). At this stage I raised the jack just enough to support the engine.

I then fully removed all four engine bracket bolts. I also removed a central bolt on the bracket that connects to a bracket supporting the air box. I then wiggled the engine bracket until it came loose. Bit of trial and error here, including pushing up on the engine mount from below, but eventually it became loose enough to remove the old mount.

It was then a question of inserting the new mount, making sure the locating pin on the bottom of the mount was seated in the right hole on the subframe bracket, and slotting the engine mount bracket onto the bolt on top of the mount.

Because of instances where the bracket bolts have broken or fallen out in use, I took this opportunity to replace them on both sides with new ones of a higher tensile strength (10.9). These were used with nord-lock washers and lubricated threads. I found it was possible to locate each bolt in its hole and seat it by hand (but I don't have massive hands) before tightening to the approved torque for the type of fastener and securing method (32 NM in my case). It was necessary for me to raise the engine very very slightly before all bolts threaded smoothly. If you're in a similar position go very slowly with this. Whilst it was easy with my jack to make very small increases in height, it's very difficult to be so precise going the other way and I would hate to have raised it too much and then had to risk reversing the jack with a relatively unsupported engine.

Torque the top and bottom bolts on the engine mount (Vibra-Technics advised 45 NM), reinsert the bolt for the air box bracket and reconnect the plug near the upper rear engine bracket bolt. Replacement of the air intake tract and hoses/plugs is a reversal of removal. One done, one to go.

Moving to the exhaust side, I started by lowering the trolley jack and resetting at a height where it was just supporting the engine. I then removed the upper bolt from the engine mount by poking a socket on a UJ and extension bars down from above.

Access to the rear upper and lower engine bracket bolts certainly looks like it would be easier with the aluminium chassis plate removed. However I found I could reach between the gap to the left of the front suspension strut with a 13 mm ratchet spanner and exert enough torque to remove the bolts (like the intake side, these too didn't seem very tight). While I was down there I undid the lower engine mount bolt.

Moving to the front of the car, I started by removing the earth strap located just to the left of the Vanos accumulator. I then undid the bolt on the clamp around the Vanos acc and swung it gently upwards out of the way and secured it (once the clamp is removed it's just supported by flexible hose). I then removed the front two engine bracket bolts and extracted the Vanos acc clamp from within the space.

Reaching through from the front of the car it was possible to wriggle the mounting bracket enough to free the engine mount and remove it by pulling it forwards. Mine had a thin flimsy circular piece of tin type stuff on top of it rather than the more substantial heat sheild I've seen in other write-ups (never mind eh), which I refitted on top of the new mount. I then found it was also possible to insert the new mount by pushing it through from the front with a bit of twisting and turning. It was at this point I thought great, I definitely won't need to remove the aluminium chassis plate.

I found the exhaust side bracket harder to re-align than the intake side. But again it was possible to hand thread the bolts in to start off with and, after a raising the engine very slightly in small stages using the jack, it was possible to slot all the bolts in and tighten them to the required torque. You probably know this already but the front two exhaust side bolts are, at 35mm, longer than the back two because they have to go through the Vanos accumulator bracket.

Once the accumulator is re-clamped and the earth strap re-fitted, it's back on with the plastic undertray and job done.

Tools - apart from the obvious, I found a wide range of extension bars, a universal joint and ratchet spanners an invaluable aid for this job. In addition 15 mm, 16 mm and 17 mm deep sockets helped with removing and replacing the bolts on the old and new engine mounts because the threaded part sticks up some way above the nut.

In answer to the question how long did it all take? F**king ages! :oops:

I'm now going out for a drive to see what they're like.

Finally many thanks to Exdos and Beedub for their very quick answers to my question about engine lifting technique when I was planning this job. :thumbsup:
Last edited by Angus McCoatup on Mon Nov 04, 2013 7:17 am, edited 1 time in total.
2008 Interlagos Blue Z4M Coupe

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Toe-side
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Re: Vibra-Technics Engine Mount Installation

Post by Toe-side » Sun Nov 03, 2013 2:13 pm

Good write up. Interested to know if they make a difference.
Not bad for your first DIY :thumbsup:
Before: 2003 3.0 Roadster, Porsche Boxster 987S Now 981S
Success breeds complacency. Complacency breeds failure. Only the paranoid survive

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