Upgraded Engine Mounts

With the Southern Kit Car Club European road trip coming up it was time to give the car a check over and look for anything that might present reliability issues during the 1300+ miles.

One thing I've been keeping an eye on recently is the original Tiger engine mounts.  Other Avon owners have had issues with these failing and I suspected it was only a matter of time before mine gave me issues.  Upon closer inspection there did seem to be some metal fatigue setting in where the diagonal tubes meet horizontal plates.  I was not happy with this so decided now was the time to get on with fabricating a more robust replacement.

After jacking up the engine and resting it on some wooden joists I was able to remove the old engine mounts.  Straight away it was easy to see that in their natural rest position these had not been level with the top of the engine rubbers.  Instead they had been inclined and the tightening of the bolts had clamped them down onto the rubbers and had deformed the top of the rubbers over time.  This obviously meant that there was a constant force applied trying to tear the diagonal tubes from the horizontal plates, even before any twisting force is applied by an accelerating or decelerating engine.

With the original engine mounts fitted, the engine was not level.  So using the wood under the sump I raised the inlet side around 15mm to bring the bottom of the engine (sump) horizontal with the ground, when viewed from the front of the car.

Next I replicated the four flat plates.  This time out of 6mm steel instead of the previous 5mm.  For the diagonals I used 5mm thick 45mm box section.  This compares with the 1.5mm tube used previously.

Cutting these box sections to fit was a very difficult task.  Multiple compound angles and all work being undertaken with the engine in situ.  On the exhaust side I was having to work in between the small gaps between the exhaust headers - very difficult indeed.

In the end I got there.  Had them tack welded by Ashby Welding ready for a trial fit.  They fitted perfectly, with the horizontal plates resting on new rubbers, without any clamping and with absolutely no stress applied to the mounts or rubbers.  Back to the welders to have them fully welded up and here is the end result.  A very nice job done by the welder.

These have been painted up, fitted to the car and bungs inserted into the bolt holes to protect from water ingress.

Another long term to-do list job completed and hopefully another piece of reliability added to the car.

Tiger ERA Sump

Time to replace the tall original Focus sump with the shorter ERA sump from Tiger.  On the later Black Top Zetec engine both the steel sump pan and the alloy lower crank case need to be removed.  Here is the engine with just the sump pan removed.  Visible is the plastic oil pick-up pipe.  This cannot be shortened so will be replaced by a earlier steel pick-up pipe that has been modified by Tiger (chopped, shortened and welded).

 The lower crank case removed.

Four bolts in two of the main bearing end caps are replaced with Silver Top Zetec bolts that have a threaded stud on the top.  Tubular steel spacers are added to allow the windage tray to be at the right height.

The windage tray, again from an earlier Silver Top Zetec, is bolted on to the four studs using thread-locked M8 nuts.  The modified pick-up pipe is bolted on using a new gasket.  This pipe is attached to one of the studs via a mounting bracket.  Washers were used as spacers to get the right height (8-10mm from bottom of new sump).  This was checked using a ball of Plasticine.

 

On trial fitting the ERA sump fouls with the oil pump housing.  This means the sump bolt holes do not line up.  A curved recess is present on the original lower crank case (seen lower left).

A similar recess was made on the ERA sump using a round file.

Sump mounted using a new gasket and the original bolts tightened to the specified torque.

Once the car is on the road I'll think about adding some baffles to the sump to prevent oil starvation when driven hard, e.g. on the track.

The next problem is one of the engine mountings.  I had previously trimmed this to make if fit around the water pump housing.  Now with the new sump on the engine mount hits the sump edge before being flush with the mounting holes cast in the engine block.  If tightened in this state the engine mounts will 'push' the sump sideways and the large engine loads will be transmitted through the sump - not good.  Next job then is to trim a little of the lower edge of the engine mount.