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The Ford Capri Laser Page

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Last updated 26/10/21
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The Cylinder Head

The first job was to unbolt the thermostat housing from the front of the head.  The thermostat itself is clipped inside but mine was quite hard to get out because there was a load of mineral build up that had welded the thermostat in.  After removal all I could find of the rubber gasket was a few hard bits of black looking stuff.  The thermostat housing was cleaned and repainted and a new thermostat kit (with rubber and paper gaskets, and a new clip) was purchased and fitted.  Note that the thermostat must be mounted so that the supports are vertical (there is usually a sketch on the box).  Next thing was to remove the oil spray bar which is attached with two bolts.  The spray bar was washed carefully in petrol to remove any tar build up.  The bar was inspected to make sure that the oils ways were clear.  It is vital that this bar is in good working order otherwise you will wear out your camshaft in no time.  Do not be tempted to make the spray holes larger as they have been designed to produce the correct oil flow at the correct pressure.

It was quite exciting turning the head over to see what state it was in.  Were any of the valves cracked or holed?  In the end it was as to be expected from a 140,000 mile engine - rather coked up but in one piece.  The inlet and exhaust valves both had about two millimetres of deposit on them and the mating face of the valves looked glazed and pitted.  The exhaust valve seats were particularly glazed over.  Unlike the inlet valves which only ever see cold gas, these are exposed to the hot gases and as a result wear more quickly.  In fact it is only the exhaust valves that need to be fitted with hardened inserts when converting the head to unleaded.  The inlet valves are always larger than the exhaust valves because it is harder to suck gas in to the cylinder than it is blow it out again.

I decided to keep costs down I would strip the head myself and prepare it for unleaded machining.  To do this job needs a spring compressor.  I actually borrowed one from someone at work and it was 'homemade'.  The first thing to do was to remove the rockers that sit under the cam shaft.  These were removed by first pulling off the retainer springs and slackening off the lock nut arrangement on the ball stud and screwing it right down.  This lowers the rocker to such a degree that it will slide out from under the cam shaft when rotated in the correct place.  It is essential that all the bits stay together so I had 8 storage bags ready and labelled.  After removing all 8 rockers the cam spins freely.  In my rebuild I replaced the camshaft but this was done after the conversion to unleaded.

To get the valves out I tightened the spring compressor onto the valve so that it pushed the spring down tight.  With the spring fully compressed the two small collets were removed.  These often need a bit of a flick with a screw driver and great care is needed to make sure they don't fall out on the floor.  I for one never put my fingers in to grab them in case the spring compressor suddenly slips - ouch!!  Once the collets were removed the spring compressor was slackened off to allow the spring to lift away.  The valve was now free to be removed.  It was surprisingly easy to do this job and you end up being quite efficient at it by the time the last one has been removed.

The last things to come off were the valve stem oil seals, which are the rubber grommets at sit inside the spring and prevent oil travelling down the stem of the valve.  There is always a new set of these in the head gasket set and they should always be replaced.  You will probably find that they are quite hard and brittle compared with the new ones that are soft and flexible.  It is the failure of these that causes the car to emit clouds of white smoke on start-up.  They can be replaced without taking the head off but it is a bit tricky an requires a special spring compressor tool.  The usual method is to stuff a load of old rope into the cylinder through the spark plug hole and wind the piston up to the top.  The valve that is being compressed then presses on the squashed up rope and the spring can be compressed to allow the collets to be removed.  I had this job done once and was amazed how quick the mechanic did it!

With all the valves, collets, springs, rockers and retainer clips all safely bagged and numbered the head was ready for machining.  In my case I took the head to St. Ives Engineering which was about 2 miles away.  I decided to wrap the head up in some blankets and take it on my push bike in my rucksack.  However I seriously underestimated just how heavy the dammed thing was and very nearly gave myself a hernia cycling up the hill on the way!  The poor old bike nearly gave up the ghost as well.

I was greeted by Andy the owner who inspected the head and told me everything looked good.  The deal was to fit unleaded inserts, clean the head and valves, regrind in all the valves and fix the broken exhaust stud.  The pinto is a very common engine so everything was pretty straightforward.  I assumed that I would need some new exhaust valves but according to Andy 'as long as they have some meat on them' they are fine to reuse although he did not recommend grinding them in from scratch with amateur equipment.

The head took two weeks to get done.  I was promised seven days but made the mistake in telling them that I wasn't in a hurry.  Still it was no big deal - in the meantime I proceeded to strip and rebuild the alternator and distributor and take the old exhaust off the car:

The distributor was removed by unbolting and removing the retaining plate at the point where the shaft goes into the engine block.  The entire distributor literally just lifts out with a bit of a twist.  My overhaul involved removing the clips for the cap (shot blast and repainted), the condenser and points and the vacuum mechanism (which needs to be unclipped from inside the distributor first).  The latter was checked for service by sucking on the tube and noting the movement.  The distributor body was then washed in white spirit and came up remarkably clean.  I did not strip it down any further as it was not malfunctioning.  Instead I gave it a total soak in WD40 and carefully re-assembled her.

The alternator was also given a good clean.  The rear contacts were cleaned up and the bushes were unclipped and inspected.  After all these years there was at least 50% left intact so I decided not to bother replacing them.  The alternator has always performed faultlessly on this car.

The exhaust was not much fun to remove at all.  They make it look so easy at places like ATS but that is because the car is a long way off the ground.  I did however manage to replace the existing exhaust system with a performance system purchase from the Capri Club during this rebuild.  Removing the old system involved a lot of crawling about in tight spaces under my car.  After a lot of pulling, tugging and swearing I cut my losses and attacked it with a hacksaw.  This was much better and it was quite easy to saw through.  Finally the last piece that swings up over the axle fell to the ground and it was all over.  Putting the new one one was just as much fun but that had to wait until the head was rebuilt.

Eventually the call came through that the head was ready and I was off to collect it.  I was delighted with the results; she literally looked brand new.  The valves were all polished and clearly showed a small Ford logo on the base!  The broken stud was fixed and everything was ground in tight.

During the wait for the head to be finished I decided that a new camshaft was needed and I duly ordered a new one from the Capri Club.  It was a 'mild road' performance cam whatever that means.  The profile of the cam is meant to give more power between 2000 and 5000 rpm which is where most people need it.  It is madness to replace the cam and not the followers so I obtained a set of these from Burton Power.  Close inspection of the old ones showed a line across the wear zone where the hardened metal surface had been worn through.  The old camshaft also had considerable wear on the lobes which had developed a 'vertical drop' on one side of each profile.  I decided that I was only going to replace the cam and followers during the rebuild.  The springs seemed fine to me and the other bits don't suffer as much wear.  If I had chosen a seriously hot cam then it would have been sensible to change and uprate the springs as well otherwise you can end up with a nasty bounce!

With the head on the bench it was time to replace the camshaft.  This turned out to be a lot easier than I had feared.  The cam comes out backwards and I have heard many a story of cowboys who have supposedly punched holes in the bulkhead to get them out with the head still in the car!  On the bench things are a bit easier.  The front sprocket has to come off first.  The trick here is to jam a bar from your socket set in the back to stop it rotating and then the front nut should come undone with a good heave.  The sprocket was a actually a bit reluctant to come off so I spent the next ten minutes gently tapping it from the rear with a block of wood.  after a while a noticeable gap appeared and eventually the entire sprocket fell of the spindle.

The camshaft was held in place at the back with a small thrust plate that is easily removed and then the entire shaft simply slides out backwards.  The three bearing shells that the cam sits in all looked OK to me.  They actually have small oil holes in them to keep them permanently lubricated.  The new cam slotted straight in easy as pie although the bearing surfaces need oiling first.  The front of the camshaft was located into a plastic oil seal which came in the head gasket set.  This was simply prised out using a small screwdriver and the replacement seal pressed into place.

The front sprocket is located in place using a metal key that is 'half moon' shaped and slots into the shaft of the cam.  You need to rescue this from the old cam and insert it in the slot of the new one.  It just taps into the slot and the sprocket simply slides over it.  Unfortunately in my case it was a bit of a tight fit so I first had to file a bit off the edges.

In my case I had obtained a second hand vernier pulley from Dave at the Capri Club.  This is a modified sprocket that has an adjustable edge to allow minor cam adjustments once the engine is up and running.  It is important to get hold of one of these if you have fitted an uprated camshaft as there is no other way of setting them up correctly.  To begin with the vernier was set with zero offset (it moves about 5mm left and right) to complete the rebuild.

With the new camshaft sitting nice and snug it was time to fit the new followers which is a reverse of the procedure for removal.  Each follower was slipped under the camshaft and wiggled into place on the ball stud.  The stud was then raised upwards to give the correct valve clearance, and the locking nut was then clamped tight.  In practice this was a slow and laborious job but in the end I stood back and there she was - a completely rebuilt unleaded cylinder head.

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