Technical help and FAQ

Changing the Timing Wheel

This has been written with the SE5 and SE5A in mind, the only difference I can think of when working on the SE6 is the bracing strut, so hopefully it will also help the larger car owners. It does not apply to the 2.8 engines.

You will need
• 1/2" AF combination spanner
• 7/16" AF socket (1/4" drive recommended)
• Long extension for 1/4" drive
• 1/4" drive ratchet ratchet
• 1/2" AF socket (1/2" drive)
• 5/8" AF socket (1/2" drive)
• 1/2" drive ratchet
• 1/2" drive ratchet
• 1/2" drive Torque wrench
• Short extension for 1/2" drive
• 2 Slot screwdrivers
• Pliers
• Rubber or hide mallet
• 1 Ton jack
• 2 axle stands
• Large bowl to hold radiator coolant
• A podger bar (A slender tapered steel rod, a centre-punch will do at a pinch)

Useful, but not essential
• Torch
• Inspection mirror
• Hot air gun

Preparation

• Disconnect the battery earth lead
• Remove the spare wheel
• If your handbrake is not particularly strong, a pair of checks should be put against the rear wheels

Now would be a good time to check whether you already have a steel wheel fitted

• Undo the two 1/2" AF nuts holding the fuel pump to the timing cover and remove it.
• If the rubber pipes are long enough you can tie it out of the way, otherwise undo the pipes.
• Shine the torch into the hole in the timing cover.
• A fibre timing wheel will be a dark brown colour, with no inner metal rim visible. (The centre of the wheel is steel, but you will not be able to see this from the fuel pump hole).
• A nylon timing wheel will be a light brown colour, with a steel centre ending just beneath the tooth level
• A steel wheel will be silver, the teeth especially should show clean surfaces, although the rest of the wheel might have baked-on gums discolouring the surface.

Assuming that the wheel is fibre or nylon, proceed to dismantle the crossrace and remove the timing cover.

Using a 1/2" AF socket
• undo the bolts holding the top spare wheel tray to the transverse brace
• undo the two bolts holding the top spare wheel tray to the lower tray
• undo any bolts still holding the tray to the side pieces.

• Using a 1/2" AF socket,undo the two bolts visible through the circular holes in the spare wheel tray that bolt into the radiator. Keep these bolts apart from the other ones, they are shorter in length to avoid puncturing the radiator.
• Remove the spare wheel tray.
• Position the bowl under the radiator
• using a 5/8" socket, undo the radiator drain plug.

• Once the coolant has drained, replace the radiator drain plug, so you won't have to look for it later
• undo the hose clips on the L-shaped pipe running from the radiator to the expansion tank
• remove the pipe complete with clips.

Using a 1/2" AF combination spanner and 1/2" AF socket
• slacken the alternator tension bolt
• push the alternator towards the rocker cover as far as it will go.
• Remove the fan belt.

Using the 1/2" AF socket, and possibly the spanner for the two awkward bolts
• remove the 8 bolts securing the transverse brace to the suspension towers.
• Take careful note of any earth straps which terminate on these bolts; on my cars the alternator is earthed to the right-hand side of the brace, and a thinner earth wire terminates on the left-hand side.
• The brace will be held firmly in place by the inwards loading of the towers.
• To remove the loading, jack up the car and place an axle stand beneath the chassis close to the rearmost bracket for the lower wishbone.
• Tap the left-hand side of the transverse brace backwards, and tap the right-hand side forwards, and take the brace out.

Go underneath the car with the 7/16" AF socket
• undo the sump bolts securing the front timing cover. Starting with the right-hand side of the sump, undo the bolt that is in the middle of the sweeping 90 degree bend, and then the remaining 5 bolts.

Removing the crankshaft pulley

• Put the car in 4th gear
• make sure the handbrake is firmly on
• put the 5/8" AF socket on the bolt securing the crankshaft pulley. This bolt is likely to resist coming undone. Do not try a steady pressure on the ratchet, it will just turn the engine over. Try a sharp tug.
• If the bolt refuses to give, it has possibly been fitted with a thread locking agent. Using a hot air gun, apply heat to the head of the bolt for a minute or two, and try again.
• When undoing the bolt, a thick spacer washer will also come off.
• Be careful when trying to remove the crankshaft pulley; the alloy timing cover is fragile. Using a pair of suitable levers, try to get the pulley to wiggle from side to side.
• If it is stuck, put some heat into the rim of the pulley using the hot air gun, and allow time for the heat to propagate to the centre.
• Do not apply heat to the exposed crank area, it will cause the key to expand and grip the pulley even tighter.

Removing the timing cover

After removing the pulley, use a 1/2" AF socket to undo the timing cover bolts.
• Do not undo any of the water pump bolts.
• Take note of the different length bolts that come out; the longest go into the lower holes in the timing cover, the shortest into the top holes.
• Lift the timing cover away.

Positioning the crankshaft for replacement of the timing wheel

• Look for the small dot in one tooth of the timing wheel. If it is not vertically downwards in the 6 o'clock position, refit the crankshaft pulley and rotate the engine.
• You might need to remove the spark plugs, but I have been able to turn it by wearing welders gloves and exerting a steady twist.
• As the dot on the timing wheel nears the 6 o'clock position, you should be able to see a similar dot on the crankshaft gear coming to meet it.
• Continue rotating the engine until the dots are in line.

Removal of the old timing wheel

• Using the 5/8" AF socket, undo the bolt securing the fuel cam and timing wheel.
• As before, a steady pressure will tend to try and turn the engine over, but a sharp tug should get the bolt moving.
• Remove the bolt and the large washer, and the fuel cam.
• Set into the centre of the timing wheel is a small scroll pin (a hollow peg), that locates the fuel cam. Test the secureness of this pin with the pliers. If it is at all loose, remove it completely and keep in a safe place.
• Using a screwdriver and another suitable lever, try to get the timing wheel wiggling from side to side by putting one lever behind it at the 7 o'clock position, and the other behind it at the 2 o'clock position.
• Do not heave on them with all your might, I have had one person ring me up asking for a cam because he snapped the driving end off.

Fitting the replacement timing wheel

• When you have removed the timing wheel, you should be able to see that the keyways in the crankshaft and camshaft are facing each other.
• The action of removing the timing wheel will have cause a small amount of rotation; do not correct this.
• Pick up the steel timing wheel and hold it so that the small hole for the scroll pin is facing you, and the keyway is pointing down.
• Move it into position against the end of the camshaft.
• Using an inspection mirror, make sure that the tooth which is marked by the dot on the timing wheel is aligned with the appropriate valley marked with a dot on the crankshaft gear.
• Once you are happy that the teeth are correctly aligned, start tapping the wheel on the centre boss with the rubber mallet.
• It will try to go on the camshaft with a slight vertical slant because of the action of the teeth meeting.
• Vary the position in which the mallet blows land to keep the wheel square.
• Once it has located on the first 1/8" of an inch of the camshaft, stop, and use the inspection mirror to verify that the two dots are really going to line up with each other; it is very easy to get one tooth out due to the twisting action.
• Drive the wheel onto the shaft with a series of taps. As soon as you are certain it is square, you can use the bolt and thick washer from the crankshaft pulley to draw the timing wheel on the remaining distance. When you think the timing wheel has bottomed out on the shoulder of the camshaft, remove the bolt and washer.
• It is a good idea now to rotate the engine slowly and carefully through two complete revolutions, listening for any strange noises, or feeling for any sudden resistance.
• When you are happy that the two gears are meshing properly, fit the scroll pin to the timing wheel, then fit the fuel cam, and screw the bolt into position.
• Using a torque wrench, tighten the bolt to the figure given in the workshop manual

Refitting the timing cover

• Refit the timing cover.
• Tighten the bolts loosely, until they have just met the cover.
• Go under the car with the 7/16" AF socket and refit the six sump bolts, tightening them firmly, to the setting in the workshop manual.
• Check the remaining sump bolts while you are under there, it is often possible to get a part-turn on many of them due to the sump gasket shrinking slightly with age.
• Tighten the front cover bolts to the setting in the workshop manual.
• Refit the crankshaft pulley, and torque the bolt up to the setting in the workshop manual.

Refit the transverse brace.

• Line up the left-hand bolt holes and loosely fit the four bolts.
• The right-hand side of the brace will be reluctant to line up with the bolt holes. Use a tapering bar (such as a Phillips screwdriver), to lever in one of the holes while fitting the diagonally-opposite bolt. Then switch the lever to another hole and fit the bolt into the hole you first used for leverage.
• The remaining bolts can then be fitted.
• Make sure that any earth wires are re-terminated.
• Tighten up all 8 bolts.

Replenish the fluids

• Refit the L-shaped hose, and tighten the hose clips.
• Refit the radiator drain plug, and pour the coolant back in.
• You might find it slow to refill, but spinning the water pump pulley will help to purge some of the air past the thermostat.

Refit the ancillaries and check operation

• Refit the fuel pump and also the fuel pipes, if you had to remove these.
• Refit the fan belt and set to the correct tension.
• Refit the battery leads.
• You can now start the engine and let it idle for a while, adding any remaining coolant that wouldn't go in earlier.
• There will probably be a singing noise from the new steel wheel, this will last for a few hundred miles until the teeth bed in properly.
• Put the pressure cap back on once the engine has fully warmed up, and wait until the fan is cutting in and out to look for any leaks from the hose joints you disturbed.
• When you are happy, refit the spare wheel tray.

I would suggest changing the oil after 3000 miles, and also changing the oil filter, because a small amount of metal particles may build up in the oil as the timing wheel teeth adapt themselves to the crankshaft gear.

The singing noise is only evident at low engine speeds. I never noticed it on my first Scimitar after changing the wheel, and only had a faint noise from the other engines I built up, but the wheel I recently changed, that prompted this article, made quite a noticeable noise for a while.

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