Blog: "replacing Cam belt on Esprit S2 1978"

[Widget]

Recently changed the Cam (timing) belt on my Lotus Esprit S2 (1978) as I realised that the belt had been on the car for nearly 10 years, even though it has probably done about 1000 miles in that time. So lucky there then!

As I have never done this process before, I took photos and notes for my own reference and have posted them here in the hope they are useful for other intrepids.

 

Tools:

10mm spanner, sockets and wiggle drives to remove airbox

13mm (actually half inch) socket and spanner to remove alternator pivot.

17mm socket and spanner to remove alternator tensioner slide.

24mm spanner to loosen locknut on belt tension adjuster.

Wide screwdriver for loosening adjuster.

17mm socket and spanner to remove bolts holding tensioner.

Low profile pulley puller to fit 4.5” pulley preferably with 4 or more “hooks” to spread load on aluminium pulley.

19mm socket for drive shaft centre set screw.

Torque wrench for above socket.

Brace bar for above socket.

Effective way of locking flywheel in place. (I used a large screwdriver and wedged it tight.)

Random pry bars, chocks of wood, old big screwdrivers etc.

Pillows, sheets of hardboard, blankets etc:- to make clambering around the engine bay as comfortable as possible.

 

Parts:

Toothed belt: GATES 5146 (check this is correct for your vehicle)

V-Belt: 6218 GATES (check this is correct for your vehicle)

 

Lets Go! =>

First I unbolted battery then the air box (10mm spanner, sockets and wiggle drives), then I unbolted the alternator tensioner  (17 mm socket and spanner) and then the pivot shaft (13mm socket and spanner).

Below is a photo of this stage.

 

The below photo is of the various pulleys and things.

 Next I turned over the engine to find Top Dead Centre, set this to the pointer in the flywheel window, checked Inlet and Exhaust marks opposite each other on the Cams, then locked the flywheel in place with a large screwdriver and an old hammer as a wedge. See photos below.

 Above - TDC lined up with pointer in fly wheel window.

 

Above - IN-EX markers lined up on Cams.

 Above - flywheel locked in place. There is a recess behind the fly wheel that the screwdriver fitted in and conveniently held the fly wheel stationary.

Then cable tied the two cams together, as below…

 

At this stage I marked up the belt and pulleys to match up with the new belt using various distinctive marks, as in photo above.

Next, to remove the Belt Tensioner.

Using 24mm spanner I released the lock nut on the belt tensioner adjuster and used a large screwdriver to release the tension. The Lotus-big-black-book-of-curiosity states not to wind out more than 12mm however as can be seen in later photos, on my tensioner 20mm is OK. Also the hole to lock the tensioner with 4mm rod is under one of the bolts’ washer so impractical and when I inspected the tensioner on the bench, the unit would not compress enough to locate this hole to the groove in the tensioner piston anyway… Photos below.

 

 

In the photo above can be seen the two retainer “bolts” that hold the assembly to the engine. One was easy to remove with a 17mm spanner  the other tuned out to be a stud that I had to extract by locking two suitable nuts together and using these to wind out the stud. Sadly I didn’t note the thread size of the stud.

 

 

Above can be seen the tensioner assembly bits ready for a good clean and inspection. The 4mm drill was to lock the piston in place but was redundant. Note there is a flat washer inside the plastic piston that the springs work against. On the right are two spacers that wanted to drop down in the engine bay when I removed the “bolts” from the assembly. The anti static earth wire needed repair too.

 

Next to get the drive shaft pulley off.

 

The drive shaft set screw unscrewed with a hefty push on a 24” brake bar (normal thread) and 19mm socket. I had my knee against the screwdriver holding the flywheel in place. There is a conical large washer also.

 

I assumed the pulley was brass by the colour so I made a simple puller out of three bolts and a length of steel flat. However when I tightened this to extract the pulley I noted the pulley was starting to warp. I realised then that it is anodised aluminium. So redesigned the puller to have four points of contact to spread the load. Photo below.

 The drive shaft set screw has been wound back in to place without the large retainer washer to give the centre bolt of the puller something to work against.

Even with this puller, I was exerting too much stress, so time for Plan B.

Usually a blow torch to heat is the answer but with such confines, rubber pipes and old oil about, a bad idea. So I tried a paint stripper heat gun with a fan shroud to direct the heat over the pulley (photo below). Within 30 seconds the pulley released and from there I was able to wind it out with the puller. 

 

Now to remove the belt.

With the new belt, I transferred the marks over from the old belt making sure that the “direction” of the belts matched. I used a 6mm rod clamped in a vice to “jump” the  teeth over in parallel.

After many checks, I installed the new belt. 

After a good cleaning and checking for distortion, the drive shaft pulley was next, using a torque wrench [value to follow] to bolt this in place.

 

Next install belt tensioner unit.

I found this very difficult to install as the unit would not compress enough to align the bolts and the angle of attack was too awkward to get any muscle power to it. So I wound out the adjuster screw completely and removed the springs. Then bolted the unit in place.

To get the adjuster back in, I tested the thread with the adjuster to find where it starts and marked up the adjuster and case. Next, inserted the springs and using a palm sized block of wood with two panel pins in (to locate with the slot of the adjuster), I compressed the adjuster and twisted. After a few tries I caught the thread and from here, winding the adjuster in was easy.

 

As I don’t have a Belt tension tester, belt tension was set to ¼ twist on the top section which is the same as the old belt (A job to deal with when I get the correct tool, but for the moment, OK to get going, I had noted that other people have written about setting the tension in the same way).

Next to check all the timing marks and fully turn the engine by hand to ensure all is good.

Next was V-belt and alternator. Getting the tension on the V-belt was not easy but with small chocks of wood and old big screwdrivers, tension was achieved.

Airbox on, Battery on, Fingers crossed and start the engine. 

Next to repair skin and bruises.

[Bibs]

Excellent post, thank you

[peteyg]

Well done Mark. It's an entertaining job but gets easier after the first time!

I use one of these to tension the cambelt 50-55lb for the standard belt

https://www.ebay.co.uk/itm/Gates-91107-Krikit-I-V-Belt-tension-gauge-tool/253218257274?epid=21017021517&hash=item3af4fbf97a:g:eqQAAOSwNchZ6j9- 

Pete

[Widget]

Thanks Pete, I will look into buying one 🙂

[Paul Coleman]

On 01/06/2018 at 14:50, Widget said:

With the new belt, I transferred the marks over from the old belt making sure that the “direction” of the belts matched.

Do the belts have a direction? I wasn't aware that they did.

[silverfrost]

I have seen some belts with direction of rotation marks, always three little arrows.

Most things are clockwise thankfully bar Honda engines.

The main thing I check on a new Cambelt is I count the old teeth on the old belt and count the teeth on the new belt to make sure they are the same !

More often when using non gen, you can be surprised how parts people can mix up, give you totally the wrong part.

[Paul Coleman]

31 minutes ago, silverfrost said:

I have seen some belts with direction of rotation marks, always three little arrows.

Most things are clockwise thankfully bar Honda engines.

The main thing I check on a new Cambelt is I count the old teeth on the old belt and count the teeth on the new belt to make sure they are the same !

More often when using non gen, you can be surprised how parts people can mix up, give you totally the wrong part.

Sure but I've not seen them on a 907 belt?

[Widget]

On 19/06/2018 at 09:21, Paul Coleman said:

Do the belts have a direction? I wasn't aware that they did.

Here is a pic of the new belt with arrows pointing to the front of the engine. I dug the old lotus supplied belt out of the bin and there are no direction markings, however the text would be the right around if you were standing in front of the engine. I have always assumed that flat belts have a direction, guessing that when made, the belt would be layered in a kind of spiral and then cut to width so the layers would either naturally tighten or loosen in use. I have no idea if that is fact, just kind of feels right.

[Steve4012]

It says on the gates website there is no direction. The arrows are simply an aid to line up with pulley markings.

https://www.gatestechzone.com/en/news/2017-03-direction-of-belt-rotation

[Sparky]

There is no direction.  But it's handy if you intend to reuse the belt.

However, I always try to fit with the arrows in the right orientation as owners get very nervous about it!

[PhilW]

What is considered the front of the engine.  Coincidentally I put a cambelt on yesterday but the engine is out and on a stand.  I put the arrows pointing to  the front of the car as if the engine was fitted.

[Widget]

11 hours ago, Steve4012 said:

It says on the gates website there is no direction. The arrows are simply an aid to line up with pulley markings.

https://www.gatestechzone.com/en/news/2017-03-direction-of-belt-rotation

Thanks Steve, there is the definitive answer! I think when I do this job again, I will follow convention as I know it would bug me seeing arrows pointing the wrong way and I would still have a tints y-wintsy amount of irrational doubt every time I see it😃

[Widget]

11 hours ago, PhilW said:

What is considered the front of the engine.  Coincidentally I put a cambelt on yesterday but the engine is out and on a stand.  I put the arrows pointing to  the front of the car as if the engine was fitted.

Good point! I have looked around on the internet and can't find a specific convention. However I was taught that the front of the engine is where piston one is and according to the Lotus-Big-Black-Book-Of-Curiosity this is the one nearest the water pump.

[910Esprit]

Crank pulley is front.  Adjacent spark plug is no 1. 

[The Ferrett]

Mark, many thanks for your write up and photos, ive just done my cambelt change on my Esprit 2.2 and it helped enormously.

Horrible job but made easier with your info.

Many thanks

Martin

[Tocus]

the strange thing is, at a Excel/Elite/Eclat you take a look to the front of the Cams "marks/dots"

and by a esprit you take a look from behind 😉