VHPD timing with Piper verniers

I bought my S1 from a swiss specialist, but I immediately noted that the car didn’t run well, despite having a horrendous fuel consumption: 16l/100km on a swiss highway with an average speed less then 100km/h!

Furthermore I noticed that unfortunately everything that was “serviced” by the specialist was more or less screwed up.
Therefore I decided to start a ground up restoration and the engine was also disassembled.

Of course the valves clearance was checked and I found that 4 of them were to tight…

Then I checked the timing and, believe it or not, the timing was at least 20° too late on the inlet and on the outlet.
Both valves were still closed at TDC with the verniers positioned on the marks that were marked originally on the Piper pulleys (!?)

I took the timing data for the VHPD from Piper’s website:

To cut a long story short here is how the setting of the camshaft should be, after taking the belt apart and setting the camshafts
with a gauge…
Note: Only the inlet camshaft needed a fine adjustment of a few degrees.

This week the engine will be reassembled and then we will see if the cure was successful or not…


Great work, more details on the car needed I reckon :thumbup:

I also tried this pair of pulleys, but believe it or not, they were roughly 170° wrong.

Fine adjustment at its best…




We are still optimizing the Emerald ECU, but the stinky VHPD is definitely cured!

For those that would be interested I could send them a short video with the engine running,
because I don’ t know how to attach the video to this post!?

Youtube for the video. Upload it there and share the link in here

Video 5 - YouTube


Video 4 - YouTube


:clap: :clap: :smiling_imp: :smiling_imp: :sunglasses: :sunglasses: :thumbup: :thumbup: Oh the sound of a K Series with VHPD’s and cams!

To optimize the carburation I have been told that it should be better to place the air temp. sensor directly in the airtbox.
Therefore we decide to place it in the hole of the breather pipe and redirect the breather hose in the gearbox oil catch tank.
I developed an adapter to place the sensor in the carbon airbox without damaging the part adding a new hole.

A friend of mine (:thumbup:) was so kind and made 4 prototypes, two in aluminum and two in Delrin.
I think I will install the part made of Delrin.

Here is the new position of the air temperature sensor and the plug that we used to close the hole in the throttle body.


New Lamba sonde optimized for the Emerald ECU:

Where are you in Switzerland? I’m looking for one S1 and would be happy to speak with other owner. I can’t send you a PM.

I’ m in Gersau, but the car is actually in northern Italy.
You could call me on: 0041 76 3396231
On Whatsapp too.


Adriano: thumbup:

Just a little update:
We checked another S1 with original 12.700 km on the clock that was “optimized” by a “specialist”
(maybe they changed the cams too, but the owner didn’t remember)

**Lousy idle
Lack of powerNote: the consumption in this case wasn’t t to high.

We checked the timing and as expected it was wrong: in this case it was to advanced

Same procedure:

  • Checked the valve clearance
  • Set the timing correctly with piper verniers:

Note: To be honest it is a little bit tricky procedure with the engine installed

  • Replaced the IAC that didn’ t work correctly (Idle Air Control Valve)
  • Changed the Lambda sensor
  • Installed an Emerald ECU
  • Bench optimization and test

    Result: Almost 193 Hp at 7800 revs/min

    The owner is, to say the least, overwhelmed by the improvement…


Awesome work ortope :clap: That must be very satisfying to tune the little VHPD as it should be. I wonder how viable is this for a novice to carry out? I would love to check my valve timing to make sure it is spot on. Perhaps a tutorial is possible? :wink:

Hi Evoman,
to be honest for a novice it is not the easiest task, beside the fact that you should use some expensive
hardware like the Mitutoyo magnetic micrometer dial gauges that we used.
I want to thank on this behalf a very good friend owner of HRT Racing in Soldiate Olona (Italy).
He lent me the parts.
By the way, HRT builds up, among other things, the racing engines for MV Agusta…

You will do an assistant to do the job.
The easiest way to get the setting done is when you have the engine out of the car or at least with the rear clam off.
With the clam on the car you have to take off the right wheel and the wheel arch, but it is highly recommended
to take at least the rear clam off, exeption made if you love Kamasutra.
Now you can start!

  1. First you have to check the valve clearance and eventually adjust them.
    Note; This would be already a pain in the neck on a VHPD cylinder head.
  2. Measure the current timing with 3 micrometer dial gauges at top dead center when the valves are partially open
    with the right tension on the timing belt
    Note: If you would read 3,00 mm on the intake and 2.54on the exhaust (thank you Dave Andrews for the data) , you are done!
    Unfortunately this is very unlikely the case.
  3. Remove the belt tension and the belt from the camshaft pulley and turn the camshafts until you read 3.00 on the intake
    and 2.54 on the exhaust
    Note: Using a pair of Piper-Cam adjustable verniers is highly recommended
  4. Place the belt on the verniers and then turn the engine clockwise and double check your reading.
  5. If necessary fine tune the valve opening with the verniers until you achieve the correct setting
    Note: Turn the engine only clockwise, not back and forth.

Now you have theoretically finished, but to optimize the result a multi band oxygen sensor (Lambda) and an Emerald ECU should
be installed and the car then bench tested to optimize the result.
See my former post on this behalf.

The result will be a powerful engine with a lot of torque and a low fuel consumption.
For me it was definitively worth it!

The easiest way IMHO is to plan a short vacation in northern Italy and let Cerini (https://www.lotuscerini.com) do the job, LOL


P.s.: I would also recommend to install a remote thermostat too…

Just, have a bash - what’s the worst that can hapen? :laughing:

I had some vernier pulleys fitted and timed at Craig Moncrieff thsi year, when the water pump and timing belt were being changed. Not a massive difference to be honest, but then still running the stock 190 ECU.

Did you optimize the ECU bench testing your car?

Normally a multipoint oxygen sonde and an Emerald ECU should make the difference…

My car has also following modifications:

  1. S1 K Series High Flow Flexi Sports Cat
  2. Sport silencer

I’ am quite pleased with the result.


Adriano that sounds a fantastic idea! A trip to northern Italy would be a nice way to spend some time whilst the Exige is fettled by the pros :grin: