Performance Camshaft fitting instructions

This page provides all the information you will need to fit your performance camshaft correctly.

We also have a pdf download of these camshaft fitting instructions available here.

1. Basic Information Checks.

  • Connector.

    Check the Cam number

    Check the Cam number is impact marked on the cam and agrees with the cam that you have ordered.

  • Connector.

    Check the cam is identical

    Check the cam is identical to the cam you are replacing except for the cam lobe profile.

  • Connector.

    check that the Valve springs

    After installing the camshaft check that the Valve springs are not coil binding. They should have a minimum of .75mm clearance between coils. If they do coil bind you will either have to cut the valve springs seals or fit extended valve collars if they are available.

  • Connector.

    Check valve poundage

    If you are fitting springs that are not supplied by Newman Cams check the valve poundage at full lift. As a rough guide the following poundage rates will apply at full life

2. Nominal Guide to full lift cam nose poundage rates

Up to 7000 RPM – Full Lift Pressure 160lbs
Up to 10000 RPM – Full Lift Pressure 200 lbs
Up to 6000 RPM – Full Lift Pressure 160lbs
Up to 8500 RPM – Full Lift Pressure 200lbs
Up to 7000 RPM – Full Lift Pressure 160lbs
Up to 8000 RPM – Full Lift Pressure 170lbs
Up to 7000 RPM – Full Lift Pressure 160lbs
Up to 8000 RPM – Full Lift Pressure 180lbs
Up to 8000 RPM – Full Lift Pressure 120lbs
Up to 10000 RPM – Full Lift Pressure 160lbs
These are only a basic guide as the exact poundage depends on the profile and the weight of the valve gear.
Most standard valve springs fitted by the original manufacturer will work on Ph1/2/3 Cams. As they are designed with a life of over 200000 miles they are normally overrated by 25%. Also when the cam lift is increased, so the spring rate increases, as the spring is compressed. So what has a full lift pressure of 140 lbs when the lift has been increase by 2 mm, the nose pressure will increase dependent on the spring to around 160 lbs.

3. Summary of valve springs

  • Use the lightest spring possible
  • Using heavier springs than required uses up power, hammers valve seats and can lead to premature wear of cam lobes and cam followers/rocker arms.
  • You will gain more power by using a lighter valve spring than removing a few grams from the valve gear.
  • Valve bounce can normally be traced to reaching a given RPM and the engine not wanting to rev any more. On an engine with open trumpets this can sometimes show as a blow back of vapour as the engine literally decompresses itself.

4. Cam Followers

  • As a general rule it is essential to fit new can followers with a new cam.
  • You can either fit the cams followers that we supply or fit O.E. Cam followers supplied by a main dealer. There are some followers that are being supplied that work on a standard engine but fail in a more highly stressed engine.
  • Note: We will only consider any claim against our camshafts if the cam has been fitted with either cam followers supplied by us or O.E. Cam followers.

5. Piston to valve clearance

If no material has been machined off the head or block, PH1/2/3 Cams can normally be fitted without machining the piston crowns. If the head or block has been machined or you are fitting PH4/5/6 cams, you will need 1.5mm/.060 clearance between the valve and piston at TDC. This can be checked by assembling the engine placing blue tack on the valve and turning the engine over by hand and then measuring the compressed thickness.
If you are going to use vernier pulleys, it is advisable to do this check with the exhaust vernier retarded back by 5 degrees and the inlet vernier advanced by 5 degrees. This will then cover any vernier adjustment required.

6. General assembly information

There are various ways of timing in camshafts. They all require the following:-
A dial gauge if possible with 12mm lift. A timing disk.

General notes on Timing Camshafts
On PH1/2/3 cams our cams are ground so you can use the timing marks on the existing sprockets or pulleys as marked by the engine manufacturer. This applies to all pushrod engines.
This method will work on OHC engines providing the cylinder head face has not been machined to increase the compression ratio by machining the head when the timing belt/chain tensioner is adjusted it will move the timing on both of the cam/cams.
If you are fitting PH1/2/3/4/5 cams with the engine in situ and cannot get a timing disk or dial gauge to the engine and you are fitting vernier pulleys, set the engine up with the standard pulleys and take them off and fit the vernier pulleys. This way you are never going to be more than 5 degrees out. You will have a basis for tuning the engine in on the pulleys.
We always recommend before timing in the cams that you set the engine up on the standard timing marks using the standard sprockets/pulleys.

There are 3 methods of setting valve timing not using the existing timing marks:-
a. The full lift method
b. Full lift at TDC method
c. Opening and closing method

7. Timing the camshaft

Lubricate the cam and cam follower faces with Hypoid EP80/90 Oil or a cam Lube.
Time the camshaft/s either by the standard timing marks or the full lift at TDC method.
Turn the engine over with the spark plugs out manually with a spanner and ensure there is no valve to piston contact. If there is check the valve timing.
Starting the Engine:-

  1. Remove the spark plugs, turn the engine over on the starter motor until the oil light goes out/or the oil pressure registers pressure. Replace spark plugs.
  2. Start the engine as you would in normal use. There is no need to run the engine at 3000 RPM for 20 minutes. Just treat the engine as if it was new for the 100 miles then off you go.
  3. To obtain maximum performance on PH3/4/5 cams a visit down to the rolling road is advisable.
Fit a timing disk (Our timing disks are dual sided with a full lift degrees on one side and timing on the reverse side) on the crank. Find TDC on No 1 piston with a dial gauge from the top of the piston. You will find that there is a period of around 5 degrees where the piston does not seem to move. Take the midway position.
Set the timing disk at 0.
Note the full lift on the inlet from your spec sheet EG 110 degrees.
Turn the crank clockwise 110 degrees
Fit the dual gauge in the valve cap or the cam follower of the No 1 inlet cam lobe. Turn the cam around until you obtain full lift. You will find there is a period of around 3 degrees at full lift where the dial gauge does not move take the midway position now attached the sprocket or pulley and fit the chain or belt.
Your cam is now timed correctly but double check the above procedure with the chain or belt attached.
Note the full lift on the inlet and exhaust from your spec sheet E.G. 110 degrees.

  1. Turn the crank clockwise 110 degrees
  2. Fit the dial gauge on the valve cap or the cam follower of the No1 inlet cam lobe turn the cam around until you obtain full lift you will find there is a period of around 3 degrees at full lift where the dial gauge does not move take the midway position. Now attach timing belt /chain to crank and bolt up inlet cam.
  3. Turn the crank anti clockwise 110 degrees
  4. Fit the dial gauge on the valve cap or the cam follower of the No 1 exhaust cam lobe. Turn the cam around until you obtain full lift. You will find there is a period of around 3 degrees at full lift where the dial gauge does not move. Take the midway position. Now attach the timing belt/chain.

After setting the cams you can run a double check by turning the timing disk round and checking the opening and closing periods.

If your specification sheet has a lift at TDC data available Note the lifts at the TDC on the inlet and exhaust valves.
E.G. Inlet 2mm at TDC
Set the engine at TDC on No 1 cylinder
Set the dial gauge on No 1 inlet cam bucket or valve cap to zero in the middle of the base circle. I.E. 180 degrees opposite the full lift part of the lobe.
Turn the inlet cam clockwise until you reach 2mm on opening side of the cam.
Now attach the timing belt/chain
If your specification sheet has a lift at TDC data available Note the lifts at TDC on the inlet and exhaust valves.
E.G. Inlet 2mm at TDC. Exhaust 1.75
Set the engine at TDC on No 1 cylinder
Set the dial gauge on No 1 inlet cam bucket or valve cap to zero in the middle of the base circle. I.E. 180 degrees opposite the full lift part of the lobe.
Turn the inlet cam clockwise until you reach 2mm on opening side of the cam.
Set the dial gauge on No 1 exhaust cam bucket or valve cap to zero in the middle of the base circle.
I.E. 180 degrees opposite the full lift part of the lobe.
Turn the inlet cam clockwise until you reach 2mm on opening side of the cam.
Set the dial gauge on No 1 exhaust cam bucket or valve cap to zero in the middle of the base circle.
I.E. 180 degrees opposite the full lift part of the lobe.
Turn the exhaust cam anti clockwise until you reach 1.75mm on closing side of the cam.
Now attach the timing belt/chain
Set the engine at TDC
Note the opening and closing timings EG 20-60-60-20
Wind the crank forward to 20 degrees AFTDC.
Set the dial gauge on No 1 inlet cam bucket or valve cap to zero in the middle of the base circle. I.E. 180 degrees opposite the full lift part of the lobe.
Turn the cam clockwise until the tappet clearance is taken up and the dial gauge indicates that the inlet valve is opening. Around .01”/.025mm
Now attach the belt/chain.
After setting the cams you can run a double check on the opening and closing periods.

8. General observations of Valve Timing

The easiest way to obtain the correct valve timing is by fitting Verniers Pulleys
If you cannot obtain the correct valve timing with existing sprockets or pulleys these are the options:-
Elongate the holes in the sprocket or pulley turning it into a basic vernier adjustment
With a woodruff key the key can be filed where it fits against the sprocket face so the sprocket can be moved round.

9. Setting up the engine with vernier pulleys

The settings we supply with our camshafts must be regarded as nominal and are a basis for fine tuning your engine as the camshafts we supply are not going to be fitted to the same spec engine I.E. inlet system, cylinder head, ignition, fuel, exhaust system.
What we are doing when fitting performance camshafts is the get the maximum amount of petrol and air vapour into the combustion chamber without either blowing through the exhaust valve or blowing back up the induction system.
To do this with engines of differing specification you will need to fine tune by adjust the vernier pulleys
By doing this we are trying to balance out the reverse air wave pulses.

10. Procedure for adjusting valve timing with vernier pulleys

The settings we supply with our camshafts must be regarded as nominal and are a basis for fine tuning your engine as the camshafts we supply are not going to be fitted to the same spec engine I.E. inlet system, cylinder head, ignition, fuel, exhaust system.
What we are doing when fitting performance camshafts is the get the maximum amount of petrol and air vapour into the combustion chamber without either blowing through the exhaust valve or blowing back up the induction system.
To do this with engines of differing specification you will need to fine tune by adjust the vernier pulleys
By doing this we are trying to balance out the reverse air wave pulses.

On single cam engines we are limited on the adjustment as we have to move both inlet and exhaust lobes

  1. Ensure after the initial valve timing set up is made that you note the venier position so you can find the initial setting
  2. The first adjustment on single cam engines is to advance the pulley in 2 degree stages until the best performance is obtained if after the first 2 degree adjust is made the engine does not improve you can try retarding the cam by 2 degrees.
On twin cams engines we have 4 options for the fine tuning the valve timing.

  1. Ensure after the initial valve timing set up is made that you note the vernier position so you can find the initial setting
  2. The first adjustment is to advance the inlet cam by 2 degrees until no further performance is obtained. If after the first adjustment no performance is obtained try retarding the cam by 2 degrees.
  3. After find the best running position of the inlet cam retard the exhaust cam by 2 degrees if no further performance increase is obtained try advancing the cam.

    If after adjusting the cams you find no improvement the original settings cams were correct.

These engines are the hardest to set up if you look into our spec sheet we do not normally give left at TDC specification this is due to pivot hights of the valve stem, cam base circle, and ball stud being variable from engine to engine, as the angle of the rocker arm increase the rocker ratio changes, so with these engines you may have to accept a compromise of valve timing to cam lift at TDC.

We hope the information supplied may be useful when setting up your engine. If you have any queries regarding any of the above please feel free to contact us.

We also have a pdf download of these camshaft fitting instructions available here.