Jump to content

Recommended Posts

Good day,

I have just replaced the camshaft in my 3A and am in the process of setting up the valve timing. I have used the time honoured method utilising a timing wheel and mechanical stop to exactly determine No1 TDC. I now intend to set No1 inlet at max lift and install the chain. My question / issue is: the valve timing diagram I have from the manual shows the inlet valve opening 15 degrees BTDC and closing 55 degrees ABDC. Thus a duration of 250 degrees. This means the cam lobe for No1 inlet is at its highest 110 degrees ATDC. The new cam spec, which is sold as a basic road cam, has a duration of 278 degrees and thus to maintain the max lift point at 110 degrees ATDC the No1 inlet valve starts to open 14 degrees earlier at 29 degrees BTDC. Can anybody confirm my maths as I only want to do this once. 

Thanks in advance Geoff

Link to post
Share on other sites

If the cam supplier says the installation figure is 110 deg After Top Dead Centre, follow their instructions and install that way.  Check the cam supplier's rocker clearances for that cam as they could well be different to what you have previously used.  Use those rocker clearances when running.


Peter W


Link to post
Share on other sites

Agree with both of the above posts, cam manufacturers will squirm at the  slightest opportunity if something goes wrong "post installation".

The best advice would be to follow their instructions to the letter.....their install  angle, their cam followers, their cam lube, etc etc. They can't squirm then.


Link to post
Share on other sites

Thanks everyone for your input but I finally tracked down the cam information on the moss website. Nothing came with the cam. The inlet timing is 31 before TDC 67 ABDC and the install point is 108 degrees ATDC. I will be going ahead using this data.

Cheers Geoff 

Link to post
Share on other sites

On the Moss Europe Web Site.





Profile: Road

Inlet Timing: 31-67

Exhaust Timing: 67-31

Camshaft Duration: 278˚

Lift: 0.260”

Install Figure: 108˚

Inlet Valve Clearance: 0.013”

Exhaust Valve Clearance: 0.013”

Power Band: 1000-5000


Peter W

Edited by BlueTR3A-5EKT
Link to post
Share on other sites


I made my own Cam degree wheel from this https://www.blocklayer.com/degree-wheel.aspx

Enter Cam spec, select wheel size and print. I used a diameter of 200mm which seemed to be about the max useable size and stuck it to a disc cut from 2mm thick aluminium sheet



Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.