Camshaft deegreeing question

[delcbr]

valve clearances are 0.25mm
If I am setting the cam up with the opening and closing points And the Timing card states Timing of inlet @1mm opens -7 and closes 57 degrees
So the question is do I still take it to 1mm or do I subtract or add the 0.25mm?

[delcbr]

Stevesingo very useful information there thanks. It does state that the lobe angle is 122 degrees so is that not where I set peak lift midpoint?

[delcbr]

Ok thanks for all the help from everyone to let you all understand it's a set of used PTG cams 280 degree for a BMW. PTG were a BMW racing company in the USA.I have no other information to help me degree them. The figures I quoted were for a set of similar cams for my engine from catcams.
The cams I have already fitted to my engine using BMW can setting tools as the camshafts are BMW parts the engine revs smoothly and quickly but I feel it's lacking power in the high rpm area maybe not enough overlap for scavenging to take place.
So now I want to explore at what degrees when are the valves opens and closing and compare to Schrick and catcam offerings. So that's why it was important for me to know if I needed to factor in the valve clearances.

[delcbr]

The exhaust lobe angle is 108 degrees.
So at 108 degrees on the timing disc it should be at maximum lift midpoint?
Using catcams values it says opens 43 degrees closes 7 degrees,
43+180+7=230
230/2=115
115-7=108
Is that how you set it up for exhaust?

But the one for inlet lobe centre is 122 which I thought is where I set max lift mid point but you said 115 degrees?

[delcbr]

Can't do that unfortunately. There is no adjustment possible as it's chain and fixed sprockets. I would have to remove the vanos to move the camshaft to another position then refit vanos again.

[delcbr]

Stevesingo this is the standard information here
http://www.catcams.com/products/camshafts/datashee...

[delcbr]

That's what I was trying to ask too :-)
Couldn't find a definite answer from googling and researching but found no mention of deducting valve clearance from measuring the valve opening and closing in degrees. Only deducting the valve clearance when measuring valve lift at TDC.
There's a part of the camshaft called the heel which then leads onto the ramp which is the part which gently brings the camshaft into contact with the cam follower then once in contact it moves onto the Flank.
The other thing worth mentioning is measuring duration at 1mm lift actual duration as it tells you more about the duration than measuring at 0.1mm which is advertised duration.
http://www.tildentechnologies.com/Cams/CamBasics.h...

[delcbr]

I read the crane cams article. It doesn't apply to measuring cam duration it's only for setting the valve clearances.
Read this instead
http://www.catcams.co.uk/acatalog/Durations_Explai...

[delcbr]

It seems you do add on the valve clearance so I would bring my inlet valve to 1.25mm before I start measuring.

[delcbr]

Iv finally worked out how to do it all but you need to know your peak valve lift in degrees for your engine. For example my engine is 108 degrees for exhaust valve fully open. And 122 degrees for inlet fully open.regardless of what cams are used. The next thing you need to do is using a dial test indicator (mag base and clock) measure your duration and write it down. For example my valve clearances are 0.25mm and I want to measure at 1mm so I start measuring at 1.25mm.
Say it's 230 degrees.
So now you have peak lift and degrees what next?
230/2=115 degrees for my engine the exhaust is 108 peak lift.
FOR EXHAUST ALWAYS SUBTRACT THE CLOSING VALUE.
But we don't know this yet. But we have 115 and 108 the difference is 7. So your closing value is 7 degrees after TDC
to find the opening value it's 180+7=187
230-187=43 degrees open before BDC.
To check it's right add the two opening and closing points together plus 180.
43+7+180= 230

For inlet i know 122 is peak valve lift and measured degrees is 230.
230/2=115
FOR INLET MINUS THE OPENING FIGURE
115 minus what gives us 122?
It's -7 two minus makes a positive so basically the inlet is opening and exhaust are closing at the same point. Iv checked these against known cam spec sheet and it all ties in with same values.which can be found here http://www.catcams.com/products/camshafts/datashee...

Try another one because the minus thing is confusing.
Measured degrees 251 for inlet
251/2=126
126- inlet figure? what gives us 122
Inlet opens 4 degrees
180+4
251-184=67 degrees closing
To check 67+4+180=251 :-)
See here http://www.catcams.com/products/camshafts/datashee...

[delcbr]

Ok understood

[delcbr]

Well every cam listed for my engine has the same peak lift points as 108 for exhaust and 122 for inlet.

[delcbr]

BMW M3 3.0 it has alloy head.
Yes variable cam timing on inlet only 122-80 degrees.
But set the cams up retarded.
Iv got the tools but not the knowledge until now. I used the BMW cam alignment tools to set up the cams because I don't have a timing sheet. But now i can measure the duration and calculate the opening and closing points and set it up accordingly.

[delcbr]

Carlt5 did you receive my email ok?

[delcbr]

Check your junk email lol