Technical 866 Cam Setup!

[Sporty_5_Seicento]

Hi Guys,

Im actually from the cinq/sei section of the fiatforum but i thought i would ask in the punto section as no one on the cinq/sei section seems to be able to answer my questions.

I got an 866 cam (from user davethetrike very pleased with it, dont know if he still remembers). Its all fitted now but i dont know how to set it up.

Just to inform you I have a seicento SPI 2000 sporting, well tuned. Due to head being skimmed to max marks and the use of the thinner metal punto headgasket I believe my valve timing to be 6 degrees out due to the lowering of the head, but thats just a guess.

What i really need to know is how to set up the 866 cam correctly in my engine. I have a piper vernier pulley thats not installed at the moment as im not sure how to set it up.

In the instructions it says you need to know what the max degrees of lift that the cam is, which is where my problems start considering i dont know that for the 866 cam. I dont know if this is correct or not.

If anyone knows how to setup the value timing could you please explain step by step and it would be much apreciated.

Using the marks are useless as TDC does not line up with the mark on the crank pulley (by about half a tooth) and its supposed to according to the fiat manual.

Many Thanks
Matt

 

[Lowtechguy]

You set it up on the rolling road.

 

[davethetrike]

hmm
each tooth on the crank is 6 degrees. The pulley should have half the amount of teeth? 30? So a half a cog is 6 degrees? Mind you the standard cam would've given the same problem so why don't you set it up like the standard cam?

I don't have my punto cd with me. I'll try and find it. Do a search on here or psc I know I've seen the duration at least...

 

[Lowtechguy]

hmm
each tooth on the crank is 6 degrees. The pulley should have half the amount of teeth? 30? So a half a cog is 6 degrees? Mind you the standard cam would've given the same problem so why don't you set it up like the standard cam?

I don't have my punto cd with me. I'll try and find it. Do a search on here or psc I know I've seen the duration at least...

Each tooth on the cam is 6 degrees, the crank is half the size - hence 12 degrees.

 

[Sporty_5_Seicento]

I dont think thats quite correct.


If the cam has 38 teeth and one complete revolution is 360 degrees each tooth will be 360/38 which equals 9.47 degrees on each tooth. The Crank pulley from my understanding must have half the number of teeth of the cam pulley which is therefore 19 teeth. 360/19 = 18.94 degrees. The reason the timing is out is not due to incorrect setup but due to the relocation of the head by skimming aproximately 2.5mm off it.

I havent got the money for a rr session. All i really need to know is either the degrees at which the cam needs to open and close.

OR

The degrees at which max lift should be set to.


Hope this makes things clearer.

Thanks for all your help.

Matt

 

[davethetrike]

I dont think thats quite correct.


If the cam has 38 teeth and one complete revolution is 360 degrees each tooth will be 360/38 which equals 9.47 degrees on each tooth. The Crank pulley from my understanding must have half the number of teeth of the cam pulley which is therefore 19 teeth. 360/19 = 18.94 degrees. The reason the timing is out is not due to incorrect setup but due to the relocation of the head by skimming aproximately 2.5mm off it.

I havent got the money for a rr session. All i really need to know is either the degrees at which the cam needs to open and close.

OR

The degrees at which max lift should be set to.


Hope this makes things clearer.

Thanks for all your help.

Matt

I'm working on the wrong assumption sorry. I was thinking half the number teeth not half the diameter of pulley

oh:

 

[richcinq]

The way I would do it is:


Get number 1 to tdc on exhaust stroke(needs to be spot on)

Remove cam cover

slacken off cam sproket to camshaft bolts(Im assuming you have a vernier pulley)

turn the camshaft untill both inlet and exhaust vales are being pushed open exactly the same amount(equal overlap where both valves will be slightly open), you may need a DTI gauge for this as thats what I used.

tighten pulley...job done.


The reason for this is that when you have equal overlap on exhaust and inlet valves the exhaust gasses leaving the cylinder help to pull fresh air in through the inlet valve. This will only work on N/A engines.


I did this with my car and it made a noticable difference with the smoothness of the drive.


Rich.